PHYLOGENETICS OF THE SCOLYTINI (COLEOPTERA: CURCULIONIDAE:
SCOLYTINAE) AND HOST-USE EVOLUTION
By
Sarah Marie Smith

A DISSERTATION
Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of
Entomology – Doctor of Philosophy

2013

ABSTRACT
PHYLOGENETICS OF THE SCOLYTINI (COLEOPTERA: CURCULIONIDAE:
SCOLYTINAE) AND HOST-USE EVOLUTION
By
Sarah Marie Smith
The Nearctic bark beetle genus Scolytus was revised based in part on a molecular
phylogeny. Monophyly of the native species was tested using mitochondrial (COI) and nuclear
(28S, CAD, ArgK) genes and 43 morphological characters in parsimony and Bayesian
phylogenetic analyses. Parsimony analyses of molecular and combined datasets provided
variable results while Bayesian analysis recovered most nodes with posterior probabilities >90%.
Native angiosperm and conifer-feeding Scolytus spp. were recovered as paraphyletic. Twentyfive species were recognized. Four new synonyms were discovered: Scolytus praeceps LeConte
1868 (=S. abietis Blackman 1934; = S. opacus Blackman 1934), S. reflexus (= S. virgatus Bright
1972; =S. wickhami Blackman 1934). Two species were removed from synonymy: Scolytus
fiskei Blackman 1934 and S. silvaticus Bright 1972. Neotypes were designated for the following
species: Scolytus aztecus Wood 1967, S. hermosus Wood 1968 and S. mundus Wood 1968. A
key, diagnosis, redescription, distribution, host records and images were provided for each
species.
The influence of plants in the diversification of herbivorous insects, specifically those
that utilize moribund and dead hosts, is unclear. Scolytini, a diverse tribe of weevils, specialize
on many different plant taxa as a source of food. The phylogenetics of the Scolytini were

reconstructed using Bayesian analyses to examine the origin, test the monophyly of Scolytini
genera, and illuminate patterns of host-use and feeding habits among the tribe. Analyses were
based on COI, 28S, CAD and ArgK. Ancestral host usage was reconstructed using likelihood
criteria. Diversification of the Scolytini generally occurred well after host taxa diversified, as a
combination of host shifts and lineage tracking. Repeated independent shifts to the same hosts
occurred. Diversification occurred on common and widespread hosts, there was a single
origination of conifer-feeding from angiosperm-feeding species and evolution of fungus-feeding
from phloem-feeding ancestors. Overall, the observed patterns of Scolytini host-use can be
explained by a combination of the sequential evolution and host-use oscillation hypotheses.
The Neotropical bark beetle genera Cnemonyx Eichhoff 1868 and Scolytus Geoffroy1762
were reviewed as part of ongoing research into the higher-level taxonomy of the Scolytini.
Ceratolepsis Chapuis 1869 was removed from synonymy with Cnemonyx and seven new
combinations are reported: Ceratolepsis amazonicus Eggers 1929, C. boliviae (Blackman) 1943,
C. hylurgoides (Schedl) 1948, C. insignis (Wood) 1969, C. jucundus Chapuis 1869, C.
maculicornis Blandford 1896 and C. niger (Eggers) 1929. One new species was described:
Scolytus rabagliatus. Cnemonyx setulosus (Eggers) 1929 was removed from synonymy with C.
panamensis (Blandford) 1896. Four new synonyms were discovered: Ceratolepsis Chapuis (=
Coptosomus Schedl 1952), Cnemonyx setulosus (Eggers) 1929 (= Cnemonyx similis (Eggers)
1929), Scolytus proximus Chapuis 1869 (=Scolytus brevicauda Wichmann 1915) and Scolytus
thoracicus Chapuis 1869 (= Scolytus plaumanni Wood 2007). One new distribution record was
reported: Scolytus multistriatus in South America (Brazil).

Copyright by
SARAH MARIE SMITH
2013

This work is dedicated to my family who have provided continuous support for all of my
academic endeavors and allowed me to pursue my dreams.

v	
  

ACKNOWLEDGEMENTS
This dissertation would not have been possible without the strong support from my
colleague Anthony Cognato. My graduate committee, Drs. L. Alan Prather, Therese Poland and
Michael Gottfried and my advisor Deborah McCullough. Thank you Deb for being there for me
in my time of need and your support. I’ll make it up to you! This study was enhanced by
thoughtful discussions with Donald Bright, Malcolm Furniss and members of the Holistic Insect
Systematics Lab including Gary Parsons, Aaron Smith, Jiri Hulcr, Stephanie Dole, Bernice
DeMarco and Nicholas Barc.
Specimens were generously donated to this research by the following individuals: Alex
Petrov, Thomas Atkinson (University of Texas), Sudabe Amini (University of Guilan), Massimo
Faccoli (University of Padova), Miloš Knížek (Forestry and Game Management Research
Institute), Bjarte Jordal (University of Bergen), Åke Lindelöw (Swedish University of
Agricultural Sciences), Nathan Lord (University of New Mexico), Jorge Macías-Sámano
(Synergy) and Robert Rabaglia (USDA-FS). This work would not have been possible without the
institutions that loaned material and their curators listed herein. Terry Erwin (USNM) generously
allowed me access to his Ecuador canopy fogging material and David Furth (USNM) for
facilitating my studies at the Smithsonian.
My domestic fieldwork would not have been as productive without the assistance of
Debra Allen-Reid (USDA-FS), Ken Bush, Alan Gillogly, Donald Bright, Barbara Barr, Malcolm
Furniss (USDA-FS) and Anthony Cognato. Special thanks to Don and Anthony without whom I
would not know how to identify conifers or collect scolytines in western forests.
I would like to thank my foreign collaborators who facilitated in the acquisition of
specimens during my fieldwork: Guyana, Robin McCall (UG), Environmental Protection

vi	
  

Agency, collecting permit (#020307-BR-070). Panama, Donald Windsor (STRI), Authoridad
Nacional del Ambiente collecting permit, export permits (#SE/A-89-08, #SEX/A-112-08 and
#SEX/A-68-12). Peru, Gerardo Lamas (UNMSM), Nigel Pitman, Rocio Martinez, Instituto
Nacional de Recursos Naturales research and export permits (#0044-2008 and #011735). Costa
Rica, Francisco Campos, Organization for Tropical Studies research and export permit (#1122010 SINAE and DGVS-489-2010). Ecuador, Kelly Swing, Hernan Alvarez (USFQ), Michael
Caterino and Alexey Tishechkin (SBMN), Minesterio del Ambiente permit (#0019-FAU-MADPO-PNY).
I would like to thank my parents, Thomas and Debra Smith, and my grandmothers,
Catherine Smith and Shirley Boatman for always encouraging my curiosity and supporting my
dreams and Ripley for her patience and moral support throughout my degree program.
This research was supported by NSF-PEET grant (DEB 0328920), USDA-FS Early
Detection and Rapid Response of Exotic Bark Beetles (07-DG-11420004-182), Michigan State
University Competitive Discretionary Funding Program awarded to Anthony I. Cognato. Support
was also provided by the Norwegian Research Council (214232) and the University of Bergen,
Norway (F20) awarded to Bjarte H. Jordal (Univeristy of Bergen). Additional funding from the
Amazon Conservation Association Graduate Field Research Grant, American Museum of
Natural History Theodore Roosevelt Memorial Grant, Entomological Society of America
Systematics and Evolutionary Biology student travel grant, Museum of Comparative Zoology
Ernst Mayr Travel Grant in Animal Systematics, Organization for Tropical Studies’ Ruggles
tuition aid scholarship and Michigan State University (Department of Entomology Hutson
Funds, MSU Evolutionary Biology and Behavior Travel Fellowship, MSU College of Natural

vii	
  

Science) and the Hagen Bashian Trust support scholarship from the MSU college of Agriculture
and Natural Resources awarded to SMS.
Please note that figures have been edited to conform with the Michigan State University
dissertation formatting guidelines. Please refer to resulting publications for the final version of
the figures.

viii	
  

TABLE OF CONTENTS
LIST OF TABLES……………………………………………………………………………….xii
LIST OF FIGURES……………………………………………………………………………..xiv
CHAPTER 1
A MONOGRAPH OF THE NEARCTIC SCOLYTUS GEOFFROY (COLEOPTERA:
CURCULIONIDAE: SCOLYTINAE)
Abstract …………………………………………………………………………………...2
Introduction ……………………………………………………………………………….3
Natural History ……………………………………………………………………4
Systematics ……………………………………………………………………….7
Sexual Dimorphism ………………………………………………………………8
Taxonomic History ……………………………………………………………….9
A checklist of the Nearctic Scolytus species …………………………………….11
Materials and Methods …………………………………………………………………..12
Materials ………………………………………………………………………...12
Morphology ……………………………………………………………………...12
Taxonomic Characters …………………………………………………………..15
Taxa, DNA sequences and Alignment …………………………………………..20
Methods ………………………………………………………………………….22
Morphology ……………………………………………………………………...22
Molecular ………………………………………………………………………..22
Species Concept …………………………………………………………………24
Results …………………………………………………………………………………...25
Phylogenetics of Nearctic Scolytus ……………………………………………...25
Morphology ……………………………………………………………………...25
Combined Analyses ……………………………………………………………..27
Discussion ……………………………………………………………………………….29
Phylogenetic Analyses …………………………………………………………..29
Taxonomic Implications ………………………………………………………...31
Scolytus Geoffroy ………………………………………………………………..32
Taxonomic Treatment …………………………………………………………...33
Glossary of Terminology ………………………………………………………..33
General …………………………………………………………………………..34
Head ……………………………………………………………………………..34
Elytra …………………………………………………………………………….34
Abdomen ………………………………………………………………………...35
Damage Pattern ………………………………………………………………….36
Key to the adults of Nearctic Scolytus Geoffroy ………………………………..37
Species Descriptions …………………………………………………………….46
Introduced Species Group ……………………………………………………….46
Scolytus mali (Bechstein) ………………………………………………………..47
Scolytus multistriatus (Marsham) ……………………………………………….52
Scolytus rugulosus (Müller) ……………………………………………………..57

v	
  

Scolytus schevyrewi Semenov …………………………………………………...62
Native Hardwood Clade …………………………………………………………67
Scolytus fagi Walsh ……………………………………………………………...67
Scolytus muticus Say ……………………………………………………………70
Scolytus quadrispinosus Say ……………………………………………………76
Conifer Clade ……………………………………………………………………81
Scolytus aztecus Wood ………………………………………………………….82
Scolytus dentatus Bright ………………………………………………………...85
Scolytus fiskei Blackman, removed from synonymy ……………………………88
Scolytus hermosus Wood ………………………………………………………..95
Scolytus laricis Blackman ………………………………………………………98
Scolytus monticolae (Swaine) ………………………………………………….103
Scolytus mundus Wood ………………………………………………………...108
Scolytus obelus Wood ………………………………………………………….111
Scolytus oregoni Blackman …………………………………………………….115
Scolytus piceae (Swaine) ………………………………………………………119
Scolytus praeceps LeConte …………………………………………………….126
Scolytus reflexus Blackman ……………………………………………………132
Scolytus robustus Blackman …………………………………………………...140
Scolytus silvaticus Bright, removed from synonymy ………………………….145
Scolytus subscaber LeConte …………………………………………………...147
Scolytus tsugae (Swaine) ………………………………………………………152
Scolytus unispinosus LeConte …………………………………………………157
Scolytus ventralis LeConte …………………………………………………….166
CHAPTER 2
PHYLOGENETICS AND EVOLUTION OF HOST-USE AMONG THE SCOLYTINI
(COLEOPTERA: CURCULIONIDAE: SCOLYTINAE)
Abstract ………………………………………………………………………………...175
Introduction …………………………………………………………………………….176
Study Group ……………………………………………………………………178
Materials and Methods …………………………………………………………………179
Taxa, DNA sequences and Alignment …………………………………………179
Bayesian Analyses ……………………………………………………………..180
Hosts …………………………………………………………………………...181
Ancestral State Reconstruction ………………………………………………...181
Conservation of Host-Use ……………………………………………………...183
Estimating Divergence Times ………………………………………………….183
Results ………………………………………………………………………………….185
Phylogenetic Results …………………………………………………………...185
Ancestral State Reconstruction of Feeding Habit and Host-Use ………………186
Conservation of Host-Use ……………………………………………………...187
Estimating Divergence Times ………………………………………………….187
Discussion ……………………………………………………………………………...187
Taxonomic Implications ……………………………………………………….187
Evolution of Host-Plant use by Insects ………………………………………...190

vi	
  

Correlation with Host-Use Oscillation Hypothesis …………………………….195
Conservation of Host-Use ……………………………………………………...196
Ancestral State Reconstruction of Feeding Habit and Host-Use ………………196
Estimating Divergence Times ………………………………………………….199
Conclusion ……………………………………………………………………………..200
Future Directions ………………………………………………………………………201
CHAPTER 3
PROGRESS TOWARD A REVISION OF THE SCOLYTINI I (COLEOPTERA:
CURCULIONIDAE: SCOLYTINAE)
Abstract ………………………………………………………………………………...204
Introduction …………………………………………………………………………….205
Taxonomic History of the Scolytini…………………………………………….205
Materials and Methods …………………………………………………………………207
Results and Discussion ………………………………………………………………...208
Ceratolepsis Chapuis 1869 status restored …………………………………….208
Included species ………………………………………………………………..210
Cnemonyx Eichhoff 1868 ………………………………………………………211
Taxonomic Changes ……………………………………………………………211
Scolytus Geoffroy 1762 ………………………………………………………...213
New Distribution Record ………………………………………………………213
Taxonomic Changes ……………………………………………………………213
Species Description …………………………………………………………….214
Conclusion ……………………………………………………………………………..217
APPENDICES …………………………………………………………………………………218
Appendix A: Tables and Figures for Chapter 1 ………………………………………..219
Appendix B: Tables and Figures for Chapter 2 ………………………………………..352
Appendix C: Tables and Figures for Chapter 3 ………………………………………..427
LITERATURE CITED ………………………………………………………………………...434

vii	
  

LIST OF TABLES
Table 1.1. Host genus for conifer-feeding (Pinaceae) Nearctic Scolytus species……………...220
Table 1.2. Host plant families for all Scolytus species occurring in the Nearctic……………...221
Table 1.3. Morphological character matrix of 43 characters for 37 species. Characters and states
are described in Materials and Methods………………………………………………………..222
Table 1.4. Table of Nearctic specimens sequenced, the collection locality, collector and host.226
Table 1.5. Table of Nearctic specimens sequenced to assess intraspecific variation, the collection
locality, collector and host……………………………………………………………………...235
Table 1.6. Table of PCR primers and the annealing temperatures used for the amplification of
gene sequences…………………………………………………………………………………244
Table 1.7. Intraspecific differences among COI, 28S, CAD and ArgK expressed as the
proportion of sites differing between sequences. N/A applies to taxa for which sequence data was
not available……………………………………………………………………………………245
Table 1.8. Interspecific differences among COI, 28S, CAD and ArgK expressed as the
proportion of sites differing between sequences among sister taxa. N/A applies to taxa for which
sequence data was not available……………………………………………………………….246
Table 1.9. Partition Bremer support values for the four gene parsimony phylogeny with gaps
treated as missing data. Nodes refer to Figure 1.4……………………………………………..248
Table 1.10. Partition Bremer support values for the four gene parsimony phylogeny with gaps
treated as a fifth character state. Nodes refer to Figure 1.5…………………………………….250
Table 1.11. Partition Bremer support values for the combined phylogeny with gaps treated as
missing data. Nodes refer to Figure 1.7………………………………………………………...252
Table 1.12. Partition Bremer support values for the combined phylogeny with gaps treated as a
fifth character. Nodes refer to Figure 1.8………………………………………………………254
Table 2.1. Scolytini genera, diversity, distribution, feeding habits and common host families.353
Table 2.2. Table of Scolytini specimens sequenced, the collection locality, collector, host and
matrix name…………………………………………………………………………………….354
Table 2.3. Properties of the data included in the Bayesian analysis of all genes and the model of
nucleotide evolution selected by the AIC criterion in MrModel test. PI = parsimony informative
characters; Steps = the shortest parsimony tree produced by analysis of the partition for included
taxa; CI = consistency index for included taxa…………………………………………………373

viii	
  

Table 2.4. Camptocerus species distribution, known host families and genera………………..374
Table 2.5. Ceratolepsis, Cnemonyx and Loganius species distribution, known host families and
genera…………………………………………………………………………………………...375
Table 2.6. Scolytus species distribution, known host families and genera……………………..376
Table 2.7. Estimates of clade ages (mya) generated using a Bayesian relaxed molecular clock in
BEAST with fossil calibrations of the oldest Scolyini at 100 mya (analysis A) and 120 mya
(analysis B)……………………………………………………………………………………..382

ix	
  

LIST OF FIGURES
Figure 1.1. Morphological phylogeny of Nearctic Scolytus. Phylogram of one of 1016 most
parsimonious trees (262 steps; consistency index 0.332; retention index = 0.539) generated for
37 taxa with 43 characters from a heuristic search of 1000 stepwise random additions with TBR
in PAUP*. Numbers above the node indicate bootstrap values (>50) based on 1000
pseudoreplicates. Bremer support values are listed below the node and were generated from a
heuristic search of 100 random addition sequence replicates. The Nearctic hardwood and conifer
clades are indicated in blue and green respectively. Non-monophyletic species are indicated in
brown. For interpretation of the references to color in this and all other figures, the reader is
referred to the electronic version of this thesis (or dissertation)………………………………..256
Figure 1.2. Bayesian tree found by analysis of data using the molecular dataset. Numbers above
the nodes are Bayesian posterior probabilities. Taxa in brown were not recovered as
monophyletic. Scolytus fiskei is listed in purple and is considered a synonym of S. unispinosus
…………………………………………………………………………………………………..261
Figure 1.3. Mitochondrial COI phylogeny of Nearctic Scolytus. Phylogram of one of 2958 most
parsimonious trees (1434 steps: consistency index 0.356; retention index 0.809) generated from a
heuristic search of 1000 stepwise random additions with TBR in PAUP*. Numbers above the
node indicate bootstrap values (>50) based on 1000 pseudoreplicates. Bremer support values are
listed below the node and were generated from a heuristic search of 100 random addition
sequence replicates. Mean intraspecific nucleotide differences (listed next to each taxon) and
mean interspecific interspecific nucleotide differences (right of solid lines) are given. Taxa
highlighted in red were not recovered as monophyletic………………………………………..264
Figure 1.4. Phylogram of one of 94, 002 most parsimonious trees found by parsimony analysis
of the four gene dataset with gaps treated as missing data (2,451 steps. consistency index 0.479;
retention index 0.773) generated from a heuristic search of 1000 stepwise random additions with
TBR in PAUP*. Numbers above the node indicate bootstrap values (>50) based on 1000
pseudoreplicates. Node numbers are given below the node and refer to PBS values in Table 1.9.
Taxa in brown, blue and green were not recovered as monophyletic. Scolytus fiskei is listed in
purple and is considered a synonym of S. unispinosus. Scolytus laricis is listed in green and was
not recovered as monophyletic. Scolytus oregoni (blue) is a distinct species but was not
monophyletic in this analysis. * denotes species that are recognized as valid.………………270
Figure 1.5. Phylogram of one of 59,010 most parsimonious trees found by parsimony analysis of
the combined molecular dataset with gaps as a fifth character (2,647 steps. consistency index
0.479; retention index 0.773) generated from a heuristic search of 1000 stepwise random
additions with TBR in PAUP*. Numbers above the node indicate bootstrap values (>50) based
on 1000 pseudoreplicates. Node numbers are given below the node. Node numbers refer to PBS
values in Table 1.10. Taxa in brown, blue and green were not recovered as monophyletic.
Scolytus fiskei is listed in purple and is considered a synonym of S. unispinosus. Scolytus laricis
is listed in green and was not recovered as monophyletic. Scolytus oregoni (blue) is a distinct

x	
  

species but was not monophyletic in this analysis. * denotes species that are recognized as
valid.……………………………………………………………………………………………275
Figure 1.6. Bayesian tree found by analysis of data using the combined molecular and
morphological dataset. Numbers above the nodes are Bayesian posterior probabilities. Taxa in
brown were not recovered as monophyletic. Scolytus fiskei is listed in purple and is considered a
synonym of S. unispinosus. * denotes species that are exotic in the Nearctic.…………………280
Figure 1.7. Strict consensus tree of 22,003 most parsimonious trees found by parsimony analysis
of the combined molecular and morphological dataset with gaps treated as missing data (2,902
steps. consistency index 0.458; retention index 0.769) generated from a heuristic search of 100
stepwise random additions with TBR in PAUP*. Numbers above the node indicate bootstrap
values (>50) based on 1000 pseudoreplicates. Node numbers are given below the node and refer
to PBS values in Table 1.11. Taxa in brown were not recovered as monophyletic. Scolytus fiskei
is listed in purple and is considered a synonym of S. unispinosus. * denotes species that are
recognized as valid……………………..……………………………………………………….283
Figure 1.8. Strict consensus tree of 13,003 most parsimonious trees found by parsimony analysis
of the combined molecular and morphological dataset with gaps as a fifth character (3,097 steps.
consistency index 0.48; retention index 0.771) generated from a heuristic search of 1000
stepwise random additions with TBR in PAUP*. Numbers above the node indicate bootstrap
values (>50) based on 1000 pseudoreplicates. Node numbers are given below the node and refer
to PBS values in Table 1.12. Taxa in brown were not recovered as monophyletic. Scolytus fiskei
is listed in purple and is considered a synonym of S. unispinosus. * denotes species that are
recognized as valid.……………………………………….……………………………………288
Figure 1.9. Sexual dimorphism of the head (Scolytus reflexus) lateral profiles of male (A) and
female (B), anterior view of male (C) and female (D)…………………………………………293
Figure 1.10. Terminology of the head. Terms are defined in the glossary section (Scolytus
reflexus male).……………………….………………………………………………………….294
Figure 1.11. General habitus terminology. Terms are defined in the glossary section (Scolytus
fagi male).……………………………………….……………………………………………...295
Figure 1.12. Dorsal terminology. Terms are defined in the glossary section (Scolytus fagi male).
……………………………………….………………………………………………………….296
Figure 1.13. Abdominal venter terminology. Terms are defined in the glossary section (Scolytus
ventralis). ……………………………………….……………………………………………...297
Figure 1.14. Damage pattern. Terms are defined in the glossary section (Scolytus monticolae).
……………………………………….………………………………………………………….298
Figure 1.15. Elytral apices consist of two general shapes: rounded (A) (Scolytus rugulosus) and
truncate (B) (Scolytus robustus)………………………………………………………………...299
xi	
  

Figure 1.16. Lateral views of Scolytus mali male 3.2 – 4.1mm (A) and female 3.0 – 4.2mm (B).
……………………………………….…………………………………………………………300
Figure 1.17. Dorsal view of Scolytus mali male ………………………………………………301
Figure 1.18. Lateral views of Scolytus multistriatus male 2.2 – 3.9mm (A) and female 2.4 –
3.3mm (B) …………………………….………………………………………………………..302
Figure 1.19. Dorsal view of Scolytus multistriatus male………………………………………303
Figure 1.20. Lateral views of Scolytus rugulosus male 1.9 – 2.6mm (A) and female 2.0 – 3.1mm
(B).……………………………………….……………………………………………………..304
Figure 1.21. Dorsal views of Scolytus rugulosus male………………………………………...305
Figure 1.22. Lateral views of Scolytus schevyrewi male 2.8 – 3.5mm (A) and female 2.3 –
3.6mm (B) .…………………………….……………………………………………………….306
Figure 1.23. Dorsal view of Scolytus schevyrewi male………………………………………...307
Figure 1.24. Lateral views of Scolytus fagi male 3.3 – 5.5mm (A) and female 3.9 – 5.6mm (B).
……………………………………….…………………………………………………………308
Figure 1.25. Dorsal view of Scolytus fagi male………………………………………………..309
Figure 1.26. Lateral views of Scolytus muticus male 2.2 – 5.3mm (A) and female 3.1 – 5.1mm
(B). ……………………………………….…………………………………………………….310
Figure 1.27. Dorsal view of Scolytus muticus male……………………………………………311
Figure 1.28. Lateral views of Scolytus quadrispinosus male 2.8 – 4.2mm (A) and female 2.9 –
5.0mm (B).………………………………….…………………………………………………..312
Figure 1.29. Lateral views of Scolytus quadrispinosus male…………………………………..313
Figure 1.30. Lateral views of Scolytus aztecus male 5.0mm (A) and female 4.6 – 5.9mm (B).314
Figure 1.31. Dorsal view of Scolytus aztecus male…………………………………………….315
Figure 1.32. Lateral views of Scolytus dentatus male 3.0 – 4.0mm (A) and female 3.4 – 4.6mm
(B)………………………………………………………………………………………………316
Figure 1.33. Dorsal view of Scolytus dentatus male…………………………………………...317
Figure 1.34. Lateral views of Scolytus fiskei male 2.2 – 2.8mm (A) and female 2.2 – 3.5mm (B).
……………………………………….…………………………………………………………318

xii	
  

Figure 1.35. Dorsal view of Scolytus fiskei male………………………………………………319
Figure 1.36. Lateral views of Scolytus hermosus male 3.0mm (A) and female 2.5 – 3.5mm (B).
……………………………………….…………………………………………………………320
Figure 1.37. Dorsal view of Scolytus hermosus male………………………………………….321
Figure 1.38. Lateral views of Scolytus laricis male 2.3 – 4.0mm (A) and female 2.6 – 4.0mm
(B).……………………………………….……………………………………………………..322
Figure 1.39. Dorsal view of Scolytus laricis male……………………………………………..323
Figure 1.40. Lateral views of Scolytus monticolae male 2.5 – 3.0mm (A) and female 2.3 –
3.5mm (B)………………………………….…………………………………………………...324
Figure 1.41. Dorsal view of Scolytus monticolae male………………………………………...325
Figure 1.42. Lateral views of Scolytus mundus male 4.0 – 4.5mm (A) and female 3.3 – 4.6mm
(B).……………………………………….……………………………………………………..326
Figure 1.43. Dorsal views of Scolytus mundus male…………………………………………..327
Figure 1.44. Lateral views of Scolytus obelus male 1.8 – 2.9mm (A) and female 1.7 – 3.0mm
(B).……………………………….……………………………………………………………..328
Figure 1.45. Dorsal view of Scolytus obelus male……………………………………………..329
Figure 1.46. Lateral views of Scolytus oregoni male 2.6 – 3.6mm (A) and female 2.8 – 4.0mm
(B).……………………………………….……………………………………………………..330
Figure 1.47. Dorsal view of Scolytus oregoni male……………………………………………331
Figure 1.48. Lateral views of Scolytus piceae male 2.5 – 3.0mm (A) and female 2.3 – 3.0 (B).
……………………………………….………………………………………………………….332
Figure 1.49. Dorsal view of Scolytus piceae male……………………………………………..333
Figure 1.50. Lateral views of Scolytus praeceps male 1.8 – 3.2mm (A) and female 1.7 – 3.5mm
(B).……………………………………….……………………………………………………..334
Figure 1.51. Dorsal views of Scolytus praeceps male…………………………………………335
Figure 1.52. Lateral views of Scolytus praeceps (=S. abietis) male (A) and female (B)………336
Figure 1.53. Lateral views of Scolytus praeceps (=S. opacus) male (A) and female (B)……..337

xiii	
  

Figure 1.54. Lateral views of male Scolytus reflexus with a reflexed sternite 5 (A) and wickhami
phenotype without reflexed sternite 5 (B) 2.4 – 3.8mm………………………………………..338
Figure 1.55. Lateral view of Scolytus reflexus female 2.5 – 4.0mm (A) and dorsal view of male
(B).……………………………………….……………………………………………………..339
Figure 1.56. Lateral views of Scolytus robustus male 2.5 – 4.0mm (A) and female 2.2 – 4.1mm
(B).……………………………………….……………………………………………………..340
Figure 1.57. Dorsal view of Scolytus robustus male…………………………………………...341
Figure 1.58. Lateral views of Scolytus silvaticus male 3.0mm (A) and female 3.3 – 3.6mm (B).
……………………………………….…………………………………………………………342
Figure 1.59. Dorsal view of Scolytus silvaticus male………………………………………….343
Figure 1.60. Lateral views of Scolytus subscaber male 2.0 – 4.3mm (A) and female 3.1 -5.0mm
(B).……………………………………….……………………………………………………..344
Figure 1.61. Dorsal view of Scolytus subscaber male…………………………………………345
Figure 1.62. Lateral views of Scolytus tsugae male 2.8 – 3.4mm (A) and female 2.3 – 3.5mm
(B).………………………………….………………………………………………………….346
Figure 1.63. Dorsal view of Scolytus tsugae male……………………………………………..347
Figure 1.64. Lateral views of Scolytus unispinosus male 2.2 – 3.2mm (A) and female 2.2 – 3.0
(B).……………………………………….……………………………………………………..348
Figure 1.65. Dorsal view of Scolytus unispinosus male……………………………………….349
Figure 1.66. Lateral views of Scolytus ventralis male 3.0 – 4.0mm (A) and female 2.2 – 4.6 mm
(B).……………………………………….……………………………………………………..350
Figure 1.67. Dorsal views of Scolytus ventralis male………………………………………….351
Figure 2.1. Bayesian tree found by analysis of data set I with all genes treated as a single
partition with GTR+I+ Γ. Posterior probabilities are listed above nodes (** ≥ 95, * ≥ 90)……383
Figure 2.2. Bayesian tree found by analysis of data set II with four data partitions, COI, 28S,
CAD, ArgK GTR+I+ Γ. Posterior probabilities are listed above nodes (** ≥ 95, * ≥ 90) ……392
Figure 2.3. Bayesian tree found by analysis of data set III with three data partitions COI, 28S
and (ArgK+CAD) with GTR+I+ Γ. Posterior probabilities are listed above nodes (** ≥ 95, * ≥
90)….
…………………………………………………………………………………………………..400
xiv	
  

Figure 2.4. Ancestral state reconstruction of feeding habit among the Scolytini calculated by
likelihood estimation with the Mk-1 model over the analysis II consensus tree topology (Figure
2.2). Taxa that are known to bore into sapwood are marked in black and taxa known to mine the
phloem are marked in white.……………………………………………………………………409
Figure 2.5. Ancestral state reconstruction of host-use among the Scolytini calculated by
likelihood estimation with the Mk-1 model over the analysis II consensus tree topology (Figure
2.2). Only most typically host family was scored for each species. Only those taxa with host
records were scored……………………………………………………………………………..410
Figure 2.6. Ancestral state reconstruction of conifer-feeding Scolytus by host genus, calculated
by likelihood estimation with the Mk-1 model over a pruned analysis II consensus tree topology
(Figure 2.2) with non-Scolytus genera removed. Only coniferous genera were scored for each
species while angiosperm feeders are marked in black………………………………………...411
Figure 2.7. Maximum clade credibility tree (in part) for Scolytini based on the minimum age
Bayesian analysis (analysis A). 95% confidence intervals for the ages of clades indicated with
blue bars. Numbers correspond to clades listed in Table 2.8. ** denotes the Quaternary period
and * denotes the Pliocene epoch. ……………………………………………………………..412
Figure 2.8. Maximum clade credibility tree (in part) for Scolytini based on the maximum age
Bayesian analysis (analysis B). 95% confidence intervals for the ages of clades indicated with
blue bars. Numbers correspond to clades listed in Table 2.8. ** denotes the Quartenary time
period and * denotes the Pliocene epoch……………………………………………………….419
Figure 3.1. Ceratolepsis diagnostic characters including the shape and setae on the antennal club
and funicle (A), the apical margins of the meso- and metathoracic tibiae unnamed with
supplemental denticles (B), the shape of the mesosternum (C) and the slightly impressed frons in
both sexes (D). …………………………………………………………………………………428
Figure 3.2. Ceratolepsis jucundus lateral (A) and dorsal view (B)……………………………429
Figure 3.3. Scolytus rabagliatus male, 3.0-3.2 mm long, lateral (A) and dorsal view (B)…….430
Figure 3.4. Scolytus rabagliatus female, 2.0-3.0 mm long, lateral (A) and dorsal view (B)…..431
Figure 3.5. Scolytus rabagliatus male venter posterior (A) and posterior oblique (B); female
venter posterior (C) and posterior oblique (D). ………………………………………………..432
Figure 3.6. Scolytus rabagliatus male head anterior (A) and anterior oblique (B); female head
anterior (C) and anterior oblique view (D). ……………………………………………………433

xv	
  

CHAPTER 1
A MONOGRAPH OF THE NEARCTIC SCOLYTUS GEOFFROY (COLEOPTERA:
CURCULIONIDAE: SCOLYTINAE)

1

Abstract
The Nearctic bark beetle genus Scolytus was revised based in part on a molecular
phylogeny. Monophyly of the native species was tested using mitochondrial (COI) and nuclear
(28S, CAD, ArgK) genes and 43 morphological characters in parsimony and Bayesian
phylogenetic analyses. Parsimony analyses of molecular and combined datasets provided
variable results while Bayesian analysis recovered most nodes with posterior probabilities >90%.
Native angiosperm and conifer-feeding Scolytus spp. were recovered as paraphyletic. Native
Nearctic species were recovered as two lineages with hardwood-feeding species sister to
introduced Palearctic hardwood-feeding species rather than native conifer-feeding species. The
Nearctic conifer-feeding species were monophyletic. Twenty-five species were recognized. Four
new synonyms were discovered: Scolytus praeceps LeConte 1868 (=S. abietis Blackman 1934;
= S. opacus Blackman 1934), S. reflexus (= S. virgatus Bright 1972; =S. wickhami Blackman
1934). Two species were removed from synonymy: Scolytus fiskei Blackman 1934 and S.
silvaticus Bright 1972. Neotypes were designated for the following species: Scolytus aztecus
Wood 1967, S. hermosus Wood 1968 and S. mundus Wood 1968. A key, diagnosis,
redescription, distribution, host records and images were provided for each species.

2

Introduction
The Scolytinae is comprised of at least 6,000 species in 26 tribes and approximately 225
genera (Wood and Bright 1992; Mandelshtam and Beaver 2003; Oberprieler et al. 2007). These
‘bark beetles’ are ubiquitous in forests worldwide. Many species contribute to the decomposition
of dead vegetation while others are capable of causing substantial host mortality. Bark beetle
adults and larvae feed on phloem and cambium of living, declining, or dead trees (Wood 1982).
Beetle feeding on phloem hastens the decomposition of trees and the introduction of
other xylophagous organisms. Some bark beetle species kill live trees by introducing fungi into
otherwise healthy trees as a by-product of phloem feeding and the galleries may girdle the host
causing mortality (Wood 1982). At high density these species cause widespread destruction of
economically valuable tree species, giving bark beetles their nefarious reputation as ecologically
and economically destructive forest pests (Furniss and Carolin 1977), the most destructive of
which is the mountain pine beetle, Dendroctonus ponderosae Hopkins 1902. This species occurs
in Rocky Mountains states and provinces of the US and Canada (Furniss and Carolin 1977).
During part of an outbreak that began in the early 1990’s more than four million hectares of pine
forest were infested in British Columbia alone (Ebata 2004; Taylor and Carroll 2004). Ips
typographus (L.) 1758, the European spruce bark beetle, is the most destructive species in
Europe and during an outbreak between 1990 and 2001 infested more than 2.8 million hectares
of spruce (Grégoire and Evans 2004). Scolytus Geoffroy 1762, contains six potential tree killing
species that cause significant mortality of both conifers (Cibrián Tovar et al. 1995) and Carya
spp. (Furniss and Carolin 1977) in the Nearctic region. Scolytus multistriatus (Marsham) is a key
vector of the fungi associated with lethal Dutch elm disease, a pathogen that has killed millions

3

of Ulmus spp. trees in forest and urban areas across much of the US (Furniss and Carolin 1977).
Mortality caused by various Scolytus species is often sporadic and short-term, although some
outbreaks locally affect thousands of acres a year (Furniss and Carolin 1977). Damage is most
severe in times of environmental stress, which is mostly associated with drought and other insect
infestations. For example, Scolytus ventralis LeConte killed approximately 72,843 hectares of
Abies spp. in California alone in a year (Furniss and Carolin 1977).
In addition to destruction caused by native North American scolytines, introductions of
exotic bark beetle species threaten native forests (Haack 2001, 2006; Brockerhoff et al. 2006;
Aukema et al. 2010, 2011; Hulcr and Dunn 2011). Exotic scolytines are among the most
frequently intercepted species from shipping dunnage and packing crates (Haack 2001, 2006).
The ability to detect and manage both native and exotic species relies on a solid understanding of
systematics, phylogenetics, and taxonomy, which has not been achieved for most groups of bark
beetles on a worldwide scale (Wood and Bright 1992). Other economically important bark beetle
genera such as Dendroctonus Erichson 1836 and Ips DeGeer 1775 have received considerable
attention and therefore have a reasonably solid understanding of the taxonomy (Wood and Bright
1992) but Scolytus is also important and notoriously difficult to identify.

Natural History
Scolytus are distributed in the Nearctic, Palearctic and Neotropical regions and some
Palearctic Scolytus species have been introduced to the Nearctic, South Africa, Australia, New
Zealand and temperate South America (Rosel and French 1975; Bain 1990; Wood and Bright
1992; Six et al. 2005; Wood 2007). In the Nearctic region, Scolytus species occur from the
Atlantic to Pacific Oceans and from the boundary of the Neotropical region to within the Arctic

4

Circle. In the Nearctic, native angiosperm feeders are generally found from the Atlantic coast to
Texas and west to the foothills of the Rocky Mountains. With the exception of S. piceae
(Swaine), conifer-feeding Scolytus are restricted to the occurrence of host trees in western
mountain ranges including the Rockies. Scolytus piceae has an expansive range from the east and
west coasts of North America and from northern California and Colorado north to the Arctic
Circle. Introduced Scolytus species are found throughout the US, northern Mexico and Southern
Canada (S. mali (Bechstein) 1805, S. multistriatus (Marsham) 1802, S. rugulosus (Müller 1802),
and S. schevyrewi Semenov 1902).
Members of the Scolytus conifer-feeding clade feed exclusively on Pinaceae genera,
including Abies Mill., Larix Mill., and Picea D.Don. ex Loudon, Pseudotsuga Carrière, and
Tsuga Carrière, but with the notable exception of Pinus L. (Wood and Bright 1992) (Table 1.1).
Members of the angiosperm feeding clade, S. muticus Say, S. fagi Walsh, S. quadrispinosus Say,
feed on the families Cannabaceae (Celtis L.), Fagaceae (Fagus L., Quercus L.) and Juglandaceae
(Carya Nutt.) respectively (Table 1.2).
All Nearctic Scolytus species are monogamous. Females select brood material, begin galley
construction and are subsequently joined by males. Males walk across the host material in search
of females. Mating occurs with the female in the gallery and the male on the bark. The female
creates an entrance tunnel at a 45-degree angle, boring through the bark to the cambium. From
the entrance tunnel, she excavates a nuptial chamber and depending on the species, also one or
two egg galleries in either direction of the entrance tunnel. The nuptial chamber and galleries are
excavated in the cambium but also etch the sapwood. Females excavate egg niches on both sides
of the egg galleries and a single egg is deposited in each niche. Adult males assist in removing
frass and generally stay with the female until egg gallery construction is complete. The male then

5

leaves the gallery and the female dies in the entrance tunnel with her abdomen projecting onto
the bark surface. Larval galleries radiate away from the egg tunnels as they feed on phloem, also
etching the sapwood. Once larvae mature, the prepupae burrow into the outer sapwood where
pupation occurs. The brood overwinters as pupae and adults emerge in the spring (Edson 1967).
Upon emergence, species may engage in maturation feeding on twig crotches and/or leaf petioles
for S. mali, S. multistriatus, S. quadrispinosus, S. rugulosus, S. schevyrewi (Hoffman 1942;
Baker 1972; Negrón et al. 2005), and within small twigs for S. fiskei (as S. unispinosus in
McMullen and Atkins 1962).
Gallery shape is directly related to the resin system of the host genus. Larix, Picea and
Pseudotsuga possess an elaborate system of resin ducts with vertical and radial ducts that are
connected to each other (Lieutier 2004). Scolytus galleries in these tree genera are consistently
parallel to the grain of the wood. The vertical ducts are abundant in these tree genera and when
the beetle constructs a vertical egg gallery both ducts are severed. As the gallery is elongated,
only vertical canals are severed. This minimizes exposure of Scolytus to host resins (Lieutier
2004). Abies and Tsuga lack resin canals and instead possess resin blisters in these genera
galleries are less constrained because there are no resin canals to avoid (Lieutier 2004). Galleries
in these genera are quite variable and may be transverse, “V” or epsilon shaped depending on the
species.
All conifer-feeding Scolytus exhibit primary attraction to host volatiles rather than to
pheromones produced by conspecifics (Macías-Sámano et al. 1998a). The attraction of
angiosperm-feeding species is not well understood but primary attraction, attraction to the host,
seems likely for native S. quadrispinosus and the invasive species S. rugulosus and S. schevyrewi
(Goeden and Norris 1964a; Kovach and Gorsuch 1985; Lee et al. 2010). Scolytus multistriatus

6

exhibits secondary attraction, attraction using pheromones, to the pheromones 4-methyl-3heptanol and multistriatin in combination with alpha-cubene (Lanier et al. 1977). In endemic
populations, Scolytus will infest over-mature or weakened standing trees, shaded out branches,
fresh logging slash, windthrown trees and fallen branches. During outbreaks, vigorous trees may
be colonized by more aggressive species such as S. quadrispinosus, S. mundus and S. ventralis
(Edson 1967; Furniss and Carolin 1977) and secondary species such as S. monticolae, S.
unispinosus (McMullen and Atkins 1959). While Scolytus species are generally common in the
forest they are rarely abundant and seldom encountered by collectors. Scolytus prefer fresh and
moist host material. Sun-baked material is not preferred, but Scolytus galleries may be present in
cooler, moister areas that receive a lot of shade or on the underside of fallen trees and branches.
Infested branches and trees typically still bear green needles (Smith, pers. obs.). The entrance can
be identified by peeling off the bark flakes with a knife and searching for white to tan colored
boring dust or by close examination of the lateral and ventral sides of trunks and branches of
smooth barked hosts. In Pseudotsuga, the entrance tunnels of Pseudohylesinus Swaine 1917 can
be easily confused with those of Scolytus, but Scolytus entrance tunnels are at a steeper angle and
the boring dust is reddish. Some Scolytus species, including S. piceae, S. monticolae and S.
subscaber typically attack shaded out branches on standing trees. Infested material can be
recognized by yellowing needles. Scolytus females typically conceal their entrance tunnels under
bark flakes (common in Picea, Pseudotsuga, Tsuga) or in rough patches of bark (Abies, Larix).

Systematics
The Scolytini currently contains 209 species and six genera including Camptocerus
Dejean 1821, Ceratolepsis Chapuis 1869, Cnemonyx Eichhoff 1868, Loganius Chapuis 1869,

7

and Scolytopsis Blandford 1896 and Scolytus. With the exception of Camptocerus, the tribe
consists of cambium feeding bark beetles. Scolytus is unusual among scolytines because it is one
of five genera in the subfamily that contain some species that feed exclusively on angiosperms
and others that feed exclusively on conifers (Wood 1986). Twenty Nearctic and three Palearctic
species feed on conifers. A single apical, unarmed spine-like process that curves toward and
extends beyond the process of the inner apical angle of the protibia and a seven-segmented
funicle readily distinguishes the tribe. All display a strongly sexually dimorphic head bearing
hair-like setae, with the male frons variously excavated and female frons typically flat to convex.
The eye is entire and the posterior area of the head is subtruncate. The pronotum is unarmed with
a costate lateral margin. In addition, the metapleural suture descends subventrally to the groove,
receiving the groove on the costal margin of the elytra, then turns abruptly and parallels the
groove near the metacoxal process (Wood 1972, 1978, 1982, 1986). Scolytus is perhaps one of
the easiest bark beetle genera to recognize with its distinctive ascendant second abdominal
sternite, the slightly if at all declivous elytra and by the basal area of the elytra that is depressed
around the triangular scutellum (Wood 1982).

Sexual Dimorphism
Scolytus species are sexually dimorphic. Sexually dimorphic structures are typically on
the frons and epistoma (Figure 1.9) and the abdominal sternites and vary by clade (see clade
discussions in results). Males typically have a flattened, impressed frons when viewed laterally
and the female frons is always more strongly convex. The male frons is more strongly and
coarsely longitudinally aciculate than the female and covered with longer, more abundant and
dense erect setae. The epistomal process (when present) is more strongly developed in the male

8

and less developed in the female. With the exception of S. piceae, the spines, tubercles, denticles,
carinae and tumescence on the venter are more pronounced in males.

Taxonomic History
There are currently 125 recognized Scolytus species around the world (Wood and Bright
1992; Wood 2007; Knížek 2011). Twenty-three species occur in the Nearctic region, including
four invasive Palearctic species. Several Nearctic Scolytus species were described as the North
American continent was explored. General entomologists including Say (1824), Riley (1867) and
Walsh (1867) first described the eastern angiosperm feeders. LeConte (1868, 1876) described the
most common California species and species native to the interior mountain ranges. The
prominent scolytine taxonomists Swaine (1910, 1917), Blackman (1934), Wood (1962, 1967,
1968) and Bright (1964, 1972) also described several Scolytus species. Scolytus californicus
LeConte (1868) was described from “California” but Blackman (1934) deemed this species a
synonym of S. scolytus (F.). Blackman also suggested that the specimen given to LeConte might
have been incorrectly labeled with the “California” locality. This species has been intercepted
within the United States on numerous occasions but has never established a population
(Blackman 1934; Wood 1982). Scolytus scolytus was therefore excluded from this monograph.
Historically, there has been a great deal of uncertainty regarding the status of several
Scolytus species, particularly: S. monticolae (Swaine) and S. tsugae (Swaine), S. abietis
(Blackman) and S. opacus (Blackman), S. reflexus Blackman and S. wickhami Blackman, and S.
fiskei Blackman and S. unispinosus LeConte. Blackman (1934) and Wood (1982) formally
revised the Nearctic Scolytus. A third revision by Edson (1967) applied as a M.S. thesis, was
never published. Wood (1982) synonymized several species described by Blackman including S.

9

abietis, S. wickhami and S. fiskei. However, Edson (1967) recognized these species based on
morphological, ecological and geographical differences. One of these species, S. abietis
Blackman, was recently removed from synonymy because of such differences (EquihuaMartinez and Furniss 2009). Within Scolytus, species are generally recognized based on
differences in male morphology, specifically the shape, concavity or lack thereof, ascending
angle and protrusion of the basal margin of the second abdominal sternite, the placement and
shape of the spine or lack thereof on the second sternite, presence or absence of a spine on the
margin of sternite 2 and 3 and the frons aciculation and vestiture. Differences among species are
generally subtle, and substantial knowledge of the intraspecific variation is needed for accurate
identifications. Also, diagnostic morphological characters are absent for females; to date
diagnostic characters are known only for females of angiosperm feeding species (Smith and
Cognato 2010a). Association with a male or comparison to previously identified females is
needed to identify female specimens of conifer feeders. Previous keys (LeConte 1876; Swaine
1918; Blackman 1934; Chamberlin 1939, 1958; Edson 1967; Bright and Stark 1973; Bright
1976; Wood 1982; Furniss and Johnson 2002) did not address the above deficiencies in species
identification. In addition, previous authors were not explicit about their species concepts, raising
doubts about the species boundaries.
Unlike previous investigations (Blackman 1934; Edson 1967; Bright 1976; Wood 1982),
this study incorporates molecular and morphological data in phylogenetic analyses, which
provides a basis for assessing species boundaries. This is the first modern taxonomic treatment of
any group of Scolytus species and will serve as the basis from which the rest of the genus will be
revised. This regional monograph of the Nearctic Scolytus provides a thorough review of
taxonomic characters, an assessment of their phylogenetic utility, an evaluation of intraspecific

10

variation for each species, a key to both sexes and fully illustrates each species and diagnostic
characteristics. There are currently 25 Nearctic Scolytus species.

A checklist of the Nearctic Scolytus species
Scolytus aztecus Wood 1967
Scolytus dentatus Bright 1964
Scolytus fagi Walsh 1867
Scolytus fiskei Blackman 1934 removed from synonymy
Scolytus hermosus Wood 1968
Scolytus laricis Blackman 1934
Scolytus mali (Bechstein) 1805 – Introduced
= Scolytus sulcatus LeConte 1868
Scolytus monticolae (Swaine) 1917
Scolytus multistriatus (Marsham) 1802 - Introduced
Scolytus mundus Wood 1968
Scolytus muticus Say 1824
Scolytus obelus Wood 1962
Scolytus oregoni Blackman 1934
Scolytus piceae (Swaine) 1910
Scolytus praeceps LeConte 1876
= Scolytus abietis Blackman 1934 syn. n.
= Scolytus opacus Blackman 1934 syn. n.
Scolytus quadrispinosus Say 1824

11

= Scolytus carya Riley 1867
= Scolytus caryae Walsh 1867
Scolytus reflexus Blackman 1934
= Scolytus virgatus Bright 1972 syn. n.
= Scolytus wickhami Blackman 1934 syn. n.
Scolytus robustus Blackman 1934
Scolytus rugulosus (Müller) 1818 - Introduced
Scolytus schevyrewi Semenov 1902 - Introduced
Scolytus silvaticus Bright 1972 removed from synonymy
Scolytus subscaber LeConte 1876
Scolytus tsugae (Swaine) 1917
Scolytus unispinosus LeConte 1876
= Scolytus sobrinus Blackman 1934
Scolytus ventralis LeConte 1868

Materials and Methods
Materials
Morphology
This revision is based upon examination of 4,957 adult ingroup specimens and 447
outgroup specimens. Specimens were obtained from field collecting events, reared from host
material, or on loan from North American and European collections. The Palearctic species
Scolytus intricatus (Ratzeburg) 1837, S. laevis Chapuis 1869, S. mali, S. multistriatus, S.
propinquus Blandford 1896, S. pygmaeus (F.) 1787, S. ratzeburgii Janson 1856, S. rugulosus, S.

12

schevyrewi, S. scolytus (F.) 1775, S. sinopiceus Tsai 1962, and S. sulciforns Rey 1892 were
selected as outgroups. Scolytus propinquus, a Neotropical species, was selected as the root taxon.
The following entomological collection abbreviations (most following Arnett et al. 1993) are
referenced in the text. Names of the curators that prepared loans are listed in parentheses.

ANSP

Academy of Natural Sciences, Philadelphia, Pennsylvania

CASC

California Academy of Sciences, San Francisco, California (David Kavanaugh)

CSCA

California State Collection of Arthropods, Sacramento, California (Andrew Cline
and Jacqueline Kishmirian)

CNCI

Canadian National Collection of Insects, Ottawa, Ontario, Canada (Hume
Douglas, Patrice Bouchard)

CSUC

C. P. Gillette Museum of Arthropod Biodiversity, Colorado State University, Fort
Collins, Colorado (Boris Kondratieff)

CUIC

Cornell University Insect Collection, Cornell University, Ithaca, New York
(James Liebherr)

DEBC

Donald E. Bright, Jr. Collection, Fort Collins, Colorado (Donald E. Bright, Jr.), to
be housed at the CNCI

EMEC

Essig Museum of Entomology, University of California Berkeley, Berkeley,
California (Cheryl Barr)

FMNH

Field Museum of Natural History, Chicago, Illinois (James Boone)

ISNB

Institut Royal des Sciences Naturelles de Belgique, Brussels, Belgium (Pol
Limbourg)

MCZC

Museum of Comparative Zoology, Harvard University, Cambridge,

13

Massachusetts (Philip Perkins)
MSUC

Albert J. Cook Arthropod Research Collection, Michigan State University, East
Lansing, Michigan (Gary Parsons)

NHMW

Naturhistorisches Museum Wien, Vienna, Austria (Harald Schillhammer)

OSAC

Oregon State Arthropod Collection, Oregon State University, Corvallis, Oregon
(Christopher Marshall)

RJRC

Robert J. Rabaglia Collection, Annapolis, Maryland (Robert J. Rabaglia)

SBMN

Santa Barbara Museum of Nature, Santa Barbara, California (Michael Caterino)

SMEC

Snow Entomological Museum, Lawrence, Kansas (Zachary Falin)

THAC

Thomas H. Atkinson Collection, Austin, Texas (Thomas Atkinson)

WFBM

William F. Barr Entomological Collection, University of Idaho, Moscow, Idaho
(Frank Merickel)

UMMZ

Museum of Zoology, University of Michigan, Ann Arbor, Michigan (Mark
O’Brien)

USNM

National Museum of Natural History, Smithsonian Institution, Washington, DC
(Including Stephen L. Wood Collection) (Natalia Vandenberg)

Additional distribution records were compiled from the following publications:
Blackman 1922, 1934; Doane et al. 1936; Edson 1967; Bright and Stark 1973; Bright 1976;
Furniss and Carolin 1977; Furniss and Johnson 1987; Gast et al. 1989; Wood and Bright 1992;
Cibrián Tovar et al. 1995; Furniss and Johnson 2002; Furniss et al. 2002; Lee et al. 2006;
Humble et al. 2010; Smith and Cognato 2010a; Furniss and Kegley 2011; Lee et al. 2011). Plant

14

nomenclature was verified using the Missouri Botanical Garden’s Tropicos database
(www.tropicos.org) and the International Plant names index (www.ipni.org).
Specimens were examined using either a Leica (Wetzlar, Germany) MZ125 or MZ16
compound microscope and illuminated with a SCHOTT (Mainz, Germany) 150W halogen light
source (model ACE®1). Images were taken with a Visionary Digital Passport II system
(Palmyra, VA) using a Canon EOS 5D Mark II, 58mm Canon Macro photo lens, Canon
Speedlite transmitter ST-E2, two Canon Speedlite 4303X II flashes and a Stack Shot (Cognisys,
Inc, Kingsley, MI). Montage images were assembled using Helicon Focus Mac Pro 4.2.8
(Helicon Soft, Kharkov, Ukraine). Measurements were made using an ocular micrometer on the
same microscope and with the same light source as above and calibrated with ROK (Shenzhen,
China) 150mm digital calipers (model DC-122A) following the protocol of Smith and Cognato
(2010b). Measurements were taken from the specimen’s dorsal surface. Length was measured
from the pronotum apex to the elytral apex. Width was measured at the widest part of the
pronotum. Proportions are given as the ratio of length to width. A maximum of 50 specimens
were measured for each species and were selected to encompass the known distribution.
If important locality data such as state or county was missing from specimen labels, the
information was inserted between square brackets in the material examined. Locality data was
obtained through examination of atlases and Google Earth. Holotypes of Scolytus sulcatus and
Scolytus californicus LeConte 1868 were not physically examined. Type images were examined
from the MCZ type database (http://insects.oeb.harvard.edu/mcz/) and the synonymy of these
species was confirmed. Scolytus californicus was not included in this revision because it is a
synonym of S. scolytus, which is not established in the Nearctic.

15

Taxonomic Characters
External anatomical terminology followed Hopkins (1909) subsequently used by Schedl
(1931), Kaston (1936), Edson (1967) and Wood (1982, 1986, 2007). Sculpture terminology
followed Torre-Bueno (1989). Several highly informative recently described Scolytini characters
were also scored (Smith and Cognato 2010b). Provisional morphological homology was assessed
by similarity and relative positions of characters as previously described. Sternites 1 and 2 are
internal and are not externally visible (Hopkins 1909) so only visible sternites are referred to in
the text. The third and fourth sternites are respectively referred to as the first and second sternites
etc., as in Smith and Cognato (2010b).
Characters were scored from both sexes unless otherwise noted. Scolytus exhibits strong
sexual dimorphism of the frons and abdominal venter; males display a wide array of
morphological features, particularly on the venter, whereas females are conserved. As a
consequence, characters were predominately male based. Characters and character state numbers
correspond to data coded in the morphological data matrix for each taxon. The character matrix
(Table 1.3) was constructed and edited using the online database MX (Yoder et al. 2006).
Character transformations were evaluated using MacClade 4.0 PPC (Maddison and Maddison
2000) and homology of characters and definitions of characters states were re-examined and
modified if necessary.
Ecological characters such as gallery pattern and host were scored. Character states were
assigned based on a comprehensive literature review (e.g. von Butovitsch 1929; Chamberlin
1939; Schedl 1948; Balachowsky 1949; Stark 1952; Chamberlin 1958; Edson 1967; Bright and
Stark 1973; Michalski 1973; Bright 1976; Furniss and Carolin 1977; Wood 1982; Atkinson and
Equihua-Martinez 1986a; Wood and Bright 1992; Pfeffer 1994; Cibrián Tovar et al. 1995; Bright

16

and Skidmore 1997, 2002; Furniss and Johnson 2002), and with field notes, and label data on
pinned museum specimens.
A total of 43 characters were used in this study (19 binary and 24 multistate). Ten
characters were coded from the head, two from the thorax, ten from the elytra, one from the
metepimeron, 17 from the venter and three ecological characters. Consistency and retention
index values (ri and ci respectively) from the morphological phylogeny (Figure 1.1) and
generated from MacClade are listed next to each character. Characters, states as follows:
1. Epistomal emargination (ci = 0.22; ri= 0.22): (0) weak; (1) moderate; (2) strong.
2. Male epistomal process (ci = 0.25; ri = 0.63): (0) absent; (1) present.
3. Male frons shape (ci =0.25; ri = 0.45): (0) convex; (1) flat; (2) impressed.
4. Male frons vestiture distribution (ci = 0.33; ri = 0.20): (0) glabrous; (1) uniform; (2)
predominately on margins; (3) epistomal region.
5. Male frons vestiture length (ci =0.4; ri = 0.0): (0) less than width of eye; (1) equal to width of
eye; (2) greater than width of eye.
6. Male frons sculpturing (ci =0.38; ri = 0.50): (0) coarsely aciculate; (1) weakly aciculate; (2)
rugose-reticulate; (3) smooth.
7. Male frons punctures (ci =0.33; ri = 0.71): (0) small, fine; (1) small, coarse; (2) impunctate.
8. Female frons shape (ci =0.67; ri = 0.50): (0) flat; (1) impressed; (2) convex; (3) excavated.
9. Female frons sculpturing (ci =0.29; ri = 0.44): (0) coarsely aciculate; (1) finely aciculate; (2)
reticulate.
10. Female frons punctures (ci =0.14; ri = 0.54): (0) small, fine; (1) small, coarse.
11. Pronotum length to width (ci = 0.50; ri = 0.50): (0) as long as wide; (1) wider than long.

17

12. Metepimeron length (ci =0.29; ri = 0.50): (0) less than half-length of metepisternum; (1) half
length of metepisternum; (2) greater than half-length of metepisternum.
13. Elytral sides sub-parallel (Michalski 1973) (ci =0.25; ri = 0.50); (0) on basal half; (1) on
apical half.
14. Interstrial setae (ci =0.22; ri = 0.56); (0) glabrous; (1) sparse; (2) moderate.
15. Interstrial impression (ci =0.13; ri = 0.42): (0) not impressed; (1) faintly impressed.
16. Interstrial width (ci =0.29; ri = 0.44): (0) equal to striae; (1) twice width of striae; (2) more
than twice the width of striae.
17. Relative size of interstrial punctures (ci =0.25; ri = 0.25): (0) equal to strial; (1) smaller than
strial.
18. Strial impression (ci =0.40; ri = 0.70): (0) not impressed; (1) weakly impressed; (2)
moderately impressed
19. Male elytral apex shape (ci =0.25; ri = 0.67): (0) rounded; (1) subquadrate.
20. Elytral apex emargination (ci =0.38; ri = 0.76): (0) absent; (1) weak; (2) moderate; (3)
strong.
21. Apical margin of elytra serrate (ci =0.20; ri = 0.33): (0) absent; (1) present.
22. Punctures on elytral apical margin (ci =0.20; ri = 0.53): (0) impunctate; (1) small, fine; (2)
large, coarse.
23. Venter appearance (Blackman 1934) (ci =0.11; ri = 0.50): (0) smooth, shining; (1)
shagreened, dull.
24. Venter setae length (ci =0.23; ri = 0.50): (0) less than 1 diameter of a puncture; (1) less than
width of segment 3; (2) greater than width of segment 3; (3) glabrous.
25. Female second sternite (ci =0.60; ri = 0.50): (0) unarmed; (1) apical; (2) basal; (3) medial.

18

26. Suture between first and second sternites (Wood 1982) (ci =0.50; ri = 0.0): (0) clearly
visible; (1) obsolete.
27. Male first sternite apical margin (ci = 0.42; ri = 0.68): (0) rounded, on vertical face; (1)
weakly elevated; (2) lip; (3) weakly produced; (4) strongly produced; (5) flush, not on vertical
face.
28. Male second sternite armature (ci =0.36; ri = 0.42): (0) unarmed; (1) basal spine; (2) medial
spine; (3) apical spine; (4) carina on basal half; (5) carina on apical half.
29. Male second sternite face (ci =0.33; ri = 0.67): (0) convex; (1) weakly concave; (2) strongly
concave; (3) flat.
30. Second sternite punctures (ci =0.25; ri = 0.63): (0) small, fine; (1) small, coarse.
31. Setal tuft on male second sternite (ci =1.00; ri = 0.0): (0) absent; (1) present.
32. Second sternite lateral spines (ci = 0.50; ri = 0.0): (0) absent; (1) present.
33. Third sternite lateral spines (ci = 0.50; ri = 0.0): (0) absent; (1) present.
34. Fourth sternite lateral spines (ci = 0.50; ri = 0.0): (0) absent; (1) present.
35. Male fourth sternite armed medially (ci = 0.17; ri = 0.29): (0) absent; (1) present.
36. Male fifth sternite (ci =0.60; ri = 0.75): (0) unarmed - lacking carina; (1) midpoint of the
carina closer to apex; (2) midpoint of the carina closer to base; (3) carina midpoint equidistant
from base and apex.
37. Relative size of male fifth sternite compared to the third and the fourth (ci =0.15; ri = 0.48):
(0) 5 larger; (1) 3+4 larger; (2) equal.
38. Male fifth sternite setal patch (ci =0.33; ri = 0.50): (0) absent; (1) present.
39. Male fifth sternite with a median depression (ci =0.33; ri = 0.50): (0) absent; (1) present.

19

40. Male metatibial setae (ci =0.50; ri = 0.0): (0) not conspicuously longer than those of other
tibiae; (1) much longer and more abundant than those of other tibiae.
41. Mating system (ci = 1.00; ri = 0.0): (0) monogamy; (1) polygamy.
42. Gallery type (ci =0.50; ri = 0.70): (0) vertical; (1) transverse; (2) epsilon; (3) multi-branched.
43. Host (ci =0.73; ri = 0.73): (0) Fabaceae; (1) Pseudotsuga; (2) Abies; (3) Picea; (4) Larix; (5)
Tsuga; (6) Ulmaceae; (7) Rosaceae; (8) Fagaceae; (9) Cannabaceae; (A) Juglandaceae; (B)
Betulaceae.

Taxa, DNA sequences and Alignment
I included 83 specimens (Table 1.4) representing 32 Scolytus species to reconstruct
phylogenies using DNA sequences from mitochondrial and nuclear genes and morphology. The
same Palearctic outgroup species used in the morphological analyses were included in the
molecular dataset. As many Nearctic species as possible were included in the analysis. I was
unable to collect fresh material for Scolytus dentatus, S. hermosus, S. mundus, and S. silvaticus,
which were therefore excluded from the molecular analyses. Sequences of the following species
were obtained from GenBank and included in the analyses: S. intricatus (HQ883677, HQ883589,
HQ883820, HQ883909) and S. scolytus (HQ883678, HQ883590, HQ883821, HQ883910). To
assess mitochondrial cytochrome oxidase I (COI) intraspecific variation, I included 88 specimens
(Table 1.5) representing 30 Scolytus species from as many populations as possible. Specimens
were included in the four-gene phylogeny only if molecular characters were available for at least
two genes.
DNA was extracted from freshly collected specimens preserved in 200 proof ethanol and
from pinned specimens that had been killed in sawdust impregnated with ethyl acetate and then

20

immediately pinned. Specimens were dissected by removing the head and thorax from the
abdomen. DNA extractions were performed on the head and thorax using a Qiagen DNEasy
blood and tissue kit (Hilden, Germany) following the manufacturer protocols except for the DNA
elution procedure, which consisted of a single elution of 100-200µl of buffer AE depending on
the size of the specimen, with specimens measuring less than 5mm in length receiving 100 µl
and those greater than 5mm in length receiving 200 µl. After the extraction process was
completed, the body parts were rinsed in 70% ethanol, glued onto a mounting board, pinned,
labeled and are vouchered in the MSUC. The resulting purified DNA was used to amplify partial
gene regions of COI, D2 region of nuclear ribosomal 28S, CAD, and Argenine Kinase (ArgK)
using the PCR primers listed in Table 1.6. The COI barcoding primers LCO 1490 and HCO 2198
did not consistently amplify scolytine COI sequences, which necessitated the construction of the
degenerate scolytine specific primers, 1495b and rev750. These primers worked best for Scolytus
specimens and have proven to be effective on a broad array of scolytine taxa (Cognato et al.
unpublished). The 1495b and rev750 primers were used to create the Scolytus specific F215 and
Rev453 primers, respectively for 5-20 years or older pinned specimens. All PCR cocktails
consisted of a total volume of 25µl and included 14.25-17.25 µl ddH20, 2.5µl 10X PCR buffer
(Qiagen), 1.0µl 25mM MgCl2 (Qiagen), 0.5µl dNTP mix (Qiagen), 2-5µl DNA template, 0.25µl
HotStar Taq DNA polymerase (Qiagen). PCR reactions were performed on a thermal cycler
(PTC-2000, MJ Research, Waltham, MA or MyCylcer Thermocycler, BioRad, Hercules, CA)
under the following conditions: one cycle for 15 min at 95°C, 40 cycles for 30 (COI) – 45 (28S,
CAD, ArgK) sec at 94°C, 45 sec at 50-58°C (see Table 1.5 for specific annealing temperatures),
1 min at 72°C and a final elongation cycle of 5 min at 72°C. PCR products were cleaned using
ExoSAP-IT (USB Corp., Cleveland, OH) and following the manufacturer protocols. Cleaned

21

PCR products were then prepared for sequencing. Each reaction contained 3.5µl of cleaned PCR
product, 1µl 33pM/µl sequencing primers (identical to those used in PCR), and 7.5µl of ddH20.
Samples were sequenced in the Michigan State University Genomics Core facility using an ABI
3730 Genetic Analyzer (Applied Biosystems, Foster City, CA).
Sequences were received as chromatograms and the sense and antisense strands were
compiled using Sequencher (Ann Arbor, MI) to trim sequences, examine for ambiguities and
create consensus sequences. Sequences were blasted in GenBank to examine for paralogous
copies and other potential problems including contamination and pseudogenes. Sequences for
COI, CAD and ArgK were aligned using SE-AL v.2.0a11 Carbon
(http://tree.bio.ed.ac.uk/software/seal/). Sequence length variation was only observed in 28S.
Sequences of 28S were either manually aligned in SE-AL using a scolytine-specific secondary
structure model (Jordal et al. 2008). Nexus files are available at http://www.scolytid.msu.edu.

Methods
Morphology
Phylogenetic analysis. The phylogeny was reconstructed using the criterion of parsimony
implemented in PAUP*4.0 b10 PPC (Swofford 2002). A heuristic search with 1,000 stepwise
random additions with tree bisection-reconnection (TBR) for 37 taxa (25 ingroup, 12 outgroup)
was performed. Characters were unordered and equally weighted. Bootstrap values were
calculated by performing 1,000 pseudoreplicates with simple additions in PAUP*. Bremer
support values were calculated by creating a constraint tree in TreeRot v.2 (Sorenson 1999) and
analyzed in PAUP* using a heuristic search with 100 addition-sequence replicates.
Molecular

22

Likelihood Phylogenetic Analyses. I analyzed the molecular and morphological datasets using
Bayesian estimation of phylogeny with MrBayes 3.2.1 (Huelsenbeck and Ronquist 2001). There
were two Bayesian analyses, one with a molecular dataset (79 taxa) and one with a combined
molecular and morphological dataset (83 taxa). Each dataset was divided into partitions, with 4
gene partitions for the molecular dataset and 5 partitions (4 gene and 1 morphological) for the
combined dataset. I selected the best model for each data partition using MrModeltest (Nylander
2004). The GTR+I+ Γ (general time reversible with a proportion of invariant sites and a gammashaped distribution of rate variation across sites) model selected by Akaike Information Criterion
(AIC) was found to have the optimal fit for the gene partitions and Γ (gamma) was chosen for
the morphology partition. Taxa that were unable to be sequenced were included in the
morphology partition of the combined dataset.
The molecular dataset was analyzed with four Metropolis-Coupled Markov Chain Monte
Carlo searches (3 heated, 1 cold) for 2 million generations with sampling every 100th iteration.
Approach to stationarity (burn-in) was 0.25. All parameters reached stability at 2 million
generations and the split deviation between runs was 0.011074. Bayesian posterior probabilities
of clades were calculated by a majority-rule consensus of those trees after the burn-in (15,000
trees).
For the combined analysis, four Metropolis-Coupled Markov Chain Monte Carlo
searches (3 heated, 1 cold) were performed for 6.5 million generations with sampling as
described for the molecular dataset. Scolytus dentatus, S. hermosus, S. mundus, and S. silvaticus
were included in this analysis with only morphological characters. All parameters reached
stability at 6.5 million generations and the split deviation between runs was 0.024100. Bayesian

23

posterior probabilities of clades were calculated by a majority-rule consensus of those trees after
the burn-in (48,750 trees).

Parsimony Phylogenetic Analysis. Two heuristic searches with 100 stepwise random additions
with tree bisection-reconnection (TBR) for 79 taxa (56 ingroup, 23 outgroup) were performed on
the molecular dataset. In the first analysis, gaps were treated as missing data and in the second
analysis, gaps were treated as a fifth character state. Partition Bremer support (PBS) values were
calculated by creating a constraint tree in TreeRot v.2 (Sorenson 1999) and analyzed in PAUP*
using a heuristic search with 100 addition-sequence replicates. Intraspecific and interspecific
differences were generated by computing pairwise distances for each gene in PAUP*.
A single gene phylogeny was reconstructed using COI using a heuristic search with 100
stepwise random additions with TBR for 89 taxa (59 ingroup, 23 outgroup).
The combined dataset was analyzed using two heuristic searches with 100 stepwise
random additions with TBR for 83 taxa (71 ingroup, 12 outgroup) and were analyzed following
the protocols listed above.

Species Concept
Species are hypotheses of unique evolutionary entities, which are tested by monophyly
(sensu Wheeler and Platnick 2000). These monophyletic groups of individuals are named if they
are diagnosable by synapomorphies or a unique combination of homoplastic characters. If
diagnostic characters are not found, the clade will retain the original species name or will be
synonymized with the sister clade. Therefore, based on species level morphological and

24

molecular phylogenies, species revisions will be based on monophyly of multiple individuals
from disjunct populations.

Results
Phylogenetics of Nearctic Scolytus
Morphology
The native Nearctic Scolytus were recovered as polyphyletic with native species forming
two clades, the native hardwood and conifer clades (Figure 1.1). The parsimony analysis
produced 1,016 most parsimonious trees with a length of 262 steps and 41 of 43 parsimony
informative characters. There was a moderate amount of homoplasy among the character states
(CI = 0.332, RI = 0.539). Overall the phylogeny was weakly supported at the peripheral nodes
and poorly supported at deeper nodes with many nodes unresolved.
The morphological phylogeny was poorly resolved and few synapomorphic characters
were found (Figure 1.1). This reflects the morphologically similarity of many taxa and
homoplasy of many characters. The morphological phylogeny recovered two clades of native
species, the native hardwood clade and the conifer clade. Two additional clades of Eurasian
species were also recovered. The outgroup taxa were poorly resolved except for S. rugulosus and
S. sinopiceus, which were recovered as sister taxa. Scolytus fiskei was found to be a distinct
lineage separate from S. unispinosus in which it was considered a synonym. The relationship
among S. obelus, S. praeceps, S. abietis and S. opacus was unresolved and S. reflexus, S. virgatus
and S. wickhami were strongly supported as monophyletic. The lack of phylogenetically
informative characters necessitated the need for further investigation using molecular characters
to illuminate species boundaries.

25

Molecular
Bayesian analysis recovered most nodes with posterior probabilities >90%. The native
Nearctic Scolytus were recovered as paraphyletic with Palearctic species (Figure 1.2). The
Bayesian analysis recovered all taxa found to be monophyletic in the morphological phylogeny
as monophyletic and the native species were recovered in two clades: native hardwood (S. fagi,
S. muticus and S. quadrispinosus) and a second clade of conifer feeders (S. aztecus, S. fiskei, S.
laricis, S. monticolae, S. obelus, S. oregoni, S. piceae, S. praeceps, S. reflexus, S. robustus, S.
subscaber, S. tsugae, S. unispinosus, and S. ventralis) (Figure 1.2). In addition, two species were
not monophyletic. Scolytus reflexus was polyphyletic with S. virgatus and S. wickhami, and S.
praeceps with S. abietis and S. opacus. Scolytus unispinosus and its synonym, S. fiskei, were not
monophyletic and were recovered as two lineages. Scolytus rugulosus, Palearctic hardwood
feeder, was sister to the conifer clade. The parsimony analysis of mitochondrial COI produced
2,958 most parsimonious trees with a length of 1,434 steps and 606 of 616 characters were
parsimony informative (CI=0.356, RI =0.809) (Figure 1.3).
The parsimony analysis of the molecular dataset with gaps treated as missing data
produced 94,002 most parsimonious trees with a length of 2,451 steps and 604 of 2,296
characters were parsimony informative (Figure 1.4). There was strong signal within the
phylogeny with the tree exhibiting a relatively low amount of homoplasy (CI=0.479, RI=0.773).
The relationships within the phylogeny were strongly supported. Support values for each node
were relatively high as compared to when gaps were treated as a fifth character (Table 1.9).
Parsimony analysis of the combined dataset with gaps treated as missing data (Figure 1.7)
produced a topology that is very similar to that of the molecular dataset except S. hermosus, S.

26

dentatus, S. mundus and S. silvaticus have been placed sister to taxa which they most strongly
resemble.
The parsimony analysis of the molecular dataset with gaps treated as a fifth character
produced 59,010 most parsimonious trees with a length of 2,647 steps and 636 of 2,296
characters were parsimony informative (Figure 1.5). Treating gaps as a fifth character resulted in
an additional 32 characters and slightly reduced the amount of homoplasy within the phylogeny
(CI=0.479, RI=0.773). However the topology was mostly unresolved and the overall support for
each node and the tree was less than the analysis with gaps as missing data (Table 1.10, Figure
1.4). The native Nearctic Scolytus were recovered as polyphyletic and the native species
occurred in three clades: conifer-feeding species; S. fagi and S. muticus sister to a clade
consisting of S. quadrispinosus and Palearctic species. Parsimony analysis of the combined
dataset with gaps treated as a fifth character state (Figure 1.8) produced a topology that is very
similar to that of the molecular dataset except the native hardwood clade was monophyletic and
S. dentatus, S. hermosus, S. mundus and S. silvaticus have been placed sister to taxa which they
most strongly resemble.

Combined Analyses
Bayesian analysis of the combined dataset recovered the native Nearctic Scolytus as
paraphyletic with native species found in two clades: native hardwood and conifer (Figure 1.6).
Bayesian analysis of the combined dataset (Figure 1.6) recovered all taxa found to be
monophyletic in the morphological phylogeny as monophyletic and the native species were
recovered in two clades: native hardwood (S. fagi, S. muticus and S. quadrispinosus) and a
second clade of conifer-feeders (S. aztecus, S. dentatus, S. fiskei, S. hermosus, S. laricis, S.

27

monticolae, S. mundus, S. obelus, S. oregoni, S. piceae, S. praeceps, S. reflexus, S. robustus, S.
silvaticus, S. subscaber, S. tsugae, S. unispinosus, and S. ventralis) sister to S. rugulosus. The
topology is almost identical to the topology of the Bayesian molecular phylogeny except S.
hermosus (unresolved), S. dentatus (unresolved), S. mundus (2 synapomorphies) and S. silvaticus
(2 synapomorphies) have been placed sister to taxa that they most strongly resemble.
Parsimony analysis of the combined dataset with gaps treated as missing data produced
22,003 most parsimonious trees with a length of 2,902 steps and 647 of 2,339 characters were
parsimony informative (Figure 1.7). There was a low amount of homoplasy in the phylogeny and
the phylogeny was strongly supported but less so than the molecular phylogeny (CI=0.458,
RI=0.769) (Table 1.11). The native Nearctic Scolytus were recovered as polyphyletic and the
native species occurred in three clades: conifer-feeding species; S. fagi and S. muticus sister to S.
quadrispinosus; the Palearctic species, as in the molecular analysis. The parsimony analysis of
the molecular dataset with gaps treated as missing data (Figure 1.4) had greater support at each
node that treating gaps as a fifth character state (Table 1.9, 1.10). The native Nearctic Scolytus
were recovered as polyphyletic with native species found in three clades, conifer, S. fagi and S.
muticus forming one lineage and S. quadrispinosus as sister to a clade of Palearctic species.
Three species were recovered polyphyletic. Scolytus reflexus was polyphyletic with S. wickhami
and S. virgatus, S. praeceps with S. abietis and S. opacus and S. fiskei with S. laricis. Scolytus
sinopiceus was sister to the conifer clade.
Parsimony analysis of the combined dataset with gaps treated as a fifth character state
produced 13,003 most parsimonious trees with a length of 3,097 steps and 679 of 2,339
characters were parsimony informative (Figure 1.8). There was a low amount of homoplasy in
the phylogeny (CI=0.48, RI=0.771) and the combined analysis was more resolved and more

28

nodes received support than the molecular analysis, which was almost completely unresolved
(Tables 1.10 and 1.12). The native Nearctic Scolytus were recovered as paraphyletic with native
species found in two clades, native hardwood and conifer. The parsimony analysis of the
molecular dataset with gaps treated as a fifth character (Figure 1.5) had much less support than
treating gaps as missing data (Table 1.12.). Treating gaps as a fifth character resulted in the
placement of S. rugulosus as sister to the conifer clade. The hardwood clade was paraphyletic
with S. fagi and S. muticus forming one lineage and S. quadrispinosus as sister to a clade of
Palearctic species. Scolytus reflexus was polyphyletic with S. virgatus and S. wickhami, as well
as S. praeceps with S. abietis and S. opacus. Scolytus oregoni was also not recovered as
monophyletic. This species is morphologically and biologically distinct. The placement on the
phylogeny is likely due to the fact that Sco ore 5 is missing some data for COI. Both Sco ore 5
and 71 were collected from the same branch and directly compared to the holotype.

Discussion
Phylogenetic Analyses
As in other phylogenetic studies, the mitochondrial COI data failed to recover many
species as monophyletic (Figure 1.3) (Cognato et al. 2005; Jordal and Hewitt 2005). Many of the
relationships found in this phylogeny did not agree with the topologies obtained from different
analyses. For example a hardwood-feeder, S. rugulosus, was found to be sister to the conifer
clade in the Bayesian analysis and the parsimony analyses with gaps treated as a fifth character,
while S. sinopiceus, a conifer-feeder, was found to be the sister taxa in the parsimony analyses
with gaps treated as missing. In addition, the hardwood clade was paraphyletic with S. fagi and S.
muticus forming one lineage and S. quadrispinosus as sister to S. multistriatus. Saturation of

29

nucleotide substitutions and a lack of lineage sorting are potential reasons for the discordance
among these mitochondrial and nuclear phylogenies (Sota and Vogler 2001; Funk and Ohmland
2003; Lin and Danforth 2004). The mitochondrial phylogeny may suffer from both phenomena
because of the observed poor resolution and support for deeper nodes and short-branch lengths
among the conifer-feeding species (Figure 1.3). As with other studies, concatenating the COI
dataset with multiple genes and morphology remedied its deficiency and elucidated the
relationships among the Scolytus species (Jordal and Hewitt 2004).
In some other molecular phylogenetic studies, treating gaps as fifth character states help
to improve phylogenetic resolution (e.g. Cognato and Vogler 2001; Lee 2001; Ruiz et al. 2009;
Dole et al. 2010). Insertion/deletion events presumably represent heritable traits, which are
potentially phylogenetically informative (Phillips et al. 2000). It was surprising that treating gaps
as fifth character states in a parsimony analysis only slightly affected species relationships
(Figures. 1.5 and 1.8) and resulted in reduced support (Tables 1.10, 1.12). Treating gaps as fifth
character states caused conflict among the molecular data, given that morphology provided the
most support (Tables 1.11, 1.12). Suboptimal alignment of length variable regions is a one
reason for reduced support and poor tree resolution (Cognato and Vogler 2001; Simmons et al.
2011). However, only 32 gaps were necessary to align our 28S data in reference to a secondary
structure model (Jordal et al. 2008) suggesting it is unlikely that the alignment is the cause of the
poor results treating gaps as fifth character states. Unraveling the cause of this underlying issue is
beyond the scope of this taxonomic revision.
When analyzed together, the genes used in this study (COI, 28S, CAD, ArgK) were
useful in resolving the Scolytus phylogeny. These genes have demonstrated similar phylogenetic
utility in other scolytine studies (Cognato and Sperling 2000; Farrell et al. 2001; Jordal et al.

30

2002; Jordal and Hewitt 2004; Jordal et al. 2004; Cognato et al. 2005; Cognato and Sun 2007;
Jordal et al. 2008; Dole et al. 2010; Cognato et al. 2011; Jordal et al. 2011; Jordal and Cognato
2012). In the four gene parsimony phylogenies, most support for each node derived from the
COI dataset followed by CAD, ArgK and 28S (Tables 1.11-1.12). A similar pattern was
observed combined analysis with gaps treated as missing data except morphology had the lowest
contribution to the phylogeny (Tables 1.9-1.10). Overall, the model-based rates of nucleotide
evolution utilized in Bayesian analysis combined with all four genes and morphology allowed us
to recover a well-supported and sufficiently resolved phylogeny which enabled the revision of
Scolytus (Figure 1.6).

Taxonomic Implications
The Nearctic Scolytus were not recovered as monophyletic but as two clades (native
hardwood and conifer) and a group of introduced Palearctic species (Figure 1.6). Members of the
native hardwood clade are sister to the Scolytus subgenus scolytus of von Butovitsch (1929)
rather than the native conifer clade. This is supported by morphological similarities between the
native hardwood clade and the Scolytus subgenus scolytus and the disparate morphology between
the conifer clade. The Scolytus subgenus scolytus clade and the native hardwood feeders share a
median impression on male sternite 5 (except S. laevis and S. quadrispinosus) and a setal patch
on sternite 5 (except S. laevis and S. quadrispinosus). Several species in these groups share the
absence of a carina on the male sternite 5 (S. laevis, S. mali, S. ratzeburgii, S. fagi and S.
muticus).
Based on the results of our phylogenetic analyses, 25 valid species occur in the Nearctic.
Several species were not recovered monophyletic in any analysis and had less than 1% difference

31

in COI sequences and were thus placed in synonymy with the oldest described species. The
following synonyms were discovered: S. praeceps (= S. abietis; = S. opacus), S. reflexus (=S.
virgatus; = S. wickhami). Scolytus fiskei was recovered as monophyletic and is removed from
synonymy with S. unispinosus. Further detail regarding the taxonomic changes are found in the
discussion section for each species.

Scolytus Geoffroy
Scolytus Geoffroy 1762; type species: Bostrichus scolytus Fabricius 1775.
Ekkoptogaster Herbst 1793; type species: Bostrichus scolytus Fabricius 1775.
Coptogaster Illiger 1807; type species: Bostrichus scolytus Fabricius 1775.
Eccoptogaster Gyllenhal 1813; type species: Bostrichus scolytus Fabricius 1775.
Scolytochelus Reitter 1913; type species: Ips multistriatus Marsham 1802.
Ruguloscolytus Butovitsch 1929; type species: Bostrichus rugulosus Müller 1818.
Etymology. Scolytus is derived from ‘Le Scolyte’, the French common name for ‘bark beetle’
(Geoffroy 1762).
Taxonomic History. For a complete discussion, see Blackman (1934) and China (1962, 1963).
Diagnostic characteristics. Scolytus is easily distinguished from all other Nearctic scolytines by
the unarmed protibia with a single curved process at the outer apical angle, flattened antennal
club with 0-1 septate procurved sutures, seven segmented funicle, the slightly declivous elytra,
the depressed scutellar notch and scutellum and by the abruptly ascending abdomen.
Redescription (modified from Wood 1982). Length 1.7 – 6.0mm, 1.7 – 2.9 times as long as
wide. Color varies from red brown to black and teneral adults are often light brown.

32

Frons sexually dimorphic (discussed above and for each species group). Eye elongate,
sinuate to shallowly emarginated and finely faceted. Antennal scape shorter than three funicle
segments; funicle seven segmented; club large, flattened, oval to obovate, minutely pubescent
and with strongly procurved sutures; suture 1 partially to completely septate and with or without
a surface groove. Pronotum large, head visible from above, lateral margins marked by a fine
raised line. Scutellum large, depressed below level of elytra and triangular. Elytra with a
depressed scutellar notch and along the basal fifth to half of elytral suture; striate; slightly
declivous apically. Anterior coxae narrowly separated. Abdomen ascending from posterior
margin of sternite 1 to meet elytral apex, sternite 2 abruptly ascending (except S. rugulosus),
often impressed, armed or both; abdomen dimorphic in most species (discussed above).

Taxonomic Treatment
There are some traditionally used terms and characters in Scolytus literature that require
clarification. The term ‘venter’ is regularly utilized. In general, the term refers to the entire
ventral surface of an organism. However in Scolytus it only pertains to the abdominal ventral
concavity, specifically sternites 2-5. The length of sternite 5 compared to sternite 3 and 4 is
another common misleading character in Scolytus literature. Rather than measuring the entire
length of segment 5, only the distance from the basal margin to the subapical carinate ridge is
measured and is compared to the combined lengths of sternites 3 and 4.

Glossary of Terminology
(modified from Hopkins 1909; Torre-Bueno 1937; Edson 1967; Harris 1979)

33

General
Apical: referring to a point at or close to the apex or tip.
Basal: referring to a point at or closest to the main body.
Impressed: a depression in a surface, typically referring the elytral striae or frons.
Concave: appearing hollowed out.
Convex: appearing rounded.
Vestiture: the surface covering composed of setae, in Scolytus the setae or either long or short.

Head (Figure 1.10)
Aciculate: refers to the longitudinal groves or scratches on the frons that can appear coarse as if
made by a knife or fine as if scratched with a needle.
Epistomal process: a raised, sinuate process composed of a median and two lateral sections
fringed apically with thick, long bristles that cover the median epistomal area just above
the mandibles.
Frons: region of the head from just above the epistoma to a point that is just dorsal to the inner
apices of the eyes.
Inner apices of eyes: the innermost mesal margins of the eyes as viewed frontally.
Strigate: having narrow, transverse lines in the cuticle.
Vertex: the top of the head, above the eyes.

Elytra (Figures 1.11 and 1.12)
Apex: end of a structure that is distal to the base.
Disc: the central upper surface of the elytra between the elytral bases and the sloped declivity.

34

Striae: longitudinal lines or groves extending along the dorsal surface of the elytra, which are
often impressed.
Interstriae: longitudinal spaces along the elytra between the striae, which are not impressed and
bear smaller punctures.
Corrugated: with alternate ridges and channels, referring to the appearance of the elytral striae
and interstriae.
Sutural dehiscence: the central notch at the apical margin of the elytra.

Abdomen (Figure 1.13)
Carina: a ridge-like or keel-shaped projection of the exoskeleton; on the venter.
Cusp: a slight projection or elevation along a margin; refers to the apical margin of sternite 1 in a
few species.
Denticle: a small tooth.
Opaque: appearing dull in luster; referring to a surface that reflects little light.
Produced: refers to a part of the exoskeleton that is extended, lengthened, or elevated.
Punctate: set with fine impressed points appearing as pinpricks.
Punctulate: minute punctures.
Rugose: appearing wrinkled.
Shagreened: covered with a closely set roughness and appearing similar to sharkskin.
Shiny: appearing glossy or bright in luster; refers to a surface that appears polished and reflects
light well.
Spine: an elongate projection of the exoskeleton that is longer than its basal width.

35

Sternite: In Scolytus there are five visible sternites. They are numbered from anterior to
posterior with sternite 1 closest to the head and sternite 5 closest to the elytral apex.
Subapical carinate ridge: a carinate ridge on sternite 5 occurring just before the apical margin.
Tubercle: a small knob-like or rounded protuberance of the exoskeleton.
Tumescence: a swelling of the exoskeleton.
Venter: the undersurface of the abdomen, in Scolytus this pertains to sternites 1-5.

Damage Pattern (Figure 1.14)
Adult gallery: the composite tunnel produced by the adult female includes 1-2 egg galleries, the
egg niches and the nuptial chamber (if present).
Egg gallery: a single extension of the adult gallery from the nuptial chamber (if present) along
which eggs are deposited in niches.
Egg niche: Notches along the sides of the egg gallery excavated by females in which as single
egg is deposited.
Larval mine: the excavation tunnel produced by the larva as it feeds.
Nuptial chamber: an enlarged area or short extension from the adult gallery at the base of the
entrance tunnel that may be used for mating or as a turning niche.
Pupation chamber: an ovoid or circular excavation at the end of a larval mine in which
pupation occurs.

Key to the adults of Nearctic Scolytus Geoffroy
This is the first key to Nearctic Scolytus adults of both sexes. Unlike previous keys (e.g.
Edson 1967; Wood 1982) apriori knowledge of the gender is not required. Only one sex is

36

necessary to identify the specimen and host or gallery information are not needed. Because the
sexual dimorphic characters are not consistent for the Nearctic species (see sexual dimorphism
discussion above), the sexes could not be evenly split. In general, males and females of native
hardwood-feeding species will key out beginning at couplet 3 and females and males of some
Abies feeding species beginning at couplet 23. The key lists the gender of the identified
specimen. If no gender is designated, the identification applies to both males and females. The
length of setae on the frons is measured relative to the midpoint of the eye.

1

Elytral apices rounded (Figure 1.15A) ………………………Scolytus rugulosus (Müller)

-

Elytral apices truncate (Figure 1.15B)…………………………………………………….2

2 (1)

Lateral profile of frons clearly flattened and/or impressed (Figure 1.9A)………………..3

-

Lateral profile of frons convex (Figure 1.9B) …………………………………………..23

3 (2)

Apical margin of sternite 3 and/or 4 armed with teeth or spines laterally and/ or medially
………………………………………………………………………….…………………4

-

Apical margin of sternite 3 and 4 unarmed……………………………………………….7

4 (3)

Apical lateral margins of sternites 3 and 4 armed with lateral teeth or spines………...….5

-

Apical lateral margins of sternites 3 and 4 unarmed………………………………………6

5 (4)

Apical margin of sternite 3 armed by three acute spines (two lateral and one medial);
apical margin of sternite 4 armed by one median tooth; sternite 1 apically descending;
sternite 2 deeply concave, basal margin produced and bearing a median tubercle………...
……………………….……………………………….Scolytus quadrispinosus Say (male)

37

-

Apical margin of sternite 3 and 4 each armed by two lateral teeth; sternite 1 horizontal;
sternite 2 convex and bearing a blunt median tubercle on the basal margin………………
…………………………………………………...Scolytus multistriatus (Marsham) (male)

6 (4)

Apical margin of sternite 4 armed by an acute median denticle; apical margins of sternites
2 and 3 may also each bear a smaller median denticle (variable)…………………………
……………………………………………………………Scolytus dentatus Bright (male)

-

Apical margin of sternite 4 thickened forming a broad carina with a blunt median
tubercle; apical margins of sternites 2 and 3 always unarmed ……………………………
…………………………………………………………..Scolytus silvaticus Bright (male)

7 (3)

Abdominal venter sternites 2-4 covered with abundant erect long hair-like setae…………
……………………………………………………………………………….…………….8

-

Abdominal venter sternites 2-4 glabrous or covered with minute ground vestiture or
short, sparse recumbent hair-like or scale-like setae ……………………………………10

8 (6)

Frons with hair-like setae on lateral and dorsal margins thicker, longer, incurved,
remaining areas of frons largely devoid of setae; frons strongly longitudinally aciculate
……………………………………………………………………….Scolytus muticus Say

-

Frons with equally distributed hair-like setae of uniform length; frons weakly to
moderately longitudinally aciculate or weakly aciculate-punctate……………………..9

9 (8)

Apical margin of elytra produced between interstriae 1 and 2, deeply emarginated at
interstria 3, produced on interstria 4 and deeply emarginated at stria 4; sternite 2 armed
with a laterally compressed tubercle that extends from the apical margin of sternite 2 to
approximately ¾ the length of sternite; frons weakly longitudinally aciculate, strongly
punctate; epistoma strongly emarginated…………………..Scolytus aztecus Wood (male)

38

-

Apical margin of elytra slightly emarginated at interstriae 3; apical margin of sternite 2
armed with a median denticle; frons moderately longitudinally aciculate, almost
impunctate; epistoma entire to faintly emarginated.………Scolytus mundus Wood (male)

10 (7) Apical margin of sternite 1 rounded; basal margin of sternite 2 flat or marked by a weak
carina; face of sternite 2 convex, often armed with a spine or tubercle…………………11
-

Apical margin of sternite 1 thickened or produced on the ventral and/or lateral margins,
forming a carinate lip along the basal margin of sternite 2, often weakly produced in S.
monticolae and S. tsugae; face of sternite 2 flat to impressed…………………….……19

11 (10) Frons impressed above epistoma or medially impressed, strongly longitudinally aciculate
……………….…………………………………………………………………………..12
-

Frons flat, weakly to moderately longitudinally aciculate or coarsely punctate ……….15

12 (11) Sternite 2 unarmed; elytral surface shining and glabrous………………………….………
…………………………………………………………...Scolytus mali (Bechstein) (male)
-

Sternite 2 armed with a spine; elytral surface dull, sparse setae present (rarely the spine
on sternite 2 is absent in S. schevyrewi) …………………………………………………13

13 (12) Base of spine touching apical margin of sternite 2; frons strongly longitudinally aciculate
…………………………………………………………..Scolytus laricis Blackman (male)
-

Base of spine not touching apical margin of sternite 2; frons strigose-punctate.………14

14 (13) Spine conical, narrow; elytra always unicolorous; elytral disc shining and glabrous;
subapical carina on sternite 5 located 1/2 width of segment from apex……………………
……………………………………………………………Scolytus piceae (Swaine) (male)

39

-

Spine broadly conical with blunted apex; elytra often with a banded appearance;
subapical carina on sternite 5 located just before end of segment…………………………
………………………………………………………Scolytus schevyrewi Semenov (male)

15 (11) Sternite 2 armed with a rounded spine…………………………………………………..16
-

Sternite 2 unarmed……………………………………………………………………….17

16 (15) Spine on sternite 2 extending from apical margin to three-fourths length of the sternite;
sternite 2 surface shining………………………………... Scolytus fiskei Blackman (male)
-

Spine on sternite 2 extending from apical margin to one half length of the sternite;
sternite 2 surface dull ……………………………….Scolytus unispinosus LeConte (male)

17 (15) Sternite 5 length at middle longer than or equal to that of sternites 3 and 4 combined;
sternite 5 without a transverse carina near base …………………………………………18
-

Sternite 5 length at middle shorter than that of sternites 3 and 4 combined; sternite 5 with
a transverse carinate ridge near base that may or may not be reflexed (variable) …………
…………………………………………………………Scolytus reflexus Blackman (male)

18 (17)

Frons either granulate or faintly longitudinally aciculate; frons with setae
uniformly distributed, fewer setae on lateral and dorsal margins, shorter, finer; elytra
glabrous (except on declivity); sternite 5 unarmed……………Scolytus fagi Walsh (male)

-

Frons moderately longitudinally aciculate, with long, fine, incurved setae predominately
on lateral and dorsal margins, fewer, shorter and finer setae medially; elytra with minute
ground vestiture……………………………………Scolytus quadrispinosus Say (female)

19 (10) Apical margin of sternite 1 moderately produced and not forming a distinct lip along
base of sternite 2…………………………………………………………………………20

40

-

Apical margin of sternite 1 distinctly thickened or strongly produced forming a lip along
base of sternite 2…………………………………………………………………………21

20 (19) Face of sternite 2 shining but minutely reticulate; elytral striae not impressed; basal
margin of sternite 2 more pronounced and produced laterally; elytral strial punctures
small, spaced 2-3 diameters of a puncture …………Scolytus monticolae (Swaine) (male)
-

Face of sternite 2 opaque; elytral discal striae impressed; basal margin of sternite 2
continuously and evenly elevated; elytral strial punctures large, spaced 1-2 diameters of a
puncture………………………………….………………Scolytus tsugae (Swaine) (male)

21 (19) Apical margin of sternite 1 distinctly thickened at most slightly produced over base of
sternite 2 ……………………………………………………………………………….22
-

Apical margin of sternite 1 strongly acutely produced forming a lip along base of sternite
2, face of sternite 2 appearing concave………………Scolytus robustus Blackman (male)

22 (21) Base of sternite 2 strongly thickened; face of sternite 2 often weakly medially impressed
just above the base; apical margin of sternite 2 unarmed…………………………………
…………………………………………………………Scolytus oregoni Blackman (male)
-

Base of sternite 2 faintly elevated; face of sternite 2 flat; apical margin of sternite 2
slightly elevated often with a median denticle…………Scolytus ventralis LeConte (male)

23 (2) Apical margin of elytra produced between interstriae 1 and 2, deeply emarginated at
interstria 3, produced on interstria 4 and deeply emarginated at stria 4 ………………
……………………………………………………………Scolytus aztecus Wood (female)
-

Apical margin of elytra entire or slightly emarginated at interstriae three………………24

24 (23) Sternite 2 armed either on the face or on apical margin by either a spine or a low median
tumescence ………………………………………………………………………………25

41

-

Sternite 2 unarmed………………………………………………………………….……35

25 (24) Sternite 2 face armed with a rounded, keel shaped or broadly acute spine that is at least as
long as its basal width …………………………………………………………………...26
-

Sternite 2 apical margin armed by a low median tumescence or small denticle ………..30

26 (25) Base of spine on sternite 2 touches the basal margin of segment; apical margins of
sternites 3 and 4 each armed by two lateral teeth ………………………………………….
…………………………………………………Scolytus multistriatus (Marsham) (female)
-

Base of spine on sternite 2 never touches basal margin of segment; apical margins of
sternites 3 and 4 unarmed………………………………………………………………..27

27 (26) Base of spine not touching apical margin of sternite 2.…………………………………28
-

Base of spine touching apical margin of sternite 2.……………………………………..29

28 (27) Spine conical, narrow; elytra always unicolorous; elytral disc shining and glabrous;
subapical carina on sternite 5 located 1/5 width of segment from apex……………………
……………………………………………………………Scolytus piceae (Swaine) (male)
-

Spine broadly conical with blunted apex; elytra often with a banded appearance;
subapical carina on sternite 5 located just before end of segment…………………………
……………………………………………………Scolytus schevyrewi Semenov (female)

29 (27) Sternite 2 armed with a stout and broadly acute spine and extending from the apical
margin to one half length of the sternite, never with a longitudinal carina………………
…………………………………………………………Scolytus fiskei Blackman (female)
-

Sternite 2 armed with a longitudinal carina and a blunt tubercle, appearing keel-shaped,
or a low median longitudinal carina…………………Scolytus praeceps LeConte, in part

42

30 (25) Apical margin of sternite 1 produced, forming a carinate lip along the basal margin of
sternite 2; sternite 2 appearing impressed……………………………………………… 31
-

Apical margin of sternite 1 rounded; basal margin of sternite 2 flat or marked by a weak
carina; face of sternite 2 convex………………………………………………………... 34

31 (30) Apical margin of sternite 2 weakly longitudinally tumescent, never pointed.……………..
…………………………………………………………Scolytus praeceps LeConte (male)
-

Apical margin of sternite 2 with a small median denticle………………………………32

32 (31) Apical margin of sternite 1 slightly elevated; sternite 2 appearing convex; median
denticle on apical margin of sternite 2 broad, broadly pointed……………………………
…………………………………………………………Scolytus mundus Wood (female)
-

Apical margin of sternite 1 strongly acutely produced, forming a lip along the base of
sternite 2, face of sternite 2 appearing impressed, median denticle on apical margin of
sternite 2 narrow, acutely pointed ……………………………………………………..33

33 (32) Second sternite punctures abundant, fine and moderately impressed, appearing distinct;
second sternite subopaque;………………………………………Scolytus obelus Wood
-

Second sternite punctures sparse, fine and shallow, almost appearing indistinct; second
sternite appearing strongly opaque…………………Scolytus subscaber LeConte (male)

34 (30) Frons finely longitudinally aciculate-punctate; sternite 1 joining base of sternite 2 more
obtusely, base of sternite 2 not finely impressed, flush with sternite 1; epistomal process
weakly developed, almost indistinct ……………Scolytus unispinosus LeConte (female)
-

Frons moderately and coarsely longitudinally aciculate-punctate; sternite 1 rounded over
onto face of sternite 2, not forming an obtuse angle, base of sternite 2 finely impressed…
……………………………….………….……………Scolytus laricis Blackman (female)

43

35 (24) Epistomal process absent………………………………………………………………...36
-

Epistomal process present, may be indistinct……………………………………………37

36 (25) Frons weakly longitudinally aciculate, strongly punctate, with uniformly distributed long
setae; elytral striae weakly impressed……………………….Scolytus fagi Walsh (female)
-

Frons finely longitudinally aciculate and glabrous or minutely setose; elytral striae not
impressed ……………………………………………...Scolytus mali (Bechstein) (female)

37 (35) Setae on frons at least 1.5 times the width of the eye at the middle……………………..38
-

Setae on frons equal in length to the width of the eye at the middle…………………….42

38 (37) Venter sternites 2-5 shining; thorax and apical and lateral margins of elytra covered with
long hair-like setae as long as the width of sternites 3 and 4 combined, with pointed
apices …………………………………………………………………………………….39
-

Venter sternites 2-5 opaque; thorax covered with setae as long as the width of sternite 3,
with quadrate apices ……………………………………………………………………..41

39 (38) Epistomal process weakly developed, and faintly emarginated medially.………………...
………………………………………………………….Scolytus hermosus Wood (female)
-

Epistomal process strongly developed, and strongly emarginated medially…………….40

40 (39) Apical margin of sternite 1 produced, forming a carinate lip along the basal margin of
sternite 2 that is about half as produced as thick; Pseudotsuga menziesii………………….
………………….……………………………………...Scolytus silvaticus Bright (female)
-

Apical margin of sternite 1 produced, forming a carinate lip along the basal margin of
sternite 2 that is twice as produced as thick; Abies religiosa……………………………..
…………………………………………………………... Scolytus hermosus Wood (male)

44

41 (38) Frons distinctly, moderately longitudinally aciculate, weakly punctate; apical margin of
sternite 1 weakly produced, forming a weak carinate lip along the basal margin of sternite
2……………………………………………………..Scolytus subscaber LeConte (female)
-

Frons indistinctly, weakly longitudinally aciculate, strongly punctate; apical margin of
sternite 1 flush with basal margin of sternite 2, appearing rounded………………………
………………………………………………………..Scolytus ventralis LeConte (female)

42 (37) Apical margin of sternite 1 rounded; sternite 2 face rugose, shining, coarsely punctate
and convex…………………………………………..Scolytus reflexus Blackman (female)
-

Apical margin of sternite 1 with thickened lip or produced, never rounded; sternite 2 face
smooth and flat …………………………………………………………………………43

43 (42) Apical margin of sternite 1 thickened, on face of sternite 2 and nearly flush with the face
of sternite 2…………………………………………Scolytus oregoni Blackman (female)
-

Apical margin of sternite 1 not thickened or on the face of sternite 2, often slightly
apically produced (unequally carinate in S. monticolae)………………………………...44

44 (43) Sternite 2 punctulate with small or minute, shallow punctures………………………….45
-

Sternite 2 distinctly punctate with large and deep punctures ……………………………47

45 (44) Apical margin of sternite 1 equally and continuously carinate…………………………….
………………………………………………Scolytus praeceps LeConte, in part (female)
-

Apical margin of sternite 1 unequally carinate, more produced laterally forming cusps on
each side of sternite 2…………….………………………………………………………46

46 (45) Elytral discal striae not impressed; sternite 2 shining in luster…….………………………
……………………………………………………Scolytus monticolae (Swaine) (female)

45

-

Elytral discal striae impressed, giving the elytra a corrugated appearance; sternite 2 dull
in luster ………..………………………………………Scolytus tsugae (Swaine) (female)

47 (44) Sternite 2 shining………………………………….Scolytus robustus Blackman (female)
-

Sternite 2 dull, opaque………………………………………………………………… 48

48 (47) Epistomal process strongly developed, distinct; frons evenly convex……………………
…………………………………………………………Scolytus dentatus Bright (female)
-

Epistomal process weakly developed, almost indistinct; frons flattened or convex with
slight medial depression………………………………Scolytus praeceps LeConte, in part

Species Descriptions
Species are redescribed and treated alphabetically by clade or group beginning with the
introduced group, native hardwood clade and conifer clade. Common names listed are the
official common names of the Entomological Society of America and/or Canada.

Introduced Species Group
The introduced species group (1.9-4.2mm long) (S. mali, S. multistriatus, S. rugulosus
and S. schevyrewi) is not monophyletic and consists of a morphologically diverse group of
Palearctic species that encompasses three formerly recognized species groups/subgenera (von
Butovitsch 1929; Balachowsky 1949). This diversity is reflected in the sexual dimorphism
exhibited by species in the group. Scolytus multistriatus and S. schevyrewi exhibit the typical
dimorphic pattern of the frons as discussed above. The lateral teeth and spine are identical in
both sexes of S. multistriatus and the spine on sternite 2 is smaller in the female compared to the
male. Sexual dimorphism of S. mali and S. rugulosus is much more subtle and differentiating the

46

sexes can be challenging. Scolytus mali males have the medial area of the frons and epistomal
regions impressed and the lateral margins of the epistoma are lightly covered with more
abundant erect setae than the female. Scolytus rugulosus males have the medial area of the frons
and epistoma slightly more impressed and the frons bearing longer more abundant erect setae.

Scolytus mali (Bechstein)
(Figures 1.16, 1.17)
Bostrichus mali Bechstein 1805: 882. Syntypes (location unknown).
= Scolytus sulcatus LeConte 1868: 167. Holotype: male labeled “[pink disc = Middle
States (Md., Del., N.Y., N.J., Pa., Conn.?, R.I.?)]; type 969." Synonymy: Brown 1950:
203.
For complete taxonomic history see Wood and Bright (1992).
Diagnosis. Both sexes of S. mali are distinguished by having sternite 2 at an oblique angle to
sternite 1, the aciculate frons, with most setae found just above the epistoma and on the lateral
epistomal margins.
Redescription (male). 3.2 – 4.1mm long (mean = 3.7mm; n = 10); 2.1 - 2.5 times as long as
wide. Head, pronotum and abdominal venter dark red-brown, legs and antennae light brown,
elytra brown to red-brown. Pronotum typically darker than elytra.
Epistoma weakly and broadly emarginated; epistomal process absent; median area above
mandibles bearing a dense patch of long yellow hair-like setae. Frons appearing convex when
viewed laterally, moderately transversely impressed above epistoma and longitudinally
impressed near median line; surface densely and finely longitudinally aciculate-punctate;
aciculations converging at epistoma; punctures small, coarse; surface sparsely covered by long,

47

fine, yellow erect hair-like setae, setae as long as the midpoint of the eye and more abundant
along the epistoma. Antennal scape short, elongate, less than length of the first four funicular
segments; club flattened, irregularly ovoid, setose with a partial septum and two arcuate sutures.
Pronotum wider than long; apical margin broadly rounded, area between the eyes lined
with scales; sides distinctly arcuate, strongly constricted near apex, and forming a weak
transverse impression near apical margin; surface smooth, shining, punctures on disc fine,
shallow and moderately abundant, lager and more abundant laterally and on apical constriction;
apical and anterolateral margins bearing sparse, erect yellow hair-like setae; base weakly
bisinuate.
Elytral sides sub-parallel on apical half, narrowing to a weakly rounded and smooth apex;
apical margin of elytral apices bearing small, fine punctures; apex weakly emarginated at the
suture. Disc smooth, shining; interstriae weakly impressed and more than twice the width of
striae, interstrial punctures uniseriate, smaller than those of striae, interstrial punctures bearing
sparse, long, semi-erect yellow hair-like setae (may have worn off); striae weakly impressed.
Declivity bearing sparse, short, erect yellow setae. Metepimeron greater than half-length of
metepisternum.
Apical margin of sternite 1 weakly elevated above the base of sternite 2. Sternite 2 nearly
at an oblique angle to sternite 1; surface smooth, shining, finely punctate with small, fine and
shallow punctures; face convex, unarmed; setae erect, short, about half of sternite 3 width in
length; lateral margins of sternites 2-4 and sternite 4 unarmed. Sternite 5 unarmed; length of
sternite 5 equal to the combined lengths of sternites 3 and 4; a setal patch is absent and a median
depression is present.

48

Female. 3.0 – 4.2mm long (mean = 3.7mm; n = 10); 2.0 - 2.5 times as long as wide. Similar to
male except epistoma feebly emarginated, frons more strongly convex when viewed laterally,
weakly aciculate, setae shorter, less than the width of the eye and less abundant.
Specimens examined. 110.
Type material. Holotype Scolytus sulcatus LeConte (MCZC).
Non-type material. CANADA: ONTARIO: Hamilton, 14-21.VI.1981, M. Sanborne (CNCI-2),
23.VII.1980, ex. malaise trap (CNCI-1). Owen Sound, 27.V.[19]65, K.E. Stewart, ex. elm [=
Ulmus sp.] (CNCI-1). Vineland Station, 8.VI.1949, W.L. Putnam, ex. apple [= Malus sp.]
(CNCI-2). QUEBEC: Cantic, 11.VIII.1945, W.J. Brown, ex. apple [= Malus sp.] (CNCI-2). CapSaint-Ignace, VII.1970 (CNCI-1). Dunham, 2.IX.1998, Vignoble, L’Orpailleur,
ECORC/CRDHAg-Cord (DEBC-1). Napierville, 2mi N.E., 13.VIII.1945, W.J. Brown (CNCI-1).
Noyan, 0.75mi W., 15.VIII.1945, W.J. Brown (CNCI-1). UNITED STATES:
CONNECTICUT: [Fairfield Co.]: Greenwich, 22.VII.1933, F.J. Dillaway, ex. in plum [=Prunus
sp.] (USNM-2). New Haven Co.: New Haven, 25.VI.1956, C.W. O’Brien (EMEC-1). MAINE:
[Androscoggin Co.]: Livermore Falls, 5.VIII.1975, ex. plum [=Prunus sp.] (USNM-1).
MARYLAND: Montgomery Co.: Ashton, 4mi S.W., 31.V.1986, G.F. & J.F. Hevel, ex. malaise
trap (USNM-1). MASSACHUSETTS: Worchester Co.: 16.II.[19]53, ex. indoors (USNM-2).
MICHIGAN: Allegan Co.: Fennville area, 30.VI.2003, P. McGhee, ex. apple trees [= Malus sp.]
(MSUC-6). Genesee Co.: Richfield County Park, N43°100610, W-83°.55810, 16.VI.2008, R.
Mech, PI Anthony Cognato (MSUC-1). Ingham Co.: Lansing, 2mi N., E. State Rd., N42.7842°
W84.5362°, 261m, 2-18.VI.2007, PI Anthony Cognato, ex. Lindgren trap with ipslure (MSUC1). Kalamazoo Co.: Gourdneck Lake State Game Area, 16.VII.2011, S.M. Smith, A.I. Cognato,
ex. Prunus sp. (MSUC-2). Oakland Co.: Farmington Hills, N42°27.668’ W83°25.579’,

49

2.VII.2004, B. Sullivan, ex. Lindgren funnel with multistriatus lure (MSUC-2). Saginaw Co.: St.
Charles, 25.VI.1968, J.G. Truchan, ex. rotary trap (MSUC-1), 25.VI.1969 (MSUC-1). Wayne
Co.: 20.VI.1960, G. Steyskai (USNM-2). NEW JERSEY: [Essex Co.]: Maplewood, 7.VI.[19]34,
D. Fivaz, ex. on elm [=Ulmus sp.] (USNM-12). [Morris Co.]: Chatham, 25.III.[19]34, W.D.
Buchanan (USNM-1). NEW YORK: Albany Co.: Near Rensselaerville, Huyck Preserve, 310.VII.1967, R. &J. Matthews, ex. window pane trap (CNCI-1). [Suffolk Co.]: Cutchogue,
[19]45, Tuthill ,ex. in apple [=Malus sp.] (USNM-26). [Tompkins Co.]: Groton, 24.V.1942, N.M.
Downie (FMNH-1), 23.VI.1946 (FMNH-2). [Westchester Co.]: Armonk, 5.VI.[19]35, H.
Dietrich, ex. apple [= Malus sp.] (CNCI-2). OHIO: Medina Co.: 15.VI.[19]62, C.L. Griswold
(DEBC-4). PENNSYLVANIA: Luzerne Co.: Nanticoke, 20.IX.[19]60, ex. Malus sp. (CNCI-1).
Nuangola, 12.V-23.VIII.1983, S. & J. Peck, ex. forest intercept (CNCI-1). WASHINGTON
D.C.: 5.IV.1983, E.R. Hodges, ex. on sweater of collector (USNM-1). ADDITIONAL
SPECIMENS: Czech Republic (MSUC-21) and Italy (MSUC-1).
Distribution. CANADA: Ontario, Quebec. UNITED STATES: Connecticut, Maine,
Massachusetts, Michigan, New York, Ohio, Pennsylvania, Washington D.C.
Hosts. Malus spp. (apple), Prunus spp. (cherry), Ulmus spp. (elm), Pyrus spp. (pear), and Sorbus
spp. (mountain ash).
Common name. Large shothole borer.
Biology. This species colonizes dying and weakened limbs of its host as well as fresh slash.
Typical host material is 15-38cm in diameter but branches as small as 8cm are colonized
(Pechuman 1938).
Adult galleries of S. mali are somewhat variable and are either parallel with the grain of
the wood or at a slight oblique angle. Galleries consist of a nuptial chamber and a single egg

50

gallery. The adult gallery strongly scores the sapwood and range in size from 3.5-6.0cm in
length. Egg niches are constructed along the gallery and score the sapwood. Six to 100 eggs may
be laid along the egg galleries with the typical gallery having 40 eggs. Larval mines lightly score
the sapwood and radiate perpendicular to the egg gallery. The larval galleries later meander often
at an oblique angle to the grain of wood, forming a fan shaped pattern. Pupation occurs within
the sapwood and broods can overwinter as larvae. The following year, adults emerge and feed at
twig crotches before selecting host material (Pechuman 1938; Balachowsky 1949; Baker 1972;
Wood 1982). In New York, S. mali has one generation per year although there are two
generations per year in temperate Europe (Pechuman 1938).
Collection notes. The author collected this species from an 8cm diameter Prunus sp. branch that
broke during a recent windstorm. Females constructed gallery entrances beneath large flakes of
bark on the sides and bottom surfaces of the branch. Specimens were infesting the same limbs as
Phloeotribus liminaris (Harris) 1852.
Remarks. This species is native to the Palearctic region and was first detected in New York in
1868 when it was described as S. sulcatus LeConte (1868). LeConte (1868) noted in his
description that the species most strongly resembled the Palearctic species S. rugulosus and did
not mention the collection date of the specimens. Interestingly no other specimens of the species
were collected until 1933, 65 years after the initial discovery. These specimens were collected
from southeastern New York, northern New Jersey and western Connecticut. It is likely that like
LeConte’s S. califonicus (=S. scolytus), S. mali was collected in 1868 but populations never
became established. The later collections may be the result of multiple introduction events
(Pechuman 1938).

51

Brown (1950) recognized that LeConte’s species was morphologically and behaviorally
identical to that of S. mali and placed S. sulcatus into synonymy. The native range of S. mali is
Europe (except the Scandinavian Peninsula), Central Asia, Siberia and the Russian Far East
(Michalski 1973).

Scolytus multistriatus (Marsham)
(Figures 1.18, 1.19)
Ips multistriatus Marsham 1802: 54. Syntypes (location unknown).
= Scolytus javanus Chapuis 1869: 56. Holotype male, labeled “Java, Solier, Dejean”
(ISNB). Synonymy Schedl 1954: 137.
For complete taxonomic history see Wood and Bright (1992).
Diagnosis. Both sexes of the species are distinguished by the presence of lateral teeth on the
apical margins of sternites 2-4 and by a median conical spine on the basal margin of sternite 2.
Redescription (male). 2.2 – 3.9mm long (mean = 2.81mm; n = 20); 2.0 - 2.6 times as long as
wide. Head, pronotum, and abdominal venter dark red-brown, legs light brown, antennae yellowbrown, elytra usually dark red-brown but may be brown. Color is not uniform and the surface
frequently contains patches of red-brown mixed with dark red brown. Pronotum typically darker
than elytra.
Epistoma weakly and broadly emarginated; epistomal process absent; median area above
mandibles bearing a dense patch of long yellow hair-like setae. Frons appearing flattened when
viewed laterally; surface moderately and coarsely longitudinally aciculate-punctate; aciculations
converging at epistoma; punctures small, coarse; surface moderately and uniformly covered by
long, fine, yellow erect hair-like setae, setae longer than the midpoint of the eye. Antennal scape

52

short, elongate, less than length of the first four funicular segments; club flattened, thinner on
apical half, irregularly ovoid, setose with a partial septum and two sharply arcuate sutures.
Pronotum wider than long; apical margin broadly rounded, area between the eyes lined
with scales; sides distinctly arcuate, strongly constricted near apex, and forming a weak
transverse impression near apical margin; surface smooth, shining, punctures on disc fine,
shallow and moderately abundant, lager and more abundant laterally and on apical constriction;
apical and anterolateral margins bearing sparse, erect yellow hair-like setae; base weakly
bisinuate.
Elytral sides sub-parallel on apical half, narrowing to a subquadrate and smooth apex;
apical margin of elytral apices bearing small, fine punctures; apex entire the suture. Disc smooth,
shining; interstriae weakly impressed and more than twice the width of striae, interstrial
punctures uniseriate, smaller than those of striae, interstrial punctures bearing sparse, long, semierect yellow hair-like setae (may have worn off); striae weakly impressed. Declivity bearing
sparse, short, erect yellow setae. Metepimeron greater than half-length of metepisternum.
Apical margin of sternite 1 weakly elevated above the base of sternite 2. Sternite 2 nearly
perpendicular to sternite 1; surface smooth, shining, finely punctate with small, coarse punctures;
face flattened; basal margin armed with a long, smooth, conical spine with it’s extending from
the basal margin to half the segment; each lateral margin of sternites 2-4 armed with a lateral
tooth. Sternite 4 unarmed. Sternite 5 carinate ridge closer to the apical margin than the basal
margin of the segment; length of sternite 5 greater than the combined lengths of sternites 3 and 4;
a setal patch or median depression is absent.

53

Female. 2.4 – 3.3mm long (mean = 2.95mm; n = 20); 2.2 - 2.7 times as long as wide. Similar to
male except epistoma feebly entire, frons strongly convex when viewed laterally, weakly
aciculate, setae shorter, less than the width of the eye and less abundant.
Specimens examined. 165.
Type material. Holotype Scolytus javanus Chapuis (ISNB).
Non-type material. CANADA: ALBERTA: Calgary, 19.VII.[19]94, T. Reichardt, ex. pheromone
trap no. EBB XI (CNCI-2). ONTARIO: St. Catherines, 22.VI.1961, Kelton, Brumpton (CNCI1). Toronto, 1970, ex. reared on elm [= Ulmus sp.] (CNCI-1). Queenston, 26.VI.[19]50, ex. elm
[= Ulmus sp.] (CNCI-1). QUEBEC: Montreal, 14.VII.1977, E.J. Kiteley (CNCI-1); Ile de
Montreal, Ile de Sainte Hélène, 12.VIII.1985, L. Lariviere (CNCI-1). MEXICO:
CHIHUAHUA: Cuidad Juarez, II.1987, I.C. Rodriguez (CNCI-2). UNITED STATES:
CALIFORNIA: [Alameda Co.]: Berkeley, 23.V.1962, ex. elm [=Ulmus sp.] (EMEC-2). Contra
Costa Co.: Antioch [Dunes] National Wildlife Refuge, 10.X.[19]91, J.A. Powell (EMEC-1).
Fresno Co.: 11.I.1950, N.J. Smith (SBMN-2). Inyo Co.: Big Pine, 4000ft, V.1971, D. Guiliani,
ex. black light (CASC-1), VII.1971 (CASC-1). COLORADO: Mesa Co.: Grand Junction,
X.1979, D. Leatherman, ex. European ash [=Fraxinus sp.] (CSUC-1). Weed Co.: Briggsdale,
1.IX.198, D. Leatherman (CSUC-1). GEORGIA: Clarke Co.: Whitehall forest, 17-24.IX.1976,
R. Turnbow, ex. window trap F-8 (CNCI-1). ILLINOIS: Alexander Co.: Horseshoe Lake,
28.IX.1968, T.E. Brooks (CNCI-4). KENTUCKY: Green Co.: 9.VII.1941, C. Cook (MSUC-1).
MASSACHUSETTS: [Hampshire Co.]: Northampton, 10.VIII.1974, E.J. Kiteley (MSUC-1).
[Suffolk Co.]: Forest Hills [=Boston], 3.VI[?], W.M. Mann (USNM-1). MICHIGAN: Antrim
Co.: Eastport, ca. 3mi N., N45°08’30” W85°22’50”, 3-5.VII.2003, F.W. Stehr, ex. UV light
(MSUC-1). Cass Co.: Cassopolis, 2.VI.2007, A.D. Smith (MSUC-3). Genesee Co.: Richfield

54

County Park, N43.100610° W-83.55810°, ex. Lindgren with EtOH (MSUC-1). Ingham Co.:
Lansing, 2mi N., E. State Rd., N42.7842° W84.5361°, 261m, 16-30.VII.2007, PI A.I. Cognato
(MSUC-1); G.L. Parsons, ex. UV light. & white lights (MSUC-1). East Lansing, 1.X.1957, R.C.
Fox (MSUC-1), 2.X.1957 (MSUC-5), 3.X.1957 (MSUC-7), 4.X.1957 (MSUC-1), 5.X.1957
(MSUC-3), 6.X.1957 (MSUC-4), 10.X.1957 (MSUC-1), 15.X.1957 (MSUC-5); 25.VI.1981, R.
Fischer (MSUC-1); N42°11.320’ W84°27.867’, 258m, 16.IX.2011, S.M. Smith, A.I. Cognato,
I.A. Cognato, ex. Ulmus sp. (MSUC-7); Michigan State University campus, 17.VI.2011, D.G.
McCullough (MSUC-3). Kalamazoo Co.: Gourdneck Lake State Game Area, 19.VI.2011, A.I.
Cognato, ex. Ulmus sp. (MSUC-21). Kalkaska Co.: T27N R7W S18, 28.XII.1986, P. Waclawski,
ex. basement wood (MSUC-1), 20.XII.1987 (MSUC-1), 3.I.1987 (MSUC-5). Lapeer Co.: Potter
Lake, 19.VI.1967, Brivio (MSUC-2). Macomb Co.: East of Memphis, 3.V.1964, C. Brivio
(MSUC-1), 17.VI.1965 (MSUC-1), 21.VIII.[19]66 (MSUC-2), 23.VIII.1969 (MSUC-1),
30.VIII.1969 (MSUC-1). Saginaw Co.: St. Charles, 30.V.1969, J.H. Truchan, ex. rotary trap at
6ft height level (MSUC-2), 11.VI.1969, ex. rotary trap at 12ft height level (MSUC-1),
16.VI.1969 (MSUC-3). Sanilac Co.: Port Sanilac, 20.VI.1986, Brivio (MSUC-1). MONTANA:
Choteau Co.: Great Falls, VII-VIII.1977, S. Kohler, ex. caught in flight, sticky trap, multilure
bait (CNCI-1). Gallatin Co.: Bozeman, VII-VIII.1977, S. Kohler, ex. caught in flight, sticky trap,
multilure bait (CNCI-1). NEW YORK: [Westchester Co.]: Yonkers, VIII.1935, H. Dietrich, ex.
elm [=Ulmus sp.] (CNCI-3). OKLAHOMA: [Oklahoma Co.]: Jones, 13.VI.1957, D. Alexander
(USNM-1). TEXAS: [El Paso Co.]: El Paso, 045483, 17.VII.[19]94, lot 94 07975, ex. Mexico –
in log of Prunus sp. (USNM-10). WYOMING: Carbon Co.: Medicine Bow National Forest, VIVIII.1999, ex. Polyphorus volvatus [=Cryptoporus volvatus (Peck) Shear] (CSUC-1).

55

ADDITIONAL SPECIMENS: Czech Republic (MSUC-2), Italy (MSUC-8) and Russia
(MSUC-22).
Distribution. CANADA: Alberta, Manitoba, Ontario, Quebec. MEXICO: Chihuahua. UNITED
STATES: Alabama, Arizona, Arkansas, California, Colorado, Florida, Georgia, Idaho, Illinois,
Indiana, Kansas, Kentucky, Louisiana, Maryland, Massachusetts, Michigan, Missouri, Montana,
New Jersey, New Mexico, New York, Nevada, Ohio, Oklahoma, Pennsylvania, Rhode Island,
South Dakota, Texas, Utah, Virginia, Washington D.C., Wyoming.
Hosts. All native and introduced Ulmus spp. including U. americana L. (American elm) and
Zelkova serrata (Thunb.) Makino.
Common names. Smaller European elm bark beetle and the European elm bark beetle.
Biology. Scolytus multistriatus colonizes cut, stressed, weakened and diseased elm trees (Ulmus
spp.) (Wood 1982). It seldom attacks healthy and vigorous trees (Bright 1976). Scolytus
multistriatus females produce an aggregation pheromone to aggregate conspecifics to host trees.
The pheromone bouquet is composed of three components: (-)-4-methyl-3-heptanol, (-)-2,4dimethyl-5-ethyl-6,8-dioxabicylo[3.2.1]octane (α)-multistriatin and (-)-α-cubebene (Pearce et al.
1975).
The adult gallery is excavated parallel to the grain of the wood and consists of a single
egg gallery without a nuptial chamber. The adult gallery ranges in size from 2.5-5.0cm in length.
Egg niches are constructed along the gallery and score the sapwood. Twenty four to 96 eggs may
be laid singly along the egg gallery. Larval mines lightly score the sapwood and radiate
perpendicular to the egg gallery. The larval galleries later meander often at an oblique angle to
the grain of wood, forming a fan shaped pattern. Larvae construct pupal chambers in the bark
(Bright 1976).

56

There are one and one-half generations per year in Canada and three in the southern US
(Furniss and Johnson 2002). In Canada, adults emerge in June and July and feed at twig crotches
of healthy trees for 7-10 days before selecting host material (Chamberlin 1958; Baker 1972). The
brood from these adults either emerges in August or September or overwinters as larvae.
Scolytus multistriatus is the principal vector of the Dutch elm disease fungus Ceratocystis
ulmi (Buisman) C. Moreau in North America. This beetle vectored disease killed 50-75% of the
elms population in northeastern North America prior to the 1930s (Bloomfield 1979). S.
multistriatus adults become covered in fungal spores upon emergence from brood material.
Adults inoculate elms with the Dutch elm disease fungus as they feed in twig crotches. The
feeding activity leaves wounds in the bark that allow spores to be transferred from the beetle’s
cuticle to the tree tissues (Bright 1976).
Collection notes. None.
Remarks. This species is native to the Palearctic region and is primarily distributed throughout
Europe but also occurs in Iran and Algeria. Scolytus multistriatus was first detected in North
America in 1909 from elm trees on the Harvard University campus in Massachusetts (Chapman
1910).

Scolytus rugulosus (Müller)
(Figures 1.20, 1.21)
Bostrichus rugulosus Müller 1818: 247. Syntypes: (IRSNB, ZIFH).
For complete taxonomic history see Wood and Bright (1992).

57

Diagnosis. Both sexes of S. rugulosus are distinguished by the rounded elytral apices, the serrate
elytral apex, the deeply emarginated apex and by the face of sternite 2 at an oblique angle to
sternite 1.
Redescription (male). 1.9 – 2.6mm long (mean = 2.4mm; n = 10); 2.1 - 2.7 times as long as
wide. Color red-brown to dark red brown, antenna yellow-brown. Pronotum typically darker than
elytra.
Epistoma weakly and broadly emarginated; epistomal process absent; median area above
mandibles bearing a dense patch of long yellow hair-like setae. Frons appearing convex when
viewed laterally, slightly transversely impressed above epistoma; surface moderately and finely
longitudinally aciculate-punctate; aciculations converging at epistoma; punctures small, coarse;
surface moderately and uniformly covered by long, fine, yellow erect hair-like setae, setae longer
than the midpoint of the eye. Antennal scape short, elongate, less than length of the first four
funicular segments; club flattened, irregularly ovoid, setose with a partial septum and two
arcuate sutures.
Pronotum wider than long; apical margin broadly rounded, area between the eyes lined
with scales; sides distinctly arcuate, strongly constricted near apex, and forming a weak
transverse impression near apical margin; surface smooth, shining, punctures on disc fine,
shallow and moderately abundant, lager and more abundant laterally and on apical constriction;
apical and anterolateral margins bearing sparse, erect yellow setae; base weakly bisinuate.
Elytral sides sub-parallel on basal half, narrowing to a strongly rounded and moderately
serrate apex; apical margin of elytral apices bearing large, coarse punctures; apex strongly
emarginated at the suture. Disc glabrous, smooth, shining; interstriae not impressed and equal in
width to striae, interstrial punctures uniseriate, equal in size to those of striae, interstriae bearing

58

moderately abundant short, semi-erect yellow-brown hair-like setae; striae not impressed.
Declivity bearing sparse, short, erect yellow setae. Metepimeron less than half-length of
metepisternum.
Apical margin of sternite 1 rounded, flush with the base of sternite 2. Sternite 2 nearly at
an oblique angle to sternite 1; surface shagreened, dull finely punctate with small, coarse and
shallow punctures; face flattened, unarmed; setae abundant, erect, long, greater than width of
segment 3 in length; lateral margins of sternites 2-4 and sternite 4 unarmed. Sternite 5 carinate
ridge closer to the apical margin than the basal margin of the segment; length of sternite 5 greater
than the combined lengths of sternites 3 and 4; a setal patch is absent median depression is
present.
Female. 2.0 – 3.1mm long (mean = 2.5mm; n = 10); 2.1 - 2.8 times as long as wide. Similar to
male except frontal setae shorter, less than the width of the eye and less abundant.
Specimens examined. 99.
Type material. None examined.
Non-type material. CANADA: BRITISH COLUMBIA: Vancouver, 5.VII.1975, N.M. Downie
(FMNH-2). NOVA SCOTIA: Middleton, 11.VI.1938 (CNCI-2). ONTARIO: Brimley,
17.VII.[19]21 (CNCI-1), 30.VII.[19]22 (CNCI-1). Ottawa, 21.VIII.1999, A.T. Howden, ex. wild
grape [= Vitis sp.] (CNCI-1). Simcoe, 3.IX.1931, J.A. Hall (CNCI-2). Smith Falls, V.1940, H.S.
Fleming (CNCI-1). UNITED STATES: CALIFORNIA: [Los Angeles Co.]: San Marino,
25.VI.[19]42, G.P. Mackenzie (FMNH-1). [Orange Co.]: Santa Ana, 1.IV.1943, L.R. Gillogly,
ex. bait traps (USNM-1). [Placer Co.]: Penryn, 1.X.1929, A.T. McClay (FMNH-2).
DELAWARE: [Kent Co.]: Camdem, XII.1940, J.M. Amos (FMNH-1). INDIANA: Madison Co.:
10.VIII.1937, ex. apricot [=Prunus armeniaca] (FMNH-2). Porter Co.: Jackson Township,

59

Maple Knoll Farm, 6.IV.[19]60, C.C. Gregg (FMNH-10). Tippecanoe Co.: 7.VI.1956, N.M.
Downie (FMNH-2), 1.XI.1978 (FMNH-1). MICHIGAN: Allegan Co.: Fennville area,
30.VI.2003, P. McGhee, ex. on apple trees [= Malus sp.], (MSUC-1). [Cass Co.]: Edwardsburg,
30.VIII.1928 (MSUC-6). [Ingham Co.]: [East Lansing], Agriculture College [= Michigan State
University campus], 1.I.1917 (MSUC-3). Isabella Co.: 16.IX.[19]55, R.R. Dreisbach (MSUC-1).
[Kent Co.]: Grand Rapids, 17.X.[19]11 (MSUC-6). [Lenawee Co.]: Adrian, 20.VII.1900
(MSUC-7). Livingston Co.: Howell, 214 Inverness St, N42.61678° W84.92810°, 23.V7.VI.2007, R. Mech, ex. Lindgren trap with EtOH + alpha (MSUC-1). Midland Co.:
24.VII.[19]46, R.R. Dreisbach (MSUC-1), 14.IX.[19]56 (MSUC-1). Oakland Co.: A.W.
Andrews (MSUC-1); 28.VI.[19]47, B. Summerville (MSUC-1). [Washtenaw Co.]: Manchester,
21.V.1913 (MSUC-4), 31.V.1913 (MSUC-7). NEW YORK: Onodaga Co.: Syracuse, X.1987,
R.J. Rabaglia, ex. mountain ash [= Sorbus sp.] (RJRC-1). [Tompkins Co.]: Ithaca, ex. peach [=
Prunus sp.] (CASC-1). [Ulster Co.]: Oliverea, 20.VI.[19]18 (USNM-1). Wayne Co.: 26.VI.1950,
Shumaker (USNM-1), 8.VIII.[19]51 (USNM-1). [Unspecified County]: (CASC-2).
PENNSYLVANIA: Allegheny Co.: Upper St. Clair Township, 28.VIII.[19]59 (EMEC-1).
[Philadelphia Co.]: Philadelphia, 20.V.[18]98 (USNM-1). UTAH: [Utah Co.]: Vineyard,
6.IX.[19]23, T. Spalding (USNM-1). WASHINGTON: [Whitman Co.]: Steptoe Butte State Park,
9.VII.1971, N.M. Downie (FMNH-1). WASHINGTON D.C.: 26.VII.1943, L.J. Bottimer, ex. on
Prunus sp. (CNCI-2). ADDITIONAL SPECIMENS: Brazil (MSUC-21), Czech Republic
(MSUC-1), Hungary (MSUC-1), Morocco (MSUC-1) and Italy (MSUC-2).
Distribution. CANADA: British Columbia, Nova Scotia, Ontario. GREENLAND. MEXICO:
Durango. UNITED STATES: Arkansas, California, Colorado, Connecticut, Delaware, Florida,
Georgia, Idaho, Illinois, Indiana, Kansas, Kentucky, Louisiana, Maryland, Massachusetts,

60

Michigan, Mississippi, Missouri, Montana, New Jersey, New York, North Carolina, Ohio,
Pennsylvania, South Carolina, Texas, Utah, Virginia, Washington, Washington D.C, West
Virginia, Wisconsin.
Hosts. Stone and pome fruit trees including Malus spp. (apple), Pyrus spp. (pear), and Prunus
spp. (cherry) and is less commonly in Crataegus (hawthorn), Sorbus (mountain ash) and Ulmus
spp. (elm).
Common name. Shothole borer.
Biology. Scolytus rugulosus primarily attacks and kills small twigs and branches but may kill
whole trees through the process of excavating adult galleries and larval feeding. Twigs injury is
the result of feeding activity at the base of the bud. Attacks can begin near an injury or on a
healthy tree (Chamberlin 1939; Bright and Stark 1973).
The S. rugulosus adult gallery is parallel with the grain of the wood. The adult gallery
solely consists of an egg gallery and lacks a nuptial chamber. The adult gallery strongly scores
the cambium, lightly scores the sapwood and ranges in size from 1.0-5.0cm in length (Bright and
Stark 1976; Furniss and Johnson 2002). Eggs are laid singly in larval niches on both sides of the
egg gallery. Larval mines first radiate perpendicular to the egg gallery against the grain of the
wood and later turn parallel with the grain (Bright and Stark 1973). The larval stage typically
lasts one month. Pupation occurs in the bark for summer emergence. If the brood is unable to
complete development during the warmer months, larvae will burrow 1-2cm deep within the
sapwood to overwinter. The following year, adults emerge and feed at twig crotches before
selecting host material (Baker 1972). There are one to four generations per year depending on
locality with more generations occurring in warmer climates (Chittenden 1898; Baker 1972;
Wood 1982).

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Remarks. This species is native to the Palearctic region and was first detected in North America
in 1877 from New York (Chittenden 1898). The native range of S. rugulosus encompasses
Europe, North Africa, Asia Minor, middle Asia to Zabaikalye, Russia (Michalski 1973).

Scolytus schevyrewi Semenov
(Figures 1.22, 1.23)
Scolytus schevyrewi Semenov 1902: 265. Holotype, male (location unknown).
For complete taxonomic history see Wood and Bright (1992).
Diagnosis. The S. schevyrewi male most strongly resembles that of S. piceae because in both
species the spine on the second sternite never attains the apical margin. Males are differentiated
from those of S. piceae by the laterally compressed spine and the banded appearance of the
elytra.
The female is differentiated from that of S. piceae by the banded pattern of the elytra and
by the low median carina (variable and may be absent) that does not touch either margin on the
second sternite.
Redescription (male). 2.8 – 3.5mm long (mean = 3.2mm; n = 10); 2.0 – 2.2 times as long as
wide. Color red-brown to dark red brown. The elytra of most species appears banded with a
characteristic dark brown band on reddish colored elytra, but may also be solely dark brown or
red-brown without a band. Antennae yellow-brown. Pronotum typically darker than elytra.
Epistoma weakly and broadly emarginated; epistomal process absent; median area above
mandibles bearing a dense patch of long yellow hair-like setae. Frons appearing impressed when
viewed laterally; surface moderately and coarsely reticulate punctate to weakly longitudinally
aciculate; punctures dense, small and coarse; surface moderately covered by long, fine, yellow

62

erect hair-like setae, setae longer than the midpoint of the eye, setae on lateral and dorsal margins
longer, thicker and incurved. Antennal scape short, elongate, less than length of the first four
funicular segments; club flattened, thinner on apical half, irregularly ovoid, setose with a partial
septum and two arcuate sutures.
Pronotum wider than long; apical margin broadly rounded, area between the eyes lined
with scales; sides distinctly arcuate, strongly constricted near apex, and forming a weak
transverse impression near apical margin; surface smooth, shining, punctures on disc fine,
shallow and moderately abundant, larger, coarser, deeper and more abundant laterally and on
apical constriction; apical and anterolateral margins bearing sparse, erect yellow hair-like setae;
base weakly bisinuate.
Elytral sides sub-parallel on basal half, narrowing to a moderately rounded and smooth
apex; apical margin of elytral apices bearing small, fine punctures; apex weakly emarginated at
the suture. Scutellar notch densely covered in recumbent white setae (may wear off). Disc
glabrous, smooth, shining; interstriae not impressed and equal in width to striae, interstrial
punctures uniseriate, equal in size to those of striae, interstriae bearing sparse short, semi-erect
yellow hair-like setae; striae weakly impressed. Declivity bearing sparse, short, erect yellow
setae. Metepimeron half-length of metepisternum.
Apical margin of sternite 1 flush with the base of sternite 2. Sternite 2 nearly
perpendicular to sternite 1; surface shagreened, dull, finely punctate with small, fine and shallow
punctures; face convex; densely covered with semi-recumbent, long setae that are as long as the
width of sternite 3 or less; face armed with median laterally compressed spine (rarely absent) that
has its base close to the basal margin but does not touch it; lateral margins of sternites 2-4 and
sternite 4 unarmed. Sternite 5 carinate ridge closer to the apical margin than the basal margin of

63

the segment; length of sternite 5 greater than the combined lengths of sternites 3 and 4; a setal
patch or median depression is absent.
Female. 2.3 – 3.6mm long (mean = 3.2mm; n = 10); 1.7 – 2.4 times as long as wide. Similar to
male except epistoma feebly emarginated, frons flattened when viewed laterally, weakly
longitudinally aciculate, setae shorter, less than the width of the eye and less abundant; weakly
transversely impressed above epsistoma and longitudinally impressed in median area. Apical
margin of sternite 1 weakly elevated above the base of sternite 2. Second sternite armed with a
low median carina (variable and may be absent) that does not touch either margin.
Specimens examined. 24.
Type material. None examined.
Non-type material. UNITED STATES: CALIFORNIA: Los Angeles Co.: Whittier, Whittier
Fertilizer, 7.IX.2006, A. Sanchez, ex. Lindgren funnel + ETOH & alpha pinene (DEBC-1).
COLORADO: Adams Co.: Aurora, wood recycler, N39°807’, W104°.994’, 9.VII.2003, P.
McPherren, ex. funnel trap with Ips lure (MSUC-11), 15.IV.2003 (MSUC-1), 26.IV.2003
(MSUC-1), 2.V.2003 (MSUC-1), 29.V.2003 (MSUC-1). MICHIGAN: Ingham Co.:
N42°11.320’ W84°27.867’, 258m, 16.IX.2011, S.M. Smith, A.I. Cognato, I.A. Cognato, ex.
Ulmus sp. (MSUC-1). Wayne Co.: Trenton-Woodhaven, 26.VII.2004, T. Dutton, ex. Lindgren
funnel alpha-pinene Trap WY4 (MSUC-1). UTAH: Weber Co.: Ogden, Ogden Nature Center,
13.VII.2003, ex. funnel trap with alpha pinene & ethanol lure (MSUC-6).
Distribution. CANADA: Alberta, British Columbia, Manitoba, Ontario, Saskatchewan.
UNITED STATES: Arizona, California, Colorado, Connecticut, Delaware, Idaho, Illinois,
Indiana, Kansas, Maryland, Michigan, Minnesota, Missouri, Montana, Nebraska, Nevada, New

64

Jersey, New Mexico, Ohio, Oklahoma, Oregon, Pennsylvania, South Dakota, Texas, Utah,
Virginia, Washington, Wyoming.
Hosts. Ulmus spp. including U. americana L. (American elm), U. pumila L. (Siberian elm), U.
thomasii Sarg. (rock elm) and U. procera Salisb. (English elm).
Common name. Banded elm bark beetle.
Biology. This species prefers to attack drought stressed elms (Negrón et al. 2005). Scolytus
schevyrewi locate a suitable host via host tree volatiles (Lee et al. 2010).
The adult gallery consists solely of a single egg gallery parallel with grain of the wood
(Lee et al. 2006). The adult gallery strongly scores the sapwood. Egg niches are constructed
along the gallery and score the sapwood. Twenty to 120 eggs are laid along the egg galleries
(Lee et al. 2010). Larval mines lightly score the sapwood and radiate perpendicular to the egg
gallery. The larval galleries later meander often at an oblique angle to the grain of wood, forming
a fan shaped pattern. Pupation occurs in the outer bark and broods overwinter as mature larvae or
pupae (Lee et al. 2006). In California, adult flight occurs from April-September or October. In
Nevada, Utah, Wyoming, Colorado, Kansas and Utah, flight occurs from May to September (Lee
et al. 2011). There are two to three generations per year (Lee et al. 2011). Development from egg
to adult takes 30-45 days (Negrón et al. 2005). Upon emergence, adults feed at twig crotches
before selecting host material (Negrón et al. 2005).
Collecting Notes. None.
Remarks. This species is native to the Palearctic region, from western Russia and Uzbekistan
and east to China, Mongolia and Korea (Michalski 1973). Scolytus schevyrewi was first detected
in North America in 2003. The first specimens were collected in Colorado and Utah. By 2005, it
was recorded from 21 states suggesting that it had been present for many years before its initial

65

detection (Negrón et al. 2005; LaBonte 2010). Subsequent review of bark beetle survey
collections revealed the earlier occurrence of this species in Denver, Colorado in 1994 and
Clovis, New Mexico in 1998 (Lee et al. 2006).
In areas where populations of S. schevyrewi and S. multistriatus are both present, the
abundance of S. multistriatus is decreasing to the point where this once common species is
difficult to find (Negrón et al. 2005; Lee et al. 2010). This competitive displacement of S.
multistriatus by S. schevyrewi is likely the result of differences in fecundity, generation time, and
emergence. Scolytus schevyrewi produces larger broods that may overwinter as pupae, have a
quicker development period, have an earlier flight, and exhibit rapid, strong aggregation to host
kairomones as compared to S. multistriatus (Lee et al. 2010).
Scolytus schevyrewi is a highly morphologically variable species. LaBonte (2010)
provides an excellent discussion regarding intraspecific variation exhibited within S. schevyrewi.
There is considerable variation observed in the shape and appearance of spine on the second
sternite. The male spine on the second sternite is typically well developed with a blunt apex that
is broader than the base and appears triangular when laterally viewed. In females the spine is
variously reduced and may even be absent. In most males, the spine is closest to the apical
margin of the second sternite. In some males the base of the spine is closer to basal margin. Most
individuals exhibit the characteristic dark brown band on reddish colored elytra, which is the
derivative of the species’ common name. Occasionally individuals have been encountered with
unicolorous dark brown or reddish elytra. Additional variation was also observed in the
coloration of the pronotum. The pronotum can vary from almost entirely dark brown with
reddish coloration along the margins (common form) to the entire dorsal surface being reddish
with dark brown margins (uncommon form) (LaBonte 2010).

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Native Hardwood Clade
The native hardwood clade (2.2-5.6mm long) (S. fagi, S. muticus, and S. quadrispinosus)
is monophyletic. The sexual dimorphism of the native hardwood clade is different from the
introduced group and the conifer clade as both the males and females have an impressed frons
that is strongly longitudinally aciculate, except S. fagi in which the males have a faintly
longitudinally aciculate frons and the female frons is granulate punctate. This group arguably has
the strongest degree of sexual dimorphism with S. quadrispinosus and S. muticus each
possessing a strongly excavated second sternite numerous spines and teeth or a large setal patch
on sternite 5 respectively. The abdominal venter of S. fagi is identical in both sexes.

Scolytus fagi Walsh
(Figures 1.24, 1.25)
Scolytus fagi Walsh 1867: 58. Neotype: male, labeled “Galesburg, Illinois, Liebeck Collection”
(MCZC). Neotype designated Smith and Cognato 2010b: 36.
Diagnosis. Both sexes of S. fagi are distinguished from S. mali and S. muticus by the rugosereticulate frons that is covered by uniformly distributed setae.
Redescription (male). 3.3-5.5mm long (mean = 4.45mm; n = 20); 1.96 - 2.75 times as long as
wide. Color dark red-brown to black, antenna light brown. Pronotum typically same color as
elytra.
Epistoma weakly and broadly emarginated; epistomal process absent; median area above
mandibles bearing a dense patch of long yellow hair-like setae. Frons appearing flattened when
viewed laterally, slightly transversely impressed above epistoma and along median line; surface

67

rugose-reticulate and strongly punctate; punctures small, coarse; surface moderately and
uniformly covered by long, fine, yellow erect hair-like setae, setae longer than the midpoint of
the eye. Antennal scape short, elongate, less than length of the first four funicular segments; club
flattened, thinner on apical half, irregularly ovoid, setose with a partial septum and two arcuate
sutures.
Pronotum wider than long; apical margin broadly rounded, area between the eyes lined
with scales; sides distinctly arcuate, strongly constricted near apex, and forming a weak
transverse impression near apical margin; surface smooth, shining, punctulate and punctures
moderately abundant, lager, coarse and more abundant laterally and on apical constriction; apical
and anterolateral margins bearing sparse, erect yellow hair-like setae; base weakly bisinuate.
Elytral sides sub-parallel on apical half, narrowing to a weakly rounded and smooth apex;
apical margin of elytral apices bearing small, fine punctures; apex weakly emarginated at the
suture. Disc smooth, shining; interstriae not impressed and more than twice the width of striae,
interstrial punctures uniseriate, smaller than those of striae, punctures bearing short recumbent
yellow setae slightly longer than the size of a puncture (may be broken off); striae moderately
impressed. Declivity bearing sparse, short, erect yellow setae. Metepimeron half-length of
metepisternum.
Apical margin of sternite 1 weakly elevated above the base of sternite 2. Sternite 2 nearly
perpendicular to sternite 1; surface smooth, shining, finely punctate with large, fine and shallow
punctures; face flattened; setae semi-recumbent, short, about half the length of segment 3 or less;
apical margin unarmed; lateral margins of sternites 2-4 and sternite 4 unarmed. Sternite 5
unarmed; length of sternite 5 greater than the combined lengths of sternites 3 and 4; a setal patch
is absent and a median depression is present.

68

Female. 3.9 - 5.6mm long (mean = 4.65mm; n = 20); 1.9 - 2.8 times as long as wide. Similar to
male except epistoma feebly emarginated, epistomal process absent, frons convex when viewed
laterally, weakly longitudinally strigate-punctate, setae shorter, less than the width of the eye and
sparse; weakly transversely impressed just above epistoma and between inner apices of eyes.
Second sternite unarmed.
Specimens examined. 74.
Type material. Neotype Scolytus fagi Walsh (MCZC).
Non-type material. CANADA: ONTARIO: Point Pelee National Park, 27.IX.1989, K. Dunster,
ex. Celtis tenuifolia (CNCI-9). UNITED STATES: MISSISSIPPI: [Sharkey Co.]: Rolling Fork,
VIII.1976, J.D. Solomon, ex. Nuttall oak [= Quercus sp.] (USNM-1). PENNSYLVANIA:
Cumberland Co.: Roadway Dr @ Schneider Dr, 40.229030°N, 77.111580°W, 26.VI.2009, L.R.
Donovall, (MSUC-25), 29.V.2009, ex. Lindgren-alpha pinene/EtOH (MSUC-4), 29.V.2009, ex.
Lindgren-EtOH (MSUC-1). Dauphin Co.: Wildwood on Industrial Rd., 40.316325°N,
76.888783°W, 6.VIII.2009, S.-E. Spichiger, ex. Lindgren-EtoH (MSUC-2). Lancaster Co.: 7031
Elizabethtown Rd., 40.182583°N, 76.498783°W, 23.VII.2009, ex. Lindgren-BEBB/EtOH
(MSUC-1). York Co.: 400 Mundis Rd., 40.030170°N, 76.705330°W, 10.VI.2009, S. Rebert, ex.
Lindgren-alpha/EtOH (MSUC-4). TEXAS: [Colorado Co.]: Columbus, [18]88 (MSUC-4,
USNM-15). [Unspecified county]: (USNM-3). Fort Worth, 31.VII.[19]12, ex. bred from
hackberry [=Celtis sp.] (USNM-4).
Distribution. CANADA: Ontario. UNITED STATES: Illinois, Kansas, Mississippi, Ohio,
Pennsylvania, Texas.

69

Hosts. Celtis occidentalis L. (common hackberry), C. tenuifolia Nutt. (dwarf hackberry), Celtis
laevigata Willd. var. texana Sarg. (Texan sugarberry), Fagus grandifolia Ehrh. (American
beech), and Quercus spp. (oak).
Common name. None.
Biology. The gallery of the species has been reported as very confused and undecipherable.
Larvae were reported boring in the wood. In addition, the species did not appear to colonize
healthy trees (Packard 1890). Smith and Cognato (2010a) summarized all information known
about this species.
Collection notes. None.
Remarks. This species is very rarely encountered. Most museum collections occurred in the
early 1900’s and most recent collections have been from Lindgren funnel traps. There are many
gaps in the known distribution of S. fagi but the species likely occurs throughout the eastern US
associated with its host trees.

Scolytus muticus Say
(Figures 1.26, 1.27)
Scolytus muticus Say 1824: 182. Holotype: male, Missouri (ANSP, lost).
Diagnosis. Scolytus muticus are differentiated from other Scolytus species by the presence of
long, erect hair-like setae on the elytral interstriae and on the abdominal venter. The male is
further distinguished by a pair of strongly elevated areas on the basal two-thirds, each densely
covered with abundant fine, long hair-like setae.

70

Redescription (male). 2.2 – 5.3mm long (mean = 3.65mm; n = 20); 1.75 - 2.6 times as long as
wide. Head, pronotum, legs and abdominal venter dark red-brown, antennae yellow-brown,
elytra usually dark red-brown but occasionally red-brown. Pronotum typically darker than elytra.
Epistoma moderately and broadly emarginated; epistomal process absent; median area
above mandibles bearing a dense patch of long yellow hair-like setae. Frons appearing strongly
flattened when viewed laterally; surface finely and densely longitudinally aciculate; aciculations
converging at epistoma; impunctate; setae on lateral and dorsal margins covered by long, thick,
incurved, yellow erect hair-like setae, setae longer than the midpoint of the eye, median areas
covered with sparse, shorter and thinner setae. Antennal scape short, elongate, less than length of
the first four funicular segments; club flattened, irregularly ovoid, setose with a partial septum
and three very sharply arcuate sutures.
Pronotum wider than long; apical margin broadly rounded, area between the eyes lined
with scales; sides distinctly arcuate, strongly constricted near apex, and forming a weak
transverse impression near apical margin; surface smooth, shining, punctures on disc fine,
shallow and moderately abundant, lager, coarser and dense laterally and on apical constriction;
apical and anterolateral margins bearing sparse, erect yellow hair-like setae; base weakly
bisinuate.
Elytral sides sub-parallel on apical half, narrowing to a subquadrate and smooth apex;
apical margin of elytral apices bearing small, fine punctures; apex entire at the suture. Disc
reticulate, shining; interstriae faintly impressed and equal to width of striae, interstrial punctures
large, uniseriate, equal in size to those of striae, interstrial punctures bearing moderately
abundant, long, semi-erect yellow hair-like setae (may have worn off); striae moderately

71

impressed. Declivity bearing sparse, short, erect yellow setae. Metepimeron half-length of
metepisternum.
Apical margin of sternite 1 weakly elevated above the base of sternite 2. Sternite 2 nearly
perpendicular to sternite 1; surface reticulate, shining, densely and coarsely punctured with large
and coarse punctures; face flattened; setae moderately abundant and longer than the width of
sternite 3; apical margin unarmed; lateral margins of sternites 2-4 and sternite 4 unarmed.
Sternite 5 unarmed; length of sternite 5 greater than the combined lengths of sternites 3 and 4; a
median depression is absent; a pair of strongly elevated areas on basal two-thirds, each densely
covered with abundant fine, long hair-like setae, apical third strongly impressed.
Female. 3.1 – 5.1mm long (mean = 4.0mm; n = 20); 1.96 - 2.45 times as long as wide. Similar to
male except epistoma feebly emarginated, epistomal process absent, frons less strongly flattened
when viewed laterally, finely and narrowly longitudinally aciculate, setae shorter, less than the
width of the eye and less abundant; weakly transversely impressed between inner apices of eyes
and. Second sternite unarmed. Sternite 5 without a pair of strongly elevated areas on basal twothirds or setal patches.
Specimens examined. 214.
Type material. None examined.
Non-type material. CANADA: ONTARIO: Pelee Island, 29.VI.1940, W.J. Brown (CNCI-1).
Point Pelee National Park, 23.VI.[19]31, W.J. Brown (CNCI-1); 27.IX.1989, K. Dunster, ex.
Celtis tenuifolia (CNCI-1), 2.VIII.1990 (CNCI-1). UNITED STATES: COLORADO: Jefferson
Co.: Upper Bear Creek, 11.IX.1980, D. Leatherman, ex. Douglas fir [=Pseudotsuga menziesii]
(CSUC-1). ILLINOIS: Alexander Co.: Pleasant Valley, 15.VI.1979, B.C. Weber, ex. Trap 6, Ht.
2 (USNM-1), 22.VI.1979, ex. Trap 14, Ht. 4 (USNM-1). Champaign Co.: 28.X.1960, ex.

72

hackberry [= Celtis sp.] (EMEC-4). Sangamon Co.: Springfield, 29.V.2003, C. Helm (CUIC-1).
Stephenson Co.: Freeport, 4.VII.[19]17 (USNM-1). INDIANA: Tippecanoe Co.: 6.VI.1971,
N.M. Downie, ex. Celtis occidentalis (USNM-6). IOWA: [Story Co.]: Ames, 18.VIII.1926, H.H.
Harris (DEBC-2), 1.IV.1936 (DEBC-1), 22.V.1939, E. Polderboer (DEBC-1); 22.V.1939, C.
Vocom (USNM-2); E. Snead (USNM-1). KANSAS: Douglas Co.: Lawrence, 5mi N.E., Kansas
University Natural History Research Station, 9.VII.1982, D.H. Wahl (CNCI-1). Lawrence,
10.VI.[19]20, M.W. Blackman (USNM-8); 5.IX.1950, S.L. Wood (USNM-4). Riley Co.: G.A.
Dean (DEBC-1); Popenoe (DEBC-1). [Unspecified County]: Manhattan, 1.VI.[19]29, F. Kruger
(DEBC-1); 5.VI.[19]29, T.N. Winburn (DEBC-1); 8.V.1968, G. Hevel (USNM-1).
KENTUCKY: Christian Co.: 15.VI.1960, J.M. Campbell (CNCI-1). LOUISANA: Jefferson
Parish: New Orleans, 4.XII.1975, emerged II.1976, S.G. Wellso, ex. Celtis laevigata wood
(MSUC-13). Saint Bernard Parish: J.N. Knull, ex. reared from Celtis missippiensis [= Celtis
tenuifolia] (USNM-3). MARYLAND: [Cecil Co.]: Port Deposit, 26.VI.1977, D. Jump (USNM1), 13.VII.1977 (USNM-1), 9.VI.1979 (USNM-2), 3.VII.1979 (USNM-1). Montgomery Co.:
Bethesda, 25.V.1981, W.E. Steiner (USNM-1). Plummers Island, II-III.1912, E.A. Schwarz, ex.
branch of Celtis sp. (USNM-30). MICHIGAN: Ingham Co.: East Lansing, Agriculture College
[Michigan State University] (MSUC-8); S21 T4N R1W, VII.1970, S.G. Wellso (MSUC-12).
East Lansing, IV.1972, D.K. Young (MSUC-4); 15.VI.1970, S.G. Wellso, ex. merged from
Celtis occidentalis (MSUC-7). Okemos, 12.VIII.1969, S.G. Wellso (MSUC-1), 5.VI.1976
(MSUC-1); 28.V.1970, S.G. Wellso, ex. Celtis occidentalis (MSUC-2), 10.VIII.1969 (MSUC-1).
Kalamazoo Co.: Gourdneck Lake State Game Area, 19.VI.2011, A.I. Cognato, ex. funnel trap
with EtOH (MSUC-1). Wayne Co.: Grosse Ile, Pke [sic! = Parke] lane, N42.17060°
W84.14496°, 23.V-7.VI.2007, R. Mech, ex. Lindgren trap with ipslure (MSUC-1), ex. Lindgren

73

trap with EtOH + alpha (MSUC-1), 20.VI-6.VII.2007, ex. Lindgren trap with ipslure (MSUC-1),
7-20.VI.2007 (MSUC-5). MISSISSIPPI: [Unspecified County]: 19.V.1920, M.W. Blackman
(CNCI-1). MISSOURI: [Boone Co.]: Columbia, 24.IV.1954, P.J. Spangler (USNM-1).
NEBRASKA: Dixon Co.: Ponca, Ponca State Park, 42.607161°N -96.73223°W, 23.VIII.2007,
T.P. Miller, ex. funnel trap with PSB alpha-pinene (MSUC-1). Knox Co.: Crofton, Lewis and
Clarke Lake, 42.8321983°N -97.575555°W, 5.IX.2007, T.P. Miller, ex. funnel trap with Sirex
(MSUC-1). [Lancaster Co.]: Lincoln, 29.VIII.[19]53, R. Roselle, ex. elm [=Ulmus sp.] (USNM1). Sarpy Co.: Fontenelle Forest, 41.171478°N -95.9068166°W, 30.V.2006, N. Haxton, ex.
funnel trap with ethanol lure (MSUC-1), 7.VII.2006 (MSUC-1). NEW JERSEY: [Burlington
Co.]: Riverton, 12.II.1934, Wadley, ex. on Hackberry [=Celtis sp.] (USNM-1). [Essex Co.]:
Newark (USNM-1). [Somerset Co.]: North Branch, 9.III.1937, C.H. Hoffman, ex. from gallery
made in honey locust [=Gleditsia triacanthos] (USNM-1). NEW YORK: [Tompkins Co.]: Ithaca,
18.VI.[19]59, ex. in Celtis occidentalis (CUIC-11). NORTH CAROLINA: Macklenburg Co.:
Charlotte, 15-20.VI.2006, J.F. Cornell, ex. FIT in vacant lot (MSUC-1). NORTH DAKOTA:
[Ransom Co.]: Mcleod, 5mi N.W., 4.VII.1968, H.F. Howden (CNCI-1). OHIO: [Hamilton Co.]:
Cincinnati, 6.VI.[?] (USNM-1), 24.VI.[?] (USNM-1), 9.VII.[?] (USNM-1). [Unspecified
County]: Columbus (USNM-1); 11.V.[19]14 (DEBC-2). OKLAHOMA: Latimer Co.: V.1982, K.
Stephan (USNM-2). PENNSYLVANIA: [Allegheny Co.]: Allegheny [=Pittsburgh],
7.VIII.[18]95 (CUIC-12). [Dauphin Co.]: Harrisburg, T.H. Hubbell (CUIC-1). Hummelstown,
26.VI.[19]37, J.N. Knull (CUIC-6). TEXAS: Brazos Co.: College Station, 13.IV.1964, S.G.
Wellso (MSUC-1), 26.IV.1964 (MSUC-1). [Unspecified County]: Dallas, Hopk. U.S. 9929-X,
F.C. Bishop, ex. hackberry [=Celtis sp.] (USNM-5). VIRGINIA: Clarke Co.: Boyne, 2mi S.,
U[niversity of] Virginia Blandy Experimental Farm, 8-18.VI.1990, D.R. Smith, ex. malaise trap

74

(USNM-1), 19-30.VI.1990 (USNM-1), 1-12.VII.1990 (USNM-1). Essex Co.: Dunnsville, 1mi
S.E., 37º 52’N, 76º48’W, 29.V-9.VI.1993, D.R. Smith, ex. malaise trap (USNM-1); 24.VI9.VII.1992 (USNM-1). Fairfax Co.: Mount Vernon, 27.VI.1915, ex. Cornus stricta (USNM-1).
[Unspecified County]: Falls Church, 4.III.1921, E.A. Chapin (USNM-1). WASHINGTON D.C.:
21.V.1908 (MSUC-5). WEST VIRGINIA: Morgan Co.: Near Great Cacapon, 25.V.1985, G.F.
& J.F. Hevel (USNM-2). Wood Co.: Hopk. U.S. 6675, ex. Celtis (USNM-1).
Distribution. UNITED STATES: Colorado, District of Columbia, Florida, Iowa, Illinois,
Kansas, Kentucky, Maryland, Michigan, Mississippi, Missouri, New Jersey, North Carolina,
North Dakota, Ohio, Oklahoma, Pennsylvania, South Carolina, Tennessee, Texas, Virginia, West
Virginia.
Hosts. Celtis occidentalis L. (common hackberry) and Celtis laevigata Willd. (sugar hackberry).
Common name. Hackberry engraver.
Biology. Scolytus muticus prefers to colonize dead, dying or felled trees and the broken, dead
and dying branches of live hackberry (Blackman 1922; Doane et al. 1936; Bright 1976).
The biology of this species is not well known. Adult galleries of S. muticus are parallel
with the grain of the wood and consist of a single egg gallery without a nuptial chamber. The
adult gallery strongly scores the sapwood and range in size from 2.5-5.0cm in length (Blackman
1922). Larval mines first radiate perpendicular to the egg gallery and later meander, giving the
galleries a tortuous appearance (Blackman 1922; Bright 1976). Larvae construct pupal chambers
in burrows 2-3cm deep within the sapwood (Bright 1976). There are two generations per year in
the southeastern US and one generation per year in the northeastern US (Blackman 1922; Baker
1972).
Collection notes. None.

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Remarks. The holotype of Scolytus muticus has been lost (Wood 1982), however, Say’s (1824)
description is unambiguous as to the characteristics of this species.
Wood (1982) reports S. muticus as having a transverse gallery that is perpendicular to the
grain of the wood. Other authors including Blackman (1922), Baker (1972), and Bright (1976)
report this species as having a gallery that is parallel to the grain of the wood. After examining
the literature and photographs provided by T.H. Atkinson, it is likely that Wood erred in his
description and that the gallery is parallel with the grain of the wood.

Scolytus quadrispinosus Say
(Figures 1.28, 1.29)
Scolytus quadrispinosus Say 1824: 182. Holotype: male, Missouri (ANSP, lost).
= Scolytus carya Riley 1867: 68. Not located. Synonymy: LeConte 1876: 371.
= Scolytus caryae Walsh 1867: 58. Not located. Synonymy: LeConte 1876: 371.
Diagnosis. The S. quadrispinosus male is easily distinguished by it the autapomorphic features
of the abdominal venter which include: the apical margin of sternite 3 armed by three acute
spines (two lateral and one medial), the apical margin of sternite 4 armed by one median tooth,
sternite 1 apically descending, sternite 2 deeply concave, with the basal margin produced and
bearing a median tubercle.
The female is distinguished by the flattened and moderately, finely longitudinally
aciculate frons, bearing long, fine, incurved setae on the lateral and dorsal margins.
Redescription (male). 2.8 – 4.8mm long (mean = 4.0mm; n = 20); 1.8 - 2.25 times as long as
wide. Color red-brown to dark red-brown. Pronotum typically darker than elytra.

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Epistoma weakly emarginated; epistomal process strongly produced and moderately
elevated, surface smooth, shining; median area above mandibles bearing a dense patch of long
yellow hair-like setae. Frons appearing strongly flattened when viewed laterally; surface
strongly, densely and coarsely aciculate-punctate; aciculations converging at epistoma; punctures
small, coarse; surface moderately and covered by long, fine, yellow erect hair-like setae, setae
longer than the midpoint of the eye, setae on lateral and dorsal margins longer, thicker and
incurved. Antennal scape short, elongate, less than length of the first four funicular segments;
club flattened, irregularly ovoid, setose with a partial septum and two arcuate sutures.
Pronotum wider than long; apical margin broadly rounded, area between the eyes lined
with scales; sides distinctly arcuate, strongly constricted near apex, and forming a weak
transverse impression near apical margin; surface smooth, shining, punctures on disc fine,
shallow and moderately abundant, lager and more abundant laterally and on apical constriction;
apical and anterolateral margins bearing sparse, erect golden setae; base weakly bisinuate.
Elytral sides sub-parallel on apical half, narrowing to a weakly rounded and serrate apex;
apical margin of elytral apices bearing large, coarse punctures; apex entire at the suture. Disc
smooth, shining; interstriae weakly impressed and twice the width of striae, interstrial punctures
large, uniseriate, smaller than those of striae, interstrial punctures bearing sparse, long, semierect yellow hair-like setae (may have worn off); striae moderately impressed. Declivity bearing
sparse, short, erect yellow setae. Metepimeron half-length of metepisternum.
Apical margin of sternite 1 strongly and acutely produced and descending; sternite 2
deeply concave, basal margin produced and bearing a median tubercle. Sternite 2 nearly
perpendicular to sternite 1; surface shagreened, dull, finely and obscurely punctate with small,
fine and shallow punctures; apical margin armed with a broad median denticle, occasionally

77

absent. Apical margin of sternite 3 armed by three acute spines (two lateral and one medial);
apical margin of sternite 4 armed by one median tooth. Sternite 5 carinate ridge closer to the
basal margin than the apical margin of the segment; length of sternite 5 less than the combined
lengths of sternites 3 and 4; a median depression is absent, and the apical half of the segment is
pubescent.
Female. 2.9 – 5.0mm long (mean = 3.9mm; n = 20); 1.8 - 2.4 times as long as wide. Similar to
male except epistoma feebly emarginated, frons less strongly flattened when viewed laterally,
moderately and finely aciculate, setae shorter, less than the width of the eye and uniformly
distributed. Apical margin of sternite 1 weakly elevated above the base of sternite 2. Sternite 2
face flattened, nearly perpendicular to sternite 1; setae erect and short, about half the length of
segment 3. Venter unarmed.
Specimens examined. 143.
Type material. None examined.
Non-type material. CANADA: ONTARIO: Queenston, 15.VII.1938, D.F. Patterson, ex. Carya
ovata (CNCI-2); Z17 E464 N4820, 20.VII.2004, Seaforth, ex. handpicked from eastern white
pine [=Pinus strobus], 04-5-0265 (CNCI-1). UNITED STATES: GEORGIA: 1.IX.[19]45
(CASC-4). ILLINOIS: [Cook Co.]: Edgebrook (CNCI-2). [Unspecified County]: Willow
Springs, 21.VIII.[19]04, (FMNH-1), 13.V.[19]05, A.B Wolcott (FMNH-4). KANSAS: [Shawnee
Co.]: Topeka, 16.VI.[?], Popenoe (USNM-1). MASSACHUSSETS: [Unspecified County]:
(CASC-1). MICHIGAN: [Ingham Co.]: East Lansing, 15.VII.1932, (MSUC-4). Wayne Co.:
Detroit, 18.VIII.1902 (MSUC-3). [Unspecified County]: Lansing, 9.IX.1929 (MSUC-36).
MISSOURI: Dent Co.: 28.VIII.1973, M.P. Rolling (USNM-1), 31.VIII.1973 (USNM-3).
[Unspecified County]: (FMNH-1). MINNESOTA: [Sherburne Co.]: Elk River, 8.VII.1959, E.J.

78

Kingsley (CNCI-2). MISSISSIPPI: [Madison Co.]: Canton 16.VI.[19]04 (CUIC-1). [Oktibbeha
Co.]: [Starkville], Agriculture College of Mississippi [=Mississippi State University],
15.IV.1922, F.M. Hull (CUIC-1). NEW JERSEY: [Middlesex Co.]: Dunellen (CUIC-1). NEW
YORK: Onondaga Co.: 10.VI.1942, N.M. Downie (FMNH-2), 14.VII.1946 (FMNH-1).
Syracuse, C.J. Drake, ex. Hickoria glabra [=Carya glabra] (USNM-1). [Orange Co.]: Highland
Falls, 20.VI.1920, F. Schott (CUIC-1). Middletown (CUIC-1). [Queens Co.]: Long Island
Aquaduct, 14.VII.1912 (MSUC-4). [Tompkins Co.]: Groton, 7.VII.1946, N.M. Downie (FMNH1). Ithaca, 4.VIII.1928, P.P. Babiy (CUIC-1). [Westchester Co.]: Mount Vernon, VII.1913, ex.
from hickory [=Carya sp.] (CASC-14). Yonkers, 28.V.1935, P.A. Readio, H. Dietrich, ex. taken
on air trap (CUIC-1). [Unspecified County]: New York City, 15.V.1912, (CNCI-1), 13.V.1912
(CUIC-1). NORTH CAROLINA: [Buncombe Co.]: Asheville, Bent Creek, 17.VI.[19]29
(FMNH-1). PENNSYLVANIA: [Allegheny Co.]: Allegheny [=Pittsburgh], (FMNH-3),
24.VI.[18]93 (CUIC-1). Cumberland Co.: Roadway Dr @ Schneider Dr, 40.229030°N, 77.111580°W, 26.VI.2009, L.R. Donovall (MSUC-1). [Dauphin Co.]: Harrisburg, 19.IV.1911
(CASC-1), VI.1911 (CASC-3); 1.III.[19]11, emerged 7.IV.[19]11, Champlain (CASC-12);
Hopk. U.S. 10935-E, 13-14.VII.[?], W.S. Fisher, ex. Hicoria [= Carya sp.] (CUIC-1).
Hummelstown, 20.VI.[19]15 (CUIC-1). Linglestown, 8.VI.1912, W.S. Fisher (CNCI-1, CUIC2). [Philadelphia Co.]: Angora [=Philadelphia], IX.[19]15, H.A. Kaeber, ex. Hickory bark
[=Carya sp.] (USNM-7). [Westmoreland Co.]: Jeannette, H.G. Klages (CASC-2). [Unspecified
County]: Ford City, 28.VIII.[19]11 (USNM-1). Tyrone, VII.[19]12, lot 367, ex. Fraxinus alba
[=Fraxinus americana] (CASC- 7). TENNESSEE: [Hamilton Co.]: Chattanooga, 2.VI.[19]19,
Leach (FMNH-1).

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Distribution. CANADA: Ontario, Quebec. UNITED STATES: Alabama, Connecticut,
Delaware, District of Columbia, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky,
Louisiana, Maryland, Michigan, Minnesota, Mississippi, Missouri, New Jersey, New York,
North Carolina, Ohio, Pennsylvania, South Carolina, Ohio, Pennsylvania, South Carolina,
Tennessee, Texas, Virginia, West Virginia, Washington, D.C., Wisconsin.
Hosts. Primary hosts: Carya spp. (hickory). Incidental hosts: Juglans cinerea L. (butternut) and
Carya illinoinensis (Wangenh.) K.Koch (pecan).
Common name. Hickory bark beetle.
Biology. Scolytus quadrispinosus is one of the most destructive pests of hardwoods in the US
and the most important pest of hickory (Doane et al. 1936; Baker 1972). The species generally
attacks and kills single trees, or only treetops. However, outbreaks can develop during periods of
drought, killing large tracts of hickory. Scolytus quadrispinosus kills its host by mass attack in
which a multitude of broods develop in the phloem and cambium, effectively girdle the host tree
(Blackman 1922).
Adult galleries are parallel with the grain of the wood and deeply score the sapwood. The
adult gallery is short (2.5-5.0cm), and consists of a single egg gallery (Blackman 1922). Eggs are
deposited singly in niches on each side of the egg gallery with 20-60 niches per gallery
(Blackman 1922). After the eggs have been laid, the female constructs a postovipositional
feeding tunnel parallel to the egg gallery (Goeden and Norris 1965b). Larval mines are in the
cambium. From the egg gallery, the larval mines are first perpendicular to the grain of the wood
and then gradually turn and diverge creating a fan shaped appearance. The larvae bore into the
inner bark to overwinter. Larvae pupate the following spring and emerge as adults the following
summer (Blackman 1922). Upon emergence, adults feed at twig crotches and leaf petioles before

80

selecting a host (Baker 1972; Goeden and Norris 1964b). There is one generation per year in the
north with larvae completing their development in March and April and emergence in May.
There may be two generations per year in the south with the brood overwintering as larvae
(Doane et al. 1936). See Goeden and Norris (1964a,b, 1965a,b) for more information regarding
the biology of this species.
Collection notes. None.
Remarks. The holotype of Scolytus quadrispinosus is lost (Wood 1982), however Say’s (1824)
description is unambiguous as to the characteristics of this species. The holotype of S. caryae
Walsh was likely deposited in Walsh’s type collection, which was housed in the Chicago
Academy of Science Museum. This collection burned in the Great Chicago Fire and the
holotypes were lost (Sheppard 2004; J. Colby, pers. comm.).

Conifer Clade
The conifer clade (1.7-5.9mm) (S. aztecus, S. dentatus, S. fiskei, S. hermosus, S. laricis, S.
monticolae, S. mundus, S. obelus, S. oregoni, S. piceae, S. praeceps, S. reflexus, S. robustus, S.
silvaticus, S. subscaber, S. tsugae, S. unispinosus, and S. ventralis) is monophyletic. The sexual
dimorphism exhibited by species in the clade follows the general pattern outlined above except
for the shape of the frons, which is quite variable. In some species, the frons is convex in both
sexes with the female frons more strongly convex than that of the male (S. hermosus, S. obelus,
S. praeceps, and S. subscaber). Scolytus laricis males have a flattened and impressed frons when
viewed from a lateral profile and that of the female is convex. In the remaining species, the male
frons appears flattened when viewed from a lateral profile.

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Scolytus aztecus Wood
(Figures 1.30, 1.31)
Scolytus aztecus Wood 1967: 120. Neotype: male, labeled “Durango, Potreyo del Sauto y
Cebadillas, 19.IV.[19]90, J. Tulio Mendez M., 935-A, ex. Pseudotsuga menziesii”
(USNM). Here designated.
Diagnosis. Scolytus aztecus adults of both sexes are distinguished by the characteristics of the
elytral apex with the apical margin produced between interstriae 1 and 2, deeply emarginated at
interstriae 3, produced on interstriae 4 and deeply emarginated at stria 4.
Description male. 5.0mm long (mean = 5.0mm; n = 2); 2.5 times as long as wide. Body dark
red-brown to black, antennae light brown, legs light brown to dark red-brown. Pronotum
typically darker than elytra.
Epistoma broadly and deeply emarginated; epistomal process weakly developed and low;
median area above mandibles bearing a dense patch of long yellow hair-like setae. Frons
appearing flattened when viewed laterally, slightly transversely impressed above epistoma;
surface moderately and coarsely longitudinally aciculate-punctate; aciculations converging at
epistoma; punctures large, coarse and more dense medially above the epistoma; surface
moderately and uniformly covered by long, fine, yellow erect hair-like setae, setae longer than
the midpoint of the eye. Antennal scape short, elongate, less than length of the first four funicular
segments; club flattened, almost subquadrate, setose with a partial septum and two arcuate
sutures.
Pronotum as long as wide; apical margin broadly rounded, area between the eyes lined
with scales; sides distinctly arcuate, strongly constricted near apex, and forming a weak
transverse impression near apical margin; surface smooth, shining, punctures on disc fine,

82

shallow and moderately abundant, lager and more abundant laterally and on apical constriction;
apical, anterolateral and lateral margins bearing moderately abundant, erect, yellow hair-like
setae; base weakly bisinuate.
Elytral sides sub-parallel on apical half, narrowing to a subquadrate and rounded and
serrate apex; apical margin of elytra produced between interstriae 1 and 2, deeply emarginated at
interstria 3, produced on interstria 4 and deeply emarginated at stria 4; apical margin of elytral
apices bearing large, coarse punctures; apex moderately emarginated at the suture. Disc smooth,
shining; interstriae bearing short, sparse yellow hair-like setae spaced by the length of a setae or
less; interstriae weakly impressed and more than twice the width of striae, interstrial punctures
uniseriate, smaller than those of striae; striae moderately impressed. Declivity bearing sparse,
short, erect yellow setae. Metepimeron half-length of metepisternum.
Apical margin of sternite 1 weakly elevated above the base of sternite 2. Sternite 2 nearly
perpendicular to sternite 1; surface rugose, coarsely and deeply punctate; covered with abundant
erect setae that are greater than the width of segment 3 in length; face convex; armed medially
with a laterally compressed spine with the base extending from the apical margin to ¾ of the
segment, apex rounded, shining and impunctate; lateral margins of sternites 2-4 and sternite 4
unarmed. Sternite 5 carinate ridge closer to the apical margin than the apical margin of the
segment; length of sternite 5 greater than the combined lengths of sternites 3 and 4; a setal patch
or median depression is absent.
Redescription (female). 4.6 - 5.9mm long (mean = 5.23mm; n = 4); 2.3-2.5 times as long as
wide. Similar to male except epistoma feebly and broadly emarginated, epistomal process absent,
frons convex when viewed laterally, weakly longitudinally aciculate, setae shorter, less than the
width of the eye and sparse; weakly transversely on lateral margins above epistoma; median line

83

on frons raised. Apical margin of elytra slightly produced between interstriae 1 and 2,
emarginated at interstria 3, slightly produced on interstria 4 and emarginated at stria 4. Second
sternite unarmed.
Specimens examined. 7.
Type material. Neotype Scolytus aztecus Wood (USNM).
Non-type material. MEXICO: DURANGO: Potreyo del Sauto y Cebadillas, 19.IV.[19]90, J.
Tulio Mendez M., 935-A, ex. Pseudotsuga menziesii (THAC-3). NUEVO LEÓN: Santa
Catarina, San Antonio de las Alazanas, 14.XII.2011, Gerardo Cuellar, ex. Pseudotsuga menziesii
(MSUC-3).
Distribution. MEXICO: Durango, Michoacán, Nuevo León.
Hosts. Abies religiosa (Kunth) Schltdl. & Cham. (sacred fir), A. durangensis Martínez (Durango
fir) and Pseudotsuga menziesii (Mirb.) Franco (Douglas fir). Abies species are likely the
preferred host.
Common name. None.
Biology. Scolytus aztecus is an uncommon species and little is known regarding its biology.
Scolytus aztecus colonizes both standing trees and felled trees (Wood 1967; Cibrián Tovar et al.
1995). The tops of trees attacked by S. aztecus exhibit red foliage. Scolytus aztecus has been
collected feeding in the cambium of large Abies trees, although it has also been collected from
Pseudotsuga. Because of limited host records, it is unknown whether the primary host is Abies or
Pseudotsuga. Phylogenetic placement of the species suggests Abies (Figure 1.1) because the
species belongs to a clade of Abies feeding taxa. The adult gallery is transverse across the grain
of the wood with a central nuptial chamber, similar in appearance to that of S. ventralis (see

84

Cibrián Tovar et al. 1995, plate 132). Larval mines are in the cambium and do not score the
wood. Pupation occurs in the cambium (Wood 1967; Cibrián Tovar et al. 1995).
Collection notes. None.
Remarks. The type series of this species (holotype and 2 paratypes) was lost in transit. A
neotype is here designated for this distinctive species.
This is the first description of a male for this species.

Scolytus dentatus Bright
(Figures 1.32, 1.33)
Scolytus dentatus Bright 1964: 167. Holotype: male, labeled “Calif: Monterey Co, Cone Peak, 629-63, Abies bracteata, C.J. Wray Collector” (CASC).
Diagnosis. The S. dentatus male is easily distinguished by the presence of a median denticle on
the apical margin of sternite 4, occasionally median denticles may also be present on the apical
margins of sternites 2 and 3.
The female is distinguished by its distribution in the Santa Lucia range of California and
differentiated from the S. praeceps female by the presence of a strongly developed and distinct
epistomal process and larger size.
Redescription (male). 3.0-4.0mm long (mean = 3.45mm; n = 15); 1.7 – 2.5 times as long as
wide. Head, pronotum and abdominal venter dark red-brown, antennae light brown, legs dark
red-brown to light brown, elytra light red-brown. Pronotum darker than elytra.
Epistoma moderately and acutely emarginated; epistomal process strongly produced and
elevated; median area above mandibles bearing a dense patch of long yellow hair-like setae.
Frons appearing flattened when viewed laterally, not impressed; surface moderately and finely

85

longitudinally aciculate, coarsely punctate; aciculations converging at epistoma; punctures small,
coarse; surface moderately and uniformly covered by long, fine, yellow erect hair-like setae,
setae longer than the midpoint of the eye. Antennal scape short, elongate, less than length of the
first four funicular segments; club flattened, ovoid, setose with a partial septum and two arcuate
sutures.
Pronotum wider than long; apical margin broadly rounded, area between the eyes lined
with scales; sides distinctly arcuate, strongly constricted near apex, and forming a weak
transverse impression near apical margin; surface smooth, shining, punctulate and punctures
moderately abundant, lager and more abundant laterally and on apical constriction; apical and
anterolateral margins bearing sparse, erect yellow hair-like setae; base weakly bisinuate.
Elytral sides sub-parallel on basal half, narrowing to a subquadrate and smooth apex;
apical margin of elytral apices bearing large, coarse punctures; apex not emarginated at the
suture. Disc glabrous, smooth, shining; interstriae not impressed and more than twice the width
of striae, interstrial punctures uniseriate, smaller than those of striae; striae weakly impressed.
Declivity bearing sparse, short, erect yellow setae. Metepimeron half-length of metepisternum.
Apical margin of sternite 1 strongly produced and elevated above the base of sternite 2,
sternite base 2 appearing impressed. Sternite 2 nearly perpendicular to sternite 1; surface
glabrous, shagreened, dull, finely, obscurely punctate with small, fine and shallow punctures;
face flattened. Apical margins of sternites 2 and 3 may be armed with a median denticle, median
denticle always present on apical margin of sternite 4; lateral margins of sternites 2-4 and sternite
4 unarmed. Sternite 5 carinate ridge closer to the apical margin than the basal margin of the
segment; length of sternite 5 equal to the combined lengths of sternites 3 and 4; a setal patch or
median depression is absent.

86

Female. 3.4-4.6mm long (mean = 3.7mm; n = 15); 2.2 - 2.5 times as long as wide. Similar to
male except epistoma less strongly emarginated, epistomal process less strongly produced and
elevated, frons convex when viewed laterally, weakly longitudinally aciculate, setae shorter, less
than the width of the eye and less abundant; weakly medially impressed between inner apices of
eyes and. Sternites unarmed.
Specimens examined. 95.
Type material. Holotype Scolytus dentatus Bright (CASC). Allotype, female, Scolytus dentatus,
identical data as holotype. Paratypes: UNITED STATES: CALIFORNIA: Monterey Co., Cone
Peak, 29.VI.[19]63, C.J. Wray, ex. Abies bracteata (CASC-6, CNCI-20, EMEC-39, USNM-8).
Carmel Valley, 15mi S., 22.VII.[19]63, C.J. Wray, ex. Abies bracteata, (CASC-4).
Non-type material. UNITED STATES: CALIFORNIA: Monterey Co.: Carmel Valley, 15mi S.,
23.VII.[19]63, D.E. Bright, ex. Abies bracteata (CASC-2); 30.VII.1964 (CASC-2). Cone Peak,
29.VI.[19]63, C.J. Wray, ex. Abies bracteata (CASC-1, USNM-12). Williams Canyon, Los
Padres National Forest, 24.IV.1992, D.E. Bright, G. Ferrell, ex. Abies bracteata limbs (CNCI-1).
Distribution. UNITED STATES: California.
Hosts. Abies bracteata (D. Don) Poit. (bristlecone fir, Santa Lucia fir).
Common name. None.
Biology. Little is known regarding the biology of this uncommon and narrowly geographically
restricted species. The host, Abies bracteata, is narrowly restricted to the Santa Lucia Mountains
of California. The tree is distributed in small patches in deep and moist canyon bottoms as well
as dry rocky slopes and ledges within Los Padres National Forest in Monterey County, especially
near Cone Peak and Church Creek (Griffin and Critchfield 1972; Sullivan 1993). Scolytus

87

dentatus has been collected feeding in the bole of large standing trees (Bright 1964) but is also
reported from larger limbs and fresh slash (Edson 1967).
The adult gallery of S. dentatus somewhat resembles an expanded ‘E’. The gallery is
parallel with the grain of the wood and consists of a central nuptial chamber and two egg
galleries, one below and one above the nuptial chamber. Each egg gallery ends in a pronounced
hook. Galleries strongly score the cambium and lightly score the sapwood. The adult gallery
averages 2.5-12.0cm in length (Bright 1964; Edson 1967). Egg niches are closely spaced on both
sides of the maternal gallery (Bright and Stark 1973). Larval mines are first perpendicular to the
egg gallery and later turn to form a fan shaped pattern before terminating at pupation chambers
in the sapwood (Edson 1967).
Collection notes. None.
Remarks. Considerable variation is observed in the presence of median denticles on the apical
margins of male sternites 2 and 3. Frequently males only have a median denticle on the apical
margin of sternite 4 as those on 2 and 3 may or may not be present in the male. This species is
related to S. robustus and S. subscaber based on morphological characters (Figure 1.1). Both of
these species also feed on true firs (Abies spp.) and have the apical margin of male sternite 1
strongly apically produced.

Scolytus fiskei Blackman, removed from synonymy
(Figures 1.34, 1.35)
Scolytus fiskei Blackman 1934: 25. Holotype: male, labeled “[Capitan Mountains, N. Mex. 25
April, 1907], Hopk. US 3959, W.F. Fiske Collector, Type No. 43840 USNM” (USNM).
Synonymy: Wood 1977: 388.

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Diagnosis. Scolytus fiskei is very morphologically similar to S. laricis and S. unispinosus. Males
of S. fiskei are distinguished from those of S. laricis by the frons flattened when viewed laterally,
never deeply impressed, moderately abundant frontal setae (compared to dense) and by the host
genus, Pseudotsuga. Males are distinguished from those of S. unispinosus by the following
combination of characters: abdominal venter shiny in luster, the base of the sternite 2 spine
extends from the apical margin to three-quarters the length of the segment and geographical
distribution east of the Rocky Mountains.
The female is distinguished from that of both species by the shining luster of sternite 2.
Redescription (male). 2.2 – 2.8mm long (mean = 2.4mm; n = 15); 2.1 - 2.8 times as long as
wide. Head, antennae, pronotum, and abdominal venter dark red-brown, elytra and legs yellowbrown to light brown. Pronotum typically darker than elytra.
Epistoma weakly emarginated; epistomal process present, moderately developed and low;
median area above mandibles bearing a dense patch of long yellow hair-like setae. Frons
appearing flattened when viewed laterally from epistoma to the vertex, slightly transversely
impressed above epistoma to inner apices of eyes; surface moderately and coarsely
longitudinally aciculate-punctate; aciculations converging at epistoma; punctures large, sparse
and coarse; surface moderately and uniformly covered by long, fine, yellow erect hair-like setae,
setae longer than the midpoint of the eye. Antennal scape short, elongate, less than length of the
first four funicular segments; club flattened, irregularly ovoid, setose with a partial septum and
two broadly arcuate sutures.
Pronotum wider than long; apical margin broadly rounded, area between the eyes lined
with scales; sides distinctly arcuate, strongly constricted near apex, and forming a weak
transverse impression near apical margin; surface smooth, shining, punctures on disc fine,

89

shallow and moderately abundant, lager and more abundant laterally and on apical constriction;
apical and anterolateral margins bearing sparse, erect yellow hair-like setae; base weakly
bisinuate.
Elytral sides sub-parallel on apical half, narrowing to a subquadrate and smooth apex;
apical margin of elytral apices bearing small, fine punctures; apex moderately emarginated at the
suture. Disc smooth, shining; interstriae not impressed and twice the width of striae, interstrial
punctures uniseriate, smaller than those of striae; punctures bearing short sparse recumbent
yellow setae slightly longer than the size of a puncture (may be broken off); striae weakly
impressed. Declivity bearing sparse, short, erect yellow setae. Metepimeron less than half-length
of metepisternum.
Apical margin of sternite 1 rounded, 2 marked by a weak carina. Sternite 2 nearly
perpendicular to sternite 1; surface smooth, shining, finely punctate with small, fine and shallow
punctures; covered with sparse setae that are less than the width of segment 3 in length; face
convex; apical margin armed with a laterally compressed, median spine with the base extending
from the apical margin to ¾ the length of the segment, apex rounded; lateral margins of sternites
2-4 and sternite 4 unarmed. Sternite 5 carinate ridge equidistant between basal and apical
margins of the segment; length of sternite 5 less than the combined lengths of sternites 3 and 4; a
setal patch or median depression is absent.
Female. 2.2 - 3.5mm long (mean = 4.65mm; n = 15); 2.1 - 2.5 times as long as wide. Similar to
male except epistoma feebly emarginated, epistomal process weakly developed, frons convex
when viewed laterally, weakly longitudinally aciculate, setae shorter, less than the width of the
eye and less abundant; weakly transversely impressed between epistoma and inner apices of

90

eyes. Second sternite apical margin armed with an acute median denticle, with base extending
from apical margin to half-length of segment.
Specimens examined. 297.
Type specimens. Holotype Scolytus fiskei Blackman (USNM).
Non-type specimens. CANADA: BRITISH COLUMBIA: Aspen Grove, 12.VII.1931, H.
Richmond (CNCI-11, FMNH-2). Clinton, 6mi N., 7.VII.1972, D.E. Bright, ex. Pseudotsuga
menziesii (CNCI-7). Creston, 8.VI.1958, H. & A. Howden (EMEC-1). Fort Steele, 14.VI.[19]26,
R. Hopping (CASC-1). Indian Meadows, Midday Creek, 13.VII.1920, R. Hopping, ex.
Pseudotsuga taxifolia [=P. menziesii] (CASC-2,CNCI-2). Lumby, Creighton Valley,
3.VI.[19]22, R. Hopping (CASC-1). Merritt, Midday Valley, 27.VI.1926, W. Mathers (CASC-2).
Trinity Valley, 24.VI.1928, J.R. Howell, ex. Pinus monticola (CASC-1), 10.VII.1928 (CASC-1).
UNITED STATES: ARIZONA: Pima Co.: Tucson, Mount Lemmon, 11.VI.1969, S.L. Wood,
ex. Pseudotsuga menziesii (MSUC-2). COLORADO: Boulder Co.: Nederland, 5-7km N.,
5.VIII.2009, D.E. Bright, B.A. Barr, ex. branches of Pseudotsuga menziesii (CNCI-4). [La Plata
Co.]: Durango, Junction Creek Rd., 10000ft, 12-17.VII.1968, E.C. Becker (CNCI-1). Larimer
Co.: Roosevelt National Forest, Big Thompson Canyon, N40°24.456’ W105°24.565’, 7080ft,
5.V.2010, S.M. Smith, D.E. Bright, B.A. Barr, ex. Pseudotsuga menziesii (MSUC-36). IDAHO:
[Adams Co.]: Tamarack, 10mi S., 3.VII.1967 (WFBM-1). Boise Co.: Idaho City, 2.VI.1970
(WFBM-9), 1.I.1971 (WFBM-4). Lowman, Edna Creek, 6.VII.[19]72, A. Vaccares, G. Starr, ex.
Douglas fir stump [=Pseudotsuga menziesii] (WFBM-1). Bonner Co.: 6.VI.1986, M.M. Furniss,
J.B. Johnson, ex. Pseudotsuga menziesii (WFBM-7). Priest Lake, Indian Creek, 6.VI.1986, M.M.
Furniss, J.B. Johnson, ex. Pseudotsuga menziesii (WFBM-25). Priest Lake 6.VI.1986, M.M.
Furniss, J.B. Johnson, ex. Pseudotsuga menziesii (WFBM-1). Boundary Co.: Parker Creek,

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8.VI.1986, M.M. Furniss, J.B. Johnson, ex. Pseudotsuga menziesii (WFBM-5). Clearwater Co.:
Elk River, 12mi S.E., Hopk. U.S. 58536, 9.VII-16.VII.1973, R.D. Oakes (WFBM-1), 30.VII6.VIII.1973 (WFBM-1); Hopk. U.S. 58771, 25.VI-1.VII.1974, J.M. Wells, ex. in flight (WFBM1). Custer Co.: Herd Lake, Hopk. U.S. 60796-A, 3.IX.1978, M.M. Furniss, ex. Pseudotsuga
menziesii (WFBM-9). MacKay, 9mi N.E., 19.VII.1985, M.M. Furniss, J.B. Johnson, ex.
Pseudotsuga menziesii (WFBM-3). Summit, W. of Pass Creek, 19.VII.1985, M.M. Furniss, J.B.
Johnson, ex. Pseudotsuga menziesii (WFBM-12). Latah Co.: Big Sand Creek, Hopk. U.S. 53545,
11.VI.1969, M.M. Furniss (WFBM-1), 20.VI.1969 (WFBM-1). Moscow, 20.XI.1961, R.E.
Stecker, ex. reared from Doug fir [=Pseudotsuga menziesii] (WFBM-33). Moscow Mountain,
Hopk. U.S. 48869, 18.VII.1967, ex. Pseudotsuga menziesii (WFBM-3). Viola, 21.VI.1985, S.J.
Gast, M.M. Furniss, ex. Pseudotsuga menziesii (WFBM-2). Nez Perce Co.: Forest, III.1985,
M.M. Furniss, ex. Pseudotsuga menziesii (WFBM-6). Shoshone Co.: Red Ives Ranger Station,
V.1983, M.M. Furniss, ex. Pseudotsuga menziesii (WFBM-1). Valley Co.: Cascade, 7mi E.,
14.VI.1966, R.L. Furniss (WFBM-1). MONTANA: Lake Co.: Swan Lake, 28.VI.1963, M.M.
Furniss, ex. Pseudotsuga menziesii (WFBM-1). Madison Co.: Alder, 18km S.W., 8.IX.1978,
M.M. Furniss, ex. Pseudotsuga menziesii (WFBM-6), 12mi S.W. Alder (WFBM-16). Park Co.:
Livingston, 10mi S.E., 23.VII.1988, M.M. Furniss, J.B. Johnson, ex. Pseudotsuga menziesii
(WFBM-2). NEW MEXICO: Otero Co.: Cloudcroft, 4.VI.1969, tree 53, S.L. Wood, ex.
Pseudotsuga menziesii (MSUC-2). Sierra Co.: Emory Pass, 24.VII.1974, D.E. Bright, ex.
Pseudotsuga menziesii (CNCI-1). WASHINGTON: [Whitman Co.]: Pullman, 23.VI.1951, N.M.
Downie (FMNH-1). WYOMING: [Teton Co.]: Jackson, A.D. Hopkins, ex. Pseudotsuga
menziesii (USNM-1).

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Distribution. CANADA: British Columbia. UNITED STATES: Arizona, Colorado, Idaho,
Montana, New Mexico, Washington, Wyoming.
Hosts. Pseudotsuga menziesii (Mirb.) Franco (Douglas Fir).
Common name. None.
Biology. Scolytus fiskei colonizes suppressed limbs and branches of Pseudotsuga menziesii as
well as fresh slash (Edson 1967; Smith, pers. obs.). The adult gallery is bayonet shaped and
parallel with the grain of wood and consists of two egg galleries, one below and one above the
nuptial chamber and a turning niche. The female constructs the adult gallery more in the
cambium and lightly scores the sapwood. Larval mines are perpendicular to the egg gallery and
turn to form a fan shaped pattern (Edson 1967; Furniss and Johnson 2002; Smith, pers. obs.). The
adult gallery measures 3.8-9.0cm in length (Edson 1967). The following year adults emerge and
excavate tunnels within twigs of Douglas fir for maturation feeding causing twig flagging
(reported as S. unispinosus McMullen and Atkins 1962).
Like most Scolytus species, there is a very limited amount of information known about S.
fiskei. For many years it was considered a synonym of S. unispinosus and was thus referred to as
S. unispinosus in publications. Very little was written about this species in the US (see Wood and
Bright 1992) other than host preference and gallery descriptions (Keen 1938; Edson 1967; Bright
1976). McMullen and Atkins (1962) reported some notes on the biology of S. unispinosus in
British Columbia and appear to have reported a combined account of S. unispinosus and S. fiskei.
The authors noted the gallery of the S. unispinosus studied in their investigations as “in about 15
per cent of the galleries over 20 days of age were the type described by Chamberlin and Keen [S.
unispinosus, which has only a single egg gallery]; the majority were of the forked type and were
similar to those of S. tsugae [referencing a forked or bayonet shaped gallery that is made by S.

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fiskei]”. McMullen and Atkins (1959) had previously considered S. monticolae a synonym of S.
tsugae. Their description matches the gallery description of S. fiskei, which like has two egg
galleries as part of a bayonet shaped adult gallery. Because most of the specimens are of S. fiskei,
this article does offer some information regarding the biology of the species be used with caution
because not all of the findings may apply to S. fiskei.
Collection notes. None.
Remarks. The holotype of S. fiskei does not bear a locality label. Blackman’s (1934) description
states the holotype was collected at the Capitan Mountains, New Mexico.
Furniss and Johnson (2002) report S. unispinosus from Alberta, Canada. These specimens
are likely S. fiskei based on the geographic distribution of the species in the Rocky Mountains.
Wood (1977: 388) placed S. fiskei in synonymy with S. unispinosus after examining both
holotypes and 164 specimens from Arizona to British Columbia and concluded that there was too
much intraspecific variation to recognize them as separate species. I assessed the intraspecific
and interspecific variation (Tables 1.7 and 1.8) for each of the four genes for each species.
Scolytus fiskei intraspecific variation for COI was low, 0.0-0.0231, and averaged 0.0183 among
all sampled populations. Scolytus unispinosus intraspecific variation was also low, 0.00160.0282 and averaged 0.0121. Interspecific variation between S. fiskei and S. unispinosus was
much higher, 0.0331-0.0521 and averaged 0.043 among populations. Similar differences were
also observed with CAD (Table 1.8). The species have separate geographical ranges with S.
fiskei occurring primarily in the Rocky Mountains and British Columbia while S. unispinosus
occurs in the Cascade and Sierra mountains from California to British Columbia. Both species
are sympatric in the Interior Plateau of British Columbia near Merritt. The species are separated
by the characters listed in the diagnosis and by the galleries. The galleries of S. fiskei contain two

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egg galleries; one above and one below the nuptial chamber. The gallery of S. unispinosus only
contains a single egg gallery. In addition, the gallery of S. fiskei lightly scores the sapwood while
that of S. unispinosus deeply scores the sapwood. After examining the types, 950 specimens of
both species and testing the monophyly of each species using four genes, it is apparent that S.
fiskei is a distinct lineage and is here removed from synonymy with S. unispinosus.

Scolytus hermosus Wood
(Figures 1.36, 1.37)
Scolytus hermosus Wood 1968: 12. Neotype: male, labeled “Tlaxco 11mi. N., 8900ft,
9.VII.1967, S.L. W[ood], ex. Abies religiosa” (USNM). Here designated.
Diagnosis. Both sexes of S. hermosus resemble the S. silvaticus female. The female is
distinguished by having a weakly developed epistomal process and the male is distinguished by
having the apical margin of sternite 1 produced, forming a carinate lip along the basal margin of
sternite 2 that is twice as produced as thick and by the host genus, Abies.
Redescription (male). 3.0mm long (mean = 3.0mm; n = 1); 1.5 times as long as wide. Head,
antennae, pronotum, and abdominal venter dark red-brown, elytra and legs yellow-brown to light
brown. Pronotum typically darker than elytra.
Epistoma weakly emarginated; epistomal process weakly developed and low; median
area above mandibles bearing a dense patch of long yellow hair-like setae. Frons appearing
convex when viewed laterally, slightly transversely impressed above epistoma and between inner
apices of eyes; surface moderately and finely longitudinally aciculate-punctate; aciculations
converging at epistoma; punctures small, coarse; surface moderately and uniformly covered by
long, fine, yellow erect hair-like setae, setae longer than the midpoint of the eye. Antennal scape

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short, elongate, less than length of the first four funicular segments; club flattened, elongate,
almost subquadrate, setose with a partial septum and two arcuate sutures.
Pronotum wider than long; apical margin broadly rounded, area between the eyes lined
with scales; sides distinctly arcuate, strongly constricted near apex, and forming a weak
transverse impression near apical margin; surface smooth, shining, punctures on disc fine,
shallow and moderately abundant, lager and more abundant laterally and on apical constriction;
apical and anterolateral margins bearing sparse, erect yellow hair-like setae; base weakly
bisinuate.
Elytral sides sub-parallel on apical half, narrowing to a subquadrate and smooth apex;
apical margin of elytral apices bearing large, coarse punctures; apex moderately emarginated at
the suture. Disc smooth, shining; interstriae not impressed and more than twice the width of
striae, interstrial punctures uniseriate, smaller than those of striae, interstrial punctures bearing
sparse, long, erect yellow hair-like setae (may have worn off); striae weakly impressed. Declivity
bearing sparse, short, erect yellow setae. Metepimeron half-length of metepisternum.
Apical margin of sternite 1 produced, forming a carinate lip along the basal margin of
sternite 2 that is twice as produced as thick, basal margin of sternite 2 appearing impressed,
Sternite 2 nearly perpendicular to sternite 1; surface shagreened, dull, finely punctate with small,
fine and shallow punctures; setae moderately abundant, recumbent and short, about four times
the length of a puncture; face weakly concave; apical margin armed with a broad median
denticle, occasionally absent; lateral margins of sternites 2-4 and sternite 4 unarmed. Sternite 5
carinate ridge closer to the apical margin than the basal margin of the segment; length of sternite
5 greater than the combined lengths of sternites 3 and 4; a setal patch or median depression is
absent.

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Female. 2.5 - 3.5mm long (mean = 3.27mm; n = 6); 2.1 - 2.3 times as long as wide. Similar to
male except epistoma feebly emarginated, epistomal process absent, frons more strongly convex
when viewed laterally, weakly longitudinally aciculate, setae shorter, less than the width of the
eye and less abundant; weakly transversely impressed above epistoma. Apical margin of sternite
1 weakly elevated above the base of sternite 2. Second sternite unarmed.
Specimens examined. 20.
Type material. Neotype Scolytus hermosus Wood (USNM). Paratypes: MEXICO: [PUEBLA]:
Tlaxco, 11mi. N., 8900ft, 9.VII.1967, S.L. W[ood], ex. Abies religiosa (USNM-15).
Non-type material. MEXICO: CHIHUAHUA: La Magdalena, Hopk. U.S. 62081-B,
27.IV.1981, M.M. Furniss, ex. Abies durangensis (USNM-1). NUEVO LEÓN: Cerro Potosi,
Hopk. U.S. 58615-C, 21.III.[19]74, M.M. Furniss, ex. Abies sp. (USNM-2, WFBM-1).
Distribution. MEXICO: Chihuahua, Nuevo León, Puebla.
Hosts. Abies religiosa (Kunth) Schltdl. & Cham (sacred fir), Abies durangensis Martínez
(Durango fir) and Pseudotsuga menziesii (Mirb.) Franco (Douglas fir). Abies species are likely
the preferred hosts.
Common name. None.
Biology. There is a paucity of information regarding the biology of this uncommon species.
Scolytus hermosus has been collected feeding in the cambium of large Abies slash greater than
10cm in diameter (Wood 1967) and weakened and dying large Pseudotsuga (Cibrián Tovar et al.
1995). The adult galleries are transverse and perpendicular with the grain of the wood (Wood
1967). This species has been reported to colonize the same material as S. mundus (Wood 1968).
Collection notes. None.

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Remarks. Part of the type series (holotype, allotype and 4 paratypes) was lost in transit. A
neotype is here designated for this species.

Scolytus laricis Blackman
(Figures 1.38, 1.39)
Scolytus laricis Blackman 1934: 24. Holotype: male, labeled “[Cedar Mountain, Moscow, ID]
Hopk. US 225d, 8636m [sic!], 6-20-[18]99, Type No. 43839” (USNM).
Diagnosis. Scolytus laricis is very morphologically similar to S. fiskei and S. unispinosus. Males
of S. laricis are distinguished from those of S. fiskei by the dull appearance of abdominal sternite
2 and by the frons densely covered by long setae. Males can be distinguished from those of S.
unispinosus by the following combination of characters: the base of the sternite 2 spine extends
from the apical margin to three-quarters the length of the segment and host.
The female is distinguished from that of S. fiskei by the dull luster of sternite 2 and is
distinguished from that of S. unispinosus by the frons moderately and coarsely aciculatepunctate; sternite 1 rounded over onto face of sternite 2, not forming an obtuse angle, base of
sternite 2 finely impressed.
Redescription (male). 2.3 – 4.mm long (mean = 3.1mm; n = 15); 1.8- 2.5 times as long as wide.
Head, pronotum, and abdominal venter dark red-brown to black, elytra and legs light brown,
antennae yellow-brown. Pronotum typically darker than elytra.
Epistoma weakly emarginated; epistomal process present, moderately developed and
elevated; median area above mandibles bearing a dense patch of long yellow hair-like setae.
Frons appearing flattened when viewed laterally from epistoma to the vertex, moderately
transversely impressed above epistoma to vertex; surface strongly and coarsely longitudinally

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aciculate-punctate; aciculations converging at epistoma; punctures sparse, large and coarse;
surface moderately to densely and uniformly covered by long, fine, yellow erect hair-like setae,
setae longer than the midpoint of the eye. Antennal scape short, elongate, less than length of the
first four funicular segments; club flattened, irregularly ovoid, setose with a partial septum and
two arcuate sutures.
Pronotum wider than long; apical margin broadly rounded, area between the eyes lined
with scales; sides distinctly arcuate, strongly constricted near apex, and forming a weak
transverse impression near apical margin; surface smooth, shining, punctures on disc fine,
shallow and moderately abundant, lager and more abundant laterally and on apical constriction;
apical and anterolateral margins bearing sparse, erect yellow hair-like setae; base weakly
bisinuate.
Elytral sides sub-parallel on apical half, narrowing to a subquadrate and smooth apex;
apical margin of elytral apices bearing large, coarse punctures; apex moderately emarginated at
the suture. Disc smooth, shining; interstriae not impressed and twice the width of striae,
interstrial punctures uniseriate, smaller than those of striae, interstrial punctures bearing minute,
recumbent setae the length of interstrial punctures (may have worn off); striae weakly impressed.
Declivity bearing sparse, short, erect yellow setae. Metepimeron less than half-length of
metepisternum.
Apical margin of sternite 1 rounded, marked by a weak carina that is on ascendant part of
venter. Sternite 2 nearly perpendicular to sternite 1; surface smooth, shining, finely punctate with
small, fine and shallow punctures; covered with sparse setae that are less than the width of
segment 3 in length; face convex; apical margin armed with a laterally compressed, median spine
with the base extending from the apical margin to ¾ the length of the segment, apex rounded,

99

rarely a slightly elevated vertical carina (Oregon: Dixie Pass and Frog Lake) instead of a spine;
lateral margins of sternites 2-4 and sternite 4 unarmed. Sternite 5 carinate ridge equidistant
between basal and apical margins of the segment; length of sternite 5 less than the combined
lengths of sternites 3 and 4; a setal patch or median depression is absent.
Female. 2.6 – 4.0mm long (mean = 3.2mm; n = 15); 2.1- 2.9 times as long as wide. Similar to
male except epistoma feebly emarginated, epistomal process weakly developed, frons convex
when viewed laterally, weakly longitudinally aciculate, setae shorter, less than the width of the
eye and less abundant; weakly transversely impressed above epistoma. Second sternite apical
margin armed with a blunted median denticle, with base extending from apical margin to a third
length of segment. Sternite 5 length greater than the combined lengths of sternites 3 and 4.
Specimens examined. 294.
Type material. Holotype Scolytus laricis Blackman (USNM).
Non-type material. CANADA: BRITISH COLUMBIA: Canoe, 12.VII1933, A. Thrupp, ex.
Larix occidentalis (CASC-3). Rossland, 21.IX.[19]61, D.E. Bright, ex. Larix laricina (CNCI-2).
UNITED STATES: IDAHO: Boundary Co.: [Idaho Panhandle National Forest], Robinson
Creek campground, N48°58.197’ W116°13.068’, 2748ft, 10.VIII.2010, S.M. Smith, [A.R.
Gillogly], ex. Larix occidentalis, emerged II.2011, M.M. Furniss (MSUC-94). Clearwater Co.:
Elk River, V.1981, M.M. Furniss, ex. Larix occidentalis (WFBM-17), VII.1981 (WFBM-11).
Elk River, 13mi S.W., Hopk. U.S. 60361-A, 23.IV.1975, M.M. Furniss, ex. Larix occidentalis
(WFBM-4). Idaho Co.: Salmon Mountain, 18.VIII.1985, M.M. Furniss, J.B. Johnson, ex. Larix
lyalli (WFBM-29). Kootenai Co.: Coeur d’Alene, Hopk. U.S. 16306-B, 2.VIII.1919, J.C.
Evenden, ex. Larix occidentalis (WFBM-9), 8.VIII.1919 (MSUC-11). Deception Creek
Experimental Forest, Hopk. U.S. 58889-A, 10.VII.1968, M.M. Furniss (OSAC-4), Hopk. U.S.

100

53376, 11.VII.1968 (WFBM-2), Hopk. U.S. 60320, 25.VII.1968, (OSAC-2), Hopk. U.S. 50421B,C, 1.VII.1975 (OSAC-2)., Hopk. U.S. 60356, 30.VII.[19]68, M.M. Furniss, ex. Larix
occidentalis (WFBM-6). Latah Co.: Moscow, 2.VIII.1930, 2560ft, P. Rice, ex. trap (WFBM-1).
Moscow Mountain, Hopk. U.S. 53632-F, 23.VI.1964, M.M. Furniss, ex. in flight (WFBM-1),
Hopk. U.S. 60421-A, 1.VII.1975 (OSAC-1). MONTANA: Missoula Co: Missoula, 35mi N.W.,
3.XI.[19]65, ex. Larix occidentalis (WFBM-2). Nine Mile Creek, Hopk. U.S. 48830, 3.XI.1965,
M.M. Furniss, ex. Larix occidentalis (WFBM-2, OSAC-1). Ravalli Co.: [Bitterroot Mountains],
Trapper Peak, 2.X.[19]88, M.M. Furniss, ex. Larix lyalli (WFBM-3). [Unspecified County]:
Libby, 60mi S.E., 30.VI.[19]72, D.E. Bright, ex. Larix laricina (CNCI-7). OREGON: Crook
Co.: Summit Prairie, 12.VI.1940, Schuh, Scott, ex. Larix occidentalis (CNCI-3, EMEC-2).
[Grant Co.]: Dixie Pass, Malheur National Forest, 23.VI.1961, S.L. Wood, J.B. Karren, D.E.
Bright, ex. Larix occidentalis (CNCI-6, USNM-6). Jefferson Co.: Camp Sherman, T.O.
Thatcher, ex. Larix lyalli limbs (CSUC-10), 9.VII.[19]66, [L. Edson], ex. Larix lyalli (CNCI-2).
Suttle Lake, 4mi N., 25.VII.1939, ex. Larix lyalli (CSUC-1); 28.VII.1939, F. Grey, J. Schuh, ex.
Larix occidentalis (CASC-1, FMNH-6, MSUC-1, OSAC-14), W.J. Chamberlin, ex. Larix lyalli
(EMEC-7, WFBM-3). Suttle Lake, 4mi W., 15.VIII.1939, Schuh, Scott (MSUC-1). [Marion
Co.]: Clear Lake, 17.VIII.[19]51, R. Kangur, ex. Larch [=Larix sp.] (EMEC-4, WFBM-2).
[Umatilla Co.]: Tollgate, 28.X.1948, C. Chastain, ex. Larix occidentalis (EMEC-1). [Wasco
Co.]: [Mount Hood National Forest] Frog Lake [campground], 4S9 E17, 2.VIII.1951, R. Kangur
(CNCI-3). [WASHINGTON: Okanogan Co.: Disautel, 4.XI.1936, R.L. Furniss, ex. Larix
occidentalis (OSAC-3). [Pend Oreille Co.]: Metaline Falls, Hopk. U.S. 19905, 20.VII.1930, D.
DeLeon, ex. Larix occidentalis (OSAC-2, WFBM-1). [Stevens Co.]: Northport, 18.VII.1929, R.

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Hopping (OSAC-1). [Unspecified County]: Mount Adams, 7000ft, Hopk. U.S. 53359-C,
2.VIII.1968, M.M. Furniss, ex. on snowfield (WFBM-1).
Distribution. CANADA: British Columbia. UNITED STATES: Idaho, Montana, Oregon,
Washington.
Hosts. Larix occidentalis Nutt. (western larch) and Larix lyalli Parl. (subalpine larch).
Common name. None.
Biology. Scolytus laricis prefers to colonize suppressed lower limbs of its host and fresh slash.
The adult gallery of S. laricis is parallel with the grain of the wood and consists of two
egg galleries and a central nuptial chamber. The central nuptial chamber extends at a right angle
to the rest of the gallery and opposite the nuptial chamber is a rounded turning niche. This gives
the central part of the gallery an ovoid appearance that is different from all other Nearctic
Scolytus. Egg galleries are extended in parallel to the grain of the wood. The adult gallery scores
the sapwood more deeply than the cambium, and range in length from 6.4-11.5cm. The female
constructs widely spaced egg niches on both sides of each egg gallery. Larval mines extend
against the grain of wood and gradually diverge before terminating at pupation chambers that
deeply score the sapwood (Edson 1967; Furniss and Johnson 2002). There is one generation per
year and broods overwinter as larvae (Furniss and Johnson 2002).
Collection notes. Scolytus laricis was collected four times by the author and each time
specimens were collected from fresh broken branches that were less than 5cm in diameter with
bright green needles. Specimens were also collected from a fallen L. occidentalis of 15cm DBH.
Remarks. Furniss and Johnson (2002) reported that specimens collected from L. lyalli create a
different gallery structure than those collected from L. occidentalis (M.M. Furniss pers. comm.).
The galleries on L. lyalli are “shorter, less uniform, and with the entrance chamber often

102

extended a short distance to the sides of the gallery” (Furniss and Johnson 2002). Specimens
from L. lyalli could not be collected during the course of my investigation. I noticed slight
morphological variation among some populations but were unable to determine if the differences
represent species limits. Further study is needed to address this question.
The holotype of S. laricis does not bear a locality label. Blackman’s (1934) description
states A.D. Hopkins collected the holotype on Cedar Mountain near Moscow, Idaho. Numerous
collectors listed in the material examined reported this species as collected from L. lyalli in
Oregon. This host species occurs east of the Cascade Range in the Wenatchee Mountains in
Washington and is not known to occur in Oregon (Burns and Honkala 1990). It is probable that
the host species for these specimens was L. occidentalis.

Scolytus monticolae (Swaine)
(Figures 1.40, 1.41)
Eccoptogaster monticolae Swaine 1917: 32. Lectotype: female, labeled “[Arrowhead, British
Columbia], Pinus monticola, 2423, J.M. Swaine Coll, female” (CNCI). Lectotype
designated Bright 1967: 674.
Diagnosis. Scolytus monticolae males are easily confused with males of the S. reflexus,
especially those exhibiting the wickhami phenotype. They are easily distinguished by the size of
male sternite 5. In S. monticolae, sternite 5 is equal in length to the width of sternites 3 and 4
combined. In S. reflexus, sternite 5 is equal in length to sternite 4. Scolytus monticolae lacks an
epistomal process while S. reflexus typically has a strongly developed epistomal process. Males
are distinguished from those of S. tsugae by the following combination of characters: face of
sternite 2 shining but minutely reticulate; elytral striae not impressed; basal margin of sternite 2

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more pronounced and produced laterally; elytral strial punctures small, spaced 2-3 diameters of a
puncture.
Females of S. monticolae are distinguished from those of S. reflexus by having the apical
margin of sternite 1 weakly produced, never rounded and the face of sternite 2 smooth and flat,
and are separated from those of S. tsugae by elytral discal striae not impressed and sternite 2
shining in luster.
Redescription (male). 2.5 – 3.0mm long (mean = 2.9mm; n = 10); 2.0 - 2.5 times as long as
wide. Head, pronotum, and abdominal venter dark red-brown, legs light brown, antennae yellowbrown, elytra usually dark red-brown but may be brown. Pronotum typically darker than elytra.
Epistoma weakly emarginated; epistomal process weakly developed; median area above
mandibles bearing a dense patch of long yellow hair-like setae. Frons appearing flattened when
viewed laterally, slightly transversely impressed above epistoma; surface weakly aciculatepunctate, medial area appearing shagreened; aciculations converging at epistoma; punctures
small, coarse; surface sparsely and uniformly covered by long, fine, yellow erect hair-like setae,
setae longer than the midpoint of the eye. Antennal scape short, elongate, less than length of the
first four funicular segments; club flattened, irregularly ovoid, setose with a partial septum and
two arcuate sutures.
Pronotum wider than long; apical margin broadly rounded, area between the eyes lined
with scales; sides distinctly arcuate, strongly constricted near apex, and forming a weak
transverse impression near apical margin; surface smooth, shining, punctures on disc fine,
shallow and moderately abundant, lager and more abundant laterally and on apical constriction;
apical and anterolateral margins bearing sparse, erect yellow hair-like setae; base weakly
bisinuate.

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Elytral sides sub-parallel on basal half, narrowing to a subquadrate and smooth apex;
apical margin of elytral apices bearing large, coarse punctures; apex moderately emarginated at
the suture. Disc glabrous, smooth, shining; interstriae not impressed and twice the width of
striae, interstrial punctures uniseriate, smaller than those of striae, interstrial punctures bearing
minute, recumbent setae the length of interstrial punctures (may have worn off); striae not
impressed. Declivity bearing sparse, short, erect yellow setae. Metepimeron less than half-length
of metepisternum.
Apical margin of sternite 1 weakly elevated above the base of sternite 2, more
pronounced and produced laterally forming two cups. Sternite 2 nearly perpendicular to sternite
1; surface smooth, shining, finely punctate with small, fine and shallow punctures; face flattened,
depressed above the basal margin of sternite 2; apical margin unarmed; covered in recumbent
setae twice the width of a puncture; lateral margins of sternites 2-4 and sternite 4 unarmed.
Sternite 5 carinate ridge closer to the apical margin than the basal margin of the segment; length
of sternite 5 less than the combined lengths of sternites 3 and 4; a setal patch or median
depression is absent.
Female. 2.3 – 3.5mm long (mean = 3.0mm; n = 10); 2.3 - 2.7 times as long as wide. Similar to
male except epistoma feebly emarginated, frons convex when viewed laterally, strigate, setae
shorter, less than the width of the eye and less abundant; weakly transversely impressed between
inner apices of eyes. Second sternite unarmed. Length of sternite 5 is greater than the combined
lengths of sternites 3 and 4.
Specimens examined. 123.
Type material. Lectotype Eccoptogaster monticolae Swaine (CNCI).

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Non-type material. CANADA: BRITISH COLUMBIA: Merritt, Midday Valley, 27.VI.1926, W.
Mathers (USNM-2), 4.IX.1926 (USNM-2). Trinity Valley, 4.VII.1954, ex. Pseudotsuga taxifolia
(USNM-4). UNITED STATES: COLORADO: Custer Co.: Hillside, 6mi W., Duckett Creek,
FR331, Rita Alta Fuelwood area, 23.V.2000, D. Leatherman (CSUC-1). [Garfield Co.]:
Glenwood Springs (CASC-1). Jefferson Co.: Buffalo Creek, 6.VIII.2004, D. Leatherman, ex.
Douglas fir [=Pseudotsuga menziesii] (CASC-2). IDAHO: Benewah Co.: St. Maries, Hopk. U.S.
618074, 28.VIII.1978, M.M. Furniss, ex. Pseudotsuga menziesii (USNM-32). Boise Co.: Boise
National Forest, Bogus Basin, Bogus Basin Rd., N43°44.347’ W116°07.099’, 6047ft,
8.VIII.2010, S.M. Smith, A.R. Gillogly, ex. Pseudotsuga menziesii (MSUC-8). Bonner Co.:
Priest River Experimental Forest, Hopk. U.S. 61809-A, 25.X.1978, M.M. Furniss, ex.
Pseudotsuga menziesii (USNM-26). Kootenai Co.: Coeur d’Alene, 30.VIII.1919, J.C. Evenden
(MSUC-12); 7.VIII.1919, J.C. Evenden, ex. Pseudotsuga menziesii (MSUC-4). Shoshone Co.:
Coeur d’Alene National Forest, N47°25.708’ W115°53.464’, 3728ft, 15.VIII.2010, S.M. Smith,
A.R. Gillogly, ex. Pseudotsuga menziesii (MSUC-19). Prichard, 23.VII.1920, J.C. Evenden, ex.
Abies grandis (MSUC-2). MONTANA: [Sanders Co.]: Trout Creek, 1.VIII.1981, J. Dunkel, ex.
Douglas fir (USNM-2). OREGON: [Unspecified County]: Santiam National Forest,
22.VIII.[19]14, W.J. Chamberlin, ex. Abies amabalis (EMEC-1). WASHINGTON: [Kittitas
Co.]: Easton (USNM-1). [Yakima Co.]: Cliffdell, 7.VII.[19]35, R.H. Beaner (USNM-1).
WYOMING: [Park Co.]: Cody, Hopk. U.S. 34220-F, 10.V.[19]56, H.E. Ostmark, ex.
Pseudotsuga taxifolia [=P. menziesii] (CSUC-2).
Distribution. CANADA: British Columbia. UNITED STATES: Colorado, Idaho, Montana,
Oregon, Utah, Washington, Wyoming.
Hosts. Pseudotsuga menziesii (Mirb.) Franco. (Douglas fir).

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Common name. None.
Biology. Scolytus monticolae commonly infests the bole, suppressed branches and fresh slash of
Douglas fir. Scolytus monticolae (as S. tsugae, see remarks below) has been reported to kill
sapling and pole-sized Douglas fir trees in British Columbia (McMullen and Atkins 1959) and
Wyoming (Furniss and Carolin 1977) that had been drought stressed.
Adult galleries of S. monticolae strongly resemble those of S. reflexus, parallel with the
grain of the wood and bayonet shaped. The adult galleries consist of two egg galleries and a
central nuptial chamber. From the central nuptial chamber, one egg gallery extends with the
grain of the wood and the other egg gallery is slightly transversely extended and then extends
parallel with the grain. The nuptial chamber is oblique to the egg galleries. The adult gallery
scores the sapwood more than the cambium and averages 5.0-9.0cm in length. Egg niches are
generally placed in pairs along the egg galleries and score the sapwood. Larvae extend their
mines perpendicular to the egg gallery before diverging in a fan shaped pattern. Pupation may
occur under the bark or in the sapwood. In Idaho, S. monticolae has one generation per year with
flight occurring in July (Furniss and Johnson 2002; Smith, pers. obs.). Broods overwinter as
larvae and emerge the following summer (Edson 1967; Furniss and Johnson 2002).
Collection notes. The author found this species to be common in suppressed limbs and slash in
Idaho.
Remarks. The lectotype does not bear a locality label. Swaine’s (1917) description states the
lectotype was collected at Arrowhead, British Columbia.
In their paper describing the biology of S. tsugae, McMullen and Atkins (1959)
considered S. monticolae a synonym of S. tsugae based on correspondence with G.R. Hopping
(page 417). Wood (1966: 30) formally synonymized S. monticolae with S. tsugae, and later

107

removed the species from synonymy (Wood 1982; M.M. Furniss, pers. comm.). However, Wood
(1982) did not explicitly state that he was the author that recognized the species. These two
species are closely related and have subtle morphological differences. This has led to a confusing
account of both species in the literature. The majority of which seems to be applicable to S.
monticolae rather than S. tsugae. The above diagnostic characters and different biologies readily
differentiate the species.

Scolytus mundus Wood
(Figures 1.42, 1.43)
Scolytus mundus Wood 1968: 13. Neotype: female, labeled “18 km N Tlaxco, Puebla, Mexico,
Wood coll.” (USNM). Here designated.
Diagnosis. This species most strongly resembles S. aztecus and S. ventralis. Both sexes are
differentiated by elytral apices slightly emarginated only at interstria 3, by sternite 3 covered
with abundant erect setae that are greater than the width of segment 3 in length. The male can
also be differentiated by the apical margin of sternite 2 armed with a broad median denticle;
larger size, the geographic distribution.
Redescription (male). 4.0 – 4.5mm long (mean = 4.35mm; n = 4); 2.1 - 2.5 times as long as
wide. Color dark brown to black, antennae red brown. Pronotum same color as elytra.
Epistoma weakly emarginated; epistomal process absent; median area above mandibles
bearing a dense patch of long yellow hair-like setae. Frons appearing convex when viewed
laterally, moderately transversely impressed above epistoma; surface strongly and coarsely
longitudinally aciculate-punctate; aciculations converging at epistoma; punctures small, fine;
surface densely and uniformly covered by long, fine, yellow erect hair-like setae, setae longer

108

than the midpoint of the eye. Antennal scape short, elongate, less than length of the first four
funicular segments; club flattened, nearly subquadrate, setose with a partial septum and two
arcuate sutures.
Pronotum as long as wide; apical margin broadly rounded, area between the eyes lined
with scales; sides distinctly arcuate, strongly constricted near apex, and forming a weak
transverse impression near apical margin; surface smooth, shining, punctures on disc fine,
shallow and moderately abundant, lager and more abundant laterally and on apical constriction;
apical, anterolateral and lateral margins bearing abundant, erect, long dark yellow-brown hairlike setae; base weakly bisinuate.
Elytral sides sub-parallel on apical half, narrowing to a subquadrate and smooth apex;
elytral apices slightly emarginated at interstria 3 and bearing large, coarse punctures; apex
weakly emarginated at the suture. Disc smooth, shining; interstriae weakly impressed and more
than twice the width of striae, interstrial punctures uniseriate, equal in size to those of striae,
interstriae bearing moderately abundant long, erect dark yellow-brown hair-like setae; striae
weakly impressed. Declivity bearing sparse, short, erect yellow setae. Metepimeron half-length
of metepisternum.
Apical margin of sternite 1 weakly elevated above the base of sternite 2. Sternite 2 nearly
perpendicular to sternite 1; surface smooth, shining, finely punctate with small, fine and shallow
punctures; covered with abundant erect setae that are greater than the width of segment 3 in
length; face flattened; apical margin armed with a broad median denticle; lateral margins of
sternites 2-4 and sternite 4 unarmed. Sternite 5 carinate ridge closer to the apical margin than the
basal margin of the segment; length of sternite 5 greater than the combined lengths of sternites 3
and 4; a setal patch or median depression is absent.

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Female. 3.3 – 4.6mm long (mean = 4.0mm; n = 13); 1.8 – 2.6 times as long as wide. Similar to
male except epistoma feebly emarginated, epistomal process absent, frons convex when viewed
laterally, weakly longitudinally aciculate, setae shorter, less than the width of the eye and less
abundant; weakly transversely impressed between inner apices of eyes and. Apical margin of
second sternite armed by a small broad tumescence.
Specimens examined. 21.
Type material. Neotype Scolytus mundus Wood (USNM). Paratypes: MEXICO: [PUEBLA]:
Tlaxco (Tlaxcala), 11mi. N., 8900ft, 9.VII.1967, S.L. W[ood], ex. Abies religiosa (USNM-15).
Non-type material. MEXICO: [DISTRITO FEDERAL]: Desierto de los Leones National Park,
III.1951, J.M. Miller, ex. Abies religiosa (OSAC-2). HIDALGO: El Chico, 31.IX.[19]77, E.
Hernandez V., ex. Abies religiosa (CNCI-2). OAXACA: Valle Nacional, 53mi S., 10000ft,
24.V.[19]71, D.E. Bright, ex. Abies religiosa (CNCI-2). TLAXCALA: Villarreal Terrenate,
23.II.[19]78, E. Hernandez, ex. Abies religiosa (USNM-4, WFBM-5).
Distribution. MEXICO: Distrito Federal, Estado de México, Hidalgo, Michoacán, Morelos,
Oaxaca, Puebla, Tlaxcala.
Hosts. Abies religiosa. (Kunth) Schltdl. & Cham. (sacred fir).
Common name. None.
Biology. Scolytus mundus is a serious pest to Abies religiosa in Mexico and its life cycle and
habits have been well studied (see Cibrián Tovar et al. 1995). Scolytus mundus attacks the tops of
mature trees, trunks of recently cut trees and large logging slash greater than 10.0cm in diameter
(Wood 1968; Cibrián Tovar et al. 1995). Trees attacked by S. mundus exhibit red foliage at the
top of the tree. If the population density is high, subsequent generations will colonize the tree
from the top down. However, attacks rarely occur at the base and so the host tree typically

110

survives (Cibrián Tovar et al. 1995). Scolytus mundus has been reported to colonize the same
material as S. hermosus (Wood 1968).
The female initiates the attack by constructing an entrance in bark crevices at branch
nodes. The adult galleries are straight and transverse across the grain of the wood, similar to S.
ventralis and with a central nuptial chamber (see Cibrián Tovar et al. 1995, plates 130-131).
Eggs are laid in niches excavated on each side of the central nuptial chamber. The larval mines
extend parallel with the grain of wood and are first in the cambium and later penetrate into the
sapwood. Pupation occurs in the sapwood and there are two generations per year with the first
generation occurring from October to May and the second from June to October (Cibrián Tovar
et al. 1995).
Collection notes. None.
Remarks. Part of the type series (holotype, allotype and 4 paratypes) was lost in transit. A
neotype is here designated for this species.

Scolytus obelus Wood
(Figures 1.44, 1.45)
Scolytus obelus Wood 1962: 81. Holotype: male, labeled “Payson Canyon, UT, S.L Wood, 14
May 1960, Abies concolor, BLNO 001271” (USNM).
Diagnosis. Both sexes of S. obelus strongly resemble S. praeceps and are distinguished by the
presence of a small median denticle on the apical margin of sternite 2.
Redescription (male). 1.8 – 2.9mm long (mean = 2.2mm; n = 20); 2.1 - 2.9 times as long as
wide. Color red brown to dark red-brown, antennae brown. Pronotum typically darker than
elytra.

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Epistoma weakly emarginated; epistomal process weakly developed and low; median
area above mandibles bearing a dense patch of long yellow hair-like setae. Frons appearing
convex when viewed laterally, slightly transversely impressed above epistoma; surface
moderately and coarsely aciculate-punctate; aciculations converging at epistoma; punctures
small, coarse; surface moderately and uniformly covered by long, fine, yellow erect hair-like
setae, setae longer than the midpoint of the eye. Antennal scape short, elongate, less than length
of the first four funicular segments; club flattened, ovoid, setose with a partial septum and three
arcuate sutures.
Pronotum wider than long; apical margin broadly rounded, area between the eyes lined
with scales; sides distinctly arcuate, strongly constricted near apex, and forming a weak
transverse impression near apical margin; surface smooth, shining, punctures on disc fine,
shallow and moderately abundant, lager and more abundant laterally and on apical constriction;
apical and anterolateral margins bearing sparse, erect yellow hair-like setae; base weakly
bisinuate.
Elytral sides sub-parallel on apical half, narrowing to a subquadrate and weakly serrate
apex; apical margin of elytral apices bearing large, coarse punctures; apex weakly emarginated at
the suture. Disc glabrous, smooth, shining; interstriae not impressed and more than twice the
width of striae, interstrial punctures uniseriate, smaller than those of striae; striae not impressed.
Declivity bearing sparse, short, erect yellow setae. Metepimeron half-length of metepisternum.
Apical margin of sternite 1 strongly, acutely produced forming a lip along the base of
sternite 2, basal margin of sternite 2 appearing impressed. Apical margin of sternite 1 weakly
elevated above the base of sternite 2. Sternite 2 nearly perpendicular to sternite 1; surface,
shagreened, dull, finely punctate with small, fine and shallow punctures of varying size, larger

112

and more abundant near basal margin; face weakly concave; apical margin armed with an acute
median denticle; setae short, recumbent, about the length of three times that of a puncture; lateral
margins of sternites 2-4 and sternite 4 unarmed. Sternite 5 carinate ridge closer to the apical
margin than the basal margin of the segment; length of sternite 5 is equal to the combined
lengths of sternites 3 and 4; a setal patch or median depression is absent.
Female. 1.7 – 3.0mm long (mean = 2.3mm; n = 20); 2.0 - 2.7 times as long as wide. Similar to
male except epistoma feebly emarginated, epistomal process absent, frons convex when viewed
laterally, weakly aciculate, setae shorter, less than the width of the eye and less abundant; weakly
transversely impressed between inner apices of eyes. Apical margin of sternite 1 moderately
elevated above the base of sternite 2. Second sternite armed with a median tumescence or a
minute denticle.
Specimens examined. 134.
Type material. Holotype, Scolytus obelus Wood (USNM). Paratypes Scolytus obelus UNITED
STATES: UTAH: [Beaver Co.]: Beaver, 22.IV.1950, S.L. Wood, ex. Abies concolor (USNM-4).
Utah Co.: Payson Canyon, 14.V.1960, S.L. Wood, ex. Abies concolor (USNM-6), 25.VI.1962
(USNM-2).
Non-type material. UNITED STATES: ARIZONA: Coconino Co.: Coconino National Forest,
Arizona Snow Bowl, N35°19.593’, W111°42.681’, 9230ft, 27.V.2010, S.M. Smith, ex. Abies
lasiocarpa [var. arizonica] (MSUC-62). Jacob Lake, 12mi S., 31.V.1969, W. Harwood, ex.
Abies concolor branch (USNM-4). Graham Co.: Pinaleno Mountains, 15.VII.1968, D.E. Bright,
ex. Pseudotsuga menziesii (DEBC-3). [Coronado National Forest], [Pinaleno Mountains], Mount
Graham, Hospital Flat, 9050ft. 19.VIII.1952, H.B. Leech, J.W. Green (CASC-1), 8950ft,
3.VIII.1965, H.B. Leech (CASC-5). Yavapai Co.: Prescott, 1mi S., 3.VIII.1962, S.L. W[ood]

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(USNM-1). Prescott, 9mi S., 5 mi E., 7800ft, 5.VI.1969, W. Harwood, ex. Abies concolor
(USNM-6). [Unspecified County]: Santa Catalina Mountains, elev. 8500ft, 31.V.1969 (DEBC-1).
COLORADO: Costilla Co.: Ranch near Fort Garland, Forbes Trinchera, VII-VIII.1976, D.
Leatherman, ex. white fir [=Abies concolor] (CSUC-4). Huerfano Co.: Near Red Wing,
16.VII.1975, D. Leatherman, ex. white fir [=Abies concolor] (CSUC-2). NEVADA: Clark Co.:
Mary Jane Falls, 7900ft, 11.VI.1969, Harwood, ex. Abies concolor (USNM-7). [White Pine Co.]:
Baker, S9 T13N R69E, Mount Diablo Meridian, 17.V.1917, T.O. Thatcher, ex. Abies lasiocarpa,
LCNM 39-12 (CSUC-8, USNM-1, WFBM-1). Mount Wheeler, 19.VIII.1974, S.L. Wood, ex.
Abies concolor (USNM-9). NEW MEXICO: [Otero Co.]: Cloudcroft, 14-26.VII.[19]49, W.B.R.
Stromberg, ex. fir tree [=Abies sp.] (USNM-1). [Unspecified County]: Sandia Mountains, 8090ft,
29.V.1969, S.L. W[ood], ex. Abies concolor (USNM-3), 30.V.1969 (USNM-9). UTAH: Utah
Co.: Provo, Payson Canyon, VIII.1964, ex. Abies concolor (EMEC-4). [Unspecified County]:
Bryce Canyon National Park, Hopk. U.S. 35-043, 11.VII.1952, R. Washburn, ex. Abies concolor
(EMEC-2).
Distribution. UNITED STATES: Arizona, Colorado, Nevada, New Mexico, Utah.
Hosts. Abies concolor (Gord. & Glend.) Lindl. ex Hildebr. (white fir) and Abies lasiocarpa var.
arizonica (Merriam) Lemmon (corkbark fir).
Common name. None.
Biology. Scolytus obelus is an uncommonly encountered species. The species prefers to colonize
the limbs, tops and slash of its host. Infested material ranges from 3-10cm in diameter (Wood
1982).
The adult gallery of the S. obelus contains two egg galleries that branch from the central
nuptial chamber. One egg gallery extends from the nuptial chamber perpendicular to the grain of

114

wood and the second gallery extends at a 45° angle to the grain. Galleries are frequently initiated
near branch crotches and disguised under rough patches of bark. The adult gallery deeply scores
the sapwood and lightly scores the cambium. The adult galleries range in size from 1.9-6.5cm in
length. Eggs are laid in niches on both sides of each egg gallery and larval mines radiate
perpendicular to the egg gallery forming a fan shaped pattern. The larval mines gradually diverge
and lightly etch the sapwood. Pupation occurs in the sapwood (Edson 1967).
Collection notes. The author collected specimens from suppressed 2-4cm diameter branches of
A. lasiocarpa var. arizonica that had been girdled at the base by porcupines. Needles of infested
branches were pale green to yellow.
Remarks. This species is sister to S. praeceps and is very similar both in morphology and
gallery architecture. Interspecific divergence in COI nucleotide difference between these two
taxa is quite large and averages 0.1036 (Table 1.8).

Scolytus oregoni Blackman
(Figures 1.46, 1.47)
Scolytus oregoni Blackman 1934: 18. Holotype, male, labeled “Ashland Ore., May 20/19,
Glendinning, WE Colr, Pseudotsuga taxifolia, Hopk. US. 13399a, Type No. 43834
USNM” (USNM).
Diagnosis. Scolytus oregoni is a rather distinctive species and both sexes are readily
distinguished by having the apical margin of sternite 1 thickened and on the face of sternite 2 and
by the unarmed sternite 2.
Redescription (male). 2.6 – 3.6mm long (mean = 3.3mm; n = 20); 2.0 - 2.4 times as long as
wide. Color dark red-brown, antennae brown. Pronotum typically darker than elytra.

115

Epistoma weakly emarginated; epistomal process weakly developed; median area above
mandibles bearing a dense patch of long yellow hair-like setae. Frons appearing flattened when
viewed laterally, slightly transversely impressed above epistoma; surface moderately and
coarsely longitudinally aciculate-punctate; aciculations converging at epistoma; punctures
sparse, small, coarse; surface moderately and uniformly covered by long, fine, yellow erect hairlike setae, setae longer than the midpoint of the eye. Antennal scape short, elongate, less than
length of the first four funicular segments; club flattened, irregularly ovoid, setose with a partial
septum and two strongly arcuate sutures.
Pronotum wider than long; apical margin broadly rounded, area between the eyes lined
with scales; sides distinctly arcuate, strongly constricted near apex, and forming a weak
transverse impression near apical margin; surface smooth, shining, punctures on disc fine,
shallow and moderately abundant, lager and more abundant laterally and on apical constriction;
apical and anterolateral margins bearing sparse, erect yellow hair-like setae; base weakly
bisinuate.
Elytral sides sub-parallel on apical half, narrowing to a subquadrate and smooth apex;
apical margin of elytral apices bearing large, coarse punctures; apex weakly emarginated at the
suture. Disc glabrous, smooth, shining; interstriae not impressed and more than twice the width
of striae, interstrial punctures uniseriate, smaller than those of striae; striae weakly impressed.
Declivity bearing sparse, short, erect yellow setae. Metepimeron less than half-length of
metepisternum.
Apical margin of sternite 1 not elevated above the base of sternite 2. Basal margin of
sternite 2 strongly thickened, lip-like; sternite 2 nearly perpendicular to sternite 1; surface
shagreened, dull, finely punctate with small, fine and shallow punctures; face weakly concave,

116

weakly to strongly medially impressed just above the base; apical margin unarmed; setae small,
less than 1 diameter of a puncture; lateral margins of sternites 2-4 and sternite 4 unarmed.
Sternite 5 carinate ridge closer to the apical margin than the basal margin of the segment; length
of sternite 5 equal to the combined lengths of sternites 3 and 4; a setal patch or median
depression is absent.
Female. 2.8 – 4.0mm long (mean = 3.23mm; n = 20); 1.6 – 2.7 times as long as wide. Similar to
male except epistoma entire, epistomal process absent, frons convex when viewed laterally,
weakly longitudinally aciculate, setae shorter, less than the width of the eye and less abundant;
weakly transversely impressed between inner apices of eyes. Second sternite unarmed, basal
margin weakly thickened.
Specimens examined. 96.
Type material. Holotype Scolytus oregoni Blackman (USNM). Paratypes: UNITED STATES:
OREGON: [Jackson Co.]: Ashland, Hopk. U.S. 14246-C, 10.III.[19]16, P.D. Sergent, ex.
Pseudotsuga taxifolia (CNCI-2); II.[19]19, W.E Glendinning, Hopk. U.S. 1399-A (USNM-14).
Non-type material. UNITED STATES: CALIFORNIA: [Del Norte Co.]: [Six Rivers National
Forest], Gasquet R.S. [=Ranger Station], Hopk. U.S. 31722-H, 10.VII. R.L. Furniss, ex.
Pseudotsuga taxifolia (OSAC-23). Lake Co.: Middletown, 11.XI.1959, G.M. Thomas, ex.
Pseudotsuga menziesii (OSAC-1). Los Angeles Co.: Angeles National Forest, Sawmill Mountain,
34.6926°N, 118.5499°W, V.28-VI.14.2007, Caterino, Chatzimanolis, ex. Lindgren trap (SBMN4). Marin Co.: Alpine Lake, V.[19]57 (CASC-4). Mount Tamalpais 14.IX.[19]57, E.L. Smith,
ex. Pseudotsuga menziesii (OSAC-1). Woodacre Creek, 9.VII.1951, P.S. Bartholomew (CASC1). Napa Co.: Angwin, 2mi N.N.E., N. side of Howell Mountain, 1300ft, 16.VII.1974, H.B.
Leech, ex. emerged from log of Pseudotsuga menziesii (CASC-1), 21.VII.1974 (CASC-4,

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USNM-5), 22.VII.1974 (CASC-1), 25.VII.1974 (CASC-4, USNM-1), 7.VIII.1983 (CASC-1),
12.IX.1983 (CASC-2). Callistoga, 5.X.1947, S.L. Wood, ex. Pseudotsuga taxifolia (USNM-2).
Mount Saint Helena, Hopk. U.S. 15401-A, F.B. Herbert, ex. Pseudotsuga taxifolia (OSAC-1).
Riverside Co.: Santa Barbara National Forest, Black Mountain Rd., 33.8395°N, 116.7306°W,
1.VII.2005, M. Caterino (SBMN-1). [Valyermo Co.]: Fenner Canyon, Hopk. U.S. 33853-A,
15.VIII.[19]51, A.D. Moore, ex. Pseudotsuga macrocarpa (EMEC-3, OSAC-8, USNM-4).
OREGON: Benton Co.: Marys Peak, Corvallis Watershed, 9.VIII.1963, ex. rotary traps (EMEC1). Jackson Co.: Ashland, Hopk. U.S. 13363-B, 26.VI.1918, W.E.G, ex. Pseudotsuga taxifolia,
(OSAC-14). Mistletoe, Hopk. U.S. 15753-A, P.D. Sergent, ex. Pseudotsuga taxifolia [=P.
menziesii] (OSAC-3). Rogue River National Forest, Rogue River Gorge viewpoint, N42º 54.540’
W122º26.733’, 3489ft, 21.VIII.2010, S.M. Smith, ex. Pseudotsuga menziesii (MSUC-3).
Linn/Lane Co.: Blue River, 11mi N.E., H.J. Andrews experimental forest, 5.VIII.1986, Log
Decomp Study, Site 2, SE1/4 S15 T15S RSE, Trap 2WA (OSAC-1). [Tillamok Co.]: Woods,
18.XI.[19]38 (OSAC-1). Wasco Co.: The Dalles, ODA Port/Mill survey, Trap #65-01a,
14.VIII.1997, ex. Lindgren funnel with α-pinene & ethanol lure (MSUC-1).
Distribution. UNITED STATES: California, Oregon, Washington.
Hosts. Pseudotsuga menziesii (Mirb.) Franco (= Pseudotsuga taxifolia Britton) (Douglas fir) and
Pseudotsuga macrocarpa (Vasey) Mayr. (big cone Douglas fir).
Common name. None.
Biology. Scolytus oregoni colonizes large limbs and tops of its host and also fresh slash (Edson
1967; Smith, pers. obs.).
The S. oregoni adult gallery is typically constructed parallel with the grain of the wood
and has a central nuptial chamber. The gallery structure is typically bayonet shaped but may also

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be longitudinal. Each egg gallery extends in opposite directions with the grain of the wood from
the central nuptial chamber. The nuptial chamber is transverse to the egg galleries. The adult
gallery deeply scores the sapwood and lightly scores the cambium. The adult gallery averages
6.0-18.0cm in length. Egg niches are closely spaced and deeply score the sapwood. Larvae
extend their mines perpendicular to the egg gallery in a fan shaped pattern before terminating in
pupation chambers, which are constructed in the sapwood (Edson 1967).
Collection notes. None.
Remarks. Specimens of S. oregoni are very rarely collected and the species and is perhaps the
least common of the conifer-feeders in the United States. There are many gaps that occur in its
distribution range, especially between northern and southern California. Considerable variation is
observed in the male sternite 1 and 2 across the geographic range especially between northern
California, Oregon and Washington and southern California. Southern California populations
colonize Pseudotsuga macrocarpa while individuals from the rest of the range colonize P.
menziesii. In addition, S. oregoni males from California and particularly southern California have
a greater impression of the second sternite and thicker margin between sternite 1 and 2 compared
to Oregon and Washington.

Scolytus piceae (Swaine)
(Figures 1.48, 1.49)
Eccoptogaster piceae Swaine 1910: 34. Lectotype: male, labeled “ St. Anne’s, Que., July 21,
1907” (CUIC). Lectotype designated Bright 1967: 674.

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Diagnosis. Both sexes are easily diagnosed by the large conical median spine on the face of the
second sternite, of which the spine base never touches any margin, by the lack of lateral denticles
on the apical margins of sternites 2-4 and by the unicolorous elytra.
Redescription (male). 2.5 – 3.0mm long (mean = 2.4mm; n = 12); 2.3 - 2.7 times as long as
wide. Color red-brown to dark red brown, antennae yellow-brown, legs dark red-brown to yellow
brown apically. Pronotum typically darker than elytra.
Epistoma weakly emarginated; epistomal process present, moderately developed and low;
median area above mandibles bearing a dense patch of long yellow hair-like setae. Frons
appearing flattened when viewed laterally from epistoma to the vertex, slightly transversely
impressed above epistoma to inner apices of eyes; surface moderately and coarsely
longitudinally aciculate-punctate; aciculations converging at epistoma; punctures large, dense
and coarse; surface moderately and uniformly covered by long, fine, yellow erect hair-like setae,
setae longer than the midpoint of the eye. Antennal scape short, elongate, less than length of the
first four funicular segments; club flattened, irregularly ovoid, setose with a partial septum and
two arcuate sutures.
Pronotum wider than long; apical margin broadly rounded, area between the eyes lined
with scales; sides distinctly arcuate, strongly constricted near apex, and forming a weak
transverse impression near apical margin; surface smooth, shining, punctures on disc fine,
shallow and moderately abundant, lager and more abundant laterally and on apical constriction;
apical and anterolateral margins bearing sparse, erect yellow hair-like setae; base weakly
bisinuate.
Elytral sides sub-parallel on apical half, narrowing to a subquadrate and smooth apex;
apical margin of elytral apices bearing large, coarse punctures; apex weakly emarginated at the

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suture. Disc glabrous, smooth, shining; interstriae weakly impressed and more than twice the
width of striae, interstrial punctures uniseriate, smaller than those of striae; striae weakly
impressed. Declivity bearing sparse, short, erect yellow setae. Metepimeron half-length of
metepisternum.
Apical margin of sternite 1 rounded, marked by a weak carina on ascendant part of
venter, more strongly marked laterally. Sternite 2 nearly perpendicular to sternite 1; surface
reticulate, shagreened, dull, finely punctate with small, fine and shallow punctures; covered with
sparse setae that are about twice the size of a puncture; face convex; armed with a large conical
median spine, apex rounded; lateral margins of sternites 2-4 and sternite 4 unarmed. Sternite 5
carinate ridge closer to apical margins of the segment; length of sternite 5 less than the combined
lengths of sternites 3 and 4; a setal patch or median depression is absent.
Female. 2.3 – 3.0mm long (mean = 2.3mm; n = 12); 2.3 - 2.7 times as long as wide. Similar to
male except epistoma feebly emarginated, epistomal process weakly developed, frons convex
when viewed laterally, weakly longitudinally aciculate, less coarsely punctate, setae shorter, less
than the width of the eye and less abundant; weakly transversely impressed above epistoma.
Second sternite armed with a smaller, rounded, median spine.
Specimens examined. 454.
Type material. Lectotype Eccoptogaster piceae Swaine (CUIC). Paralectotype (here
designated) Eccoptogaster piceae, female, CANADA: QUEBEC: St. Anne’s, 21.VII.1907
(CUIC-1). Paratypes: CANADA: QUEBEC: Hudson, 191[sic!] (CUIC-4).
Non-type material. CANADA: ALBERTA: Banff (CNCI-2); IX.1916 (CNCI-1); 7.IX.1967,
D.E. Bright, ex. Picea glauca (CNCI-1). Cypress Hills, 16.VII.[19]32 (CNCI-3). Edmonton,
16.I.1916, Carr (CNCI-1), 27.VIII.1916 (CNCI-1), 28.VIII.1916 (CNCI-1), 5.VII.1924, (CUIC-

121

1); 6.XII.1916 (CASC-2); 15.VII.[19]24 (CASC-2); 29.VI.[19]16, J.W. Green (CASC-3),
2.IX.[19]16 (CASC-1). [Jasper National Park], Athabasca Falls, 9.VIII.1919, J.M. Swaine
(CNCI-5). Medicine Hat, 2.IX.[19]26 (CNCI-2). Seebe, 7.VII.1966, D.F.J. Hilton, ex. Picea
glauca (CNCI-8). BRITISH COLUMBIA: Hixon, 9.VII.1972, D.E. Bright, ex. Picea sp. (CNCI2). Lorna, 6.VII.1924, G. Hopping, ex. Picea engelmannii (CASC-1), 10.VIII.1924 (CASC-1),
22.VII.1925 (CASC-1), 14.VII.1926, ex. Pinus contorta (CASC-1), 9.VII.1926 (CASC-1);
10.VII.1926, H. Richmond ex. Picea engelmannii (CNCI-1), 14.VII.1926 (CNCI-1). Pine Pass,
11.VII.1972, D.E. Bright, ex. Picea sp. (CNCI-6). Trinity Valley, 21.VII.[19]30 (CNCI-1),
29.VII.[19]30 (CNCI-1), 13.VII.1928, J.R. Howell, ex. Pinus monticolae (CASC-1);
23.VII.[19]28, H. Richmond, ex. Picea engelmannii (CASC-1). MANITOBA: Aweme,
20.IX.[19]06, E. Criddle (CNCI-1); 1.VII.1916, N. Criddle, (CNCI-2) ex. bred from spruce
[=Picea sp.], 2.VII.1916 (CNCI-4); 10.VII.[19]16 (CNCI-10) ex. spruce [=Picea sp.],
27.VII.[19]10 (CNCI-20), 14.VI.1918 (CNCI-2), 15.VI.1918 (CNCI-3); 5.VII.1916 (CNCI-3);
8.VII.1916 (CNCI-6), 9.VII.1916 (CNCI-1); 31.VII.1916 (CNCI-1); 9.VIII.1916 (CNCI-1);
10.IX.1917 (CNCI-10); 11.IX.1917 (CNCI-6); 9.VI.19[18] (CNCI-1). Brandon, 28.V.1940, L.
Peterson, ex. Picea canadensis (CNCI-2). Gillam, 21.VII.950, W.J. Brown (CNCI-1). Glen
Souris, 5.VI.[19]23, N. Criddle (CNCI-1). Grass River Provincial Park, 27.VII.1972, D.E.
Bright, ex. Pinus murrayana [=Pinus contorta murrayana] (CNCI-7). Onah, 11.VII.1924, R.M.
White (CNCI-3); N. Criddle, 25.VIII.[19]72 (CNCI-1). Telford, 24.VII.1963, ex. life table plot
(CNCI-1), 2.VIII.1963 (CNCI-1). Winnipeg, Hanham (USNM-1). NEW BRUNSWICK:
Kouchibouguac National Park, VIII.1977, D.E. Bright, Code-6224J (CNCI-1). McGraw Brook,
10mi W., 7.VII.[19]70, D.E. Bright, ex. Picea glauca (CNCI-1). NEWFOUNDLAND: Deer
Lake, 12 mi N.E., 23.VII.[19]70, D.E. Bright, ex. Picea mariana (CNCI-11). NOVA SCOTIA:

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Cape Breton Highlands National Park, MacIntosh Brook, PG703866, 21.VII.1983, D.E. & J.E.
Bright, ex. Picea glauca (CNCI-7); 29.VII.1983, McKenzie, ex. Picea sp. (CNCI-10).
Kejimkujik National Park, 16-17.VII.1967, D.E. Bright, ex. Picea glauca (CNCI-14).
ONTARIO: Carp, 5.VIII.[19]66, D.E. Bright, ex. Picea mariana (CNCI-2). Lake of the Woods,
1.VIII.1972, D.E. Bright, ex. Picea sp. (CNCI-7). Ottawa, 24.VI.1913, J.M. Swaine, ex. crawling
on dying Larix sp. (CNCI-1). Rainy River District, 3.VIII.[19]24, J.F. Brimley (CNCI-1).
QUEBEC: Aylmer, 12.VII.1924, B.B. Watson, ex. Picea glauca (CNCI-1); 30.VII.1924, A.R.
Graham (CNCI-1). Hudson, 191[sic!] (CNCI-52). Limbor/Touranine, 27.VI.1974, R. Sexton
(CNCI-1). [Gaspésie National Park], Mount Albert, 28.VII.1954, W.J. Brown, ex. north base
650ft (CNCI-1). St. Anne’s, 19.VI.[19]19 (CASC-2, CNCI-42). South March, 19.VI.1958, S.D.
Hicks (CNCI-1). SASKATCHEWAN: Big River, 23.VII.1972, D.E. Bright, ex. Picea glauca
(CNCI-1). Big River, 40mi N.W., 22.VII.[19]72, D.E. Bright, ex. Picea glauca (CNCI-1). Canoe
Lake, 21.VII.1972, D.E. Bright, ex. Picea glauca (CNCI-2). Christopher Lake, 5.VIII.1959, A.
& J. Brooks (CNCI-1). Cypress Hills, 3.IX.1967, D.E. Bright, ex. Picea glauca (CNCI-9);
24.IX.1964 (CNCI-2). YUKON: Old Crow, 28.VI.[19]81, D.E. Bright (CNCI-5). UNITED
STATES: ALASKA: [North Slope Borough]: Prudhoe Bay Rd., 8 mi N., South Fork Koyukuk
River, 150°07’W, 67°13’N, 1000ft [sic!], 8.VII.1978, Smetana, Campbell (CNCI-1). Fairbanks
North Star Borough: Fairbanks, 2.VIII.[19]55, W.F. McCambridge, ex. Picea glauca (DEBC-7).
CALIFORNIA: Siskiyou Co: Callahan, 7mi N.W., 16.VI.[19]63, D.E. Bright, ex. Picea
engelmannii (DEBC-9, EMEC-6). Happy Camp, 18mi N., 31.VII.[19]63, D.E. Bright, ex. Picea
engelmannii (DEBC-4, EMEC-7). COLORADO: Roosevelt National Forest, Chambers Lake,
11.VIII.[19]68, 9200ft, L.A. Kelton (CNCI-1). Denver Co.: Denver, Union Pacific, 14.IX.2000,
USDA APHIS, ex. Lindgren funnel APEtOH Lure, (CSUC-1). Larimer Co.: Livermore,

123

10.IX.2009, K. Smith, USDA APHIS, ex. Lindgren funnel APEtOH Lure, (CSUC-1). MAINE:
[Oxford Co.]: Wilsons Mills, 9.VIII.[19]70, D.E. Bright, ex. Picea sp. (CNCI-1).
MASSACHSUETTS: [Norfolk Co.]: Dover, 8.VII.1933, C.W. Collins, ex. reared from blue
spruce [=Picea pungens] (USNM-11). MINNESOTA: Cook Co.: Superior National Forest, Hwy
12 nr. Seagull Guard Station, 48°6’29”N, 90°50’12”W, 23.VI-9.VII.2003, K.J.K. Gandhi, ex.
Lindgren funnel trap in Pinus banksiana, wind-disturbed-salvaged-logged, site D (CASC-1).
Mille Lacs Co.: 2.VII.[19]36, H.R. Dodge, ex. under bark of tamarack tree [=Larix sp.] (CASC2). MONTANA: Glacier National Park, 15.VII.[19]29 (CUIC-1). NORTH DAKOTA: Bottineau
Co.: S30 T162 R75, Hopk. U.S. 56561-A, 27.V.1973, A.D. Tagestad, ex. collected from Picea
glauca densata (USNM-3). Rolette Co.: S15 T162 R69, Hopk. U.S. 56446, 19.V.[19]72, A.D.
Tagestad, ex. collected from Picea pungens (USNM-2). OREGON: [Jefferson Co.]: Suttle Lake,
4mi W., 3.IX.[19]39, Schuh, Gray, ex. Picea engelmannii (FMNH-3). [Unspecified County]:
Blue Mountains, 13.VII.[19]14, W.J. Chamberlain, ex. Picea engelmannii (CNCI-2). SOUTH
DAKOTA: Lawrence Co.: Near Leads, Brownsville Rd., N44.2922°, W103.7828°, 5650ft,
27.VII.2004, K.P. Dole, ex. Picea glauca (MSUC-14). [Unspecified County]: Black Hills,
7.VII.[19]75, D.E. Bright, ex. Picea glauca (CNCI-5). UTAH: [Daggett Co.]: Mckee Draw,
Ashley National Forest, 16.VI.1960, ex. Picea pungens (USNM-1). [Unspecified County]: Logan
Canyon, S27 T13 NR4, 6.VII.1948, S.L. Wood, ex. Picea engelmannii (USNM-8). WYOMING:
Carbon Co.: [Medicine Bow National Forest], Mirror Lake, 4mi W., 6.IX.2010, D.E. Bright,
B.A. Barr, ex. Picea engelmannii branches (DEBC-1); [Medicine Bow National Forest] Snowy
Mountains, WY130, Lake Marie, N41°19.965’, W106°19.516’, 3208m, 26.VII.2011, S.M.
Smith, D.E. Bright, B.A. Barr, ex. emerged 1-5.IX.2011, ex. Picea engelmannii (MSUC-36).
Johnson Co.: Buffalo, 16km SW, 20.VI.1968, S.L. W[ood], ex. Picea engelmannii (USNM-1).

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Distribution. CANADA: Alberta, British Columbia, Manitoba, Nova Scotia, Northwest
Territories, New Brunswick, Newfoundland, Ontario, Prince Edward island, Quebec,
Saskatchewan, Yukon. UNITED STATES: Alaska, California, Colorado, Idaho, Maine,
Massachusetts, Michigan, Montana, New York, North Dakota, Oregon, South Dakota, Utah,
Washington, Wisconsin, Wyoming.
Hosts. Most spruce species including: Picea breweriana S. Watson (Brewer spruce), Picea
engelmannii Parry ex Engelm. (Engelmann spruce), Picea glauca (Moench) Voss (white spruce),
Picea mariana (Mill.) B.S.P. (black spruce), Picea pungens Engelm. (blue spruce), and Picea
rubens Sarg. (red spruce). This species rarely attacks Larix spp. (larch) and Abies balsamea (L.)
Mill (balsam fir).
Common name. None.
Biology. Scolytus piceae infests dead and dying limbs (Chamberlin 1939; Bright and Stark 1973)
and is commonly found in branches of fallen spruce trees and suppressed limbs of standing hosts
(Smith, pers. obs.).
The adult gallery is parallel with the grain of the wood and bayonet shaped. From the
central nuptial chamber, one egg gallery extends with the grain of the wood and the other egg
gallery is slightly transversely extended and then extends parallel with the grain. The nuptial
chamber is oblique to the egg galleries. The adult gallery equally scores the sapwood and
cambium but in some instances may only lightly score the sapwood. Adult galleries average 5.08.0cm in length. Ten to 30 egg niches are widely spaced and deeply score the sapwood. Larvae
extend their mines perpendicular to the egg gallery before diverging in a fan shaped pattern.
Pupation may occur under the bark or in the sapwood (Edson 1967; Bright and Stark 1973).
There is likely one generation per year (Bright and Stark 1973; Furniss and Johnson 2002).

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Collection notes. None.
Remarks. The female paralectotype has been returned to CUIC from the CNCI following the
repositories listed in Swaine (1910).

Scolytus praeceps LeConte
(Figures 1.50-1.53)
Scolytus praeceps LeConte 1876: 373. Lectotype: female, labeled “Cali. [California, Calaveras,
Crotch Coll], Type 967” (MCZC). Lectotype designated Wood 1982: 439.
= Scolytus abietis Blackman 1934: 21. Holotype: male, labeled “8637iss [Sandpoint,
Idaho], 6-20-[18]99, [A.D. Hopkins], Hopk. US 224, Type No. 43837” (USNM). New
synonymy.
= Scolytus opacus Blackman 1934: 20. Holotype: male, labeled “Ouray, Colo[rado],
7,500-8,000 ft., July 1-15, [18]97, HF Wickham, Type No. 43836” (USNM). New
synonymy.
Diagnosis. Scolytus praeceps is a morphologically variable species across its range. Both sexes
most closely resemble S. obelus and is differentiated by a median tubercle on the apical margin
of sternite 2 in both sexes. The female is differentiated from that of S. dentatus by the presence
of a weakly developed and almost indistinct epistomal process and smaller size.
Redescription (male). 1.8 – 3.2mm long (mean = 2.5mm; n = 20); 2.0 - 2.9 times as long as
wide. Color dark red-brown to black, antennae yellow-brown. Pronotum typically darker than
elytra.
Epistoma weakly emarginated; epistomal process absent; median area above mandibles
bearing a dense patch of long yellow hair-like setae. Frons appearing convex when viewed

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laterally, slightly transversely impressed above epistoma and along the median line to upper level
of eyes (may not be impressed in some specimens); surface moderately and coarsely aciculatepunctate; aciculations converging at epistoma; punctures small, coarse; surface moderately and
uniformly covered by long, fine, yellow erect hair-like setae, setae longer than the midpoint of
the eye. Antennal scape short, elongate, less than length of the first four funicular segments; club
flattened, ovoid, setose with a partial septum and two arcuate sutures.
Pronotum wider than long; apical margin broadly rounded, area between the eyes lined
with scales; sides distinctly arcuate, strongly constricted near apex, and forming a weak
transverse impression near apical margin; surface smooth, shining, punctures on disc fine,
shallow and moderately abundant, lager and more abundant laterally and on apical constriction;
apical and anterolateral margins bearing sparse, erect yellow hair-like setae; base weakly
bisinuate.
Elytral sides sub-parallel on apical half, narrowing to a subquadrate and smooth apex;
apical margin of elytral apices bearing large, coarse punctures; apex weakly emarginated at the
suture. Disc glabrous, smooth, shining; interstriae not impressed and more than twice the width
of striae, interstrial punctures uniseriate, smaller than those of striae; striae not impressed.
Declivity bearing sparse, short, erect yellow setae. Metepimeron half-length of metepisternum.
Apical margin of sternite 1 strongly, acutely produced forming a lip along the base of
sternite 2, basal margin of sternite 2 appearing impressed. Sternite 2 nearly perpendicular to
sternite 1; surface glabrous, shagreened, finely punctate (obscurely punctate in some specimens)
with small, fine and shallow punctures; face weakly concave; apical margin unarmed or armed
with a longitudinal carina and a blunt tubercle, appearing keel-shaped or a low median
longitudinal carina; lateral margins of sternites 2-4 and sternite 4 unarmed. Sternite 5 carinate

127

ridge closer to the apical margin than the basal margin of the segment; length of sternite 5 equal
to the combined lengths of sternites 3 and 4; a setal patch or median depression is absent.
Female. 1.7 – 3.5mm long (mean = 2.69mm; n = 20); 2.0 – 3.0 times as long as wide. Similar to
male except epistoma feebly emarginated, epistomal process absent, frons more strongly convex
when viewed laterally, weakly aciculate, setae shorter, less than the width of the eye and less
abundant; entirely convex to weakly transversely impressed above epistoma. Apical margin of
sternite 1 weakly elevated above the base of sternite 2. Apical margin of sternite 2 unarmed or
weakly longitudinally tumescent.
Specimens examined. 627.
Type material. Holotype Scolytus praeceps LeConte (MCZC). Holotype Scolytus abietis
Blackman (USNM). Holotype Scolytus opacus Blackman (USNM).
Non-type material. CANADA: BRITISH COLUMBIA: [Big Creek Provincial Park], Lorna
[Lake], 5.VIII.1926, H. Richmond, ex. Abies lasiocarpa (CASC-2). Duncan, Genoa Bay,
16.VIII.1928, W.G. Mathers, ex. Abies grandis (CNCI-10), 17.VIII.1928 (CASC-3). UNITED
STATES: CALIFORNIA: Alpine Co.: Humboldt-Toiyabe National Forest, Hwy 88,
N38°45.824’ W119°51.498’, 6262ft, 24.VII.2010, S.M. Smith, ex. Abies concolor (MSUC-3). El
Dorado Co.: Georgetown, 10mi E., University of California Blodgett [Experimental] Forest,
VI.[19]62, R.W. Stark, ex. Abies concolor (DEBC-3, EMEC-8); 30.V.1986, K. Hobson (EMEC2), 1-2.VI.1986 (EMEC-2), 21-24.VI.1986 (EMEC-2), 1-7.VII.1986 (EMEC-9), 9-16.VII.1986
(EMEC-3); 2.VI.2003, K. Apigian (EMEC-2), 5.VI.2003 (EMEC-1). Ice House Reservoir,
25.V.2007, A.I. Cognato (MSUC-5). [Lake Tahoe], Fallen Leaf Lake, 6300ft, 5.VII.1940, H.T.
Reynolds (EMEC-2). Pacific House, 0.7mi E., 2.VII.1989, F.G. Andrews, ex. flume (CSCA-1).
Pacific House, 1mi E., 1.V.1994, C.B. Barr, ex. seining El Dorado ditch (EMEC-1). South Lake

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Tahoe, 16.VI.1988, D. Adams, ex. reared from Abies concolor (CSCA-1). [Fresno Co.]:
Huntington Lake, 23.VII.[19]19, F.C. Clark (CASC-52). Shaver, 14.IX.[19]08, Miller, ex. Abies
concolor (CNCI-3). [Madera Co.]: Northfork, 22.VI.1935, R.P. Allen (EMEC-1). Marin Co.:
Inverness, 8.VIII.[19]62, C.A. Toschi (EMEC-1). Mariposa Co.: Yosemite Valley, 7.VII.1921
(CASC-21). Mendocino Co.: Noyo River, VI.1896 (CASC-2). Modoc Co.: Alturas, Knox
Mountain, 8.VII.1964, D.L. Dahlsten (EMEC-1). Warner Mountains, 4.VII.1919, G. Hopping,
ex. Abies concolor (CASC-4, USNM-2). Monterey Co.: 30.VII.1964, D.E. Bright, ex. Abies
bracteata (CASC-8). Carmel Valley, 15mi S., 22.VI.1963, C.J. Wray, ex. Abies bracteata
(CNCI-7, DEBC-1, EMEC-5). Williams Canyon, Los Padres National Forest, 24.IV.1992, D.E.
Bright, G. Ferrell, ex. Abies bracteata limbs (CNCI-22). Nevada Co.: Donner Memorial State
Park, 10.IX.[19]87, S. Seybold, ex. collected on Abies concolor (CNCI-2, EMEC-1),
11.IX.[19]87 (CNCI-1, EMEC-1), 29.X.1987 (CNCI-2, EMEC-2). Nevada City, 28.V.1939, R.P.
Allen (CNCI-5). Riverside Co.: Mount San Jacinto State Park, 33.807°N, 116.654°W,
15.VII.2003, M. Caterino (SBMN-1). Santa Rosa Mountain, 15.IX.[19]56, D.E. Bright, D.N.
King, ex. Abies concolor (EMEC-4). San Bernardino Co.: San Bernardino National Forest, E. of
Arrowbear Lake, 34.2076°N, 117.0584°W, 29.V.2004, M. Caterino (SBMN-2); S. Fork Trail,
34.1297°N, 117.8426°W, 28.V.2004, M. Caterino (SBMN-1). San Bernardino Mountains, Dollar
Lake trail, 10.VII.1956, R.W. Bushing (EMEC-2), 11.VII.1956 (DEBC-1, EMEC-10). Sierra
Co.: Calpine, 2.3mi N.W., 5200ft, 27.VIII.1961, H.B. Leech, ex. under bark of Abies sp. (CASC9). Siskiyou Co.: McCloud, 14.VI.1961, S.L. Wood, J.B. Kerren, D.E. Bright, ex. Abies concolor
(DEBC-5). Mount Shasta, 28.VII.1980, A.J. Gilbert (CASC-1). Trinity Co.: Klamath National
Forest, FR 41N16, 0.2mi E. FR 93, N41°14.822’ W122°53.562’, 5081ft, 28.VII.2010, S.M.
Smith, ex. Abies concolor (MSUC-2). Tuolumne Co.: Cow Creek, 5mi N. Strawberry,

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18.VII.1964, C.W. O’Brien, ex. Abies sp. (CASC-102, DEBC-11). Pinecrest, IX.1966, emerged
28.III.1967, G.T. Ferrell, ex. Abies concolor (EMEC-4). Sierra Village, 10.VII.1966, B.A.
Tolden (EMEC-1). [Unspecified County]: Pinecrest, Hopk. U.S. 19192-A, 29.VII.1930, G.R.
Struble, ex. Abies concolor (DEBC-3). Shasta [-Trinity] National Forest, Hopk. U.S. 21078,
10.V.1934, K.A. Salmon (DEBC-4). COLORADO: Clear Creek Co.: Idaho Springs, 12mi S.,
12.VII.2007, D.E. Bright, B.A. Barr, ex. bole Abies lasiocarpa (CSUC-2, DEBC-4). Eagle Co.:
Basalt Mountain, 20.VI.1996, D. Leatherman (CSUC-1). IDAHO: [Bonner Co.]: Sandpoint,
2.VII.1964, N.M. Downie (FMNH-1). Clearwater Co.: Angel Butte thinning, T37N R3E, sec 3,
ex. Abies grandis #86 (USNM-10). Kootenai Co.: Coeur d’Alene, 28.IV.1922, H.J. Rust, ex.
Abies grandis (MSUC-3); 15.V.1951, 2157ft, W.F. Barr, ex. Abies grandis (EMEC-3). Latah
Co.: Flat Creek, N48°58.385’ W116°13.351’, 2713ft, 10.VIII.2010, S.M. Smith, [A.R. Gillogly],
M.M. Furniss, ex. Abies lasiocarpa, emerged II.2011, M.M. Furniss (MSUC-72). Lewis Co.:
Nezperce, 3mi N., 3.VII.[19]69, R.C. Biggum (EMEC-1). OREGON: Deschutes Co.: Deschutes
National Forest, Black Butte Rd., Black Butte, N44°24.924’ W121°38.323’, 4212ft,
31.VIII.2010, S.M. Smith, ex. Abies grandis (MSUC- 91). Paulina Lake, 2mi W., 12.VI.1940,
Schuh, Scott, ex. Abies concolor (EMEC-2). Douglas Co.: Diamond Lake, 9.VII.[19]64, D.E.
Bright, ex. Abies sp. (EMEC-7). Jackson Co.: Copper, 2mi N., 3.IX.1970, W.G. Harwood, ex.
Abies lasiocarpa, emerged 21.X.1970 (MSUC-7). [Klamath Co.]: Keno, 16.VII.[19]29, J.A.
Beal, ex. Abies concolor (CSUC-2). Linn/Lane Co.: Blue River, 11mi N.E., H.J. Andrews
Experimental Forest, 5.VIII.1988, log decomp study, site 2, SE1/4 S15 T15S RSE, trap 2WA
(OSAC-1). [Umatilla Co.]: Tollgate, 6.VI.[19]49, C. Chastain, ex. Abies grandis (CSUC-3,
EMEC-2, FMNH-1). UTAH: Utah Co.: Hobble Creek Canyon, 14.VI.[19]60, D.E. Bright, ex.
Abies concolor (DEBC-2). [Unspecified County]: (CNCI-1). 1952, T.O. Thatcher (CSUC-10).

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WYOMING: Albany Co.: Snowy Mountains, [Medicine Bow National Forest], Spruce
campground, 6.IX.2010, D.E. Bright, B.A. Barr coll., ex. Abies concolor branches (DEBC-2).
[Carbon Co.]: Saratoga, Hopk. U.S. 31518-E, 1.IX.[19]38, ex. Abies lasiocarpa (CSUC-1).
Distribution. CANADA: Alberta, British Columbia. UNITED STATES: California, Idaho,
Montana, Oregon, Utah, Washington, Wyoming.
Hosts. Abies concolor (Gord. & Glend.) Lindl. ex Hildebr. (white fir), Abies bracteata (D. Don)
Poit. (bristlecone fir) and Abies lasiocarpa (Hook.) Nutt. (subalpine fir).
Common name. None.
Biology. Scolytus praeceps prefers to colonize fresh slash but is also found in small limbs and
tops of small standing trees (Edson 1967; Bright and Stark 1973).
The adult gallery of the S. praeceps contains two egg galleries that branch from the
central nuptial chamber. Typically, one egg gallery extends from the nuptial chamber
perpendicular to the grain of wood and the second egg gallery extends at a 45° angle to the grain.
Occasionally both egg galleries are extended obliquely to the grain, at a 45° angle to the grain or
perpendicular to the grain (Edson 1967). Galleries are frequently initiated near branch crotches
and disguised under rough patches of bark. The adult gallery equally scores the sapwood and
cambium. The adult galleries range in size from 2.5-6.4cm in length. Eggs are laid in niches on
both sides of each egg gallery and larval mines radiate perpendicular to the egg gallery. The
larval mines gradually diverge forming a fan shaped pattern and lightly etch the sapwood.
Pupation occurs in the sapwood (Edson 1967). There is one generation per year and broods
overwinter as larvae (Furniss and Johnson 2002).
Collection notes. None.

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Remarks. There has been a great deal of historical uncertainty regarding the placement of S.
abietis and S. opacus since they were described. The species are extremely morphologically
similar and thus difficult to differentiate. This similarity led several authors to treat S. abietis as
either a synonym of S. opacus (Wood 1982) or as a subspecies (Bright 1976). Equihua-Martinez
and Furniss (2009) removed S. abietis from synonymy with S. opacus based on differences in
host use, submentum shape, and striations on the underside of the head and characters of the
second sternite including setae, punctures and spine shape.
The species S. abietis, S. opacus and S. praeceps were not recovered as monophyletic in
any of my analyses (Figures 1.1-1.8). I observed very low intraspecific COI and ArgK nucleotide
differences among populations (COI: 0-0.0049; mean= 0.0032), (ArgK: 0-0.0044; mean=
0.0024) and no differences in 28S or CAD (Table 1.7). Considerable variation was also observed
in the shape of the spine on the male second sternite, especially within S. praeceps. Scolytus
abietis and S. opacus are here placed in synonymy with S. praeceps because they were recovered
as polyphyletic (Figures 1.1-1.8), there are minute molecular difference among populations
sampled from California, Oregon, Idaho and Wyoming (Tables 1.4, 1.5, 1.7), the species have
identical galleries (Edson 1967, Wood 1982) and variability of the spine on male sternite 2.
The lectotype of S. praeceps bears a partial locality label. LeConte’s (1868) description
states that the lectotype was collected at Calaveras, California by Mr. Crotch.

Scolytus reflexus Blackman
(Figures 1.54, 1.55)

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Scolytus reflexus Blackman 1934: 13. Holotype: male, labeled “Sta Catalina Mts, Ariz.,
Chrisman, M. Coll, Pseudotsuga taxifolia, Hopk. U.S. 12210, Reared June 1-14 H.B.
Kirk, Type No. 43831 USNM” (USNM).
= Scolytus virgatus Bright 1972: 1490. Holotype: male, labeled “MEX., N.L., Cerro
Potosi, V.2.71, 8500’, D.E. Bright, Pseudotsuga menziesii, CNC No. 12604” (CNCI).
New Synonymy.
= Scolytus wickhami Blackman 1934: 13. Holotype: male, labeled “ Buena Vista, Col.
H.F. Wickham July 1-6 ’96, 7,900-8,000 ft, Type No. 43832 USNM” (USNM). New
Synonymy.
Diagnosis. Scolytus reflexus Males exhibiting the reflexus phenotype are readily distinguished
by the presence of a strong recurved subapical carinate ridge on sternite 5 that is medially
produced to form a slightly recurved and subrostriform ridge that appears “reflexed”. Males of
this species exhibiting the wickhami phenotype are easily confused with males of S. monticolae.
They are easily distinguished by the size of male sternite 5. In S. reflexus, sternite 5 is equal in
length to sternite 4. In S. monticolae, sternite 5 is equal in length to the width of sternites 3 and 4
combined. Scolytus monticolae lacks an epistomal process while S. reflexus typically has a
strongly developed epistomal process.
Scolytus reflexus females are distinguished from those of S. monticolae by having the
apical margin of sternite 1 rounded and by the sternite 2 face rugose, shining, coarsely punctate
and convex.
Redescription (male). 2.4 – 3.8mm long (mean = 3.2mm; n = 20); 1.8 – 2.5 times as long as
wide. Color dark red-brown to black, antenna brown. Pronotum typically darker than elytra.

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Epistoma weakly to acutely and deeply emarginated; epistomal process weakly to
strongly developed and elevated; median area above mandibles bearing a dense patch of long
yellow hair-like setae. Frons appearing flattened when viewed laterally, slightly transversely
impressed above epistoma; surface moderately longitudinally aciculate and deeply and coarsely
punctate; aciculations converging at epistoma; punctures small, coarse; surface moderately and
uniformly covered by long, fine, yellow erect hair-like setae, setae longer than the midpoint of
the eye. Antennal scape short, elongate, less than length of the first four funicular segments; club
flattened, irregularly ovoid, setose with a partial septum and three sharply arcuate sutures.
Pronotum wider than long; apical margin broadly rounded, area between the eyes lined
with scales; sides distinctly arcuate, strongly constricted near apex, and forming a weak
transverse impression near apical margin; surface smooth, shining, punctures on disc fine,
shallow and moderately abundant, lager and more abundant laterally and on apical constriction;
apical, anterolateral and lateral margins bearing sparse, erect yellow hair-like setae; base weakly
bisinuate.
Elytral sides sub-parallel on apical half, narrowing to a subquadrate and smooth apex;
apical margin of elytral apices bearing small, fine punctures; apex moderately emarginated at the
suture. Disc smooth, shining; interstriae weakly impressed and more than twice the width of
striae, interstrial punctures uniseriate, smaller than those of striae, interstriae bearing minute,
recumbent setae less than length of a puncture; striae weakly impressed. Declivity bearing
sparse, short, erect yellow setae. Metepimeron half-length of metepisternum.
Apical margin of sternite 1 rounded, marked by a weak carina on vertical face of
segment. Sternite 2 nearly perpendicular to sternite 1; surface rugose, shagreened, finely punctate
with small, coarse and shallow punctures; face convex; setae moderately abundant, long, erect

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and longer than the width of sternite 3, lateral margins of sternites 2-4 and sternite 4 unarmed.
Sternite 5 typically armed with strong recurved subapical carinate ridge but may instead be
modified and medially produced to form a slightly recurved and subrostriform ridge that appears
“reflexed” (Chiricahua Mountains and Chihuahua, Mexico populations). Sternite 5 carinate ridge
closer to the apical margin than the basal margin of the segment; length of sternite 5 less than the
combined lengths of sternites 3 and 4; a setal patch or median depression is absent.
Female. 2.5 – 4.0mm long (mean = 3.2mm; n = 20); 1.87 – 2.5 times as long as wide. Similar to
male except epistoma entire, epistomal process absent, frons convex when viewed laterally,
weakly longitudinally aciculate, setae shorter, less than the width of the eye and less abundant;
weakly transversely impressed just above epistoma and between inner apices of eyes. Second
sternite unarmed, setae sparse, recumbent erect and the size of three diameters of a puncture.
Length of sternite 5 greater than the combined lengths of sternites 3 and 4, armed with an apical
strong recurved subapical carinate ridge.
Specimens examined. 357.
Type material. Holotype Scolytus reflexus Blackman (USNM). Holotype Scolytus virgatus
Bright (CNCI). Holotype Scolytus wickhami Blackman (USNM). Paratypes Scolytus reflexus
UNITED STATES: ARIZONA: [Cochise Co.]: Chiricahua Mountains, 18.VI.[?], Hubbard,
Schwarz (EMEC-1). Pima/ Pinal Co.: Santa Catalina Mountains, M. Chrisman, reared
25.VI.[19]14, H.B. Kirk, ex. Pseudotsuga taxifolia [=P. menziesii] (EMEC-1). Paratypes
Scolytus wickhami UNITED STATES: ARIZONA: [Cochise Co.]: Chiricahua Mountains,
Hopk. U.S. 5558-A, 5.VIII.[19]07, J.L. Webb, ex. Pseudotsuga taxifolia [= P. menziesii] (CNCI1). NEW MEXICO: [Lincoln Co.]: Capitan Mountains, Hopk. U.S. 5674, J.L. Webb, ex.
Pseudotsuga taxifolia [= P. menziesii] (CNCI-1). Paratypes Scolytus virgatus MEXICO:

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NUEVO LEON: Cerro Potosi, 8500ft, 2.V.[19]71, D.E. Bright, ex. Pseudotsuga menziesii
(CNCI-4).
Non-type material. MEXICO: CHIHUAHUA: San Juanito, 16km N.E., 50m, 19.VII.1960, S.L.
Wood, ex. Pseudotsuga menziesii (MSUC-3, USNM-7). San Juanito, Hopk. U.S. 58592,
16.III.1974, M.M. Furniss, ex. Pinus sp. (USNM-1, WFBM-5). DURANGO: Hopk. U.S. 58685,
24.III.1974, M.M. Furniss, ex. Pseudotsuga menziesii (USNM-14). UNITED STATES:
ARIZONA: Cochise Co.: Chiricahua Mountains, 21.VII.1916, C.R. Bruck, (DEBC-2),
29.IX.[19]47, D.J. & J.N. Knull (DEBC-4). Coronado National Forest, Chiricahua Mountains,
N31°54.915’ W109°16.040’, 8196ft, 20.V.2010, S.M. Smith, ex. Pseudotsuga menziesii
(MSUC-7). Huachuca Mountains, Upper Carr Canyon, 7500ft, 6-10.VIII.[19]52, H.B. Leech,
J.W. Green (CASC-1). [Coconino Co.]: Jacob Lake, Kaibab National Forest, 19.VI.[19]66, [L.
Edson], ex. Pseudotsuga menziesii (EMEC-3). Greenlee Co.: Hannagan [Meadows]
campground, 12.VII.1968, D.E. Bright, ex. Pseudotsuga menziesii (CNCI-5). Pima Co.: Tucson,
Mount Lemmon, 11.VI.1969, S.L. Wood, ex. Pseudotsuga menziesii (MSUC-1). Pima/Pinal
Co.: Santa Catalina Mountains, 9000ft, 6.VI.1926, R.B. Streets (CASC-1); 5.VIII.1968, D.E.
Bright, ex. Pseudotsuga menziesii (CNCI-1); Bear Wallow, 7800ft, 11.VI.1969, S.L. Wood
(USNM-5). Santa Cruz Co.: Carr Canyon, 8.VIII.1962, S.L. Wood, ex. Pseudotsuga taxifolia
[=P. menziesii] (USNM-12). Yavapai Co.: Prescott National Forest, Mount Union Lake, [L.
Edson], ex. Pseudotsuga menziesii (EMEC-1). COLORADO: [Boulder Co.]: Boulder, Hopk.
U.S. 17700-Y, 21.IV.[19]37, J.A. Beal, ex. Pseudotsuga taxifolia [=P. menziesii] (CSUC-3,
USNM-5). Chaffee Co.: N. of Poncha Pass, 25.VII.1997, D. Leatherman, ex. ponderosa pine
[=Pinus ponderosa] (CSUC-1). Clear Creek Co.: Idaho Springs, 7.5mi S., 12.VII.2007, D.
Bright, B.A. Barr, ex. bole Pseudotsuga menziesii (DEBC-3). Lawson, 26.VII.1994, D.

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Leatherman, ex. Douglas fir [=Pseudotsuga menziesii] (CSUC-4). Near Lawson, 26.VII.1994, S.
Kelley, ex. Pseudotsuga menziesii (CNCI-2). [Garfield Co.]: Glenwood Springs, VII.[?] (CASC1). Jefferson Co.: 1-15.VII.2010, Colorado Dept of Agriculture, ex. Lindgren funnel UHR EtOH
& Ω-pinene conifer (CSUC-3). Buffalo Creek, 6.VIII.2004, D. Leatherman, ex. Douglas fir
[=Pseudotsuga menziesii] (CSUC-1). Larimer Co.: Estes Park, 19.VI.[19]35, ex. Pseudotsuga
taxifolia [=Pseudotsuga menziesii] (USNM-3); 28-VI-13.VII.2010, Colorado Dept of
Agriculture, ex. Lindgren funnel UHR EtOH & Ω-pinene conifer (CSUC-3). Fort Collins,
29.VI.[19]35, (USNM-2). Mount Margaret trailhead, 4.VIII.1994, D. Leatherman, ex. Douglas
fir [=Pseudotsuga menziesii] (CSUC-1). Pingree Park, 30.VIII.1995, D. Leatherman (CSUC-1).
Poudre Canyon, 27.V.1975, D. Leatherman, ex. Douglas fir [=Pseudotsuga menziesii] (CSUC1). Rist Canyon, 28.X.[19]56, D.E. Bright, ex. Pseudotsuga taxifolia [=P. menziesii] (DEBC-1);
S28 T8 NR70W, 3.III.1957, T.O. Thatcher, ex. Pseudotsuga taxifolia [=P. menziesii] (DEBC-7).
Rist Canyon Picnic Area, 26.VI.2008, D. Leatherman, ex. fallen Douglas fir [=Pseudotsuga
menziesii] (CSUC-3). Roosevelt National Forest, Big Thompson Canyon, N40°24.456’
W105°24.565’, 7080ft, 5.V.2010, S.M. Smith, D.E. Bright, B.A Barr, ex. Pseudotsuga menziesii
(MSUC-2). Red Feather Lakes, 12.III.2003, D. Leatherman, ex. Douglas fir [=Pseudotsuga
menziesii] (CSUC-1), VI.2000 (CSUC-3). CR 63E, 2mi S. off Hwy 14, 4.VII.2007, D.
Leatherman, ex. Douglas fir [=Pseudotsuga menziesii] (CSUC-11). Mineral Co.: Wolf Creek
Pass off US 160, Sheep Mountain, 25.VII.2005, D. Leatherman, ex. Douglas fir [=Pseudotsuga
menziesii] (CSUC-1). Prowers Co.: Red Feather Lakes, VI.2000, D. Leatherman, ex. Douglas fir
[=Pseudotsuga menziesii] (CSUC-1). Pueblo Co.: SR 165, 5mi S.E. San Isabel Millset trailhead,
23.VI.2000, D. Leatherman, ex. Douglas fir [=Pseudotsuga menziesii] (CSUC-3). Teller Co.:
Ridgewood Subdivision, 5.VIII.2004, D. Leatherman, ex. Douglas fir [=Pseudotsuga menziesii]

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(CSUC-1). Weld Co.: Red Feather Lakes, VI.2000, D. Leatherman, ex. Douglas fir
[=Pseudotsuga menziesii] (CSUC-1). NEVADA: [Lander Co.]: Austin, 12.VIII.[19]40, D.E.
Hardy (USNM-1). NEW MEXICO: Otero Co.: Cloudcroft, 4.VI.1969, tree 53, S.L. Wood, ex.
Pseudotsuga menziesii (MSUC-14); 11-13.VII.[19]74, D.E. Bright, ex. Pseudotsuga menziesii
(CNCI-4). Lincoln National Forest, Apache Point Observatory, N32°47.046’ W105°48.841’,
9116ft, 15.V.2010, S.M. Smith, ex. Pseudotsuga menziesii (MSUC-145). [Sandoval Co.]: Jemez
Springs, Hopk. U.S. 37218-F, ex. Pseudotsuga menziesii (USNM-4); Hopk. U.S. 37214-D,
1.IX.[19]57, F.M. Yasinski, ex. Pseudotsuga taxifolia [=P. menziesii] (USNM-15). TEXAS:
Culberson Co.: Guadalupe Mountains National Park, The Bowl, 17.VII.1974, Bright, ex.
Pseudotsuga menziesii (CNCI-6). UTAH: [Utah Co.]: Wasatch National Forest, Mount
Timpanogos, 13.VII.1957, D.E. Bright, ex. Abies concolor. [Unspecified County]: Logan
Canyon, 5000ft, 31.XII.1945, S.L. Wood, ex. Douglas fir [=Pseudotsuga menziesii] (USNM-3),
28.IV.1946 (USNM-2), 16.VI.,1946 (USNM-4), 3.VII.1946 (USNM-4).
Distribution. MEXICO: Chihuahua, Durango, Nuevo Leon. UNITED STATES: Arizona,
Colorado, Nevada, New Mexico, Texas, Utah.
Hosts. Pseudotsuga menziesii (Mirb.) Franco (= Pseudotsuga taxifolia Britton) (Douglas fir).
Common name. None.
Biology. Scolytus reflexus is relatively common throughout its range and is found in fresh slash
and branches of Douglas fir (Edson 1967).
The adult gallery consists of two egg galleries and a central nuptial chamber. The adult
gallery is parallel with the grain of the wood and bayonet shaped. From the central nuptial
chamber, one egg gallery extends parallel with the grain of the wood and the other egg gallery is
slightly transversely extended and then extends parallel with the grain. The nuptial chamber is

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oblique to the egg galleries. The adult gallery equally scores the sapwood and cambium and
averages 3.9-7.6cm in length. Egg niches are closely spaced and score the sapwood. Larvae
extend their mines perpendicular to the egg gallery before diverging in a fan shaped pattern.
Pupation may occur under the bark or in the sapwood (Edson 1967).
Collection notes. The author has collected S. reflexus in the Chiricahua Mountains, Arizona and
Apache Point Observatory, New Mexico killing small (less than 10cm DBH) Douglas fir trees.
This species was also reported killing Douglas fir in the Sacramento Mountains and Santa Fe
National Forest of New Mexico, and was tentatively and incorrectly identified as S. monticolae
(USFS 2004). Scolytus monticolae strongly resembles S. reflexus (see diagnosis) but does not
occur in New Mexico.
Remarks. Wood (1977: 388) placed S. reflexus and S. wickhami in synonymy with S. tsugae.
Wood (1982) removed S. reflexus from synonymy with S. tsugae. In this publication he also
listed S. wickhami as a synonym of S. reflexus and cited Wood (1977) for the synonymy. Wood
and Bright (1992: 364) also cite Wood (1977) for the synonymy. However, S. wickhami was
never removed from synonymy with S. tsugae and designated as a synonym of S. reflexus.
In his description of S. virgatus, Bright (1972) posited that the species was closely
related to S. wickhami or either a subspecies or variety. Wood (1982) considered S. wickhami a
synonym of S. reflexus, but as discussed above, never formally placed it in synonymy. All three
species are here treated as one slightly morphologically variable species. I assessed intraspecific
variation within these three species for four genes (Table 1.7). It was found to be small for each
gene with the average COI divergence of 0.0130 among sampled populations (Table 1.7). There
are two main characteristics found that vary among the populations; the male fifth sternite carina
and the male epistomal process. There are two main phenotypes observed in populations;

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reflexus and wickhami. The reflexus phenotype includes individuals that were previously
considered to be S. reflexus with the male sternite 5 armed with a strong recurved subapical
carinate ridge that at its crest is closer to the basal than the apical margin of the segment. This
character is only found in the Chiricahua Mountains, Arizona and in Chihuahua, Mexico. The
wickhami phenotype includes individuals that were formerly considered S. wickhami and S.
virgatus. In the wickhami phenotype the process on the male fifth sternite is reduced in the
wickhami phenotype and but still forms strong recurved subapical carinate ridge. However it is
important to note that both the reflexus and wickhami phenotypes are sympatric in the
Chiricahua Mountains. The male epistomal process also varies from a strongly developed and
elevated ridge above the epistoma to weakly developed and elevated ridge. In general, the ridge
is more strongly developed in the reflexus phenotype but considerable variation is observed
especially in the wickhami phenotype. Additional variation is observed in the density of
punctures on the male second sternite and the coarseness of the male frons aciculations. In
addition, the gallery structure of S. reflexus and S. wickhami are identical; the gallery of S.
virgatus is has not been noted. Scolytus wickhami and S. virgatus are here designated as
synonyms of S. reflexus.

Scolytus robustus Blackman
(Figures 1.56, 1.57)
Scolytus robustus Blackman 1934: 19. Holotype: male, labeled “Prescott N.F. Ariz., VII-24[19]30, M.W. Blackman Collector, Abies concolor, Hopk. US 20410E, Type No. 43835
USNM” (USNM).

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Diagnosis. The S. robustus male is quite distinctive with its strongly flattened frons, apical
margin of sternite 1 strongly, acutely produced forming a lip along the base of sternite 2, basal
margin of sternite 2 appearing impressed and by the unarmed apical margin of sternite 2.
The S. robustus female is morphologically similar to that of S. ventralis. The S. robustus
female is distinguished by having the apical margin of sternite 1 forming a carinate lip along the
basal margin of sternite 2.
Redescription (male). 2.5 – 4.0mm long (mean = 3.2mm; n = 20); 1.8 – 2.7 times as long as
wide. Head, pronotum and abdominal venter dark red-brown, antennae light brown, legs dark
red-brown to light brown, elytra red-brown. Pronotum typically darker than elytra.
Epistoma moderately emarginated; epistomal process strongly developed and elevated;
median area above mandibles bearing a dense patch of long yellow hair-like setae. Frons
appearing flattened when viewed laterally, slightly transversely impressed above epistoma;
surface moderately and coarsely longitudinally aciculate-punctate; aciculations converging at
epistoma; punctures small, coarse; surface moderately and uniformly covered by long, fine,
yellow erect hair-like setae, setae longer than the midpoint of the eye. Antennal scape short,
elongate, less than length of the first four funicular segments; club flattened, irregularly ovoid,
setose with a partial septum and two sharply arcuate sutures.
Pronotum wider than long; apical margin broadly rounded, area between the eyes lined
with scales; sides distinctly arcuate, strongly constricted near apex, and forming a weak
transverse impression near apical margin; surface smooth, shining, punctures on disc fine,
shallow and moderately abundant, larger and more abundant laterally and on apical constriction;
apical and anterolateral margins bearing sparse, erect yellow hair-like setae; base weakly
bisinuate.

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Elytral sides sub-parallel on apical half, narrowing to a subquadrate and weakly serrate
apex; apical margin of elytral apices bearing large, coarse punctures; apex moderately
emarginated at the suture. Disc smooth, shining; interstriae not impressed and more than twice
the width of striae, interstrial punctures uniseriate, smaller than those of striae, interstriae bearing
minute, recumbent setae less than length of a puncture; striae weakly impressed. Declivity
bearing sparse, short, erect yellow setae. Metepimeron half-length of metepisternum.
Apical margin of sternite 1 strongly, acutely produced forming a lip along the base of
sternite 2, basal margin of sternite 2 appearing impressed. Sternite 2 nearly perpendicular to
sternite 1; surface glabrous, shining, rugose, finely punctate with small, fine and shallow
punctures; face flattened, unarmed or with a weak median tumescence on apical margin; lateral
margins of sternites 2-4 and sternite 4 unarmed. Sternite 5 carinate ridge closer to the apical
margin than the basal margin of the segment; length of sternite 5 equal to the combined lengths
of sternites 3 and 4; a setal patch or median depression is absent.
Female. 2.2 – 4.1mm long (mean = 3.2mm; n = 20); 1.9- 2.5 times as long as wide. Similar to
male except epistoma feebly emarginated, epistomal process less strongly developed and
elevated, frons convex when viewed laterally, weakly longitudinally aciculate, setae shorter, less
than the width of the eye and less abundant; weakly transversely impressed between inner apices
of eyes and. Second sternite unarmed.
Specimens examined. 143.
Type material. Holotype Scolytus robustus Blackman (USNM).
Non-type material. UNITED STATES: ARIZONA: [Coconino Co.]: Grand Canyon North Rim,
Kaibab National Forest, VI.[19]66, [L. Edson] (EMEC-4). [Graham Co.]: Pinaleno Mountains,
Swift Trail, 3mi, Lady Bug Saddle, 11.IX.1964, C.W. O’Brien, ex. Abies sp. (CASC-1, CNCI-4,

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EMEC-2); Coronado National Forest, SR 366, N32°37.702’ W109°49.472’, 7896ft, S.M. Smith,
ex. Abies concolor (MSUC-2). COLORADO: Costilla Co.: Near Fort Garland, Forbes Trinchera
Ranch, VII-VIII.1976, D. Leatherman ex. white fir [=Abies concolor] (CSUC-1). Huerfano Co.:
Near Red Wing, 16.VII.1975, D. Leatherman, ex. white fir [=Abies concolor] (CSUC-4). Pass
Creek, 20.VIII.1975, D. Leatherman, ex. white fir [=Abies concolor] (CSUC-2). La Plata Co.:
Columbine Lake, 11.VIII.2004, D. Leatherman, ex. subalpine fir [=Abies lasiocarpa] (CSUC-1).
NEVADA: Clark Co.: 19.VII.[19]29, C.C. Searl (DEBC-1, EMEC-4). Cathedral Rock, emerged
7-9.V.2002, R. Turnbow, ex. Abies sp. (WFBM-2). White Pine Co.: Baker, 17.V.1939, T.O.
Thatcher (CNCI-2). NEW MEXICO: Bernalillo Co.: Cibola National Forest, Sandia Peak,
9.VII.[19]68, D.E. Bright (CNCI-1); NM536, N35°12.853’ W106°24.743’, 8753ft, 10.V.2010,
S.M. Smith, A.I. Cognato, ex. Abies concolor (MSUC-15), N35°11.655’ W106°24.075’, 8317ft
(MSUC-30). [Santa Fe Co.]: Santa Fe, Little Teseque Canyon, 14.VI.[19]35, Van Dyke (CASC3). [Unspecified County]: Sandia Mountains, tree 9, 29.V.1969, S.L. Wood, ex. Abies concolor
(MSUC-13), tree 18, 30.V.1969 (MSUC-19). TEXAS: [Unspecified county]: San Antonio, Hopk.
U.S. 3938, W.F. Fiske, ex. bred 15.VI.[19]07 (USNM-3). UTAH: Cache Co.: Logan (CNCI-1).
[San Juan Co.]: Mount Navajo, 8500ft, 10.VI.[19]36, McAbee (CASC-4). Utah Co.: Payson
Canyon, 14.V.1960, D.E. Bright, ex. Abies concolor (CNCI-3); 20.V.1961, S.L. Wood, ex. Abies
concolor (USNM-9). [Unspecified County]: Bryce Canyon National Park, 10.V.1981, M.M.
Furniss, ex. Abies concolor (WFBM-10). UNSPECIFIED STATE: (CASC-1).
Distribution. UNITED STATES: Arizona, Colorado, Nevada, New Mexico, Texas, Utah.
Hosts. Principle host: Abies concolor (Gord. & Glend.) Lindl. ex Hildebr (white fir). Incidental
host: Abies lasiocarpa (Hook.) Nutt (subalpine fir).
Common name. None.

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Biology. Scolytus robustus is found in the limbs and tops of its host and fresh slash. Galleries are
often initiated near limb bases (Edson 1967).
The adult gallery of S. robustus contains two egg galleries that branch from the central
nuptial chamber. Gallery shape is quite variable and ranges from ‘S’ shaped at an oblique angle
to the grain to nearly perpendicular against the grain. Typically one egg gallery obliquely
extends from the central nuptial chamber against the grain of wood for a short distance before
becoming apically recurved. The second egg gallery is identical to the first but runs in the
opposite direction. However galleries may extend perpendicular to the grain of the wood or may
not be apically recurved. The adult gallery deeply scores the sapwood and range in size from 2.57.0cm in length. Egg niches are distinct, score the sapwood and are closely spaced along the egg
galleries. Larval mines rapidly diverge perpendicular to the adult gallery and are parallel with the
grain of the wood. Larval mines terminate in pupation chambers that score the sapwood (Edson
1967).
Collection notes. The author collected this species from 10cm diameter slash with thick (5mm)
bark.
Remarks. There was a relatively large amount of intraspecific variation (0.0537) observed in
mitochondrial COI sequences from specimens collected from Arizona and New Mexico and low
variation observed between the two Arizona populations (Tables 1.5 and 1.7). Scolytus robustus
only occurs on Abies. In southeastern Arizona, Abies spp. and S. robustus are confined to high
elevation sites on the sky islands. These Arizona populations are isolated from the New Mexico
populations by large areas that are unsuitable for Abies. No specific geographic morphological
differences were observed among the examined specimens.

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Scolytus silvaticus Bright, removed from synonymy
(Figures 1.58, 1.59)
Scolytus silvaticus Bright 1972: 1489. Holotype: male, labeled “MEX., N.L., Cerro Potosi,
V.3.71, 1100’, D.E. Bright, Pseudotsuga menziesii, CNC No. 12603” (CNCI).
Diagnosis. The S. silvaticus male is distinguished from other species by having the apical margin
of sternite 4 thickened, forming a broad carina with a blunt median tubercle.
The female is distinguished from the morphologically similar male of S. hermosus by
having the apical margin of sternite 1 produced, forming a carinate lip along the basal margin of
sternite 2 that is about half as produced as thick and by the host and is distinguished from the S.
hermosus female by having a strongly developed epistomal process.
Redescription (male). 3.0mm long (mean = 3.0mm; n = 1); 2.0 – 2.1 times as long as wide.
Color dark red-brown to black. Pronotum same color as elytra.
Epistoma moderately and broadly emarginated; epistomal process weakly developed;
median area above mandibles bearing a dense patch of long yellow hair-like setae. Frons
appearing flattened when viewed laterally, slightly transversely impressed above epistoma;
surface moderately and coarsely aciculate-punctate; aciculations converging at epistoma;
punctures small, coarse; surface moderately and uniformly covered by long, fine, yellow-brown
erect hair-like setae, setae longer than the midpoint of the eye. Antennal scape short, elongate,
less than length of the first four funicular segments; club flattened, almost subquadrate, setose
with a partial septum and two broadly arcuate sutures.
Pronotum wider than long; apical margin broadly rounded, area between the eyes lined
with scales; sides distinctly arcuate, strongly constricted near apex, and forming a weak
transverse impression near apical margin; surface smooth, shining, punctures on disc fine,

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shallow and moderately abundant, larger and more abundant laterally and on apical constriction;
apical and anterolateral margins bearing sparse, erect dark yellow-brown setae; base weakly
bisinuate.
Elytral sides sub-parallel on apical half, narrowing to a subquadrate and smooth apex;
apical margin of elytral apices bearing small, fine punctures; apex moderately emarginated at the
suture. Disc smooth, shining; interstriae not impressed and more than twice the width of striae,
interstrial punctures uniseriate, smaller than those of striae; interstrial punctures bearing sparse,
recumbent, long dark yellow-brown setae; striae weakly impressed. Declivity bearing abundant,
long, erect dark yellow-brown hair-like setae. Metepimeron half-length of metepisternum.
Apical margin of sternite 1 moderately elevated above the base of sternite 2, sternite 2
appearing impressed. Sternite 2 nearly perpendicular to sternite 1; surface smooth, shining, finely
punctate with small, fine and shallow punctures; setae small, about two diameters of a puncture
in length; face flattened; lateral margins of sternites 2-4 unarmed. Apical margin of sternite 4
thickened forming a broad carina with a blunt median tubercle. Sternite 5 carinate ridge closer to
the apical margin than the basal margin of the segment; length of sternite 5 greater than the
combined lengths of sternites 3 and 4; a setal patch or median depression is absent.
Female. 3.3 – 3.6mm long (mean = 3.4mm; n = 3); 2.2 – 2.8 times as long as wide. Similar to
male except epistomal process more strongly developed, frons convex when viewed laterally,
weakly aciculate, setae shorter, less than the width of the eye and sparse; weakly transversely
impressed between inner apices of eye. Second sternite unarmed.
Specimens examined. 4.
Type material. Holotype Scolytus silvaticus Bright (CNCI). Allotype, female, identical data as
holotype. Paratypes, identical data as holotype (CNCI-2).

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Non-type material. None examined.
Distribution. MEXICO: Nuevo Leon.
Hosts. Pseudotsuga menziesii (Mirb.) Franco. (Douglas fir).
Common name. None.
Biology. Scolytus silvaticus is only known from a single collecting event from broken branches
of Pseudotsuga menziesii (Bright 1972). The gallery and biology of this species are unknown but
the gallery structure is presumably similar to that of other Pseudotsuga feeding Scolytus, parallel
with the grain of the wood.
Collection notes. None.
Remarks. Wood (1975: 22) placed S. silvaticus in synonymy with S. hermosus, which occurs on
the same mountain as S. silvaticus. Wood reasoned that only one Scolytus species could occur in
the same location and that the observed morphological variation was due to intraspecific
differences. In addition, he stated that Bright’s image of the S. silvaticus male was a normal male
of S. hermosus. I here remove S. silvaticus from synonymy with S. hermosus because of the
many distinct morphological and host differences originally noted by Bright (1972). In the male
of S. silvaticus, the apical margin of sternite 1 is moderately thickened and weakly produced, the
posterior margin of sternite 3 is slightly medially thickened and the posterior margin of sternite 4
is in strongly produced and thickened medially, forming a broad carina with a blunt median
tubercle. In the male of S. hermosus sternite 1 apical margin is thickened and strongly produced
and sternites 3-4 are flat and S. hermosus colonizes Abies species rather than Pseudotsuga. It is
also not uncommon for multiple Scolytus species to have overlapping distributions.

Scolytus subscaber LeConte

147

(Figures 1.60, 1.61)
Scolytus subscaber LeConte 1876: 373. Lectotype: female, Vanc. [Vancouver, B.C.], Type 968”
(MCZC). Lectotype designated Wood 1982: 443.
Diagnosis. The S. subscaber male most closely resembles those of S. obelus and S. praeceps. It
is distinguished from that of S. obelus by the sparse, obscure, fine and shallow punctures of
sternite 2, the dull luster of sternite 2 and by the geographic distribution. The male can be
distinguished from that of S. praeceps by the presence of a median denticle on the apical margin
of sternite 2.
Scolytus subscaber females closely resemble those of S. ventralis and are distinguished
by the distinctly, moderately longitudinally aciculate and weakly punctate frons, the weakly
produced apical margin of sternite 1 that forms a weak carinate lip along the basal margin of
sternite 2.
Redescription (male). 2.0 – 4.3mm long (mean = 3.5mm; n = 20); 1.8 – 2.3 times as long as
wide. Head, pronotum and abdominal venter dark red-brown, antennae light brown, legs dark
red-brown to light brown, elytra red brown. Pronotum typically darker than elytra.
Epistoma moderately and very broadly emarginated; epistomal process moderately
developed and elevated; median area above mandibles bearing a dense patch of long yellow hairlike setae. Frons appearing convex when viewed laterally, slightly transversely impressed above
epistoma; surface moderately and coarsely longitudinally aciculate-punctate; aciculations
converging at epistoma; punctures minute, fine; surface moderately and uniformly covered by
long, fine, yellow erect hair-like setae, setae longer than the midpoint of the eye. Antennal scape
short, elongate, less than length of the first four funicular segments; club flattened, ovoid, setose
with a partial septum and three arcuate sutures.

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Pronotum wider than long; apical margin broadly rounded, area between the eyes lined
with scales; sides distinctly arcuate, strongly constricted near apex, and forming a weak
transverse impression near apical margin; surface smooth, shining, punctures on disc fine,
shallow and moderately abundant, larger and more abundant laterally and on apical constriction;
apical and anterolateral margins bearing sparse, erect yellow setae; base weakly bisinuate.
Elytral sides sub-parallel on apical half, narrowing to a subquadrate and smooth apex;
apical margin of elytral apices bearing small, fine punctures; apex moderately emarginated at the
suture. Disc smooth, shining; interstriae not impressed and more than twice the width of striae,
interstrial punctures uniseriate, smaller than those of striae; punctures bearing short sparse
recumbent yellow setae slightly longer than the size of a puncture (may be broken off); striae
weakly impressed. Declivity bearing sparse, short, erect yellow setae. Metepimeron half-length
of metepisternum.
Apical margin of sternite 1 strongly, acutely produced forming a lip along the base of
sternite 2, basal margin of sternite 2 appearing impressed. Sternite 2 nearly perpendicular to
sternite 1; surface glabrous, shagreened, dull, finely and obscurely punctate with small, fine and
shallow punctures; face weakly concave; apical margin armed with a broad median denticle;
lateral margins of sternites 2-4 and sternite 4 unarmed. Sternite 5 carinate ridge closer to the
apical margin than the basal margin of the segment; length of sternite 5 greater than the
combined lengths of sternites 3 and 4; a setal patch or median depression is absent.
Female. 3.1 – 5.0mm long (mean = 3.85mm; n = 20); 1.9 – 2.6 times as long as wide. Similar to
male except epistoma feebly emarginated, epistomal process absent, frons more strongly convex
when viewed laterally, weakly longitudinally aciculate, setae shorter, less than the width of the

149

eye and less abundant. Apical margin of sternite 1 weakly elevated above the base of sternite 2.
Second sternite unarmed, face weakly rugose, punctures larger, deeper
Specimens examined. 111.
Type material. Lectotype Scolytus subscaber LeConte (MCZC).
Non-type material. UNITED STATES: CALIFORNIA: Alpine Co.: Stanislaus National Forest,
Hermit Valley, Hopk. U.S. 19193-A, J.M. Miller, ex. Abies concolor (EMEC-1, OSAC-4).
Humboldt-Toiyabe National Forest, Hwy 89, 6.6mi E. NF 4188, N38°39.906’ W119°38.540’,
8011ft, 24.VII.2010, S.M. Smith, ex. Abies magnifica (MSUC-3). El Dorado Co.: Echo Lake,
Hopk. U.S. 18381-A, 27.V.[19]31, J.M. Miller, ex. Abies magnifica (CSUC-1, EMEC-17,
OSAC-20, USNM-3). Lake Tahoe, Fallen Leaf Lake, 22.VII.1930, A.C. Browne (CASC-1).
Uncle Tom’s, 0.1 road mile W., 28.VII-12.VIII.1978, J.A. Benedictis, ex. from pheromone trap
baited with E-11 tetradecenyl acetate (EMEC-1). [Madera Co.]: Bass Lake, Hopk. U.S. 19376A, 2.VII.[19]32, G.R. Struble, ex. Abies concolor (EMEC-2, OSAC-3). Sugar Pine [community],
12.VIII.1920, E. Schiffel (CASC-1). Placer Co.: Lake Tahoe, 1mi N., 3.VIII.[19]67, G.T. Ferrell
(EMEC-3). Plumas Co.: LaPort, Hopk. U.S. 17933-A, J.M. Miller, ex. Abies magnifica (EMEC2, OSAC-2). [Unspecified County]: Stanislaus National Forest, Hopk. U.S. 19818, J.M. Miller,
ex. Abies concolor (OSAC-1). IDAHO: Clearwater Co.: Pierce, 4mi W.N.W., 18.VII.1973, H.L.
Osborne, ex. flight trap (USNM-1). Latah Co.: 1992, M.M. Furniss, ex. Abies grandis (WFBM1). Flat Creek, 11.II.1995, M.M. Furniss, ex. Abies grandis (WFBM-4). Harvard, 3.5mi N.N.E.,
6.VIII.1973, H.L. Osborne, ex. flight trap (USNM-1). Moscow, 20.VII.[19]73, LC-1 (USNM-1),
24.VII.[19]73, LC-1 (USNM-2). Potlatch, 4mi N.E., 3.VIII.1973, H.L. Osbourne, ex. flight trap
(USNM-1). OREGON: [Benton Co.]: [Corvallis], Kiger Island, IX.1922, W.J. Chamberlain
(USNM-1). [Klamath Co.]: Crater Lake [National Park], 11.VI.[19]33, Hopk. U.S. 18966-A,

150

W.J. Buckhorn, ex. Abies concolor (EMEC-4), 14.XII.[19]33 (EMEC-3, OSAC-20, WFBM-1).
WASHINGTON: [Chelan Co.]: Lake Wenatchee [State Park], VII.[19]69 (EMEC-1). [King
Co.]: Seattle, 9.VI.[19]12 (OSAC-2). [Thurston Co.]: Olympia, 25.IV.[18]94 (OSAC-2).
Distribution. CANADA: British Columbia. UNITED STATES: California, Idaho, Montana,
Oregon, Washington.
Hosts. Principal host: Abies grandis (Dougl. Ex D. Don) Lindl. (grand fir), Incidental hosts:
Abies lasiocarpa (Hook.) Nutt. (subalpine fir), Abies magnifica A. Murr. (red fir).
Common name. None.
Biology. Furniss and Kegley (2011) provide detailed and thorough account of the biology of S.
subscaber. Adults infest suppressed branches in the crowns of mature trees and are rarely found
in slash (Edson 1967; Furniss and Kegley 2011). Scolytus subscaber is also associated with a
staining fungus, Spicaria anomale (Corda) Harz. that kills the host cambium (Wright 1938).
The adult galleries of S. subscaber are distinct from other Scolytus species. Adult
galleries are epsilon (“ε”) shaped and are deeply excavated in the sapwood. The gallery consists
of a central nuptial chamber and two egg galleries that are recurved around the nuptial chamber
(Edson 1967). The adult gallery 2-5cm in length and varies by branch size, with larger branches
having larger galleries (Furniss and Kegley 2011). Egg niches lightly score the sapwood. In
Oregon 12-30 eggs are laid per gallery and in Idaho the upper limit appears to be 12 (Furniss and
Kegley 2011). Larval mines radiate from the egg gallery in all directions, often crossing each
other. The larval mines are located in the phloem and cambium for about the first centimeter of
their length. After the first centimeter, larval mines lightly score the sapwood. Pupation
chambers are formed in the cambium or outer bark. There is one generation per year and the

151

brood overwinters as larvae. In Idaho, flight occurs in July and adults leave the gallery once eggs
have been laid (Furniss and Kegley 2011).
Collection notes. Old galleries of this species were observed by the author while hiking along
the Tuolumne Grove Trail in Yosemite National Park on 23.VII.2010.
Remarks. The lectotype bears a partial locality label. LeConte’s (1868) description states the
lectotype was collected at Vancouver Island.

Scolytus tsugae (Swaine)
(Figures 1.62, 1.63)
Eccoptogaster tsugae Swaine 1917: 32. Lectotype: female, labeled “Entomological Branch,
Ottawa, Canada No. 2251, female, J.M. Swaine Coll., Lectotype CNCNo. 9239” (CNCI).
Lectotype designated Bright 1967: 674.
Diagnosis. Scolytus tsugae most strongly resembles S. monticolae and the two species are easily
and often confused. Both sexes are distinguished from those of S. monticolae by the impressed
elytral discal striae, giving the elytra a corrugated appearance, by the dull luster of sternite 2 and
the host genus Tsuga.
Redescription (male). 2.8 - 3.4mm long (mean = 3.1mm; n = 16); 2.1-2.5 times as long as wide.
Body dark red-brown and antennae light brown. Pronotum typically darker than elytra.
Epistoma weakly emarginated; epistomal process absent; median area above mandibles
bearing a dense patch of long yellow hair-like setae. Frons appearing flattened when viewed
laterally, slightly transversely impressed above epistoma; surface weakly longitudinally aciculate
and moderately punctate; aciculations converging at epistoma; punctures small, coarse; surface
moderately and uniformly covered by long, fine, yellow erect hair-like setae, setae longer than

152

the midpoint of the eye. Antennal scape short, elongate, less than length of the first four funicular
segments; club flattened, irregularly ovoid, setose with a partial septum and two arcuate sutures.
Pronotum wider than long; apical margin broadly rounded, area between the eyes lined
with scales; sides distinctly arcuate, strongly constricted near apex, and forming a weak
transverse impression near apical margin; surface smooth, shining, punctures on disc fine,
shallow and moderately abundant, larger and more abundant laterally and on apical constriction;
apical and anterolateral margins bearing sparse, erect dark yellow-brown hair-like setae; base
weakly bisinuate.
Elytral sides sub-parallel on basal half, narrowing to a subquadrate and smooth apex;
apical margin of elytral apices bearing large, coarse punctures; apex moderately emarginated at
the suture. Disc glabrous, smooth, shining; interstriae weakly impressed and more than twice the
width of striae, interstrial punctures uniseriate, smaller than those of striae; striae weakly
impressed, elytra with a corrugated appearance. Declivity bearing sparse, short, erect yellow
setae. Metepimeron less than half-length of metepisternum.
Apical margin of sternite 1 weakly and continuously elevated above the base of sternite
2. Sternite 2 nearly perpendicular to sternite 1; surface glabrous, shagreened, dull, finely punctate
with small, fine and shallow punctures; face flattened; apical margin unarmed; lateral margins of
sternites 2-4 and sternite 4 unarmed. Sternite 5 carinate ridge closer to the apical margin than the
basal margin of the segment; length of sternite 5 greater than the combined lengths of sternites 3
and 4; a setal patch or median depression is absent.
Female. 2.3 - 3.5mm long (mean = 3.0mm; n = 16); 1.9-2.8 times as long as wide. Similar to
male except epistoma feebly emarginated, epistomal process present, moderately developed, low,

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frons convex when viewed laterally, weakly strigate, setae shorter, less than the width of the eye
and less abundant; weakly transversely impressed between inner apices of eyes.
Specimens examined. 369.
Type material. Lectotype Eccoptogaster tsugae Swaine (CNCI). Paralectotypes Eccoptogaster
tsugae (CNCI), [Unspecified locality]: 2251 (CNCI-12, CUIC-2, EMEC-1), 2327 (CNCI-2).
Non-type material. CANADA: BRITISH COLUMBIA: Adams Lake, 8.V.[19]22, R. Hopping,
ex. Tsuga mertensiana (CASC-1). Bowman Creek, 10.VIII.1928, R. Hopping, ex. Tsuga
heterophylla (CASC-2). Garibaldi, 7.VII.1988, R.J. Rabaglia (RJRC-1). Merritt, Midday Valley,
5.VI.1926, Wm. Mathers, 17134, lot 94, ex. Pinus ponderosa (CASC-1), 11.VI.1926, 17190, lot
23 (CNCI-1). North Vancouver, Lynn Canyon, 1.VI.[19]23, N.L. Cutler, L. 17003, ex. Abies
amabalis (CASC-12, CNCI-2). Pender Harbor, 17189, lot 1, 11.V.[19]26, G.R. Hopping, ex.
Tsuga heterophylla (CNCI-9); lot 2, 12.V.[19]26 (CASC-1, CNCI-8), lot 4, 29.V.[19]26 (CASC1, CNCI-6), lot 5, 1926 (CNCI-1), 13.VI.1928 (CASC-4). Terrace, Mrs. W.W. Hippisley (CNCI1). Trinity Valley, 16.VIII.1927, J.R. Howell (CASC-2), 1722, lot 46, 10.VII.1928, (CASC-1),
lot 50, 24.VII.1928 (CASC-1), 17339, lot 12, 19.VI.[19]30, (CASC-2); 16.VI.1927, 17213, lot
27, E.A. Rendell (CASC-1). Vancouver, 11.VI.1935, A. Graham, ex. Tsuga mertensiana
(CASC-2); 27.V.1939, W.G. Mathers, ex. Tsuga heterophylla (CASC-2), 31.V.1939 (CASC-5),
5.VI.1939 (CASC-3), 12.VI.1939 (CASC-3), 27.VI.1939 (CASC-5), 4.VII.1939 (CASC-1),
10.VII.1939 (CASC-2). UNITED STATES: CALIFORNIA: Yosemite National Park, Hopk.
U.S. 15727-A, 2.VII.1918, J.E. Patterson, ex. Tsuga mertensiana (OSAC-4). Alpine Co.: Ebbetts
Pass, 8730ft, 13.VIII.[19]63, D.E. Bright, ex. Tsuga mertensiana (CNCI-8, EMEC-9). Eldorado
Co.: [Georgetown, 10mi E.], Blodgett [Experimental] Forest, 2.VI.2003, K. Apigian (EMEC-1),
30.V.1986, K. Hobson (EMEC-1). Pollock Pines, 22.VI.[19]48, A. Bartel (EMEC-1). Lassen

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Co.: Grassy Lake, 27.IX.[19]14, lot 142, ex. Tsuga mertensiana (CASC-2). Nevada Co.:
39.4149°N, 120.3109°W, Tahoe National Forest, Sagehen Basin, Carpenter Ridge, 15.VII.2003,
M. Caterino (SBMN-1). IDAHO: Bonner Co.: Priest River Experimental Forest, Hopk. U.S.
61810, 28.X.1978, M.M. Furniss, ex. Tsuga heterophylla (USNM-8). Priest Lake, Reader Bay,
6.VIII.1985, M.M. Furniss, J.B. Johnson, ex. Tsuga heterophylla (WFBM-54). Boundary Co.:
Idaho Panhandle National Forest, Roman Nose, N48°40.911’ W116°34.345’, 4353ft, S.M.
Smith, A.R. Gillogly, ex. Tsuga heterophylla (MSUC-7). Kootenai Co.: Deception Creek
Experimental Forest, Hopk. U.S. 58885-B, 10.VII.1968, M.M. Furniss, ex. Tsuga heterophylla
(OSAC-1), 16.VII.1968 (OSAC-1), 24.VII.1968 (OSAC-4), 30.VII.1968 (OSAC-2), 8.VIII.1968
(OSAC-1). Magee, VII.[19]29, R.L. Furniss, ex. hemlock [=Tsuga sp.] (OSAC-4). MONTANA:
[Unspecified County]: Glacier [National] Park, 8.VII.[19]49, D. Giuliani (CASC-1). OREGON:
[Douglas Co.]: Diamond Lake, Hopk. U.S. 20959-A, VII.[19]31, R.L. Furniss, ex. Tsuga
mertensiana (OSAC-18). Hood River Co.: Mount Hood National Forest, Hwy 35, Sherwood
Forest campground, N45°19.278’ W121°37.104’, 4293ft, 2.VIII.2010, S.M. Smith, ex. Tsuga
heterophylla (MSUC-5). Klamath Co.: Crescent Lake, 6.VII.[19]60, [L. Edson], ex. Tsuga
mertensiana (CASC-4). Crater Lake [National Park], Hopk. U.S. 18.916-A, 22.V.[19]30, W.J.
Buckhorn, ex. Tsuga mertensiana (OSAC-30), Hopk. U.S. 18,950-A, 16.VI.[19]31, (OSAC-44);
Hopk. U.S. 18851-A, 14.VI.[19]31, J.A. Beal, ex. Tsuga mertensiana (OSAC-6, USNM-2);
Hopk. U.S. 20537-A, 17.VI.[19]33, F.P. Keen, ex. Tsuga mertensiana (OSAC-19);
24.VIII.[19]62, D.E. Bright, ex. Tsuga mertensiana (CNCI-1); 12.VIII.1984, M.M. Furniss, ex.
Tsuga mertensiana (WFBM-16); Hopk. U.S. 20807-A, R.L. Furniss, ex. Tsuga heterophylla
(OSAC-2). Linn Co.: Santiam Pass 7.VII.[19]64 (EMEC-1). [Yamhill Co.]: McMinnville,
27.XI.1937, K.M. & D.M. Fender (OSAC-1). WASHINGTON: King Co.: Montlake Terrace,

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20.VIII.[19]62, D.E. Bright, ex. Tsuga heterophylla (CNCI-4). Seattle, 27.V.[19]07 (OSAC-1),
10.IV.[19]12 (OSAC-2), 12.IV.[19]12 (OSAC-1). UNSPECIFIED LOCALITY: Hopk. U.S.
13247-A, ex. Tsuga mertensiana (OSAC-2). Summit Viola Trail, 9.IX.1910, J.M. Miller, ex.
Tsuga mertensiana (OSAC-1).
Distribution. CANADA: Alberta, British Columbia. UNITED STATES: California, Idaho,
Montana, Oregon, Washington.
Hosts. Tsuga heterophylla Sarg. (western hemlock) and Tsuga mertensiana (Bong.) Carrière
(mountain hemlock).
Common name. Hemlock engraver.
Biology. Scolytus tsugae attacks fresh slash, the main bole and large branches of hemlock (Edson
1967).
Scolytus tsugae is an uncommon and poorly studied species. The adult galleries of S.
tsugae are typically perpendicular to the grain of the wood and 4-10cm in length (Edson 1967;
Furniss and Johnson 2002). Adult galleries score the cambium slightly more than the sapwood.
However, Edson (1967) reported that specimens from a series in northern California produced an
adult gallery that was oriented obliquely to the grain of the wood. Galleries consist of a central
nuptial chamber and two egg galleries. Each egg gallery is extended perpendicular to the grain of
the wood from the central nuptial chamber. Egg niches are irregularly spaced and faintly score
the sapwood. Larval tunnels are extended parallel with the grain of the wood, etching the
sapwood lightly at first and deeply near the pupation chamber. There is one generation per year
and broods overwinter as larvae (Furniss and Johnson 2002).
Collection notes. The author collected this species from fresh logging slash limbs that were 610cm in diameter in Idaho and Oregon.

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Remarks. The lectotype does not bear a locality label. Swaine’s (1917) description states the
type series was collected at “Cherry Creek valley, Vernon District, British Columbia, Glacier,
B.C., Jasper Park, Alta.” from both Tsuga mertensiana and Pseudotsuga mucronata [=P.
menziesii]. In Bright’s (1967) lectotype designation he lists the locality of the lectotype as
“Glacier, BC, XI-26-15, Tsuga mertensiana”.
For many years S. monticolae was considered a synonym of S. tsugae (see S. monticolae
remarks). In their paper describing the biology of Scolytus tsugae, McMullen and Atkins (1959)
actually described the biology of S. monticolae. In their investigation the species studied was
from Pseudotsuga menziesii rather than Tsuga spp. and created vertical instead of transverse
galleries.

Scolytus unispinosus LeConte
(Figures 1.64, 1.65)
Scolytus unispinosus LeConte 1876: 372. Lectotype: male, labeled “ Or. [Oregon], Type 965”
(MCZC). Lectotype designated: Wood 1982: 432.
= Scolytus sobrinus Blackman 1934: 23. Holotype: male, labeled “Burke Colr, Kent,
WA, Pseudotsuga taxifolia [= P. menziesii], Hopk. US 41900, Type No. 43838”
(USNM). Synonymy: Wood 1966: 30.
Diagnosis. Scolytus unispinosus is very morphologically similar to S. fiskei and S. laricis. Males
of S. unispinosus are distinguished from those of S. laricis by the frons flattened when viewed
laterally, never deeply impressed, less moderately abundant frontal setae (compared to dense)
and by the host genus, Pseudotsuga. Males are distinguished from those of S. fiskei by the
following combination of characters: abdominal venter dull in luster, the base of the sternite 2

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spine extending from the apical margin to half the length of the segment and by the geographical
distribution.
The female is distinguished from that of S. fiskei by the dull luster of sternite 2 and is
distinguished from that of S. laricis by the frons finely aciculate-punctate; sternite 1 joining base
of sternite 2 more obtusely, base of sternite 2 not finely impressed, flush with sternite 1;
epistomal process weakly developed, almost indistinct.
Redescription (male). 2.2 – 3.2mm long (mean = 2.7mm; n = 15); 2.3 - 2.7 times as long as
wide. Head, antennae, pronotum, and abdominal venter dark red-brown. Elytra and legs yellowbrown to light brown. Pronotum typically darker than elytra.
Epistoma weakly emarginated; epistomal process present, weakly developed and low;
median area above mandibles bearing a dense patch of long yellow hair-like setae. Frons
appearing flattened when viewed laterally from epistoma to the vertex, slightly transversely
impressed above epistoma to inner apices of eyes; surface moderately and coarsely
longitudinally aciculate-punctate; aciculations converging at epistoma; punctures sparse, small
and fine; surface sparsely and uniformly covered by long, fine, yellow erect hair-like setae, setae
longer than the midpoint of the eye. Antennal scape short, elongate, less than length of the first
four funicular segments; club flattened, irregularly ovoid, setose with a partial septum and two
arcuate sutures.
Pronotum wider than long; apical margin broadly rounded, area between the eyes lined
with scales; sides distinctly arcuate, strongly constricted near apex, and forming a weak
transverse impression near apical margin; surface smooth, shining, punctures on disc fine,
shallow and moderately abundant, larger and more abundant laterally and on apical constriction;

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apical and anterolateral margins bearing sparse, erect yellow hair-like setae; base weakly
bisinuate.
Elytral sides sub-parallel on apical half, narrowing to a subquadrate and smooth apex;
apical margin of elytral apices bearing small, fine punctures; apex moderately emarginated at the
suture. Disc smooth, shining; interstriae not impressed and twice the width of striae, interstrial
punctures uniseriate, smaller than those of striae; punctures bearing short sparse recumbent
yellow setae slightly longer than the size of a puncture (may be broken off); striae weakly
impressed. Declivity bearing sparse, short, erect yellow setae. Metepimeron less than half-length
of metepisternum.
Apical margin of sternite 1 rounded, marked by a weak carina. Sternite 2 nearly
perpendicular to sternite 1; surface shagreened, dull, finely punctate with small, fine and shallow
punctures, that are nearly obscure; covered with sparse setae that are less than the width of
segment 3 in length; face convex; apical margin armed with a laterally compressed, median spine
with the base extending from the apical margin to half the length of the segment, apex rounded;
lateral margins of sternites 2-4 and sternite 4 unarmed. Sternite 5 carinate ridge closer to apical
margin of the segment; length of sternite 5 less than the combined lengths of sternites 3 and 4; a
setal patch or median depression is absent.
Female. 2.2 – 3.0mm long (mean = 2.7mm; n = 15); 2.3 - 2.7 times as long as wide. Similar to
male except epistoma feebly emarginated, epistomal process feebly developed, frons convex
when viewed laterally, weakly longitudinally aciculate, setae shorter, less than the width of the
eye and less abundant; weakly transversely impressed between epistoma and inner apices of
eyes. Second sternite apical margin armed with an acute median denticle, with base extending
from apical margin to half-length of segment.

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Specimens examined. 655.
Type material. Lectotype Scolytus unispinosus LeConte (MCZC). Holotype Scolytus sobrinus
Blackman (USNM). Paratypes Scolytus sobrinus Blackman UNITED STATES: OREGON:
[Jackson Co.]: Little Applegate River, Hopk. U.S. 14238-B, J.E. Patterson (EMEC-6). Ashland,
Hopk. U.S. 14264-T, F.P. Keen (EMEC-3). WASHINGTON: [King Co.]: Kent, Hopk. U.S.
4190-A, [H.E.] Burke, ex. Pseudotsuga taxifolia [=P. menziesii] (EMEC-5).
Non-type material. CANADA: BRITISH COLUMBIA: Cloverdale, 28.XII.[19]22, N.L. Cutler,
ex. Tsuga heterophylla (CASC-32, CNCI-11). Duncan, Genoa Bay, 10.VII.1928, W.G. Mathers,
ex. Pseudotsuga taxifolia [=P. menziesii] (CNCI-1). Indian Meadows, Midday Creek,
13.VII.1920, R. Hopping, ex. Pinus ponderosa (CNCI-1). Merritt, Midday Valley, 31.V.1926,
W. Mathers (CNCI-1), 2.VII.1926 (CNCI-2); 7.VII.1926, R. Hopping (CNCI-1), 3.VIII.1923
(CNCI-1), 15.VIII.19[23] (CNCI-1). Nanaimo, [Pacific] Biological Station, 23.VI.1920 (CASC1). Nelson Island, West Lake, 1701, 23.VI.1922, R. Hopping, ex. Pseudotsuga taxifolia [=P.
menziesii] (CNCI-12). Oliver, 25mi N.W., 15.VI.1958, H. & A. Howden (EMEC-3). Pender
Harbor, 30.VI.1928, G. Hopping, ex. Pseudotsuga taxifolia [=P. menziesii] (CASC-2).
Squamish, Diamond Head trail, 3200ft, 9.VIII.1953, G.J. Spencer (CNCI-1). Shuswap,
24.IV.[19]13, T. Wilson, ex. Douglas fir [=Pseudotsuga menziesii] (CNCI-1). Vancouver,
7.VI.1934, W. Mathers ex. Pseudotsuga taxifolia [=P. menziesii] (CASC-1), 11.VI.1934 (CASC2). Vanguard, 23.VI.[19]32, R. Hopping, ex. Pseudotsuga mucronata [=P. menziesii] (CASC-2,
CNCI-2). Vernon, 27.V.1932, R. Hopping (CASC-1). UNITED STATES: CALIFORNIA: Del
Norte Co.: 3.VII.[19]24, E.B. Leach (EMEC-1). El Dorado Co.: [Georgetown, 10mi E.],
Blodgett Experimental Forest, 4000ft, 26.V.1986, Hobson, Atkinson, ex. Lindgren trap,
ponderosa pine resin, H&L B.P. fractions, burned over area (EMEC-3); 27.V.1986, Hobson,

160

Irving, ex. Lindgren trap, ponderosa pine resin, untreated Oleo, burned over area (EMEC-2);
30.V.1986, Hobson, Atkinson, ex. Lindgren trap, unbaited, logged area (EMEC-1); 30.V.1986,
Hobson, Atkinson, ex. Lindgren trap, unbaited, burned over area (EMEC-2). Placerville, Hopk.
U.S. 33961-A, 26.III.[19]54, M.M. Furniss, ex. Pseudotsuga taxifolia [=P. menziesii] (EMEC16). Pollack Pines, 22.VI.[19]48, R.C. Bynum (EMEC-6). Humboldt Co.: Blocksburg,
13.V.[19]34, B.P. Biven (CASC-2). Orleans, 15mi N.W., 13.VI.[19]64, D.E. Bright, ex.
Pseudotsuga taxifolia [=P. menziesii] (EMEC-7). Orick, 11mi S., 11.VI.[19]62, D.E. Bright,
B.A. Barr, ex. Pseudotsuga taxifolia [=P. menziesii] (DEBC-4, EMEC-3). Lake Co.: Whispering
Pines, 14.IV.1964, ex. Douglas fir [=Pseudotsuga menziesii] (CASC-1). Los Angeles Co.:
Coquillett (EMEC-2). Madera Co.: 1.VII.[19]38 (EMEC-1). Marin Co.: Inverness, 11.X.[19]61,
D.E. Bright, ex. Pseudotsuga taxifolia [=P. menziesii] (DEBC-3, EMEC-2). [Mariposa Co.]:
[Yosemite National Park], Yosemite Valley, Hopk. U.S. 2810, Hopkins (EMEC-4). Mendocino
Co.: (CASC-7). 14.VII.[19]22, E.R. Leach (CASC-4). Bransomb, CDFA#870697,
11.VII.[20]01, M. Garvin, ex. Lindgren funnel trap with ISP (CSCA-1), 25.VII.[20]01 (CSCA3). Flynn Creek between Comptche and Navarro, 17.VIII.1953, P.S. Bartholomew (CASC-1).
Mill Creek, 20.III.[19]59, R.E. Stevens, ex. Douglas fir [=Pseudotsuga menziesii] (EMEC-13).
Noyo River, VI.1896 (CASC-14). Napa Co.: Angwin, 2mi N.N.E., North side of Howell
Mountain, 1300ft, 24.V.1974, H.B. Leech, ex. emerged from log of Pseudotsuga menziesii
(CASC-3, USNM-6), 20.VII.1974 (CASC-16), 21.VII.1974 (CASC-11), 22.VII.1974 (CASC-4),
23.VII.1974 (CASC-8), 25.VII.1974 (CASC-15), 26.VII.1974 (CASC-2, USNM-3), 27.VII.1974
(CASC-1), 28.VII.1974 (CASC-6, USNM-3), 1.VIII.1974 (CASC-3), 3.VIII.1974 (CASC-3),
7.VII.1974 (CASC-3). Callistoga, 26.V.[19]57 (CASC-4); 4.X.1947, T.O. Thatcher, ex.
Pseudotsuga taxifolia [=P. menziesii] (EMEC-3); 1.V.[19]63, D.E. Bright, ex. Pseudotsuga

161

menziesii (EMEC-3). Nevada Co.: Grass Valley, 17.I.1961, ex. Pseudotsuga taxifolia [=P.
menziesii] (CASC-2). Middleton [labeled as Lake Co.], Hopk. U.S. 37588-A, R.W. Bushing, ex.
Pseudotsuga menziesii (EMEC-3), G.M. Thomas (EMEC-3). [Placer Co.]: Colfax, 1mi E.,
Hopk. U.S. 34068-A, 31.I.[19]37, ex. Pseudotsuga menziesii (EMEC-4). Towle, 11.XI.1932
(EMEC-1). Plumas Co.: Walker Mine, 15.VII.[19]30 (EMEC-3). [San Francisco Co.]: San
Francisco, Hopk. U.S. 8557, 11.V.[18]99, ex. on pine [=Pinus sp.] (EMEC-1), 15.V.[18]99
(EMEC-1). Santa Cruz Co.: 16.IV.[19]59, J.E. Henry (WFBM-16). Aptos, New Brighton Beach
State Park, 13.IX.1986, D. Adams, ex. Pinus radiata (EMEC-54). Shasta Co.: Hat Creek,
17.VI.[19]62, D.E. Bright, B.A. Barr, ex. Abies concolor (EMEC-2). Siskiyou Co.: Grass Valley,
16.X.[19]60, R.W. Bushing, emerged XI.1960, ex. Pseudotsuga menziesii (EMEC-6). Sonoma
Co.: (CNCI-1). Fort Ross, 2mi E., 2.XI.1947, T.O. Thatcher, ex. Pseudotsuga taxifolia [=P.
menziesii] (EMEC-3). Mount Saint Helena, 3.VI.[19]31, E.C. Zimmermann, ex. digger pine
[=Pinus sabiniana] (EMEC-1); Hopk. U.S. 21,125-F, 3.IV.1934, R.L. Furniss, ex. Pseudotsuga
taxifolia [=P. menziesii] (EMEC-4). Sebastopol, Hopk. U.S. 32638-A, 20.I.1940, ex.
Pseudotsuga taxifolia [=P. menziesii] (DEBC-4, EMEC-5). Stillwater Cove, 12.V.1951, H.R.
Moffitt (EMEC-1). Trinity Co.: 14.V.[19]23, ex. Pseudotsuga taxifolia [=P. menziesii] (CASC4). [Unspecified County]: (CUIC-7). Yosemite National Park, Hopk. U.S. 20953-B, 19.VI.1932,
J.M. Miller, ex. Pseudotsuga taxifolia [=P. menziesii] (EMEC-8). IDAHO: Bonner Co.:
Sandpoint, 13.VI.931, N.M. Downie (FMNH-1), 9.VII.1977 (FMNH-1); 9.VII.1977 (FMNH-1).
OREGON: [Benton Co.]: Corvallis, 17.IV.[19]16, W.J. Chamberlin, ex. Pseudotsuga taxifolia
[=P. menziesii] (EMEC-3); 8.VII.1946, K.R. Hobbs (EMEC-1). Coos Co.: Myrtle Point,
18.VI.[19]64, D.E. Bright, ex. Pseudotsuga menziesii (EMEC-10). Curry Co.: Agness, 6mi S.W.,
10.VII.1990, M.M. Furniss, J.B. Johnson, ex. Pseudotsuga menziesii (WFBM-6). Brookings,

162

12mi E.N.E., 12.VIII.1990, M.M. Furniss, J.B. Johnson, ex. Pseudotsuga menziesii (WFBM-4).
Illahe, 4mi N., 9.VIII.[19]90, M.M. Furniss, J.B. Johnson, ex. Pseudotsuga menziesii (WFBM2). Custer Co.: Herd Lake, 3.IX.1978, M.M. Furniss, ex. Pseudotsuga menziesii (WFBM-1).
Deschutes Co.: Deschutes National Forest, Black Butte Rd., Black Butte, N44°24.924’
W121°38.323’, 4212ft, 31.VIII.2010, S.M. Smith, ex. Pseudotsuga menziesii (MSUC- 44).
Douglas Co.: Roseburg, W.J. Chamberlin, ex. Pseudotsuga taxifolia [=P. menziesii] (DEBC-2,
EMEC-6, WFBM-2). [Grant Co.]: Dixie Pass, Malheur National Forest, 23.VI.1961, S.L. Wood,
J.B. Karren, D.E. Bright, ex. Pseudotsuga taxifolia [=P. menziesii] (DEBC-5). Jackson Co.:
Dead Indian Spring, 17.V.1962, J. Schuh (CNCI-1). Mistletoe, Hopk. U.S. 15753-A, P.D.
Sergent, ex. Pseudotsuga taxifolia [=P. menziesii] (EMEC-3), Hopk. U.S. 15753-B,
21.VIII.1918, P.D. Sargent (DEBC-5, EMEC-10). Pinehurst, 2mi E., 18.VII.[19]64, D.E. Bright,
ex. Pseudotsuga menziesii (CNCI-5, EMEC-6). Prospect, 10.VII.[19]64, D.E. Bright, ex.
Pseudotsuga menziesii (CNCI-11, EMEC-14). [Klamath Co.]: Klamath Falls, 17.VI.[19]64, D.E.
Bright, ex. Pseudotsuga menziesii (EMEC-2). [Lane Co.]: McCredie Springs, 19.VI.1961, D.E.
Bright, ex. Tsuga heterophylla (CNCI-2). Vaughn, J. Pierce, ex. Douglas fir limbs
[=Pseudotsuga menziesii] (WFBM-4); 21.VI.1955, J.A. Rudinsky, J.R. Pierce, ex. Doug fir
branches [=Pseudotsuga menziesii] (WFBM-3). Linn Co.: Santiam Pass, 19.VI.1951, S.L. Wood,
J.B. Karren, D.E. Bright, ex. Pseudotsuga taxifolia [=P. menziesii] (DEBC-1). [Malheur Co.]:
Monument Peak, 25.IX.[19]53, ex. Pseudotsuga taxifolia [=P. menziesii] (EMEC-3). [Marion
Co.]: Clear Lake, 17.VIII.[19]51, R. Kangur, ex. Larch [=Larix sp.] (WFBM-2). [Multnomah
Co.]: Portland, Hubbard, Schwarz (EMEC-2). [Umatilla Co.]: Tollgate, 30.VI.1950, E.S.
McClurskey, ex. on aluminum roof (CNCI-1), 1.IX.1950 (CNCI-1). [Unspecified County]: Clear
Lake, 17.VIII.[19]51, R. Kangur (EMEC-4). Detroit, 25mi E., 17.VII.1939, Schuh, Scott, ex.

163

Tsuga mertensiana (FMNH-6). Middle Sister Mountain, 8000ft, Hopk. U.S. 53349-G,
4.VIII.1968, M.M. Furniss, ex. on snowfield (WFBM-2). Portland, Wickham (CNCI-1).
Tillamook burn, 18.VII.1941, R. Kangur (EMEC-1). Warm Springs Indian Reservation,
15.VIII.[19]51, R. Kangur, ex. Douglas fir [=Pseudotsuga menziesii] (EMEC-4).
WASHINGTON: [Clallam Co.]: Port Angeles, Hopk. U.S. 130, A.D. Hopkins, ex. Pseudotsuga
taxifolia [=P. menziesii] (EMEC-1). Port Williams [Marlyn Nelson County Park at Port
Williams], Hopk. U.S. 168-F, A.D. Hopkins, ex. Pseudotsuga taxifolia [=P. menziesii] (EMEC1). Cowlitz Co.: Castle Rocks, 10mi E., 27.VI.[19]64, D.E. Bright, ex. Pseudotsuga menziesii
(DEBC-18, EMEC-9). [Grays Harbor Co.]: Humptulips, 28.V.1914, E.C. VanDyke (CASC-3).
[Kittitas Co.]: Easton (CASC-6, EMEC-2). Okanogan Co.: Disautel, 4.XI.1936, R.L. Furniss, ex.
Pseudotsuga menziesii (OSAC-17, WFBM-7). [Pend Oreille Co.]: Metaline Falls, Hopk. U.S.
21340, 17.VII.1931, W.D. Bedard , ex. Pseudotsuga taxifolia [=P. menziesii] (WFBM-15).
Skamania Co.: Mineral Springs, 27.VI.[19]64, D.E. Bright, ex. Pseudotsuga menziesii (EMEC9). [Snohomish Co.]: [labeled King Co.] Mountlake Terrace, 20.VIII.[19]62, ex. Pseudotsuga
menziesii (CNCI-3). Thurston Co.: Olympia, 7-30.V.1996, E. LaGasa, ex. Washington
Department of Agriculture port trapping survey (WFBM-1). Yakima Co.: Naches, 14mi W., Dry
Creek Ridge, Snoqualamie National Forest, 3.VII.1965, R.B. Hutt (DEBC-2). [Unspecified
County]: Mount Adams, Bird Creek, 6000-7000ft, 2.VII.1925 (CASC-1). Mount Rainier
National Park, 21.VIII.[19]62, ex. Pseudotsuga taxifolia [=P. menziesii] (CNCI-6).
Distribution. CANADA: British Columbia. UNITED STATES: California, Idaho, Oregon,
Washington.
Hosts. Pseudotsuga menziesii (Mirb.) Franco. (Douglas fir) but also likely occurs in P.
macrocarpa (Vasey) Mayr (Big cone Douglas fir) in Southern California.

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Common name. Douglas-fir engraver.
Biology. Scolytus unispinosus is very common (Chamberlin 1939; Smith pers. obs.) and attacks
the boles and branches of weakened, injured, dying and recently killed Douglas fir. Populations
of this species can build up in windfalls, slash and during drought when the species becomes
capable of killing young trees (Keen 1938; Chamberlin 1939; Wood et al. 2003). Outbreaks are
sporadic and are of short duration (Keen 1938; Wood et al 2003).
The adult gallery of this species consists of a single egg gallery that extends with the
grain of the wood. The nuptial chamber includes a short extension at a 45° angle from the egg
gallery and is located at one end on the egg gallery. The gallery deeply scores the sapwood and
lightly scores the cambium (Chamberlin 1958). The female deposits 40-100 eggs in egg niches
on both sides of the egg gallery 0.5-1.0mm apart (Doane et al. 1936). Larvae extend their mines
at a right angle to the egg gallery forming a fan shaped pattern (Chamberlin 1939). There are two
generations per year in California and the broods overwinter as either eggs or larvae (Keen 1938;
Wood et al. 2003). Adults emerge from late April through July (Keen 1958). In Oregon one
generation per year has been observed at high elevations in and two at lower elevations
(Chamberlin 1939).
McMullen and Atkins (1962) reported some notes on the biology of S. unispinosus in
British Columbia and appear to have reported a combined account of S. unispinosus and S. fiskei
(see S. fiskei biology for more information). This paper was the main source of information
regarding the biology of S. unispinosus and served as the basis for describing the biology of the
species in numerous publications (including Bright 1976; Furniss and Carolin 1977; Furniss and
Johnson 2002; Wood et al. 2003). Chamberlin (1939, 1958) provides the most reliable source of
information regarding the biology of the species.

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Collection notes. None.
Remarks. There are 25 S. sobrinus specimens bearing paratype labels found in the EMEC.
These specimens are not designated as such by Blackman (1934) and have been labeled “not
Paratype” by the authors. These specimens bear the following Hopkins numbers: 4205-A
(EMEC-2), 4272-A (EMEC-4), 1968-D1 (EMEC-1), 1968-D3 (EMEC-1), 4273-B (EMEC-1),
4204 (EMEC-2), 4220-A (EMEC-3), 4226-D (EMEC-1), 4201-A (EMEC-2), 13232-C (EMEC1), 17 (EMEC-1), 18 (EMEC-1), 19 (EMEC-2) and Sonoma, California (EMEC-3).
This species occurs along the western coastal states of the United States and British
Columbia, Canada. The range of S. unispinosus does not overlap with that of S. fiskei except in
south central British Columbia where species are sympatric in the Interior Plateau near Merritt.

Scolytus ventralis LeConte
(Figures 1.66, 1.67)
Scolytus ventralis LeConte 1868: 167. Lectotype: male, labeled “[Washington Territory] Type
970” (MCZC). Lectotype designated: Wood 1982: 441.
Diagnosis. Scolytus ventralis males are distinguished from those of other species by having the
base of sternite 2 faintly elevated and the face of sternite 2 flat, the apical margin of sternite 2 is
slightly elevated and often bears a median denticles, the second sternite is glabrous.
Females most closely resemble those of S. robustus and S. subscaber. Females are
distinguished from those of both species by the indistinctly and weakly aciculate and strongly
punctate frons and by the apical margin of sternite 1 flush with basal margin of sternite 2,
appearing rounded.

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Redescription (male). 3.0 - 4.0mm long (mean = 3.65mm; n = 20); 2.1-2.7 times as long as
wide. Head, pronotum and abdominal venter dark red-brown, antennae light brown, elytra and
legs yellow-brown to light brown. Pronotum typically darker than elytra.
Epistoma weakly emarginated; epistomal process weakly elevated; median area above
mandibles bearing a dense patch of long yellow hair-like setae. Frons appearing convex when
viewed laterally, slightly transversely impressed above epistoma; surface moderately and
coarsely longitudinally aciculate-punctate; aciculations converging at epistoma; punctures small,
coarse; surface moderately and uniformly covered by long, fine, yellow erect hair-like setae,
setae longer than the midpoint of the eye. Antennal scape short, elongate, less than length of the
first four funicular segments; club flattened, irregularly ovoid, setose with a partial septum and
three arcuate sutures.
Pronotum wider than long; apical margin broadly rounded, area between the eyes lined
with scales; sides distinctly arcuate, strongly constricted near apex, and forming a weak
transverse impression near apical margin; surface smooth, shining, punctures on disc fine,
shallow and moderately abundant, larger and more abundant laterally and on apical constriction;
apical and anterolateral margins bearing sparse, erect yellow hair-like setae; base weakly
bisinuate.
Elytral sides sub-parallel on apical half, narrowing to a subquadrate and smooth apex;
apical margin of elytral apices bearing small, fine punctures; apex moderately emarginated at the
suture. Disc glabrous, smooth, shining; interstriae not impressed and more than twice the width
of striae, interstrial punctures uniseriate, smaller than those of striae; striae weakly impressed.
Declivity bearing sparse, short, erect yellow setae. Metepimeron half-length of metepisternum.

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Apical margin of sternite 1 weakly elevated above the base of sternite 2. Sternite 2 nearly
perpendicular to sternite 1; surface glabrous, shagreened, dull, finely punctate with small, fine
and shallow punctures; face flattened; apical margin armed with a broad median denticle,
occasionally absent; lateral margins of sternites 2-4 and sternite 4 unarmed. Sternite 5 carinate
ridge closer to the apical margin than the basal margin of the segment; length of sternite 5 less
than the combined lengths of sternites 3 and 4; a setal patch or median depression is absent.
Female. 2.2 – 4.6mm long (mean = 3.56mm; n = 20); 2.1-2.7 times as long as wide. Similar to
male except epistoma feebly emarginated, epistomal process absent, frons convex when viewed
laterally, weakly longitudinally aciculate, setae shorter, less than the width of the eye and less
abundant; weakly transversely impressed between epistoma and inner apices of eyes. Second
sternite unarmed.
Specimens examined. 324.
Type material. Lectotype Scolytus ventralis LeConte (MCZC).
Non-type material. CANADA: BRITISH COLUMBIA: Duncan, Genoa Bay, 30.VI.1928, W.G.
Mathers, ex. Abies grandis (CNCI-4), 21.VI.1928 (CNCI-1), 23.VI.1928 (CASC-1), 24.VI.1928
(CASC-1), 16.VII.1928 (CASC-1), 13.VIII.1936 (CASC-1). Steelhead, 6.VII.1933, H.B. Leech,
ex. Abies amabalis (CNCI-1), 27.VII.1933 (CASC-1), 24.VII.1933 (CNCI-1), 26.VII.1933
(CNCI-1). Trail, 22km S.E., 24.V.1991, J.E. Macias, ex. Abies grandis (CNCI-1). Vancouver,
10.VI.1935, K. Graham, ex. Abies grandis (CASC-12). MEXICO: BAJA CALIFORNIA: San
Pedro Mártir, Hopk. U.S. 32716-A, 5.VI.1944, F.P. Keen, ex. Abies concolor (EMEC-1).
UNITED STATES: ARIZONA: Cochise Co.: Coronado National Forest, Chiricahua Mountains,
14.VII.2009, J. Hulcr, ex. Pseudotsuga menziesii (MSUC-3). CALIFORNIA: [Amador Co.]:
Jackson, 31.III.[19]55, ex. Abies concolor (EMEC-1). Calaveras Co.: Big Trees [State Park],

168

VII.1930, F.E. Blaisdelll (CASC-1). El Dorado Co.: Bijou at south end of Lake Tahoe, H.B.
Leech, ex. Douglas fir log [=Pseudotsuga menziesii], emerged San Francisco, 18-20.V.1965,
W.E. Kuhl (CASC-8). [Georgetown, 10mi E.], Blodgett [Experimental] Forest, 30.V.1986, K.
Hobson (EMEC-1), 11.VI.1986 (EMEC-1), 21-24.VI.1986 (EMEC-6), 25-27.VI.1986 (EMEC1), 1-7.VII.1986 (EMEC-2), 9-16.VII.1986 (EMEC-4); 30.V.1986, Hobson, Atkinson, ex.
Lindgren trap, unbaited over burned area (EMEC-3), ex. Lindgren trap, turpentine bait, logged
area (EMEC-1); 27.V.1986, Hobson, Irving, ex. Lindgren trap, ponderosa pine resin H&L B.P.
fractions, logged area (EMEC-1), ex. Lindgren trap, ponderosa pine resin, untreated oleo, burned
over area (EMEC-1). Ice House Reservoir, 23.VI.[19]90, J.B. Johnson (EMEC-1). Pacific,
8.VII.[19]62, R.L. McDonald (CASC-1). Fresno Co.: Huntington Lake, 16.VII.[19]19, F.E.
Blaisdell (CASC-5). Lassen Co.: Lassen National Forest, 20-25.VII.1994, S1/2 S35 T34N R7E,
A.I. Cognato (MSUC-20, SBMN-4); Black Mountain Experimental Forest, VII.1995, A.I
Cognato (MSUC-1). Near Loon Lake campground, 6300ft, 28.VII-12.VIII.1978, J.A. De
Benedictis (EMEC-1). Norval Flats, 5500ft, 18.VII.[19]20, J.O. Martin, ex. Abies concolor
(CASC-47). Uncle Tom’s, 0.1 road mile W., 28.VII-12.VIII.1978, J.A. De Benedictis (EMEC1). Marin Co.: VI-VIII.[19]56, D. Giuliani (CASC-1). Mariposa Co.: Miami Ranger Station, 2mi
S., 19.VII.1946, H.P. Chandler (DEBC-3). Miami Lodge, 17.VII.1946, G.R. Struble, ex. Abies
concolor (CSUC-1). Mendocino Co.: Noyo River, VI.1896 (CASC-22). Modoc Co.: Modoc
National Forest, Hwy 299, 5.3mi W. Cedarville at creek near exit from ski area, 41°32.9’N
120°14’W, 9.IX.1995, J. Schweikert, ex. swept creek side plants (CASC-1). Davis Creek, 4mi
N.E., Sugar Hill, 6300ft, 9.VI.1970, W. Middlekauff (EMEC-1). Nevada Co.: Sagehen Creek
Field Station, 39.4298°N, 120.2429°W, 12-18.VIII.2003, M. Caterino, ex. FIT (SBNM-1). Near
Sagehen campground, 39.4344°N, 120.2808°W, 15.VIII.2003, M. Caterino (SBNM-1). Sagehen

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Creek, 20.VII.1966, W.J. Turner (EMEC-1). [Placer Co.]: Cisco (USNM-1). Plumas Co.: Bartle,
9mi N., 12-15.VI.1974, L. Green, (EMEC-1). Chester, 8mi N.W., Warner Creek, 5000ft,
21.VI.1989, E.E. Lundquist (CNCI-2). Jamesville, 15-21.VIII.[19]50, M. Wasbauer, ex. Abies
concolor (EMEC-1). Riverside Co.: Mount San Jacinto State Park, 33.800°N, 116.673°W,
15.VII.2003, M. Caterino (SBMN-1). Santa Rosa Mountains, 10.IV.[19]63, D.E. Bright, ex.
Abies concolor (EMEC-1). [San Bernardino Co.]: San Bernardino Mountains, Dollar Lake trail,
10.VII.1956, H.W. Michalk (CSCA-1). Siskiyou Co.: Happy Camp, 18mi N., 31.VII.[19]63, C.J.
Wray, ex. Picea breweriana (DEBC-2, EMEC-1). Klamath National Forest, goosenest adaptive
management area, 41.5°N, 121.9°W, 26.VII.2000, ex. pitfall 3-840 (SBNM-1). McCloud,
22.VI.1914 (CASC-23), 14.VI.1962, D.E. Bright, B.A. Barr, C. Hector (CASC-1). Tehama Co.:
Mineral, 11.VIII.[19]35 (CASC-1). Trinity Co.: Carville, 30.VI.1913, ex. dug out of Abies
concolor (CASC-1), 2400-2500ft, 23.V.1934 (CASC-1). Nash Mine, 12.VI.1913 (CASC-1).
Tulare Co.: Giant Forest, 6500ft, VII.1908, Hopping (CASC-3). Kaweah, 100ft, Hopping
(CASC-1). Sequoia National Park, Redwood Canyon, 20.IX.1980, S.F. Muzzio (CASC-2).
[Unspecified county]: Pinecrest, 24.VII.1930, G.R. Struble, ex. Abies magnifica (EMEC-1).
COLORADO: Costilla Co.: Pass Creek, 17.VI.1976, D. Leatherman, ex. white fir [=Abies
concolor] (CSUC-4). Huerfano Co.: Near Red Wing, 16.VI.1975, D. Leatherman, ex. white fir
[=Abies concolor] (CSUC-1). Las Animas Co.: Monument Lake, 6.VII.1994, S. Kelley, ex. white
fir [=Abies concolor] (DEBC-2). Pueblo Co.: SR 165, 5mi S.E. San Isabel Millset trailhead, D.
Leatherman, ex. burned white fir [=Abies concolor] (CSUC- 6). IDAHO: Benewah Co.:
Plummer, 4mi S., 14.VIII.1956, W.F. Barr, E.C. Clark, ex. Abies grandis (FMNH-1). Boundary
Co.: Idaho Panhandle National Forest, Hwy 95, Robinson Lake campground, N48°58.200’
W116°13.067’, 2696ft, 13.VIII.2010, S.M. Smith, A.R. Gillogly, ex. Abies grandis (MSUC-6).

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Kootenai Co.: Coeur d’Alene, 5.IX.1919, J.C. Evenden, ex. Abies grandis (MSUC-3).
MONTANA: [Unspecified county]: Glacier [National] Park, 15.VII.[19]31 (CUIC-1). NEW
MEXICO: Bernalillo Co.: Cibola National Forest Sandia Peak, NM536, N35°11.655’
W106°24.075’, 8317ft, 10.V.2010, S.M. Smith, A.I. Cognato, ex. Abies concolor (MSUC-1).
[Otero Co.]: Cloudcroft, 900ft, W. Knaus (CNCI-1). Santa Fe Co.: Little Tesuque Canyon,
14.VI.[19]35 (CASC-1). Socorro Co.: VII[?], Wickham (CASC-1). OREGON: Benton Co.:
Corvallis, VIII.1919, W.J. Chamberlin, ex. Pseudotsuga taxifolia [= Pseudotsuga menziesii]
(EMEC-1), Kiger Island, VII.[19]22, W.J. Chamberlin (EMEC-2). Mary’s Peak, 14mi W
Corvallis. XII.1958 (EMEC-2). [Deschutes Co.]: Bend, Hopk. U.S. 33,531-B, 8.VII.[19]58, W.J.
Buckhorn, P.W. Orr, ex. Abies grandis (OSAC-8). [Klamath Co.]: Klamath Falls, Geary Ranch,
4.X.1962, J. Schuh, ex. Abies concolor (CNCI-2, FMNH-4, MSUC-7). [Linn Co.]: McMinnville,
7.VIII.1951, R. Kangur (WFBM-2). [Wallowa Co.]: Wallowa Lake, 19.VII.[19]51, Quintus, ex.
Abies concolor (WFBM-1). UTAH: Juab Co.: Mount Nebo, 20.VII.1958, D.E. Bright, ex. Abies
concolor (CNCI-2). Utah Co.: Payson Canyon, 20.V.1961, S.L. Wood, ex. Abies concolor
(USNM-18). WASHINGTON: [Jefferson Co.]: Quilcene, Hopk. U.S. 65564, 30.IX.1946
(OSAC-6). [Pend Oreille Co.]: Metaline Falls, Hopk. U.S. 21405, 17.VII.[19]31, W.D. Bedard,
ex. flying (USNM-4). [Stevens Co.]: Northport, 1.IX.1930, R. Hopping (CASC-3). [Walla Walla
Co.]: Walla Walla, VIII.1933, M.C. Lume (USNM-11). [Yakima Co.]: [Mount Baker],
Snoqualmie National Forest, Dry Creek Ridge, 14mi W. of Naches, 3.VII.1965, R.B. Hutt
(DEBC-1).
Distribution. CANADA: British Columbia. MEXICO: Baja California. UNITED STATES:
Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Utah, Washington,
Wyoming.

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Hosts. Principle hosts: Abies concolor (Gord. & Glend.) Lindl. ex Hildebr. (white fir), Abies
grandis (Douglas ex D. Don) Lindl. (grand fir), and Abies magnifica A. Murray (red fir).
Incidental hosts: Abies lasiocarpa (Hook.) Nutt. (subalpine fir).
Common name. Fir engraver.
Biology. Scolytus ventralis can cause significant fir mortality and is the most destructive coniferfeeding Scolytus species in the Nearctic (Keen 1938; Bright and Stark 1973). During a period
from 1924-1936, S. ventralis killed 15% and damaged an additional 25% of the merchantable fir
in California. It has also been reported to be quite destructive in Oregon (Keen 1938). Scolytus
ventralis is associated with a symbiotic stain fungus, Trichasporium symbioticum Wright, which
the adult beetle introduces when it excavates the adult gallery. The fungus spreads in all
directions around the gallery system (Bright and Stark 1973). Due to the potential of S. ventralis
to kill fir trees, this species is the most well studied native Scolytus in North America. Attacks
usually occur on the boles of weakened and stressed standing trees from a few feet above the
base to the top of the tree, but can also occur in large slash and fresh and fallen trees (Chamberlin
1958; Edson 1967; Furniss and Johnson 2002). Attacks at the top of the tree are more common
on overmature standing trees during drought and healthy, vigorous trees are not preferred
(Chamberlin 1958; Raffa and Berryman 1987). Trees can also become successively attacked
over a period of years and slowly die. Healthy trees may survive the attacks but can develop rots
and defects that reduce timber value (Struble 1937). Unlike most tree-killing or primary bark
beetles, S. ventralis does not have pheromone to aggregate conspecifics to host trees. The beetles
locate suitable hosts via primary attraction to host volatiles (Macías-Sámano et al 1998a,b).
Adult galleries of S. ventralis are perpendicular to the grain of the wood. Adult galleries
deeply score the sapwood, lightly score the cambium and consist of two egg galleries with a

172

central nuptial chamber (Edson 1967). The nuptial chamber is typically short and at a right angle
to the egg galleries but may also extend at an oblique angle. When this occurs, one of the egg
galleries is briefly extended at an oblique angle against the grain before becoming perpendicular
to the grain (Edson 1967). Eggs are deposited singly in triangular niches spaced 1-1.5mm apart
on each side of the egg gallery with 80-300 niches per gallery. Galleries range in size from 830cm in length (Chamberlin 1958; Edson 1967; Bright and Stark 1973; Furniss and Johnson
2002). Larval mines are perpendicular to the egg gallery and parallel with the grain of the wood.
Larval mines are also parallel to each other both above and below the egg gallery, giving the
gallery a diamond shaped appearance (Keen 1938; Edson 1967). Larval mines lightly score the
sapwood and deeply score the cambium. Larvae construct pupation chambers in the phloem or
outer bark (Edson 1967). Broods overwinter as larvae or adults (Bright and Stark 1973). The
number of generations per year varies both geographically and with elevation. Development time
can range from as little as 41 days at low latitudes and elevations to as many as 380 days at high
latitudes and elevations (Bright and Stark 1973). There is typically one generation per year
(Bright and Stark 1973). In Idaho, pupation occurs from June to July and peak flight occurs in
July (Furniss and Johnson 2002).
Collection notes. None.
Remarks. The lectotype does not bear a locality label. LeConte’s (1868) description states that
George Gibbs collected the lectotype in the Washington Territory.

173

CHAPTER 2
PHYLOGENETICS AND EVOLUTION OF HOST-USE AMONG THE SCOLYTINI
(COLEOPTERA: CURCULIONIDAE: SCOLYTINAE)

	
  

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Abstract
The influence of plants in the diversification of herbivorous insects, specifically those
that utilize moribund and dead hosts, is unclear. Scolytini, a diverse tribe of weevils, specialize
on many different plant taxa as a source of food. The phylogenetics of the Scolytini were
reconstructed using Bayesian analyses to examine the origin, test the monophyly of Scolytini
genera, and illuminate patterns of host-use and feeding habits among the tribe. Analyses were
based on rDNA nucleotides from the D2-D3 segment of 28S, and nucleotides from encoding
gene fragments of CAD, ArgK and mitochondrial COI. Ancestral host usage was reconstructed
using likelihood criteria. Results support monophyletic Scolytini, Ceratolepsis, Loganius, and
Scolytus and paraphyletic Camptocerus and Cnemonyx. Diversification of the Scolytini generally
occurred well after host taxa diversified, as a combination of host shifts and lineage tracking.
Repeated independent shifts to the same hosts occurred. Diversification occurred on common
and widespread hosts, there was a single origination of conifer-feeding from angiosperm-feeding
species.and evolution of fungus-feeding from phloem-feeding ancestors. Overall, the observed
patterns of Scolytini host-use can be explained by a combination of the sequential evolution and
host-use oscillation hypotheses, a pattern that has been found for other insect taxa that colonize
living host plants.

	
  

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Introduction
The bark and ambrosia beetles are a diverse weevil subfamily (Coleoptera:
Curculionidae: Scolytinae) with at least 6,000 recognized species and representing roughly 10%
of weevil diversity (Wood and Bright 1992; Oberprieler et al. 2007). Scolytines utilize a wide
array of plant taxa including ferns, conifers, monocots and dicots and species exhibit a multitude
of ecological feeding habits (Browne 1961; Gray 1970; Wood 1982). Despite the diversity of
feeding habits, scolytines are primarily composed of two distinct groups: true bark beetles and
ambrosia beetles. True bark beetles are phloeophagous and feed exclusively on phloem and
cambium of living, moribund, or dead host trees (Wood 1982). Ambrosia beetles, which are
xylomycetophagous, bore into the xylem of a moribund or dead host tree and cultivate a
symbiotic fungal, bacterial and yeast garden. This ambrosial feeding habit has evolved at least
ten times within the Scolytinae (Farrell et al. 2001; Jordal and Cognato 2012).
Boring under bark and into xylem hastens decomposition of woody debris via the
introduction of other xylophagous organisms (Stokland 2012). Scolytines are ubiquitous in
global forest ecosystems and primarily contribute to the decomposition of dead vegetation.
However, a small number of bark beetle species kill live trees (Wood 1982). While the majority
of scolytine species are not ambrosia beetles, they passively introduce fungi into otherwise
healthy trees as a by-product of phloem-feeding. At high densities, bark beetle species cause
widespread mortality of economically valuable tree species, giving bark beetles their nefarious
reputation as ecologically and economically destructive forest pests (Browne 1961; Furniss and
Carolin 1977).

	
  

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Bark beetles are intrinsically interesting organisms. Variation in mating systems and hostplant use provides the intellectual fodder for investigation of general evolutionary hypotheses
(e.g., Kelley and Farrell 1998; Farrell et al. 2001; Jordal et al. 2004; Hulcr and Cognato 2010;
Jordal et al. 2011; Jordal and Cognato 2012). The study of evolution of bark beetles and host
trees has been of particular interest and underlies diversification of beetle species (Farrell and
Mitter 1993; Becerra 1997; Farrell 1998; Mitter et al. 1988; McKenna et al. 2009). Once
structural and/or chemical barriers that deter or prevent beetle feeding on a particular host taxon
are overcome through natural selection, subsequent generations tend to feed only on that plant
taxon (Erhlich and Raven 1964). However, species-rich beetle lineages often feed on
phylogenetically unrelated plants, suggesting changes in host plant use are a driving force in
beetle evolution. Similarities in secondary compounds of unrelated hosts likely facilitate host
shifts and promote beetle diversity (Erhlich and Raven 1964; Jaenike 1990). Broad patterns of
the evolution of host-plant use by weevils include ancestral weevil feeding on old lineages of
conifers (such as Cycadaceae), a shift of some groups (including Scolytinae) to angiosperms and
subsequent shifts to younger conifers (such as Pinaceae) (McKenna et al. 2009). Although there
are few examples of lineage diversification of bark beetles and their hosts, shifts to novel hosts
with similar secondary compounds (Kelley et al. 1999; Kerdelhué et al. 2002; Jordal et al. 2004)
and geographic isolation (Kelley et al. 1999; Cognato et al. 2005; Ruiz et al. 2009) are important
factors in species diversification. Our understanding of evolutionary processes that form the
patterns of host-plant use is not complete because knowledge of Curculionoidea phylogeny is at
best preliminary (Oberprieler et al. 2007). Thus, detailed knowledge of host-plant preferences
and species-level phylogenies will provide a foundation for testing hypotheses related to
evolution of host and host preference (Farrell et al. 2001).

	
  

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Most research addressing evolution of host-use has focused on herbivorous insects that
feed on live, healthy plants (Farrell and Mitter 1990; Farrell 1998) rather than on insects in dying
and dead plants (Jordal et al. 2004). I aim to augment the knowledge of evolution of host-use
among phloem-feeding insects of dying and dead trees via a study of host tree use among
tropical and temperate species in a tribe of scolytine weevils. Data from this research will add to
the growing number of studies addressing the central paradigm of herbivorous insect evolution
and host-plant association (Erhlich and Raven 1964; Jermy 1976; Janz and Nylin 2008). These
results will further increase our understanding of the evolution of insect species and their
potential to invade novel host plants.

Study Group
Scolytini offers an opportunity to examine the evolution of host-use within a
monophyletic group of species that feed on a wide variety of plants. In particular, six genera
Camptocerus Dejean 1821, Ceratolepsis Chapuis 1869, Cnemonyx Eichhoff 1868, Loganius
Chapuis 1869, Scolytus, and Scolytopsis Blandford 1896, of this tribe show a diversity of hostuse and diet in the Neotropic and the Holarctic regions (Wood 1982). All genera except the
ambrosia feeding Camptocerus are phloeophagous and all genera exclusively use angiosperm
hosts, except Scolytus, which includes 22 species that feed exclusively on conifers in the
Holarctic (Table 2.1) (Smith, Chapter 1; Michalski 1973). Scolytus is unusual in this regard
because it is one of five scolytine genera that possess this broad host-use pattern (Wood 1986).
Nearly all Neotropical Scolytus species feed exclusively on woody species of the diverse and
ubiquitous (Boom 1986) angiosperm family Fabaceae. In contrast, nearly all native Nearctic
species feed on Pinaceae, including the genera Abies Mill., Larix Mill., Picea D.Don. ex Loudon,

	
  

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Pseudotsuga Carrière, and Tsuga Carrière (Smith, Chapter 1; Wood and Bright 1992). To date,
patterns of Scolytini and host tree coevolution have not been examined in a phylogenetic context.
Reconstruction of a Scolytini phylogeny allows hypotheses related to the evolution of
scolytines in relation to their hosts to be tested. Specifically, this study is designed to examine (1)
the evolution of conifer-feeding from an ancestral angiosperm-feeding lineage, (2) patterns of
host plant-use among the Scolytini, (3) the independent evolution of fungus-feeding in
Camptocerus from phloem-feeding ancestors, (4) the monophyly of Scolytini genera and the age
of Scolytini genera. This study also addresses broader evolutionary hypotheses of beetle/host
evolution including the phylogenetic conservation of host-plant use such that related beetle
species feed on related plant species.

Materials and Methods

Taxa, DNA sequences and Alignment
I sequenced up to four genes for 131 specimens (Table 2.2) representing 65 Scolytini
species including representatives of Camptocerus (13 spp.), Ceratolepsis (2 spp.), Cnemonyx (5
spp.), Loganius (3 spp.) and Scolytus (42 spp). Coptonotus cyclopus Chapuis 1869 was selected
as an outgroup species based on the result of a previous phylogenetic study (Jordal et al. 2011).
Specimens of Scolytopsis could not be sampled for this study due to unavailability. Sequences of
the following species were obtained from GenBank and included in the analyses: S. ecksteini 166
(JX416906.1), S. ecksteini 167 (JX416909.1), S. rugulosus 165 (JX089344.1), S. intricatus
(HQ883677, HQ883589, HQ883820, HQ883909) and S. scolytus (HQ883678, HQ883590,
HQ883821, HQ883910). Specimens were included in the dataset only if molecular data were

	
  

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available for at least two of the four genes. DNA extraction, amplification and sequencing
protocols were identical to those used by Smith (Chapter 1). Purified DNA was used to amplify
partial gene regions of mitochondrial cytochrome oxidase 1 (COI), D2 region of nuclear
ribosomal 28S, CAD, and Argenine Kinase (ArgK) using the PCR primers listed in Table 1.6.
Nexus files are available at http://www.scolytid.msu.edu.

Bayesian Analyses
I analyzed the dataset using Bayesian estimation of phylogeny with MrBayes 3.2.1
(Huelsenbeck and Ronquist 2001) and selected the best model for each data partition using
MrModeltest (Nylander 2004) and implemented in PAUP*4.0 b10 PPC (Swofford 2002). The
models selected by the AIC was found to have the optimal fit (Table 2.3). However MrBayes is
limited in the models of nucleotide evolution that it can accommodate and so the closest model
was implemented, GTR+I+ Γ (general time reversible with a proportion of invariant sites and a
gamma-shaped distribution of rate variation across sites) (Bennett and O’Grady 2012). The
dataset was divided into partitions by either genome (mitochondrial vs. nuclear) and by
nucleotide position. Run 1 consisted of all data under a single partition, run 2 consisted of 4
(COI, 28S, CAD and ArgK) and run 3 consisted of 3 partitions (COI, 28S, CAD+ArgK).
Parsimony analyses were not performed because they were previously found to recover several
of the species included in the analysis as para- and polyphyletic despite many discrete
morphological, ecological, behavioral and distributional similarities (see Smith, Chapter 1).
The molecular datasets were each analyzed with four Metropolis-Coupled Markov Chain
Monte Carlo searches (3 heated, 1 cold) (Huelsenbeck and Ronquist 2001) for 2-2.5 million
generations with sampling every 100th iteration. Approach to stationarity (burn-in) was 0.25.

	
  

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Burn-in discards the first 25% of trees sampled to minimize the effect of the initial posterior
distribution. All parameters reached stability and the split deviation between runs was below
0.05 indicating that the four changes had converged on a topology. Bayesian posterior
probabilities of clades were calculated by a majority-rule consensus of those trees after the burnin. Nexus files are available at http://www.scolytid.msu.edu.

Hosts
Species included in the analyses and the known hosts are shown in Table 2.4-2.6. Host
records and feeding habit were obtained from a comprehensive literature review (von Butovitsch
1929; Chamberlin 1939; Schedl 1948; Balachowsky 1949; Stark 1952; Chamberlin 1958; Edson
1967; Beaver 1972; Bright and Stark 1973; Michalski 1973; Nobuchi 1973; Bright 1976; Furniss
and Carolin 1977; Wood 1982; Yin et al. 1984; Atkinson and Equihua-Martinez 1986a; Wood
and Bright 1992; Pfeffer 1994; Cibrián Tovar et al. 1995; Bright and Skidmore 1997, 2002;
Furniss and Johnson 2002; Wood 2007; Smith and Cognato 2010b), field notes, discussions with
other scolytine experts (T.H. Atkinson, D.E. Bright, M.M. Furniss, A.V. Petrov) and label data
on museum specimens.
Host plant nomenclature was verified by querying the International Plant Name Index
(www.ipni.org) or Tropicos (www.tropicos.org) databases. Angiosperm classification follows
that of the Angiosperm Phylogeny Group (APG) III (Angiosperm Phylogeny Group 2009).

Ancestral State Reconstruction
Feeding habit and host associations were scored and entered into a nexus file in Mesquite
v. 2.75 (Maddison and Maddison 2011). The number of origins of wood-boring behavior and

	
  

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patterns of host plant-use were then traced in Mesquite using the likelihood criterion onto each
tree obtained from the above Bayesian analyses. The Markov k-1 (mk-1) model was used which
allows for equal rates of change between character states. Taxa were coded as follows:
Feeding habit:
0, phloem-feeding
1, wood boring, including ambrosia fungus feeding and xylophagy
Most frequently observed host plant family:
0, Pinaceae
1, Burseraceae
2, Ulmaceae
3, Rosaceae
4, Fabaceae
5, Juglandaceae
6, Cannabaceae
7, Betulaceae
8, Fagaceae
9, Myristicaceae
A, Clusiaceae
B, Euphorbiaceae
C, Malvaceae
Genera of coniferous hosts:
0, Picea
1, Abies

	
  

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2, Larix
3, Tsuga
4, Pseudotsuga
Total diet breath for each species could not be tested using the likelihood criterion
because current methods are unable to process polymorphic characters (Bollback 2006;
Maddison and Maddison 2011). Nexus files are available at http://www.scolytid.msu.edu.

Conservation of Host-Use
Permutation tail probability (PTP) tests were used to determine conservation of host-use
among the tribe. PTP tests measure the proportion of datsets producing a tree shorter or equal in
length to the actual tree (Faith and Cranston 1991). Performing a PTP test serves as the basis to
test the null hypothesis that there is no structure in the tree and that the observed pattern is due to
random chance. Under a PTP test, a constraint tree is loaded and characters are randomly
permutated across the topology, then the resulting length is measured (Maddison and Slatkin
1991; Faith and Cranston 1991).
PTP tests were performed in PAUP* b10 (Swofford 2002) for both the most common
utilized plant family and conifer host genus (Kelley and Farrell 1998). The host character was
randomized 10,000 times over a constraint tree. Since the phylogeny of the group is known, host
character states were randominzed over a constraint tree to test the frequency of each character
state (Maddison and Slatkin 1991; Faith and Cranston 1991).

Estimating Divergence Times

	
  

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I estimated lineage divergence times using the BEAST v1.7.5 software package
(Drummond et al. 2012). Input xml files were generated in BEAUti v1.7.5 (part of the BEAST
package) using a user-specified start tree and topology from my run 2 Bayesian analysis. The
consensus tree was pruned to remove polytomies. A Yule prior process model was selected as
the tree prior, which assumed a constant speciation rate for each lineage (Gernhard 2008). The
topology was unconstrained and allowed a separate GTR+I+ Γ with 6 gamma categories for each
gene as selected by MrModeltest. An uncorrelated lognormal relaxed molecular clock allowing
for rate variation among lineages because different lineages evolve at different rates (Drummond
et al. 2006). Two separate analyses were performed, for minimum and maximum clade ages.
Each analysis was performed with four independent chains of 60,000,000 generations with trees
sampled every 1,000 generations. The tree files were combined in TreeAnnotator v1.7.5 (part of
the BEAST package) with the burn-in set to 20,001 trees (33% burn-in). A large burn-in was
used due to limited computational resources. The remaining 40,000 trees were used to create a
maximum clade credibility (MCC) tree with mean node heights. XML files are available at
http://www.scolytid.msu.edu.
Five priors based on the fossil record were used to calibrate the phylogeny and the
minimum age for each node. Calibration 1, Scolytini: 100 mya Microborus (Hexacolini) from
Burmese amber (Cognato and Grimaldi 2009). Numerous phylogenetic studies have recovered
the Scolytini at the base of the Scolytinae and basal to the Hexacolini, indicating a minimum age
of the Scolytini of 100 mya (Jordal et al. 2011; Jordal and Cognato 2012). Calibration 2, South
American Scolytus: Scolytus poinari Bright, Dominican amber 20-17 mya (Bright and Poinar
1994). This species is morphologically aberrant from extant Scolytus in the shape of the antennal
club. It most closely resembles species from southern Brazil in the shape of the frons, abdominal

	
  

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spine placement and setal length and distribution and thus was used to date the clade of S.
excavatus and S. proximus. Calibration 3, Tubuloscolytus species group: Scolytus duplicatus
compression fossil from the Upper Miocene and Lower Turolian ~9-5.3 mya in France (Petrov
and Zherikhin 2000). The species is very morphologically similar to S. koenigi, an extant
member of the Tubuloscolytus species group and indicates a minimum clade age of 5.3 mya.
Calibration 4, Cnemonyx: Cnemonyx priscus Bright and Poinar, fossil in Dominican amber, 2017 mya (Bright and Poinar 1994). This species is easily associated with extant Cnemonyx and is
morphologically similar to C. vismiacolens Wood and C. rugulosus (Eggers) and thus was used
to calibrate Cnemonyx. Calibration 5, Cylindrobrotus: Cylindrobrotus pectinatus Kirejtshuk,
Azar, Beaver, Mandelshtam and Nel, fossil in Cretaceous Lebanese amber was thus used to
calibrate the maximum age of the Scolytini at 120 mya (Kirejtshuk et al. 2009).
Two BEAST analyses were performed: one with a maximum clade age at 100 mya
(calibration 1) and the most recent dates for each fossil calibration (analysis A) and one analysis
with a maximum age at 120 mya (calibration 5) and the most distant dates for each fossil
calibration (analysis B).

Results
Phylogenetic Results
Overall, the three Bayesian analyses produced trees with strikingly similar topology
(Figures 2.1-2.3) and the majority of genera were recovered as monophyletic with the exception
of Camptocerus s.l. and Cnemonyx. Most differences were observed in the run 1 tree (Figure 2.1)
in which S. oregoni 5 and 71 were not recovered as monophyletic, the placement of S.
quadrispinosus was unresolved with regards to Western European or Nearctic taxa and S.

	
  

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orientalis was recovered as sister to S. ecksteini rather than unresolved with S. multistriatus and
S. ecksteini. The run-3 tree (Figure 2.3) did not resolve the relationships between S. cristatus, and
the Central American taxa and the South American taxa.

Ancestral State Reconstruction of Feeding Habit and Host-Use
The Bayesian tree topologies uniformly displayed a loss of wood-boring in the most
recent common ancestor (tmrca) of the Scolytini and two separate originations of wood-boring
within the Scolytini from phloeophagous ancestors. The character was mapped onto the run-2
topology (Figure 2.4). Xylomycetophagy was the result of one shift in the tmrca of Camptocerus
s.s. and once in the tmrca of Camptocerus s.l.
The tree topologies reported identical patterns of host-plant family usage throughout the
tribe. Host-use was largely conserved among closely related taxa but several shifts to different
plant families were also observed (Figure 2.5). The tmrca of Scolytus most likely fed on
Ulmaceae or Fabaceae. All Neotropical Scolytus feed upon Fabaceae and the tmrca of the
Holarctic species fed on Ulmaceae. Several shifts away from Ulmaceae to families such as
Rosaceae, Betulaceae, Ulmaceae, Fagaceae, Juglandaceae and Cannabaceae are observed with
no reversals to Ulmaceae. There is also a shift from Pinaceae to Rosaceae. Two separate shifts to
Fagaceae, Rosaceae and Pinaceae were also observed. The tmrca of Loganius likely fed on
Euphorbiaceae, Ceratolepsis on Myristicaceae and that of Camptocerus and Cnemonyx on
Burseraceae.
The three Bayesian topologies are congruent for conifer host-use among Scolytus (Figure
2.6). Patterns of conifer host-use shows conservatism among closely related taxa. The analysis
showed two separate shifts to conifers from angiosperm feeding ancestors, once to Picea in the

	
  

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Palearctic and once to Abies in the Nearctic. From Abies there was a shift to Pseudotsuga and
shifts from Pseudotsuga to Larix, Picea and Tsuga.

Conservation of Host-Use
The PTP test failed to reject the null hypothesis that host use is uncorrelated with
phylogeny (p=1.0) for both most common host plant family (p=1.0) and for conifer host genus
(P=1.0). For most common host plant family, the length was 16 steps (CI= 0.75, RI =0.927);
however, randomization was able to generate trees with a length of 12 steps, indicating that the
pattern of host-use could have been more parsiminous. There were seven steps in the coniferhost genus (CI= 0.714, RI =0.957) and randomization produced trees with a length of five steps.

Estimating Divergence Times
The maximum clade credibility trees for analysis A (Figures 2.7) and analysis B (Figures
2.8) produced a topology similar to that of the single partition dataset, Bayesian analysis 1
(Figure 2.1). Estimates of clade ages were derived from FigTree v1.7.5 (part of the BEAST
package) (Table 2.7). Scolytini was found to have a stem age of 113-94 mya, Scolytus 59-50
mya, Camptocerus s.s. 43-34 mya, and Nearctic conifer-feeding Scolytus 20-16 mya.

Discussion
Taxonomic Implications
Camptocerus was recovered as paraphyletic with members of the genus forming two
clades, Camptocerus sensu stricto (s.s.) and Camptocerus sensu lato (s.l.). Camptocerus s.s. was
comprised of species from the aeneipennis, latipillis and costatus clades (sensu Smith and

	
  

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Cognato 2010b) and was strongly supported (pp > 95). Each clade was also monophyletic and
the relationships among clades was identical to those obtained through parsimony analysis of
morphological characters (Smith and Cognato 2010b). Camptocerus s.l. was composed of
species in the auricomus and opacicollis clades (sensu Smith and Cognato 2010b) and several
Cnemonyx species that superficially resemble Camptocerus (pp > 95). The monophyly of these
two Camptocerus clades previously found by Smith and Cognato (2010b) was not recovered,
suggesting that the generic limits between Camptocerus and Cnemonyx need to be clarified.
Loganius (pp > 95) and Ceratolepsis (pp > 95) were both recovered as monophyletic
lineages. Ceratolepsis has been removed from synonymy with Cnemonyx and Loganius should
be given new status (Smith, Chapter 3). Cnemonyx was not recovered as monophyletic and
species formed two clades, one that rendered Camptocerus paraphyletic and one clade consisting
of C. panamaensis (Blandford) and C. setulosus (Eggers). Cnemonyx s.s. were not included in
this study however these species are morphologically dissimilar from the Cnemonyx included in
this study. Cnemonyx s.s. all possess crenulations along the elytral base while Cnemonyx s.l. do
not. Cnemonyx has had a very confused taxonomic history (e.g. Schedl 1962; Wood 1972; Smith,
Chapter 3), with ambiguous generic limits and is clearly in need of revision. Ceratolepsis
amazonicus from two localities in Loreto, Peru and Orellana, Ecuador were not recovered as
monophyletic. Each specimen was obtained from large series and directly compared to the
holotype. No observable morphological differences were observed. It is possible that one of the
specimens represents a cryptic species.
Scolytus was recovered as monophyletic and formed two main clades, the first of which
was composed of Neotropical species and the second of Holarctic species. In the Neotropical
clade, there was a distinct split between the Central American and the South American species,

	
  

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except in run 2. Scolytus cristatus Wood is distributed in both Central and South America
(Petrov and Mandelshtam 2010; Wood 1982) and was found at the base of the Central American
clade, thus suggesting a colonization of Central America by South American species (Figures
2.1, 2.2). All of the Neotropical species have been collected from Fabaceae (except S.
mozolevskae Petrov and Mandelshtam 2010 for which the host was reported as an unknown
vine). Holarctic Scolytus formed several clades that corresponded to species groups initially
proposed by von Butovitsch (1929), which had been subsequently modified or dismissed by later
authors (e.g. Schedl 1948; Balachowsky 1949; Stark 1952; Michalski1973). Subsequent authors
based their classification systems on the occurrence, shape and placement of spines on the
abdominal venter. von Butovitsch’s classification system was based on the structure of the
aedeagus and proventriculus rather than external characters that often show a large amount of
intraspecific variation (e.g. LaBonte 2010; Smith, Chapter 1). von Butovitsch’s system divided
the genus into two sub genera: Scolytus s.s. and ruguloscolytus. Scolytus s.s. was composed of
five species groups: archaeoscolytus, pygmaeoscolytus, Scolytus s.s., spinuloscolytus and
tubuloscolytus. Ruguloscolytus was composed of two species groups: pinetoscolytus and
ruguloscolytus. One of von Butovitsch’s two subgenera, ruguloscolytus, and six species groups
were recovered as monophyletic with pp ≥ 90 (Figure 2.2). Species belonging to the
archaeoscolytus species group could not be sampled. von Butovitsch’s classification system was
almost identical to what my analyses recovered in regards to both his placement of species
groups and the monophyly of these groups, with two exceptions: S. quadrispinosus Say and S.
japonicus Chapuis, which von Butovitsch tentatively placed in the tubuloscolytus and
ruguloscolytus species groups, respectively, and noted uncertainty regarding this placement.
Scolytus quadrispinosus was recovered in the Scolytus s.s. species group and S. japonicus formed

	
  

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a clade with S. schevyrewi Semenov. The Nearctic Scolytus species were recovered in two
clades, the Scolytus s.s. and the ruguloscolytus clade, indicating two separate colonizations of
North America, once on angiosperm hosts in the Eastern North America from a clade of western
European species and once on coniferous hosts in Western North America from East Asian
species (Figure 2.2).

Evolution of Host-Plant Use by Insects
The ‘escape and radiate’ coevolutionary model proposed by Erhlich and Raven (1964)
states that diversification of plants is tied to the evolution of novel secondary compounds which
release plants from herbivore pressure. Corresponding evolution of a trait in herbivores that
allows circumvention of these secondary compounds leads to diversification in phytophagous
insects. This model implies reciprocal evolution in which episodes of plant radiation alternate
with radiation of herbivorous species (Thompson 1994). Several studies have supported the
‘escape and radiate’ model of coevolution but it has often been found to be extremely
asymmetrical. Escape from herbivores through the evolution of novel secondary compounds
generally has little impact on plant diversification but instead creates a new adaptive zone that
allows bursts of herbivore diversification (Farrell and Mitter 1993; Farrell 1998; Fordyce 2010).
Most research addressing this model has focused on insects that feed on living leaf tissues or
within seeds rather than on insects that consume phloem and xylem of dead and dying hostplants, such as scolytines (Jordal et al. 2004).
The alternative model is the sequential evolution model proposed by Jermy (1984) which
states that coevolutionary interactions between phytophagous insects and plants are asymmetric.
Phytophagous insects can apply diversifying selection on plant defensive traits but have an

	
  

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insignificant effect on the evolution of the host. However, diversification of host plants can lead
to increased resource heterogeneity, particularly among the diversity of biochemical and
structural traits. This diversifies plant selection pressures and increases the possibility of
evolutionary radiation among insects, especially those that consume phloem and xylem tissues of
dead and dying host-plants (Jermy 1984; Nyman 2010). The extensive radiation of angiosperms
into lineages with very different secondary compounds provided the substrate necessary for
radiations of herbivorous insects. Several studies have found that insect-plant associations are
predominately the result of continuous host-plant shifts among pre-existing host plant taxa
(Morse and Farrell 2005; Janz and Nylin 2008; Kato et al. 2010; Nyman 2010; Nyman et al.
2010; Kergoat et al. 2011; Bennett and O’Grady 2012; Leppänen et al. 2012). The sequential
evolution model is also supported based on data from recent investigations that showed the
diversification of most insect groups followed their host taxa (Gómez-Zurita et al. 2007;
McKenna et al. 2009; Nyman 2010).
Thompson (1994) identified several characteristics for host specialization in
phytophagous insects that complete their life on a single host individual: 1, the host species
should be readily available throughout the year; 2, the host should be predictably available over
time; 3, the insect should have the genetic ability to circumvent host defensives and be able to
digest the host with specialized foraging techniques, morphology or physiology; 4, hosts should
be sessile in nature and relatively easy to locate the host. Bark beetles meet these criteria and are
predisposed to host specialization for the following reasons: 1. the occurrences of tree species are
predictable through space and time because bark beetle species occur in abundant and common
host taxa and thus an individual of a common host tree is more likely to be dead or dying at any
point of time compared to rare host taxa; 2, they complete their development in a single host tree

	
  

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and, then mate and reproduce on another host tree; 3, the beetles have the ability to circumvent
host defenses; 4, Scolytini utilize host-tree volatiles to locate suitable material for colonization
(Macías-Sámano et al. 1998).
Host-use is also driven by relative host abundance along with host characteristics
including secondary compounds and anatomical defensive features such as resin canals (Browne
1961; Atkinson and Equihua-Martinez 1986a). Bark beetles are commonly found in hosts
possessing resins or latex (Browne 1961; Wood 1982; Equihua-Martinez et al. 1984; Atkinson
and Equihua-Martinez 1986a,b) and these types of trees are reportedly very common in
Neotropical and Holarctic forests (Boom 1986; Prance et al. 1976; Mori and Boom 1987;
Taggart and Cross 2009). Phloem-feeders consume living or moribund host tissues and are
exposed to latex and resins. In dead and moribund trees, however, secondary compounds are
degraded over time and phloem-feeders are exposed to less toxic compounds (Jordal et al. 2004).
Hence, the beetles have capitalized on the volatility of these compounds and use them as cues to
locate suitable trees, while avoiding the brunt of toxicity. This behavior has likely contributed to
the maintenance of host specificity among the Scolytini (Atkinson and Equihua-Martinez 1986a)
given that closely related bark beetles typically show a preference for only congeneric tree
species (Browne 1961; Deyrup and Atkinson 1987; Noguera-Martinez and Atkinson 1990).
These tree genera are generally found in very common host families with large geographic
ranges (Wood 1982; Stevens 1986). Widespread tree species tend to be more locally abundant
and have more herbivores than rare and isolated species (Lawton and Strong 1981; Lawton 1993;
Kelly and Southwood 1999; Lewinsohn et al. 2005). A host can be considered an island in an
archipelago of resource space, where abundant hosts represent larger islands on which species
are less likely to become extinct (Nyman 2010). Such hosts are a predictable food resource for

	
  

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bark beetles because it is likely that within a local area, individuals of these trees may be killed
or damaged. Thus, it appears that bark beetles meet the criteria for becoming specialized to feed
on a single genus or family of tree.
Numerous phylogenetic studies have shown that insect host-use evolution is conservative
with respect to host taxon (Farrell and Mitter 1990, 1993; Becerra 1997; Janz and Nylin 1998;
Kelly and Farrell 1998; Farrell et al. 2001; Jordal et al. 2004; Ødegaard et al. 2005; Winkler and
Mitter 2008; Fordyce 2010; Leppänen et al. 2012). Frequently host shifts within an insect genus
involve host plants that are already colonized by congeneric species, suggesting a constraint to
host range expansion and behavioral or physiological preadaptations to colonize such taxa
(Futuyma et al. 1993, 1994, 1995; Janz et al. 2001; Nosil 2002; Morse and Farrell 2005;
Weingartner et al. 2006; Nyman et al. 2006). Shifts occur more often among closely related
plants (Nyman 2010) and rarely among more distantly related taxa such as angiosperms and
conifers (Nyman 2010) or monocots and dicots (Ødegaard et al. 2005).
Browne (1961) postulated that specialist bark beetles are derived from generalists. This
hypothesis was supported in the phloem-feeding genus Dendroctonus Erichson (Kelley and
Farrell 1998) but was disputed in an investigation of the genus Coccotrypes Eichhoff (Jordal et
al. 2002). Unlike diplodiploid Dendroctonus, Coccotrypes is haplodiploid and exhibits feeding
habits that encompass fruits and seeds, leafstalks, phloem and pith. Within Coccotrypes, it was
found that generalists are derived from specialists (Jordal and Hewitt 2004). This lends support
to the idea that specialization does not always evolve from generalized feeding habits but that all
types of phylogenetic scenarios involving specialist and generalist species can occur and that
specialization is not a dead end but a dynamic process (Thompson 1994; Nosil 2002). The degree
of host specificity is directly related to feeding habit, with ambrosia beetles exhibiting low host

	
  

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specificity and phloem-feeders high host specificity (Beaver 1979). Specialization is normally at
the family level, uncommon at the genus and rare at the species level (Browne 1961). Species of
Nearctic Scolytus are restricted to feeding on hosts in a single genus of Pinaceae. Scolytus are
rarely collected from other non-host genera, but these events could be attributed to host
misidentification, forced alternative host (Kelly and Farrell 1998) or potentially local adaptation
(Slove and Janz 2011).
The oscillation hypothesis of host-plant range and speciation proposed by Janz and Nylin
(2008) posits that specialist species undergo a host range expansion, and become oligophagous
or polyphagous. This increase in host range causes a geographical range expansion as two hosts
rarely occupy exactly the same spatial distribution. These oscillations in host specificity and
range provide the foundation for speciation. As the polyphagous species spread across the host
plants’ geographic ranges, the subpopulations emerge with more restricted geographic
distributions and potentially host distributions as they undergo local adaptation. Adaptations not
only include climate, but habitat availability, host abundance, resource competitors and predators
(Janz and Nylin 2008; Slove and Janz 2011). These oscillations are maintained by the inheritance
of the ability to use ancestral hosts and allows for recurrence of this ability throughout the
phylogeny. The accumulation of hosts during periods of increased resource use drives
diversification and explains why species rich lineages frequently show shifts among host plants,
as observed within Scolytus species with regard to Ulmaceae, Betulaceae, Fagaceae and Pinaceae
(Janz and Nylin 2006, 2008; Janz 2011).
The oscillation hypothesis also helps to explain why various studies have reached a
multitude of conclusions regarding the derivation of specialization from generalization and viceversa. It also explains why species with large geographic ranges tend to be polyphagous

	
  

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(Päivinen et al. 2005; Slove and Janz 2011). Indeed this pattern of broad geographic ranges and
diet diversity is exhibited in several Palearctic Scolytus species (Table 2.6) who occupy ranges
that span large areas of Eurasia including S. ratzeburgii, S. rugulosus, S. multistriatus, S.
schevyrewi, S. carpini, S. intricatus and S. scolytus (Wood and Bright 1992; Pfeffer 1994).
Scolytus cristatus occurs in Central and South America and is distributed from Jalisco, Mexico to
Peru and southern Brazil.
Scolytus exhibits two large host shifts from angiosperms to conifers and from conifers to
angiosperms (Figure 2.5). These large shifts can be explained by the oscillation hypothesis as
well. Polygraphus grandiclava (Thompson) is a Palearctic scolytine species that has populations
that occur only on pine (Pinus), only on cherry (Prunus) and on both pine and cherry in Central
Europe. The sister species is not known but all other Holarctic Polygraphus utilize conifer hosts
(Wood 1982; Yin et al. 1984; Pfeffer 1994). An investigation into the phylogenetic history of the
P. grandiclava showed that the genetic diversity within the species was not the result of host-use,
but of geography (Avtzis et al. 2008). This suggests that in the past, the species went through a
host-range expansion and subsequently a geographic range expansion that led to local adaptation
and may eventually lead to speciation (Janz and Nylin 2008; Nylin and Janz 2009). Polygraphus
grandiclava also serves as a model as to how such a shift occurred in Scolytus rugulosus.
Scolytus rugulosus also utilizes Prunus hosts (Michalski 1973; Wood and Bright 1992; Smith,
Chapter 1) and was likely derived from a Pinaceae feeding ancestor.

Correlation with Host-Use Oscillation Hypothesis
The host-use oscillation hypothesis cannot be tested on the Scolytini at this time. Because
the hypothesis is based on the placement of specialist and generalist species in the phylogeny, the

	
  

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hypothesis is dependent on sampling. False conclusions are possible if clades are not adequately
sampled. Research examining the patterns of host-use among Nymphalid butterflies (Nylin and
Wahlberg 2008) and Nematine sawflies (Leppänen et al. 2012), have supported this hypothesis
and these groups have well-known phylogenies and host associations.

Conservation of Host-Use
The null hypothesis of random host-use among Scolytini and conifer-feeding Scolytus
species was not rejected, but this does not imply that the patterns observed among the Scolytini
was truly the result of random processes. Rather, the data do not reveal cladistic structure. A
better interpretation of this result is that several independent host shifts to families have occurred
throughout their history (Faith and Cranston 1991). The lack of conservatism of plant-use within
the Scolytini rejects the predictions of Erhlich and Raven (1964) in that radiations of plant taxa
are not responsible for the diversification of the tribe. This also suggests that shifts between
existing host plant families are the primary drivers of diversity within the Scolytini, thus
supporting the host use oscillation hypothesis. Frequent host shifts may have occurred because
the Scolytini utilize dead and degraded hosts. Beetles experience fewer dietary constraints due
to degraded secondary compounds and thus increased likelihood for host shifts (Jordal et al.
2004).

Ancestral State Reconstruction of Feeding Habit and Host-Use
The Bayesian tree topologies were congruent in the patterns of ancestral host-feeding
among all Scolytini genera (Figure 2.5). The ancestral host for Holarctic Scolytus species was
Ulmaceae and several shifts away from Ulmaceae are present in each of the Scolytus s.s. species

	
  

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groups. Spinuloscolytus was found at the base of the Holarctic Scolytus clade and contains
species that exclusively occur on Ulmaceae. The clade of S. japonicus with S. schevyrewi and
pygmaeoscolytus also primarily occur on Ulmaceae. The pygmaeoscolytus and tubuloscolytus
clades were recovered as sister. The tubuloscolytus clade exhibits two host-shifts away from
Ulmaceae (Rosales) once to Carpinus (Betulaceae) and once to Quercus (Fagaceae), both in the
Fagales. The Scolytus s.s. species group primarily occur on Ulmaceae. Within this group, there
have been with two shifts to the Fagales, including once to Betulaceae, and once to Juglandaceae
and subsequently Fagaceae. In addition, there were two shifts to other Rosales, including
Cannabaceae and Rosaceae, once from Ulmaceae to Rosaceae and once from
Fagaceae/Juglandaceae to Cannabaceae.
The ruguloscolytus subgenus sensu Butovitsch was also recovered as monophyletic and
includes two separate shifts to conifers, once in the Palearctic and once in the Nearctic. The
tmrca of the ruguloscolytus clade was likely a conifer-feeder and there was a subsequent shift to
Rosaceae in the tmrca of S. rugulosus and is sister taxa, S. amygdali (not sampled). The Nearctic
conifer-feeders show distinct patterns in their host-use with basal clades found on Abies and
subsequent shifts to Pseudotsuga and from Pseudotsuga to Larix and Tsuga (Figure 2.6).
It is interesting to note that Scolytus colonize most Pinaceae genera but do not colonize
Pinus species. This may reflect both interspecific competition for pine, as well as differential
tolerance to host resins. A multitude of genera including Dendroctonus Erichson, Ips DeGeer,
Hylastes Erichson, Hylurgops LeConte, Orthotomicus Ferrari, Pityogenes Bedel, Pityophthorus
Eichhoff, and Pseudohylesinus Swaine are feed on pine tissue, from root to twig. In contrast,
genera colonized by Nearctic Scolytus are utilized by relatively few bark beetle species
compared to Pinus spp. (Wood and Bright 1992; Pfeffer 1994). Scolytus tend to colonize taxa

	
  

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that host only a few other bark beetle species (Wood and Bright 1992; Pfeffer 1994),many of
which previously colonized pines in North America prior to the arrival of the conifer-feeding
Scolytus. Studies have also suggested that Scolytus are relatively intolerant of host resins. To
colonize pine, Scolytus species must be able to tolerate high levels of preformed monoterpenes
present in resin canals in bark and foliage. Scolytus species exposed to monoterpene resins,
however, have higher mortality rates compared to species that occur on Pinus (Raffa and
Berryman 1987).
Surprisingly the two mk-1 ancestral state reconstructions resulted in different conclusions
regarding the origination of conifer hosts among Scolytus. Mapping the most common host
family onto the topology resulted in a scenario in which there was a single shift to conifers
(Figure 2.5) and mapping conifer host genus onto the phylogeny resulted in a scenario in which
there were two separate colonizations of conifers, once to Picea and once to Abies (Figure 2.6).
Host shifts from angiosperms to conifers are relatively rare and are reportedly very difficult from
an evolutionary standpoint (Nyman 2010). It seems likely that because of the way that characters
were scored in the conifer-host genus ancestral state reconstruction, information was lost by
lumping all angiosperm-feeding taxa under a single character state. Because all previous taxa
were coded the same, the mk-1 model found two-shifts to be more probable than a single event
because of a lack of information. The most common host family ancestral state reconstruction
(Figure 2.5) should be considered a more reliable inference because of the greater information
found in more character states, which increases the amount of detailed information in the
phylogeny.
The tmrca of the clade of non-Scolytus genera likely fed on Euphorbiaceae, as the basal
genus, Loganius, is only reported to feed on Euphorbiaceae. The tmrca of Ceratolepsis was

	
  

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likely Myristicaceae. Host records are available for most species of Ceratolepsis and all have
been from Virola (Myristicaceae). Unfortunately, the host record for C. amazonicus has not been
reported. If other species had been included in the analysis, the likelihood of a Myristicaceae
specific tmrca would be greater. The tmrca of Cnemonyx and Camptocerus shifted from
Myristicacae to Burseraceae as both genera show a strong pattern of using Burseraceae hosts.
However, Cnemonyx s.l. have a more diverse host range including Burseraceae in the taxa that
most strongly resemble Camptocerus, and others that occur on both Burseraceae and Meliaceae
or Myrtaceae and one species that occurs on Clusiaceae, C. vismiacolens Wood. There is a
paucity of host records for Cnemonyx s.s. but specimens of the type species, C. galeritus
Eichhoff, have been collected from Euphorbiaceae. The phylogenetic placement of Cnemonyx
s.s. is unknown. Scolytopsis was not included in this analysis and host records indicate that
species occur on Combretaceae (Myrtales) hosts.

Estimating Divergence Times
My fossil calibrations produced clade ages that were consistent with the results of Jordal
and Cognato (2012), the only other BEAST phylogeny for scolytines that included ages for the
Scolytini (Jordal and Cognato 2012). Jordal and Cognato (2012) used BEAST to determine when
ambrosia feeding habits evolved within the subfamily using a broad taxon sample representing
half the scolytine genera and more than 200 species. Jordal and Cognato estimated the clade age
of Camptocerus to be between 40-33 mya. My analysis estimated the age of this group to be 4334 mya.
Scolytini lineage diversification occurred after that of the host plant family with three
exceptions: Camptocerus s.s., Camptocerus s.l. and Ceratolepsis. Camptocerus s.s. (43-34 mya)

	
  

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and Camptocerus s.l. (39-30 mya) have divergence times that correspond to that of the host
genus, Protium, at 40 mya (Becerra et al. 2012). Ceratolepsis (26-21 mya) may have diversified
with its host family, Myristacaceae, which is 21-15 my old (Magallón and Castillo 2009). The
similar divergence times of bark and ambrosia beetles and their hosts is characteristic of lineage
tracking. Divergence estimates for all other Scolytini lineages occurred millions of years after the
host family. All Loganius which diverged 32-26 mya use Euphorbiaceae hosts which have been
dated to 102 mya (van Ee et al. 2008). Neotropical Scolytus diverged 22-21 mya. All Neotropical
Scolytus are specific to Fabaceae, and diverged 22-21 mya. The Fabales, the plant order that
contains Fabaceae has been estimated to originate 101.1 mya (Magallón and Castillo 2009) and
Fabaceae 79-74 mya (Wikström et al. 2001). Holarctic Scolytus diverged 38-32 mya and
primarily utilize Fagaceae (90 mya), Betulaceae (88-83 mya), Juglandaceae (98-83 mya),
Ulmaceae (at least 50 mya), and Rosaceae (at least 55 mya) (Crepet et al. 2004; Wang et al.
2010; Li et al. 2011). Conifer-feeding Nearctic Scolytus diverged 20-16 mya. This clade
colonizes several lineages that are specialized to Pinaceae genera, including Abies (106-55 mya
and 73 mya in the Nearctic), Larix (87-70 mya), Pseudotsuga (87-70 mya), Picea (142 mya), and
Tsuga (78-38 mya) (Gernandt et al. 2008; Aguirre-Planter et al. 2012). The above divergence
times for the Scolytini derived from the BEAST analyses indicate that most Scolytini diverged
after their hosts, lending support to the sequential evolution and more specifically, the host-use
oscillation hypotheses.

Conclusions
This investigation represents the first molecular phylogeny of the Scolytini and results
support a monophyletic Scolytini, Ceratolepsis, Loganius, and Scolytus and paraphyletic

	
  

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Camptocerus and Cnemonyx. The currently recognized Holarctic Scolytus species groups were
found to be artificial and based on convenience of diagnosis rather than shared ancestry.
Holarctic Scolytus formed several clades that correspond to species groups proposed by von
Butovitsch (1929). These species should be revised in the context of von Butovitsch’s character
system to provide a reliable classification system. The generic limits of Cnemonyx and
Camptocerus require additional examination and taxonomic changes should be made to create
monophyletic lineages.
Scolytini diversity is the result of a combination of processes including host-shifts and
independent shifts to the same hosts, lineage tracking, and diversification on widespread and
common hosts, with shifts that occurred well after the diversification of the host family. Changes
in feeding habit, from phloem to fungus-feeding were also important in the diversification of
Camptocerus s.s and s.l., with two independent shifts to fungus-feeding. In addition, the pattern
of host-use among the Scolytini was not conservative to plant taxa. Overall, the observed
patterns of Scolytini host-use can be explained by a combination of the sequential evolution and
host-use oscillation hypotheses as well as lineage tracking, a pattern that has been found for other
insects that colonize living host plants (Morse and Farrell 2005; Gómez-Zurita et al. 2007; Janz
and Nylin 2008; McKenna et al. 2009; Nyman 2010; Kato et al. 2010; Nyman 2010; Kergoat et
al. 2011; Bennett and O’Grady 2012; Leppänen et al. 2012). This suggests that these same
processes drive host-use among taxa that colonize dead and dying hosts.

Future Directions
In the coming months, I plan to reanalyze the dataset in both MrBayes and BEAST using
sequences from additional Scolytini taxa. Additional taxa include several Cnemonyx s.l., Scolytus

	
  

201	
  

carpini from Sweden and most importantly, Scolytopsis. In May, I will also participate in a
collecting expedition to the Brazilian Atlantic forest where I could potentially acquire additional
Neotropical taxa. These additional taxa will potentially help resolve the phylogeny and elucidate
the taxonomic confusion among Camptocerus s.l. and Cnemonyx s.l. In July, I will travel to the
University of Bergen, Norway where my colleague Dr. Bjarte Jordal will provide instruction on
BEAST and how to confidently set fossil priors to minimize error and obtain a more reliable
estimate for clade ages. While I incorporated a large degree of uncertainty in my fossil
calibrations here, the calibrations will likely become more exact when I fine-tune the priors.

	
  

202	
  

CHAPTER 3
PROGRESS TOWARD A REVISION OF THE SCOLYTINI I (COLEOPTERA:
CURCULIONIDAE: SCOLYTINAE)

203	
  

Abstract
The Neotropical bark beetle genera Cnemonyx Eichhoff 1868 and Scolytus Geoffroy1762
were reviewed as part of ongoing research into the higher-level taxonomy of the Scolytini.
Ceratolepsis Chapuis 1869 was removed from synonymy with Cnemonyx and seven new
combinations are reported: Ceratolepsis amazonicus Eggers 1929, C. boliviae (Blackman) 1943,
C. hylurgoides (Schedl) 1948, C. insignis (Wood) 1969, C. jucundus Chapuis 1869, C.
maculicornis Blandford 1896 and C. niger (Eggers) 1929. One new species was described:
Scolytus rabagliatus. Cnemonyx setulosus (Eggers) 1929 was removed from synonymy with C.
panamensis (Blandford) 1896. Four new synonyms were discovered: Ceratolepsis Chapuis (=
Coptosomus Schedl 1952), Cnemonyx setulosus (Eggers) 1929 (= Cnemonyx similis (Eggers)
1929), Scolytus proximus Chapuis 1869 (=Scolytus brevicauda Wichmann 1915) and Scolytus
thoracicus Chapuis 1869 (= Scolytus plaumanni Wood 2007). One new distribution record was
reported: Scolytus multistriatus in South America (Brazil).

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Introduction
The Scolytini includes ambrosia and phloem-feeding Scolytinae among its five genera
and approximately 221 recognized species, of which 136 occur in the Neotropical and 85 in the
Holarctic regions. Most species, 133, belong to Scolytus Geoffroy, which contains species
distributed in the Holarctic and Neotropical regions. The remaining four genera strictly occur in
the Neotropics.
Wood (2007) reviewed the South American fauna in his monumental monograph, which
was intended to serve as a starting point for future investigations. However, this monograph is
problematic. Several species were described that were morphologically identical to previously
described species and several questionable synonyms were created (e.g., Mandelsham 2009,
Smith and Cognato 2010b). This publication is the second step toward a revision of the
Neotropical Scolytini and aims to clarify the genera Ceratolepsis, Cnemonyx and Scolytus. The
genus Camptocerus has recently been revised (Smith and Cognato 2010b).
To revise the Nearctic Scolytus and assemble a robust taxon sample for a phylogenetic
analysis of the Scolytini (Smith, Chapters 1 and 2), I individually examined approximately
~10,000 specimens representing almost the entire diversity of the tribe except for some
Palearctic taxa. These specimens were identified by direct comparison to the holotype, lectotype
or paratypes.

Taxonomic History of the Scolytini
Before the last tribal revision (Wood 1972), the Scolytini consisted of two clearly defined
genera (Scolytus Geoffroy 1762 and Scolytopsis Blandford 1896) and six morphologically
similar genera (Camptocerus Dejean 1821, Ceratolepsis Chapuis 1869, Cnemonyx Eichhoff

205	
  

1868, Coptosomus Schedl 1952 and Loganius Chapuis 1869). Minulus Eggers 1912 had
previously been placed in synonymy with Cnemonyx galeritus Eichhoff 1868 (Eggers 1923), the
type species of Cnemonyx. Camptocerus, Ceratolepsis, and Coptosomus possess meso- and
metathoracic tibiae that are identical to the prothoracic tibiae, in which the apical margin is
straight, sharp, and smooth on anterior edge to the base of the outer apical spine. In Cnemonyx
and Loganius, the surface of the tibial anterior edge from the apical margin to the base of the
outer apical spine bears one or more denticles. Species with these denticles also have two to
three sutures on the antennal club marked with setae. Species without denticles lack externally
marked sutures, but at least part of suture 1 is marked internally by a septum. Schedl (1962)
noted the characters used to distinguish these genera were inconsistent and formed a spectrum of
morphological variation and placed Ceratolepsis in synonymy with Camptocerus. However,
Wood (1972) determined the genus Camptocerus was a distinct group without any synonymies.
In addition, Wood found that the characters used to identify Ceratolepsis (scales on antennal
club), Cnemonyx (crenulations of elytral base), and Coptosomus (oddly placed antennal suture)
were insufficient to clearly define species groups and transferred them to the oldest described
genus, Cnemonyx. Loganius species were split between Cnemonyx and Camptocerus. Currently
there is a broad spectrum of morphological variation within Cnemonyx that can be partitioned
into discrete groups. Recent phylogenetic analyses have shown that Ceratolepsis is a
monophyletic and morphologically distinct lineage (Smith and Cognato 2010b; Smith, Chapter
2). Further investigation is necessary to determine whether Loganius and Minulus represent
monophyletic lineages.

206	
  

Materials and Methods
The following entomological collection abbreviations are referenced in the text. Names
of the curators that prepared loans are listed in parentheses.
CNCI

Canadian National Collection of Insects (Hume Douglas, Patrice Bouchard)

DEBC

Donald E. Bright, Jr. Collection, Fort Collins, Colorado (Donald E. Bright, Jr.), to
be housed at the CNCI

MSUC

Albert J. Cook Arthropod Research Collection, Michigan State University, East
Lansing, Michigan (Gary Parsons)

RJRC

Robert J. Rabaglia collection, Annapolis, Maryland, USA

USNM

National Museum of Natural History, Smithsonian Institution, Washington, DC
(Natalia Vandenberg)
Specimens were examined using either a Leica (Wetzlar, Germany) MZ125 or MZ16

compound microscope and illuminated with a SCHOTT (Mainz, Germany) 150W halogen light
source (model ACE®1). Images were taken with a Visionary Digital Passport II system
(Palmyra, VA) using a Canon EOS 5D Mark II, 58mm Canon Macro photo lens, Canon
Speedlite transmitter ST-E2, two Canon Speedlite 4303X II flashes and a Stack Shot (Cognisys,
Inc, Kingsley, MI). Montage images were assembled using Helicon Focus Mac Pro 4.2.8
(Helicon Soft, Kharkov, Ukraine). Measurements were made using an ocular micrometer on the
same microscope and with the same light source as above and calibrated with ROK (Shenzhen,
China) 150mm digital calipers (model DC-122A) following the protocol of Smith and Cognato
(2010b). Measurements were taken from the specimen’s dorsal surface. Length was measured

207	
  

from the pronotum apex to the elytral apex. Width was measured at the widest part of the
pronotum. Proportions are given as the ratio of length to width. A maximum of 20 specimens
were measured for each species and were selected to encompass the known distribution.
Results and Discussion

Ceratolepsis Chapuis 1869 status restored
= Coptosomus Schedl 1952 new synonymy
Chapuis 1869: 52. Type species, Ceratolepsis jucundus Chapuis 1869 by monotypy.
(Figures 3.1-3.2)
Diagnosis. Ceratolepsis is readily distinguished from the other Scolytini genera by unique
features of the antennal club which include: strong asymmetry, a covering of short palmate setae
and a partial septum. The sutures are never marked by rows of setae. The funicle also lacks a
setal tuft on each funicular segment and bears two to four setae on the ventral and dorsal margins
(Figure 3.1 A).
Ceratolepsis is further distinguished from Scolytus and Scolytopsis by the scutellum,
which is flush with the elytra, the unimpressed scutellar area of elytral interstriae 1 (Figure
3.2B), the gradually ascending profile of the abdominal venter, and the costal margin of the
elytra above the metepisternum unarmed by a carina (Figure 3.2 A).
Ceratolepsis is closely related to Cnemonyx and Camptocerus and is distinguished by the
lack of supplemental denticles on the apical margin of the meso- and metathoracic tibiae (Figure
3.1 B), the strongly bilobed tarsal segment 3, the lack of a carina on the base of the tenth
interstria (Smith and Cognato 2010b; Figure 3.2 A), absence of crenulations along the elytral

208	
  

base (Figure 3.2A), mesosternum shape (type G, Smith and Cognato 2010b; Figure 3.1 C) and
the elongated and distally narrowly rounded scape in both sexes (Figure 3.1 A).
Redescription. Head never sexually dimorphic. Epistoma never emarginated, often armed with a
carina. Frons concave from epistoma to the inner apices of the eyes, moderately covered with
long erect setae. Eye elongate, ovoid, entire and finely faceted. Antennal scape elongate and
narrowly rounded distally, funicle shorter than or equal in length to the scape. Each scape
segment bears 2-4 setae on the ventral and dorsal margins. Antennal club flattened, strongly
asymmetrical, covered in short palmate setae, with a short partial septum that is not marked
externally by rows of setae.
Pronotum large, head visible from above, lateral margins marked by a fine raised line.
Pronotal disc finely punctate, punctures larger, coarser toward the margins, surface appearing
smooth to strigate; median line impuctate. Pronotal base bisinuate. Meso- and metathoracic tibia
unarmed by supplemental denticles on apical margin.
Scutellum smooth, flush with the level of elytra. Elytra without a scutellar notch; striate.
Discal striae weakly impressed. Declivital striae moderately to strongly impressed, interstriae
often carinate. Elytral apex weakly serrate. Abdominal profile gradually ascending to meet the
elytra. Mesosternum shape type G (Smith and Cognato 2010b)
Distribution. Ceratolepsis is restricted to the Neotropical region from Costa Rica to Bolivia.
Biology. Ceratolepsis species have only been reported as occurring on Virola Aubl. species
(Myristicacae) (Wood 2007, Smith pers. obs.).
Comments. Chapuis’ Latin description of the genus was somewhat vague, “antennarum articuli
2-7 in faemina simplices, clava solida. Tarsorum articulus 1 duobus sequentibus, 3 bilobatus”
which translates as “antennal articles 2-7 in the female simple, club solid. Tarsal joint 1

209	
  

following 2, 3 bilobed” (S.M. Smith translated). The description of the club could be applicable
to Camptocerus species and the tarsal description is characteristic of the Scolytini. However, the
type species, C. jucundus, is morphologically distinct from Camptocerus and Cnemonyx.
The holotype of the type species of Coptosomus, C. hylurgoides Schedl, has been lost
except for a slide mount of an antenna (Wood 2007). Coptosomus is placed in synonymy with
Ceratolepsis because of the lack of supplemental denticles on the meso- and metathoracic tibiae
and by the characteristics of the antennal club.
Very little sexual dimorphism in external characters is exhibited in this genus.
Examination of the shape of abdominal tergites 7 and 8 or dissection is required to determine the
sex of specimens.

Included Species
Ceratolepsis amazonicus (Eggers) new combination
= Loganius amazonicus Eggers 1929: 60.
= Cnemonyx amazonicus (Eggers 1929). Schedl 1962: 486.
= Ceratolepsis amazonicus Schedl 1952: 349. Schedl 1962: 486.
Ceratolepsis boliviae (Blackman) new combination
=Camptocerus boliviae Blackman 1943: 378.
= Cnemonyx boliviae (Blackman). Wood 1972: 244.
Ceratolepsis hylurgoides (Schedl) new combination
= Coptodryas hylurgoides Schedl 1948: 262
= Coptosomus hylurgoides (Schedl 1948). Schedl 1952: 363.
= Cnemonyx hylurgoides (Schedl 1948). Wood 1972: 244.

210	
  

Ceratolepsis insignis (Wood) new combination
=Cnemonyx insignis Wood 1969: 9.
Ceratolepsis jucundus Chapuis status restored
= Ceratolepsis jucundus Chapuis 1869: 52.
= Cnemonyx jucundus (Chapuis 1869). Schedl 1962: 486.
Ceratolepsis maculicornis Blandford status restored
= Ceratolepsis maculicornis Blandford 1896: 127.
= Loganius maculicornis (Blandford 1896). Schedl 1962: 486.
= Cnemonyx maculicornis (Blandford 1896). Wood 1972: 244.
Ceratolepsis niger (Eggers) new combination
= Loganius niger Eggers 1929: 60.
= Cnemonyx niger (Schedl 1962: 485). Wood 1972: 244.
= Camptocerus nigricans Schedl 1962: 486 (see Wood and Bright 1992 for a complete
discussion).

Cnemonyx Eichhoff 1868
Taxonomic Changes
Cnemonyx setulosus (Eggers) 1929 removed from synonymy
= Cnemonyx similis (Eggers) 1929 new synonymy
Wood (2007) considered Cnemonyx setulosus to be a synonym of C. panamensis
(Blandford) 1896, which are closely related (Smith, Chapter 2) and superficially resemble each
other, but they are morphologically distinct. In C. setulosus, the male epistoma is weakly
excavated and is typically weakly carinate along the basal epistomal margin, the frons is
moderately excavated from the epistoma to the anterodorsal margin of the eyes and almost

211	
  

borders the ocular margin. In C. panamensis, the epistoma and frons are flattened and there is a
short median weakly elevated carina along the basal epistomal margin. In C. setulosus, the dorsal
half of the frons is covered by two thick bands of long, yellow setae, those clearly divided
between the median line while in C. panamensis the dorsal half of the frons is covered by long,
yellow setae which are contiguous across the median line. In addition, the declivital interstriae of
C. setulosus each bear 3-5 rows of pale, yellow setae while those of C. panamensis only bear 1-3
rows. The pronotum of C. setulosus appears rugose with dense, abundant setae on the anterior
half and lateral margins and that of C. panamensis appears longitudinally strigate with sparse
setae on the anterolateral areas.
With the inclusion of C. similis and C. setulosus as synonyms, Wood created a very broad
concept for C. panamensis Blandford 1896 that included a great amount of morphological
variation (Wood 2007: 191). The distribution range for his concept of C. panamensis was quite
large, spanning Costa Rica to Bolivia. With C. setulosus removed from synonymy, the range of
these species is more discrete; C. panamensis occurs in Costa Rica and Panama and C. setulosus
occurs in Bolivia, Peru and Venezuela.
Cnemonyx similis is placed in synonymy with C. setulosus because the holotypes of both
species are identical except for the development of the carina on the basal margin of the male
epistoma. In C. similis, the carina is moderately developed and in C. setulosus it is weakly
developed to absent within a brood. Similar variation in the basal epistoma carina was also
demonstrated in Camptocerus niger (F.) 1801 and its synonym C. tectus Eggers 1943 (Smith and
Cognato 2010b). Cnemonyx similis and C. setulosus were described in the same publication. I
have chosen the name C. setulosus because the name has page priority and this name best

212	
  

describes the species, which is abundantly covered in long recumbent setae on the pronotum and
the elytral interstriae.

Scolytus Geoffroy 1762
New Distribution Record
Scolytus multistriatus (Marsham) 1802. BRAZIL: Mato Grosso: Sinop, X.1975, M. Alvarenga
(DEBC-1, male). New Continent Record.

Wood (2007) reports this species as occurring in Argentina and Chile, but was never
given specimens to examine and confirm the identification. Bright (in press) also expressed
doubt regarding these records and considered them anecdotal. This specimen is the first
positively identified specimen collected from South America.

Taxonomic Changes
Scolytus proximus Chapuis 1869
=Scolytus brevicauda Wichmann 1915 new synonymy
Scolytus brevicauda had previously been considered a synonym of S. thoracicus Chapuis
(Schedl 1937: 161). Upon examination of the holotype of S. brevicauda, S. thoracicus and large
series of S. proximus, it is apparent that S. brevicauda is a synonym of S. proximus. In S.
brevicauda and S. proximus the shape of the spine on male sternite 2 is long and narrow and has
a hooked apex unlike that of S. thoracicus which is long and narrow with the apex blunted and
bifurcated appearing as though it is composed of two ‘steps’. The male frons of S. brevicauda
and S. proximus is flattened on the dorsal half and weakly transversely impressed on apical third,
and the median line is slightly elevated and bearing a median callous-like tumescence. In
213	
  

contrast, in S. thoracicus the frons is flattened on the dorsal half and strongly, transversely
impressed on the lower third, and the median area is laterally subcarinate and bears a strongly
dorsoventrally compressed tubercle. The male epistoma is broadly and weakly emarginated in S.
proximus and narrowly and deeply emarginated in S. thoracicus.

Scolytus thoracicus Chapuis 1869
= Scolytus plaumanni Wood 2007 new synonymy
After examining the holotype of S. thoracicus, the female paratype of S. plaumanni, as
well as large series of S. thoracicus from Santa Catarina, Brazil, it is evident that S. plaumanni is
S. thoracicus as the two species are morphologically identical.

Species Description
Scolytus rabagliatus Smith and Cognato, new species
(Figures 3.3-3.7)
Type Material. Holotype, female, VENEZUELA: Táchira: 42km SE San Cristobal, 700m,
19.V.1974, H. & A. Howden (DEBC). Paratypes: VENEZUELA: Intercepted at Detroit, MI,
30.VI.1983, W. Waisanen, Detroit MI 003178, ex. in dunnage (MSUC-2, RJRC-2, USNM-14).
Diagnosis. Scolytus rabagliatus has distinctive morphology: Both sexes are easily distinguished
from other Neotropical Scolytus by the presence of lateral teeth on the apical margins of sternites
2-4, the absence of a callus or bulla on sternite 5, the convex and reticulate frons that is
impressed just above the epistoma, a strongly laterally compressed and falx-shaped median spine
on sternite 2 with the base just reaching the apical margin of the segment, by the minutely and
obscurely punctured sternites 3-5 and by the dull and shagreened appearance of sternites 3-5.

214	
  

Description (male). 3.0-3.2 mm long (mean = 3.12 mm; n=4); 2.13-2.46 times as long as wide.
Head, pronotum, elytra and abdominal venter dark red-brown; legs and antennae yellow-brown.
Pronotum typically darker than the elytra.
Epistoma entire; epistomal process absent; median area above mandibles bearing a dense
patch of long yellow hair-like setae. Frons appearing convex when viewed laterally; apical third
of frons transversely impressed above epistoma; surface moderately and coarsely longitudinally
rugose-reticulate and punctate to just dorsal of inner apices of eyes; reticulations converging at
epistoma; punctures small, coarse; surface slightly and uniformly covered by long, fine, yellow
erect hair-like setae, setae longer than the midpoint of the eye. Antennal scape short, elongate,
less than length of the first four funicular segments; club flattened, oblong, about twice as long as
wide, densely setose; sutures not evident.
Pronotum about as long as wide; apical margin broadly rounded, area between the eyes
lined with scales; sides distinctly arcuate, strongly constricted near apex; basal half of pronotal
surface smooth, shining, punctures on disc fine; apical half weakly strigose, punctures shallow
and moderately abundant, larger, coarser and more abundant laterally and on apical constriction;
apical and anterolateral margins bearing sparse, erect yellow hair-like setae; base weakly
bisinuate.
Elytral bases weakly elevated from interstriae 1-6. Elytral sides sub-parallel on apical
half, narrowing to a quadrate and smooth apex; apical margin of elytral apices smooth, shining;
apex entire. Disc smooth, shining; interstrial punctures weakly impressed, interstriae more than
twice the width of striae, interstrial punctures uniseriate, equal in size to those of striae; strial
punctures weakly impressed, punctures bearing sparse, long, semi-erect pale yellow hair-like
setae from base to apex. Metepimeron less than half-length of metepisternum.

215	
  

Apical margin of sternite 1 weakly elevated above the base of sternite 2. Sternite 2 nearly
perpendicular to sternite 1; surface smooth, shagreened, finely punctate with small, coarse
punctures; face flattened; apical margin armed with a long, latitudinally flattened and wide spine
with the base extending from the basal margin to at least ¾ the length of the segment, the spine is
variable but always long, flattened and apically hooked towards the elytra, resembling a falx or a
shark caudal fin; each lateral margin of sternites 2-4 armed with a lateral tooth, lateral teeth are
progressively smaller from sternites 2-4. Sternite 5 carinate ridge runs along the apical margin of
the segment. Venter covered in moderately abundant, long erect pale yellow setae.
Female. 2.0-3.0 mm long (mean = 2.9 mm; n=15); 2.1-2.5 times as long as wide. Similar to male
except, setae more abundant on frons, spine on segment 2 smaller, shorter, narrower and less
strongly flattened with its base extending from the apical margin to 1/2 the length of segment,
spine uniformly falx-shaped.
Specimens Examined. 19.
Distribution. Venezuela (Táchira).
Host. Unknown.
Biology. Unknown. This species was intercepted in transit to Detroit, Michigan, United States of
America on 30 June 1983.
Etymology. This species name, rabagliatus honors Robert Rabaglia's (USDA Forest Service)
contribution to the knowledge of adventive bark beetles. We deviate from the accepted Latin
ending (-anus) to create a more euphonic name. It is a noun in apposition.
Notes. There was a large amount of variation observed in shape of the median spine on male
sternite 2. Of the four individuals examined, one had a median longitudinal carina instead of a

216	
  

spine and the size of the falx-shaped spine was variable but was always larger than those of the
female.
Conclusions
An accurate classification is critical to accurate species identification. The taxonomic
changes presented in this paper are an important step towards a more accurate classification
system for the Scolytini. However, further work is necessary to clarify the generic limits of the
tribe, especially within Cnemonyx. Results shown in Smith (Chapter 2) provide strong support
that Loganius is a distinct genus and should be removed from synonymy with Cnemonyx.
Loganius was not treated here because of a lack of specimens in my collection at MSU. Upon
graduation, I will travel to the USNM where representatives of all Loganius species are housed
in the S.L. Wood collection. Each species will be examined and taxonomic changes will be made
if the taxa display the unique combination of characters that define Loganius. Correct taxonomic
placement of species provides valuable insight into their biology and behaviors as closely related
species often have similar biologies.

217	
  

APPENDICES
	
  

218	
  

APPENDIX A:
Tables and Figures for Chapter 1

219	
  

Table 1.1. Host genus for conifer-feeding (Pinaceae) Nearctic Scolytus species.

220

Table 1.2. Hosts plant families for all Scolytus species occurring in the Nearctic.

221

Table 1.3. Morphological character matrix of 43 characters for 37 species. Characters and states are described in Materials and
Methods.

222

Table 1.3 (cont’d).

223

Table 1.3 (cont’d).

224

Table 1.3 (cont’d).

225

Table 1.4. Table of Nearctic specimens sequenced, the collection locality, collector and host.

226

Table 1.4 (cont’d).

227

Table 1.4 (cont’d).

228

Table 1.4 (cont’d).

229

Table 1.4 (cont’d).

230

Table 1.4 (cont’d).

231

Table 1.4 (cont’d).

232

Table 1.4 (cont’d).

233

Table 1.4 (cont’d).

234

Table 1.5. Table of Nearctic specimens sequenced to assess intraspecific variation, the collection locality, collector and host.

235

Table 1.5 (cont’d).

236

Table 1.5 (cont’d).

237

Table 1.5 (cont’d).

238

Table 1.5 (cont’d).

239

Table 1.5 (cont’d).

240

Table 1.5 (cont’d).

241

Table 1.5 (cont’d).

242

Table 1.5 (cont’d).

243

Table 1.6. Table of PCR primers and the annealing temperatures used for the amplification of gene sequences.

244

Table 1.7. Intraspecific differences among COI, 28S, CAD and ArgK expressed as the proportion of sites differing between
sequences. N/A applies to taxa for which sequence data was not available.

245

Table 1.8. Interspecific differences among COI, 28S, CAD and ArgK expressed as the proportion of sites differing between sequences
among sister taxa. N/A applies to taxa for which sequence data was not available.

246

Table 1.8 (cont’d).

247

Table 1.9. Partition Bremer support values for the four gene parsimony phylogeny with gaps
treated as missing data. Nodes refer to Figure 1.4.

248

Table 1.9 (cont’d).

249

Table 1.10. Partition Bremer support values for the four gene parsimony phylogeny with gaps
treated as a fifth character state. Nodes refer to Figure 1.5.

250

Table 1.10 (cont’d).

251

Table 1.11. Partition Bremer support values for the combined phylogeny with gaps treated as
missing data. Nodes refer to Figure 1.7.

252

Table 1.11 (cont’d).

253

Table 1.12. Partition Bremer support values for the combined phylogeny with gaps treated as a
fifth character. Nodes refer to Figure 1.8.

254

Table 1.12 (cont’d).

255

Figure 1.1. Morphological phylogeny of Nearctic Scolytus. Phylogram of one of 1016 most
parsimonious trees (262 steps; consistency index 0.332; retention index = 0.539) generated for
37 taxa with 43 characters from a heuristic search of 1000 stepwise random additions with TBR
in PAUP*. Numbers above the node indicate bootstrap values (>50) based on 1000
pseudoreplicates. Bremer support values are listed below the node and were generated from a
heuristic search of 100 random addition sequence replicates. The Nearctic hardwood and conifer
clades are indicated in blue and green respectively. Non-monophyletic species are indicated in
brown. For interpretation of the references to color in this and all other figures, the reader is
referred to the electronic version of this thesis (or dissertation).

256

Figure 1.1 (cont’d).

257

Figure 1.1 (cont’d).

258

Figure 1.1 (cont’d).

259

Figure 1.1 (cont’d).

260

Figure 1.2. Bayesian tree found by analysis of data using the molecular dataset. Numbers above the nodes are Bayesian posterior
probabilities. Taxa in brown were not recovered as monophyletic. Scolytus fiskei is listed in purple and is considered a synonym of S.
unispinosus.

261

Figure 1.2 (cont’d).

262

Figure 1.2 (cont’d).

263

Figure 1.3. Mitochondrial COI phylogeny of Nearctic Scolytus. Phylogram of one of 2958 most parsimonious trees (1434 steps.
consistency index 0.356; retention index 0.809) generated from a heuristic search of 1000 stepwise random additions with TBR in
PAUP*. Numbers above the node indicate bootstrap values (>50) based on 1000 pseudoreplicates. Bremer support values are listed
below the node and were generated from a heuristic search of 100 random addition sequence replicates. Mean intraspecific nucleotide
differences (listed next to each taxon) and mean interspecific interspecific nucleotide differences (right of solid lines) are given. Taxa
highlighted in red were not recovered as monophyletic.

264

Figure 1.3 (cont’d).

265

Figure 1.3 (cont’d).

266

Figure 1.3 (cont’d).

267

Figure 1.3 (cont’d).

268

Figure 1.3 (cont’d).

269

Figure 1.4. Phylogram of one of 94, 002 most parsimonious trees found by parsimony analysis of the four gene dataset with gaps
treated as missing data (2,451 steps. consistency index 0.479; retention index 0.773) generated from a heuristic search of 1000
stepwise random additions with TBR in PAUP*. Numbers above the node indicate bootstrap values (>50) based on 1000
pseudoreplicates. Node numbers are given below the node and refer to PBS values in Table 1.9. Taxa in brown, blue and green were
not recovered as monophyletic. Scolytus fiskei is listed in purple and is considered a synonym of S. unispinosus. Scolytus laricis is
listed in green and was not recovered as monophyletic. Scolytus oregoni (blue) is a distinct species but was not monophyletic in this
analysis. * denotes species that are recognized as valid.

270

Figure 1.4 (cont’d).

271

Figure 1.4 (cont’d).

272

Figure 1.4 (cont’d).

273

Figure 1.4 (cont’d).

274

Figure 1.5. Phylogram of one of 59,010 most parsimonious trees found by parsimony analysis of the combined molecular dataset with
gaps as a fifth character (2,647 steps. consistency index 0.479; retention index 0.773) generated from a heuristic search of 1000
stepwise random additions with TBR in PAUP*. Numbers above the node indicate bootstrap values (>50) based on 1000
pseudoreplicates. Node numbers are given below the node. Node numbers refer to PBS values in Table 1.10. Taxa in brown, blue and
green were not recovered as monophyletic. Scolytus fiskei is listed in purple and is considered a synonym of S. unispinosus. Scolytus
laricis is listed in green and was not recovered as monophyletic. Scolytus oregoni (blue) is a distinct species but was not monophyletic
in this analysis. * denotes species that are recognized as valid.

275

Figure 1.5 (cont’d).

276

Figure 1.5 (cont’d).

277

Figure 1.5 (cont’d).

278

Figure 1.5 (cont’d).

279

Figure 1.6. Bayesian tree found by analysis of data using the combined molecular and morphological dataset. Numbers above the
nodes are Bayesian posterior probabilities. Taxa in brown were not recovered as monophyletic. Scolytus fiskei is listed in purple and is
considered a synonym of S. unispinosus. * denotes species that are exotic in the Nearctic.

280

Figure 1.6 (cont’d).

281

Figure 1.6 (cont’d).

282

Figure 1.7. Strict consensus tree of 22,003 most parsimonious trees found by parsimony analysis of the combined molecular and
morphological dataset with gaps treated as missing data (2,902 steps. consistency index 0.458; retention index 0.769) generated from a
heuristic search of 100 stepwise random additions with TBR in PAUP*. Numbers above the node indicate bootstrap values (>50)
based on 1000 pseudoreplicates. Node numbers are given below the node and refer to PBS values in Table 1.11. Taxa in brown were
not recovered as monophyletic. Scolytus fiskei is listed in purple and is considered a synonym of S. unispinosus. * denotes species that
are recognized as valid.

283

Figure 1.7 (cont’d).

284

Figure 1.7 (cont’d).

285

Figure 1.7 (cont’d).

286

Figure 1.7 (cont’d).

287

Figure 1.8. Strict consensus tree of 13,003 most parsimonious trees found by parsimony analysis of the combined molecular and
morphological dataset with gaps as a fifth character (3,097 steps. consistency index 0.48; retention index 0.771) generated from a
heuristic search of 1000 stepwise random additions with TBR in PAUP*. Numbers above the node indicate bootstrap values (>50)
based on 1000 pseudoreplicates. Node numbers are given below the node and refer to PBS values in Table 1.12. Taxa in brown were
not recovered as monophyletic. Scolytus fiskei is listed in purple and is considered a synonym of S. unispinosus. * denotes species that
are recognized as valid.

288

Figure 1.8 (cont’d).

289

Figure 1.8 (cont’d).

290

Figure 1.8 (cont’d).

291

Figure 1.8 (cont’d).

292

Figure 1.9. Sexual dimorphism of the head (Scolytus reflexus) lateral profiles of male (A) and
female (B), anterior view of male (C) and female (D).

293

Figure 1.10. Terminology of the head. Terms are defined in the glossary section (Scolytus
reflexus male).

294

Figure 1.11. General habitus terminology. Terms are defined in the glossary section (Scolytus fagi male).

295

Figure 1.12. Dorsal terminology. Terms are defined in the glossary section (Scolytus fagi male).

296

Figure 1.13. Abdominal venter terminology. Terms are defined in the glossary section (Scolytus ventralis).

297

Figure 1.14. Damage pattern. Terms are defined in the glossary section (Scolytus monticolae).

298

Figure 1.15. Elytral apices consist of two general shapes, rounded (A) (Scolytus rugulosus) and
truncate (B) (Scolytus robustus).

299

Figure 1.16. Lateral views of Scolytus mali male 3.2 – 4.1mm (A) and female 3.0 – 4.2mm (B).

300

Figure 1.17. Dorsal view of Scolytus mali male.

301

Figure 1.18. Lateral views of Scolytus multistriatus male 2.2 – 3.9mm (A) and female 2.4 –
3.3mm (B).

302

Figure 1.19. Dorsal view of Scolytus multistriatus male.

303

Figure 1.20. Lateral views of Scolytus rugulosus male 1.9 – 2.6mm (A) and female 2.0 – 3.1mm
(B).

304

Figure 1.21. Dorsal views of Scolytus rugulosus male.

305

Figure 1.22. Lateral views of Scolytus schevyrewi male 2.8 – 3.5mm (A) and female 2.3 –
3.6mm (B).

306

Figure 1.23. Dorsal view of Scolytus schevyrewi male.

307

Figure 1.24. Lateral views of Scolytus fagi male 3.3 – 5.5mm (A) and female 3.9 – 5.6mm (B).

308

Figure 1.25. Dorsal view of Scolytus fagi male.

309

Figure 1.26. Lateral views of Scolytus muticus male 2.2 – 5.3mm (A) and female 3.1 – 5.1mm
(B).

310

Figure 1.27. Dorsal view of Scolytus muticus male.

311

Figure 1.28. Lateral views of Scolytus quadrispinosus male 2.8 – 4.2mm (A) and female 2.9 –
5.0mm (B).

312

Figure 1.29. Lateral views of Scolytus quadrispinosus male.

313

Figure 1.30. Lateral views of Scolytus aztecus male 5.0mm (A) and female 4.6 – 5.9mm (B).

314

Figure 1.31. Dorsal view of Scolytus aztecus male.

315

Figure 1.32. Lateral views of Scolytus dentatus male 3.0 – 4.0mm (A) and female 3.4 – 4.6mm
(B).

316

Figure 1.33. Dorsal view of Scolytus dentatus male.

317

Figure 1.34. Lateral views of Scolytus fiskei male 2.2 – 2.8mm (A) and female 2.2 – 3.5mm (B).

318

Figure 1.35. Dorsal view of Scolytus fiskei male.

319

Figure 1.36. Lateral views of Scolytus hermosus male 3.0mm (A) and female 2.5 – 3.5mm (B).

320

Figure 1.37. Dorsal view of Scolytus hermosus male.

321

Figure 1.38. Lateral views of Scolytus laricis male 2.3 – 4.0mm (A) and female 2.6 – 4.0mm
(B).

Figure 1.39. Dorsal view of Scolytus laricis male.
322

323

Figure 1.40. Lateral views of Scolytus monticolae male 2.5 – 3.0mm (A) and female 2.3 –
3.5mm (B).

324

Figure 1.41. Dorsal view of Scolytus monticolae male.

325

Figure 1.42. Lateral views of Scolytus mundus male 4.0 – 4.5mm (A) and female 3.3 – 4.6mm
(B).

326

Figure 1.43. Dorsal views of Scolytus mundus male.

327

Figure 1.44. Lateral views of Scolytus obelus male 1.8 – 2.9mm (A) and female 1.7 – 3.0mm
(B).

328

Figure 1.45. Dorsal view of Scolytus obelus male.

329

Figure 1.46. Lateral views of Scolytus oregoni male 2.6 – 3.6mm (A) and female 2.8 – 4.0mm
(B).

330

Figure 1.47. Dorsal view of Scolytus oregoni male.

331

Figure 1.48. Lateral views of Scolytus piceae male 2.5 – 3.0mm (A) and female 2.3 – 3.0 (B).

332

Figure 1.49. Dorsal view of Scolytus piceae male.

333

Figure 1.50. Lateral views of Scolytus praeceps male 1.8 – 3.2mm (A) and female 1.7 – 3.5mm
(B).

334

Figure 1.51. Dorsal views of Scolytus praeceps male.

335

Figure 1.52. Lateral views of Scolytus praeceps (=S. abietis) male (A) and female (B).

336

Figure 1.53. Lateral views of Scolytus praeceps (=S. opacus) male (A) and female (B).

337

Figure 1.54. Lateral views of male Scolytus reflexus with a reflexed sternite 5 (A) and wickhami
phenotype without reflexed sternite 5 (B) 2.4 – 3.8mm.

338

Figure 1.55. Lateral view of Scolytus reflexus female 2.5 – 4.0mm (A) and dorsal view of male
(B).

339

Figure 1.56. Lateral views of Scolytus robustus male 2.5 – 4.0mm (A) and female 2.2 – 4.1mm
(B).

340

Figure 1.57. Dorsal view of Scolytus robustus male.

341

Figure 1.58. Lateral views of Scolytus silvaticus male 3.0mm (A) and female 3.3 – 3.6mm (B).

342

Figure 1.59. Dorsal view of Scolytus silvaticus male.

343

Figure 1.60. Lateral views of Scolytus subscaber male 2.0 – 4.3mm (A) and female 3.1 -5.0mm
(B).

344

Figure 1.61. Dorsal view of Scolytus subscaber male.

345

Figure 1.62. Lateral views of Scolytus tsugae male 2.8 – 3.4mm (A) and female 2.3 – 3.5mm
(B).

346

Figure 1.63. Dorsal view of Scolytus tsugae male.

347

Figure 1.64. Lateral views of Scolytus unispinosus male 2.2 – 3.2mm (A) and female 2.2 – 3.0
(B).

348

Figure 1.65. Dorsal view of Scolytus unispinosus male.

349

Figure 1.66. Lateral views of Scolytus ventralis male 3.0 – 4.0mm (A) and female 2.2 – 4.6 mm
(B).

350

Figure 1.67. Dorsal views of Scolytus ventralis male.

351

APPENDIX B:
Tables and Figures for Chapter 2	
  

252	
  

	
  
Table 2.2. Table of Scolytini specimens sequenced, the collection locality, collector, host, matrix names and extraction names.
Species
Coptonotus cyclopus

Coptonotus cylclopus
Camptocerus aeneipennis

Camptocerus aeneipennis

Camptocerus aeneipennis

Camptocerus aterrimus

Camptocerus auricomus

Camptocerus auricomus

	
  

Collection locality, date, collector and host
Costa Rica: Puntarenas: Coto Brus: Las Cruces
Biological Station, N8°47.7', W82°57.32', 1200m,
16.VI.2010, S.M. Smith coll.
Costa Rica: Herida [GenBank]
Guyana: Region 8: Iwokrama Forest, 4.671822,
-58.684114, 66m, 4-9.III.2007, Cognato, Dole,
Hulcr, Smith, McCall coll., Ex. Ocotea oblonga
Peru: Madre de Dios: Manu: Los Amigos Biological
Station, S12°34.9' W70°6.04', 14.V.2008, S.M.
Smith, J. Hulcr coll., Ex. Protium amazonicum
Panama: Panama: Pipeline Rd, N9°10.315'
W79°45.213', 94m, 3.IX.2008, S.M. Smith, A.D.
Smith, A.R. Gillogly coll. Ex. Protium sp.
Peru: Madre de Dios: Los Amigos Biological Station,
S12°34.9' W70°6.04', 15.V.2008, S.M. Smith, J.
Hulcr coll., Ex. Protium amazonicum
Costa Rica: Heredia: Puerto Viejo, La Selva
Biological Station, N10°26' W83°59', 4.VII.2010,
S.M. Smith coll, Ex. Protium sp.
Panama: Panama: Pipeline Rd, N9°10.315'
W79°45.213', 94m, 3.IX.2008, S.M. Smith, A.D.
Smith, A.R. Gillogly coll. Ex. Protium sp.

354	
  

Matrix
name
Copt cyc 69

Extraction
name
SMS 69

Copt cyc BJ
Cam aen 1

Cam aen 1

Cam aen 27

Cam aen 27

Cam aen 29

Cam aen 29

Cam ate 6

Cam ate 6

Cam aur 23

SMS 23

Cam aur 1

Cam aur 1

	
  

Table 2.2 (cont’d).
Species
Camptocerus coccoformus

Camptocerus costatus

Camptocerus costatus

Camptocerus latipllis

Camptocerus latipllis
Camptocerus mallopterus

	
  

Collection locality, date, collector and host
Ecuador: Napo: Reserva Ethnica Waorani, 1 km S
Onkone Gare Camp, -0.652778, -76.433333, 220 m,
lot 3125, trans. 3, sta. 5, I.2006, T.L. Erwin et al.
coll., Ex. canopy fogging
Guyana: Region 8: Iwokrama Forest, 4.671822,
-58.684114, 66m, 4-9.III.2007, Cognato, Dole,
Hulcr, Smith, McCall coll, Ex. Ocotea oblonga
Peru: Loreto: 25km SE from Iquitos to Rio Momon
(Shimbilo), 5km from Pte Allegre, 109m, S3°33.094”
W73°30.967", 14.IV.2012, A. Petrov coll.
Ecuador: Napo: Reserva Ethnica Waorani, 1 km S
Onkone Gare Camp, -0.652778, -76.433333, 220 m,
lot 3293, trans. 9, sta. 3, VII.2006, T.L. Erwin et al.
coll., Ex. canopy fogging
Peru: Loreto: 58 km SSW from Iquitos to Nauta, Rio
Itaya, 120m, 6.III.2007, A. Petrov coll.
Ecuador: Napo: Reserva Ethnica Waorani, 1 km S
Onkone Gare Camp, -0.652778, -76.433333, 220 m,
lot 3129, trans. 3, sta. 9, I.2006, T.L. Erwin et al.
coll., Ex. canopy fogging

355	
  

Matrix
name
Cam cocco

Extraction
name
Cam cocco 1

Cam cos

Cam sp. 2

Cam cos 173

SMS 173

Cam lat

Cam D 1

Cam lat 52

SMS 52

Cam mall 1

Cam mall 1

	
  
Table 2.2 (cont’d).

Species
Camptocerus noel

Matrix
name
Cam noel 2

Extraction
name
Cam aen 2

Camptocerus

Cam noel 7

Cam aen 7

Cam noel 26

Cam aen 26

Cam opa 1

Cam opa 1

Cam pil 1

Cam pil 1

Cam pse 5

Cam ate 5

Camptocerus

Camptocerus

Camptocerus

Camptocerus

	
  

Collection locality, date, collector and host
Guyana: Region 8: Iwokrama Forest, 4.671822,
-58.684114, 66m, 4-9.III.2007, Cognato, Dole,
Hulcr, Smith, McCall coll., Ex. Ocotea oblonga
noel
Ecuador: Napo: Reserva Ethnica Waorani, 1 km S
Onkone Gare Camp, -0.652778, -76.433333, 220 m,
lot 3283, trans. 8, sta. 3, VII.2006, T.L. Erwin et al.
coll., Ex. canopy fogging
noel
Peru: Madre de Dios: Manu Los Amigos Biological
Station, S12°34.9' W70°6.04', 14.V.2008, S.M.
Smith, J. Hulcr coll., Ex. Protium amazonicum
opacicollis
Peru: Madre de Dios: Manu: Los Amigos Biological
Station, S12°34.9' W70°6.04', 15.V.2008, S.M.
Smith, J. Hulcr coll., Ex. Protium amazonicum
pilifrons
Ecuador: Napo: Reserva Ethnica Waorani, 1 km S
Onkone Gare Camp, -0.652778, -76.433333, 220 m,
lot 3187, trans. 9, sta. 7, I.2006, T.L. Erwin et al.
coll., Ex. canopy fogging
pseudoangustior Peru: Madre de Dios: Manu: Los Amigos Biological
Station, S12°34.9' W70°6.04', 15.V.2008, S.M.
Smith, J. Hulcr coll., Ex. Protium amazonicum

356	
  

	
  

Table 2.2 (cont’d).
Species
Camptocerus suturalis

Camptocerus suturalis

Camptocerus suturalis

Ceratolepsis amazonicus

Ceratolepsis amazonicus

Ceratolepsis insignis

Cnemonyx exiguus

	
  

Collection locality, date, collector and host
Guyana: Region 8: Iwokrama Forest, 4.671822,
-58.684114, 66m, 4-9.III.2007, Cognato, Dole,
Hulcr, Smith, McCall coll, Ex. Ocotea oblonga
Ecuador: Napo: Reserva Ethnica Waorani, 1 km S
Onkone Gare Camp, -0.652778, -76.433333, 220 m,
lot 3265, trans. 7, sta. 5, VII.2006, T.L. Erwin et al.
coll., Ex. canopy fogging
Peru: Madre de Dios: Manu: Los Amigos Biological
Station, S12°34.9' W70°6.04', 15.V.2008, S.M.
Smith, J. Hulcr coll., Ex. Protium amazonicum
Ecuador: Orellana: Tiputini Biodiversity Station,
S00º38.189' W76º08.965', 223m, 3-9.VI.2011, S.M.
Smith coll. Ex. window trap
Peru: Loreto: 25km SE from Iquitos to Rio Momon
(Shimbilo), 5km from Pte Allegre, 109m, S3°33.094”
W73°30.967, 10.V.2012, A. Petrov coll.
Panama: Panama: BCNM: Barro Colorado Island,
9°9'N, 79°50'W, 50-120m, 29.VIII.2012, S.M.
Smith, N.A. Barc coll. Ex. Virola sebifera
Panama: Panama: BCNM: Barro Colorado Island,
9°9'N, 79°50'W, 50-120m, 29.VIII.2012, S.M.
Smith, N.A. Barc coll. Ex. Protium panamense

357	
  

Matrix
Extraction
name
name
Cam sut sp 1 Cam sp. 1

Cam sut 1

Cam sut 1

Cam sut 2

Cam sut 2

Cne ama 77

SMS 77

Cne ama 174 SMS 174

Cne ins 175

SMS 175

Cne exi 177

SMS 177

	
  
Table 2.2 (cont’d).
Species
Cnemonyx panamensis

Cnemonyx rugulosus

Cnemonyx rugulosus

Cnemonyx setulosus

Cnemonyx vismiacolens

Loganius flavicornis

Loganius gracilens

Loganius opacus

	
  

Collection locality, date, collector and host
Panama: Panama: BCNM: Barro Colorado Island,
9°9'N, 79°50'W, 50-120m, 27.VIII.2012, S.M.
Smith, N.A. Barc coll. Ex. Trichila hiruta
Peru: Madre de Dios: Manu: Los Amigos Biological
Station, S12°34.9' W70°6.04', 12.V.2008, S.M.
Smith, J. Hulcr coll.
Ecuador: Orellana: Tiputini Biodiversity Station,
S00º38.189' W76º08.965', 223m, 3-9.VI.2011,
S.M. Smith coll.
Peru: Madre de Dios: Manu: Los Amigos Biological
Station, S12°34.9' W70°6.04', 12.V.2008, S.M.
Smith, J. Hulcr coll.
Guyana: Region 8: Iwokrama Forest, 4.671822,
-58.684114, 66m, 4-9.III.2007, Cognato, Dole,
Hulcr, Smith, McCall coll.
Peru: Madre de Dios: Manu: Los Amigos Biological
Station, S12°34.9' W70°6.04', 4.V.2008, S.M.
Smith, J. Hulcr coll.
Mexico: Oaxaca: Matalán, 10 km SSE; 16.76519,
-96.34564; 19.X.2011, T.H. Atkinson coll., THA-954,
Ex. Euphorbia schlechtendali
Panama: Panama: Pan-American Highway,
N8°55.598' W79°33.936', 13m, 17.VIII.2008, A.D.
Smith, A.R. Gillogly coll.

358	
  

Matrix
name
Cne pan 176

Extraction
name
SMS 176

Cne rug 5

Cne rug 5

Cne rug 76

SMS 76

Cne pan

Cne sp 2

Cne vis

Cne sp. 1

Cne fla 1

Cne fla 1

Cne gra 152

SMS 152

Cne opa 1

Cne opa 1

	
  
Table 2.2 (cont’d).
Species
Scolytus aztecus

Scolytus carpini
Scolytus cristatus

Scolytus dimidiatus

Scolytus ecksteini
Scolytus ecksteini
Scolytus ensifer
Scolytus ensifer
Scolytus excavatus

	
  

Collection locality, date, collector and host
Mexico: Nuevo Leon: San Antonio de las Alazanas:
Santa Catarina, G. Cuellar coll., Ex. Pseudotsuga
menziesii
Czech Republic: Moravia: B!eclav Kamci obora,
2004, K. Novakova coll.
Peru: Junin: Perene River, 8 km NNE from Puerto
Ocopa, Cananeden vill., S11°06' W73°60', 1100m,
2.II.2008, A. Petrov coll.
Panama: Panama: Gamboa Rd, N9°07'09.24"
W79°42'51.98", 36m, 14.VIII.2008, S.M. Smith,
A.D. Smith, A.R. Gillogly coll.
Iran: Gilan: Rasht, N37°11'55" E49°38'27",
16.VIII.2011, S. Amini coll., Ex. Ulmus sp.
Iran: Gilan: Rasht, N37°11'55" E49°38'27",
16.VIII.2011, S. Amini coll., Ex. Ulmus sp.
Czech Republic: Moravia: B!eclav Kamci obora,
2004, K. Novakova coll.
Iran: Gilan: Rasht, N37°11'55" E49°38'27",
16.VIII.2011, S. Amini coll., Ex. Ulmus sp.
Peru: Madre de Dios: Manu: Los Amigos Biological
Station, S12°34.9' W70°6.04', 22.V.2008, S.M.
Smith, J. Hulcr coll., Ex. Pterocarpus rohrii

359	
  

Matrix
name
Sco aze 161

Extraction
name
SMS 161

Sco car 61

SMS 61

Sco cris 150

SMS 150

Sco dimi

Sco casp 1

Sco eck 166

SMS 166

Sco eck 167

SMS 167

Sco ens 58

SMS 58

Sco ens 163

SMS 163

Sco exc 1

Sco exc 1

	
  
Table 2.2 (cont’d).
Species
Scolytus fagi

Scolytus fagi

Scolytus fiskei

Scolytus fiskei

Scolytus fiskei

Scolytus fiskei

	
  

Collection locality, date, collector and host
USA: Pennsylvania: Cumberland Co.: Roadway Dr
@ Schenider Dr., 29.V.2009, L.R. Donovall coll.,
Ex. Lindgren funnel trap
USA: Pennsylvania: Cumberland Co.: Roadway Dr
@ Schenider Dr., 29.V.2009, L.R. Donovall coll.,
Ex. Lindgren funnel trap
USA: Colorado: Mesa Co: Grand Mesa overlook,
8.VIII.2008, D.E. Bright, B.A. Barr coll.,
Ex. Pseudotsuga menziesii branches
USA: Colorado: Larimer Co.: Roosevelt National
Forest, 9 km E Estes Park, Hwy 34, Big Thompson
Canyon, N40°24.456' W105°24.565', 2143m,
5.V.2010, S.M. Smith, D.E. Bright, B.A. Barr coll.,
Ex. Pseudotsuga menziesii
USA: Idaho: Boise Co.: Boise National Forest, Bogus
Basin, NF275, N43°44.347' W116°07.099', 6042ft,
8.VIII.2010, S.M. Smith, A.R. Gillogly coll.,
Ex. Pseudotsuga menziesii
USA: Idaho: Latah Co.: Univeristy of Idaho
experimental forest, N46°51.764' W116°43.786',
2855ft, 10.VIII.2010, S.M. Smith, A.R. Gillogly, M.M.
Furniss coll., Ex. Pseudotsuga menziesii

360	
  

Matrix
name
Sco fagi 2

Extraction
name
Sco fagi 2

Sco fagi 1

Sco fagi 1

Sco uni 1

Sco uni 1

Sco fis 37

SMS 37

Sco fis 38

SMS 38

Sco fis 41

SMS 41

	
  
Table 2.2 (cont’d).
Species
Scolytus intricatus
Scolytus intricatus
Scolytus japonicus
Scolytus koltzei

Scolytus laevis
Scolytus laricis

Scolytus laricis

Scolytus mali

	
  

Collection locality, date, collector and host
Sweden: Smaaland: Karlsburg, 15.VII.2005, B.H.
Jordal coll., Ex. Quercus sp.
Sweden: Smaaland: Oskarshamn [GenBank]
Russia: Primorsky: Anisimovka, 14.VII.2008, B.H.
Jordal coll.
Russia: Far East, Shkotovskiy reg., 7 km S from
Anisimovka vill., 20.VI.2008, A. Napolov coll., Ex.
Tilia sp.
Denmark, Rødby Havn, 24.VIII.2005, J. Pedersen
leg.
USA: Idaho: Boundary Co.: Kaniksu National Forest,
Robinson Lake campground, N48°58.197'
W116°13.068', 2748ft, 11.VIII.2010, S.M. Smith,
A.R. Gillogly coll., Ex. Larix occidentalis
USA: Idaho: Boundary Co.: Kaniksu National Forest,
Robinson Lake campground, N48°58.385'
W116°13.351', 2748ft, 11.VIII.2010, S.M. Smith,
A.R. Gillogly coll., Ex. Larix occidentalis
USA: Pennsylvania: Lebanon Co.: Mt. Gretna,
N40.242501 W76.462406, IV-VIII.2009, S.E.
Spichiger coll., Ex. Lindgren funnel trap

361	
  

Matrix
name
Sco int 64

Extraction
name
SMS 64

Sco int BJ
Sco jap 59

SMS 59

Sco kol 157

SMS 157

Sco laevis
Sco lar 12

SMS 12

Sco lar 2

SMS 2

Sco mal 1

Sco mal 1

	
  

Table 2.2 (cont’d).
Species
Scolytus monticolae

Scolytus monticolae

Scolytus monticolae

Scolytus mozolevskae

Scolytus multistriatus
Scolytus multistriatus

Scolytus multistriatus

	
  

Collection locality, date, collector and host
USA: Idaho: Boundary Co.: Kaniksu National Forest,
Robinson Lake campground, N48°58.385'
W116°13.351', 2748ft, 11.VIII.2010, S.M. Smith,
A.R. Gillogly coll., Ex. Pseudotsuga menziesii
USA: Idaho: Soshone Co.: Coeur D'Alene National
Forest, Placer Creek Rd N47°25.746' W115°53.601',
3547ft, 15.VIII.2010, S.M. Smith, A.R. Gillogly coll.,
Ex. Pseudotsuga menziesii
USA: Idaho: Boise Co.: Boise Natioanl Forest, Bogus
Basin, NF275, N43°44.347' W116°07.099', 6042ft,
8.VIII.2010, S.M. Smith, A.R. Gillogly coll.,
Ex. Pseudotsuga menziesii
Ecuador: Orellana: Tiputini Biodiversity Station,
S00º38.189' W76º08.965', 223m, lot 3024, T.L.
Erwin et al. coll., Ex. canopy fogging
Denmark: Storstrøm: Rødbyhavn, 24.VIII.2005,
J. Pedersen coll.
USA: Michigan: Kalamazoo Co.: Gourdneck Lake
State Game Area, 19.VI.2011, A.I. Cognato coll.,
Ex. Ulmus sp.
Russia: Moscow Oblast: Dolgoprudnly, N55º58.266’,
E37º30.191’, 570m, 28.VII.2011, A.V. Petrov coll.,
Ex. Ulmus laevis

362	
  

Matrix
name
Sco mon 33

Extraction
name
SMS 33

Sco mon 34

SMS 34

Sco mon 35

SMS 35

Sco mozo 54

SMS 54

Sco mul 65

SMS 65

Sco mul 82

SMS 82

Sco mul 147

SMS 147

	
  
Table 2.2 (cont’d).
Species
Scolytus muticus

Scolytus muticus

Scolytus muticus
Scolytus obelus

Scolytus obelus

Scolytus oregoni

	
  

Collection locality, date, collector and host
USA: Pennsylvania: Cumberland Co.: Roadway Dr
@ Schenider Dr., 29.V.2009, L.R. Donovall coll., Ex.
Lindgren funnel trap
USA: Michigan: Wayne Co.: Grosse Ile, N42.17060
W83.14496, 7-20.VI.2007, R. Mech coll., Ex.
Lindgren funnel trap
USA: South Carolina: Columbia, 26.X.2011, W.
Jones coll., Ex. Celtis sp.
USA: Arizona: Cochise Co.: Coronado National
Forest, Chiricahua Mountains, N31°55.987'
W109°16.331', 7022ft, 22.V.2010, S.M. Smith coll.,
Ex. Abies concolor
USA: New Mexico: Torrance Co.: Cibola National
Forest, W. Manzano, N34°37.226' W106°24.752',
7999ft, 11.V.2010, S.M. Smith, A.I. Cognato coll.,
Ex. Abies concolor
USA: Oregon: Jackson Co.: Rogue River National
Forest, Rogue River gorge viewpoint, Hwy 62 1/4
mi N Union Creek Rd, N42°54.540' W122°26.733',
3489ft, 21.VIII.2010, S.M. Smith coll.,
Ex. Pseudotsuga menziesii

363	
  

Matrix
name
Sco mut 1

Extraction
name
Sco mut 1

Sco mut 2

Sco mut 2

Sco mut 169

SMS 169

Sco obe 18

SMS 18

Sco obe 44

SMS 44

Sco ore 5

SMS 5

	
  

Table 2.2 (cont’d).
Species
Scolytus oregoni

Scolytus orientalis

Scolytus piceae

Scolytus piceae

Scolytus piceae

Scolytus piceae

	
  

Collection locality, date, collector and host
USA: Oregon: Jackson Co.: Rogue River National
Forest, Rogue River gorge viewpoint, Hwy 62 1/4
mi N Union Creek Rd, N42°54.540' W122°26.733',
3489ft, 21.VIII.2010, S.M. Smith coll.,
Ex. Pseudotsuga menziesii
Turkmenistan: Central Kopet Dag Mountains, 16 km
S from Batken, Ipay Kala, 700m, 15.V.1996, A.
Petrov coll, Ex. Ulmus sp.
USA: Michigan: Livingston Co.: Howell, 431 Bishop
Rd, N42.5076 W83.85698, 25.VI.2009, R. Mech
coll., Ex. Lindgren funnel trap
USA: Idaho: Latah Co.: University of Idaho
Experimental Forest, N46°51.164' W116°44.838',
2939ft, S.M. Smith, A.R. Gillogly, M.M. Furniss coll.,
Ex. Picea engelmanni
USA: South Dakota: Lawrence Co.: Brownsville Rd
near Leads, N44.2922 W103.7828, 27.VII.2004,
5650ft, K.P. Dole coll., Ex. Picea glauca
USA: Wyoming: Carbon Co.: Medicine Bow National
Forest, Snowy Mountains, WY130, Lake Marie,
N41°19.965’ W106°19.516’ 3208m, 26.VII.2011,
S.M. Smith, D.E. Bright, B.A Barr coll., Emerged 15.IX.2011, Ex. Picea engelmannii branches

364	
  

Matrix
name
Sco ore 71

Extraction
name
SMS 71

Sco orien 148 SMS 148

Sco pic 1

Sco mul 1

Sco pic 7

SMS 7

Sco pic 73

SMS 73

Sco pic 83

SMS 83

	
  

Table 2.2 (cont’d).
Species
Scolytus praeceps

Scolytus praeceps

Scolytus praeceps

Scolytus praeceps

Scolytus praeceps

Scolytus praeceps

	
  

Collection locality, date, collector and host
USA: California: Siskiyou Co.: Klamath National
Forest, FR 41N16, N41°14.822' W122°53.562',
5081ft, 28.VII.2010, S.M. Smith coll., Ex. Abies
concolor
USA: Idaho: Bonner Co.: Kaniksu National Forest,
FR 232, N48°20.609' W116°20.507', 2717ft, S.M.
Smith, A.R. Gillogly coll., Ex. Abies grandis
USA: Idaho: Latah Co.: Univeristy of Idaho
experimental forest, N46°51.372' W116°44.038',
2857ft, 10.VIII.2010, S.M. Smith, A.R. Gillogly, M.M.
Furniss coll., Ex. Abies lasiocarpa
USA: Idaho: Boundary Co.: Kaniksu National Forest,
Robinson Lake campground, N48°58.200'
W116°13.067', 2696ft 13.VIII.2010, S.M. Smith,
A.R. Gillogly coll., Ex. Abies lasiocarpa
USA: California: El Dorado Co.: El Dorado National
Forest, nr. Ice House Resevoir, N38°50.002'
W120°21.160', 5413ft, 25.VII.2010, S.M. Smith
coll., Ex. Abies concolor
USA: California: Siskiyou Co.: Shasta Trinity National
Forest, Mt. Shasta, N41°20.844' W122°16.691',
4892ft, S.M. Smith coll., Ex. Abies concolor

365	
  

Matrix
name
Sco abi 14

Extraction
name
SMS 14

Sco abi 16

SMS 16

Sco opa 21

SMS 21

Sco opa 68

SMS 68

Sco pra 29

SMS 29

Sco pra 30

SMS 30

	
  
Table 2.2 (cont’d).
Species
Scolytus praeceps

Scolytus propinquus

Scolytus propinquus

Scolytus proximus
Scolytus proximus

Scolytus pygmaeus
Scolytus pygmaeus
Scolytus quadrispinosus

	
  

Collection locality, date, collector and host
USA: Wyoming: Albany Co.: Snowy Mountains,
Medicine Bow National Forest, Spruce campground,
6.IX.2010,D.E. Bright, B.A. Barr coll.,
Ex. Abies concolor
Mexico: Oaxaca: Huatulco, 15.76234, -96.12885,
41m, 23.VI.2009, T.H. Atkinson coll., THA 874,
Ex. legume tree
Mexico: Oaxaca: Huatulco, 15.76234, -96.12885,
41m, 23.VI.2009, T.H. Atkinson coll., THA 874,
Ex. legume tree
Bolivia: Santa Cruz: nr. Samaipata, above Achira
camp, 10.XI.2009, N.P. Lord coll.
Peru: Madre de Dios: Manu: Los Amigos Biological
Station, S12°34.9' W70°6.04', 22.V.2008, S.M.
Smith, J. Hulcr coll., Ex. Pterocarpus rohrii
Czech Republic: Moravia: B!eclav Kamci obora,
2004, K. Novakova coll.
Denmark: Storstrøm: Rødbyhavn, 24.VIII.2005, J.
Pedersen coll.
USA: Pennsylvania: Cumberland Co.: Roadway Dr
@ Schenider Dr., 24.VII.2009, L.R. Donovall coll.,
Ex. Lindgren funnel trap

366	
  

Matrix
name
Sco pra 91

Extraction
name
SMS 91

Sco pro 1

Sco pro 1

Sco pro 2

Sco pro 2

Sco prox 3

Sco prox 3

Sco prox 2

Sco sasp 2

Sco pyg 62

SMS 62

Sco pyg 67

SMS 67

Sco qua 1

Sco qua 1

	
  
Table 2.2 (cont’d).
Species
Scolytus quadrispinosus

Scolytus ratzeburgii
Scolytus reflexus

Scolytus reflexus

Scolytus reflexus

Scolytus reflexus

	
  

Collection locality, date, collector and host
USA: Maryland: Ann Aruridel Co.: Annapolis,
26.V.2012, R.J. Rabaglia coll., Ex. Lindgren funnel
trap
Russia: Primorsky: Anisimovka, 12.VII.2008, B.H.
Jordal coll.
USA: Arizona: Pima Co.: Coronado National Forest,
Santa Catalina Mountains, N32°24.529'
W110°42.678', 7869ft, 22.V.2010, S.M. Smith coll.
Ex. Pseudotsuga menziesii
USA: Arizona: Cochise Co.: Coronado National
Forest, Chiricahua Mountains, N31°54.915'
W109°16.040', 8196ft, 20.V.2010, S.M. Smith coll.
Ex. Pseudotsuga menziesii
USA: Colorado: Larimer Co.: Roosevelt National
Forest, 9 km E Estes Park, Hwy 34, Big Thompson
Canyon, N40°24.456' W105°24.565', 2143m,
5.V.2010, S.M. Smith, D.E. Bright, B.A. Barr coll.
Ex. Pseudotsuga menziesii
USA: Colorado: Boulder Co.: Roosevelt National
Forest, St. Vrain canyon, N40°10.072'
W105°23.623', 2127m, 24.VII.2011, S.M. Smith,
D.E. Bright, B.A. Barr coll.,
Ex. Pseudotsuga menziesii

367	
  

Matrix
name
Sco qua 170

Extraction
name
SMS 170

Sco ratz 60

SMS 60

Sco ref 26

SMS 26

Sco ref 27

SMS 27

Sco ref 32

SMS 32

Sco ref 85

SMS 85

	
  
Table 2.2 (cont’d).
Species
Scolytus reflexus

Collection locality, date, collector and host
Mexico: Nuevo Leon: San Antonio de las Alazanas:
Santa Catarina, G. Cuellar coll.,
Ex. Pseudotsuga menziesii

Scolytus reflexus

USA: Arizona: Cochise Co.: Coronado National
Forest, Chiricahua Mountains, N31°55.360'
W109°15.702', 7882ft, 20.V.2010, S.M. Smith coll.,
Ex. Pseudotsuga menziesii
USA: New Mexico: Otero Co.: Lincoln National
Forest, Apache Point observatory, N32°47.046'
W105°48.841', 9116ft, 16.V.2010, S.M. Smith coll.,
Ex. Pseudotsuga menziesii
USA: New Mexico: Colfax Co.: Highway 64 near Ute
Park, N36°33'9.26" W105°07'6.74", 2242m,
24.VI.2004, A.I. Cognato, S.A. Stephens coll.,
Ex. Pinus ponderosa
USA: Arizona: Graham Co.: Coronado National
Forest, Pinaleno Mountains, N32°37.702'
W109°49.472', 7896ft, 23.V.2010, S.M. Smith coll.
Ex. Abies concolor
USA: New Mexico: Taos Co.: Carson National Forest,
Agua Piedra campground, Hwy 75, N36°07.960'
W105°31.828', 8477 ft, 13.V.2010, S.M. Smith, A.I.
Cognato coll., Ex. Abies concolor

Scolytus reflexus

Scolytus reflexus

Scolytus robustus

Scolytus robustus

	
  

368	
  

Matrix
name
Sco vir 162

Extraction
name
SMS 162

Sco wick 24

SMS 24

Sco wick 25

SMS 25

Sco wick 74

SMS 74

Sco rob 3

SMS 3

Sco rob 43

SMS 43

	
  
Table 2.2 (cont’d).
Species
Scolytus robustus

Scolytus rugulosus
Scolytus rugulosus
Scolytus rugulosus

Scolytus rugulosus
Scolytus schevyrewi
Scolytus scolytus
Scolytus semenovi
Scolytus sinopiceus

Scolytus sinopiceus

	
  

Collection locality, date, collector and host
USA: Arizona: Cochise Co.: Coronado National
Forest, Chiricahua Mountains, N31°54.665'
W109°16.336', 2445m, 5.VIII.2012, S.M. Smith,
A.I. Cognato coll., Ex. Abies concolor
Hungary: Gy!r-Moson-Sopron: Sopron, 2003, F.
Lakatos coll.
Morocco: 30 km S. Asni, Tizi'n'Test, 18.IV.2002, B.H.
Jordal coll,. Ex. Prunus dulcis
Czech Republic: South Bohemia: Jind"ich#v Hradec
env. $ím%", 23.VII.2011, M.Kní&ek lgt.,
Ex. Prunus sp.
Iran: Gilan: Khoshkestalkh, N37°27'01" E49°42'06",
17.VII.2011, S. Amini coll., Ex. Malus sp.
USA: Missouri: Saint Louis Co.: Maryland Heights,
22.V.2008, Ex. Lindgren funnel trap
Denmark: NEJ, Tofte Skov [GenBank]
Russia: Primorksy, N43º00'34" E134º07'43", 1721.VIII.2007, A. Napolov coll.
China: Qinghai: MaiXiu Forest Preserve, N35º16.288'
E101º55.904', 2927m, 21.V.2008, A.I. Cognato coll.,
Ex. Lindgren funnel trap
China: Sichuan: Highway 213 near Zhangla,
9.VII.2004, A.I. Cognato coll., Ex. Picea purpurea

369	
  

Matrix
name
Sco rob 178

Extraction
name
SMS 178

Sco rug 66

SMS 66

Sco rug 72

SMS 72

Sco rug 79

SMS 79

Sco rug 165

SMS 165

Sco sch 2

Sco sch 2

Sco sco BJ
Sco sem 156

SMS 156

Sco sin 1

Sco sin 1

Sco sin 70

SMS 70

	
  
Table 2.2 (cont’d).
Species
Scolytus subscaber

Scolytus subscaber

Scolytus sulcifrons

Scolytus triarmatus

Scolytus tsugae

Scolytus tsugae

	
  

Matrix
Collection locality, date, collector and host
name
USA: Idaho: Boundary Co.: Kaniksu National Forest, Sco sub 51
Robinson Lake campground, N48°58.197'
W116°13.068', 2748ft 13.VIII.2010, S.M. Smith,
A.R. Gillogly coll., Ex. Abies lasiocarpa
USA: California: Alpine Co., Toiyabe National Forest, Sco sub 6
11.6 miles E of Markleeville, N38°39.906'
W119°38.540', 24.VII.2010, S.M. Smith coll.,
Ex. Abies magnifica
Russia: Moscow Oblast: Dolgoprudnly, N55º58.266’, Sco sul 146
E37º30.191’, 570m, 28.VII.2011, A.V. Petrov coll.,
Ex. Ulmus laevis
Sweden: Uppsala: Tierp, WGS 84, N60°18.310´
Sco tri 171
E17°28.716, 8.VI2012, Å. Lindelöw coll.,
Ex. reared from bark of standing Ulmus glabra
USA: Idaho: Soshone Co.: St. Joe National Forest,
Sco tsu 10
N47°00.790' W116°12.359', 3192ft, 15.VIII.2010,
S.M. Smith, A.R. Gillogly coll., Ex. Tsuga occidentalis

Extraction
name
SMS 51

USA: Idaho: Boundary Co.: Kaniksu National Forest, Sco tsu 11
N48°40.911' W116°34.345', 4353ft, 12.VIII.2010,
S.M. Smith, A.R. Gillogly coll.,Ex. Tsuga heterophylla

SMS 11

370	
  

SMS 6

SMS 146

SMS 171

SMS 10

	
  
Table 2.2 (cont’d).
Species
Scolytus unispinosus

Scolytus unispinosus

Scolytus unispinosus

Scolytus unispinosus

Scolytus unispinosus

	
  

Matrix
name
Sco fis 1

Collection locality, date, collector and host
USA: Oregon: Deschutes Co.: Deschutes National
Forest, Black Butte Rd, Black Butte, N40º24.924’
W121º38.323’, 4212ft, 1.VIII.2010 S.M. Smith coll.,
Ex. Pseudotsuga menziesii
USA: Oregon: Hood River Co.: Mount Hood National Sco uni 39
Forest, Sherwood Campground, Hwy 35,
N45°19.278' W121°37.104', 4293ft, 2.VIII.2010,
S.M. Smith coll., Ex. Pseudotsuga menziesii
USA: Oregon: Klamath Co.: Deschutes National
Sco uni 42
Forest, NF 4672, N43°30.474' W121°52.147',
4923ft, 31.VII.2010, S.M. Smith coll.,
Ex. Pseudotsuga menziesii
USA: Oregon: Jackson Co.: Rogue River National
Sco uni 40
Forest, NF 60, N42°53.926' W122°19.177', 4547ft,
30.VII.2010, S.M. Smith coll.,
Ex. Pseudotsuga menziesii
USA: Oregon: Marion Co.: Williamette National
Sco uni 151
Forest, Breitenbush Rd, N44º47.200’ W121º56.557’,
2645ft, 1.VIII.2010, S.M. Smith coll.,
Ex. Pseudotsuga menziesii

371	
  

Extraction
name
SMS 1

SMS 39

SMS 42

SMS 40

SMS 151

	
  

Table 2.2 (cont’d).
Species
Scolytus ventralis

Scolytus ventralis

Scolytus ventralis

Scolytus ventralis

	
  

Collection locality, date, collector and host
USA: Idaho: Boundary Co.: Kaniksu National Forest,
Robinson Lake campground, N48°58.385'
W116°13.351', 2748ft, 11.VIII.2010, S.M. Smith,
A.R. Gillogly coll., Ex. Abies lasiocarpa
USA: New Mexico: Torrance Co.: Cibola National
Forest, W. Manzano, N34°37.325' W106°24.642',
8026ft, 11.V.2010, S.M. Smith, A.I. Cognato coll.,
Ex. Abies concolor
USA: California: El Dorado Co.: El Dorado National
Forest, nr. Ice House Resevoir N38°50.002'
W120°21.160', 5413ft, 25.VII.2010, S.M. Smith
coll., Ex. Abies concolor
USA: Arizona: Coconino Co.: Arizona Snowbowl,
N36°24.381' W112°05.619', 8923ft, 30.V.2010 S.M.
Smith, K. Bush coll., Ex. Abies lasiocarpa

372	
  

Matrix
name
Sco ven 22

Extraction
name
SMS 22

Sco ven 48

SMS 48

Sco ven 49

SMS 49

Sco ven 50

SMS 50

	
  
Table 2.3. Properties of the data included in the Bayesian analysis of all genes and the model of nucleotide evolution selected by the
AIC criterion in MrModel test. PI = parsimony informative characters; Steps = the shortest parsimony tree produced by analysis of the
partition for included taxa; CI = consistency index for included taxa.

	
  

373	
  

	
  

Table 2.4. Camptocerus species distribution, known host families and genera.

	
  

X

Meliaceae

X
X
X

X

Burseraceae

Region
Central & South America
South America
Central & South America
South America
South America
South America
South America
South America
South America
Central & South America
South America
South America
South America

Chrysobalanaceae

Camptocerus
Species
aeneipennis
aterrimus
auricomus
coccoformus
costatus
latipilis
mallopterus
niger
noel
opacicollis
pilifrons
pseudoangustior
suturalis

Eurosid I
Eurosid II
Malpighiales Sapindales

Lauraceae

Magnoliids
Laurales

X

X

Genera
Protium; Ocotea
Protium
Protium; Cedrela; Ocotea
Ocotea

X
X

X

374	
  

X
X
X

Protium; Hirtella; Licania
Protium; Ocotea
Protium

X
X

X

Protium
Protium; Ocotea

	
  
Table 2.5. Ceratolepsis, Cnemonyx and Loganius species distribution, known host families and genera.

	
  

Meliaceae

Eurosid II
Sapindales
Burseraceae

Region
South America
Central & South America
Central & South America
Central America
Mexico & Central America
South America
South America
South America
Mexico
Central America

Euphorbiaceae

Species
amazonicus
insignis
panamensis
exiguus
setulosus
rugulosus
vismiacolens
flavicornis
gracilens
opacus

Clusiaceae

Genus
Ceratolepsis
Ceratolepsis
Cnemonyx
Cnemonyx
Cnemonyx
Cnemonyx
Cnemonyx
Loganius
Loganius
Loganius

Myristicaceae

Angiosperms
Magnoliids Eurosid I
Magnoliales Malpighiales

X
X

X
X
X

X

X

X

Genera
Virola
Protium; Vismia; Trichila
Protium
Tetragastris; Trichilia
Vismia

X
X

375	
  

Hippomane

	
  
Table 2.6. Scolytus species distribution, known host families and genera.
Pinopsida Angiosperms
Eudicots
Core Eudicots

	
  

X
X

X

X
X
X
X
X
X
X
X
X
X
X
X
X
X
X

376	
  

X

Ulmaceae

Rosaceae

Rhamnaceae

Cannabaceae

Rosales
Elaeagnaceae

Saliceae

Malpigaceae

Euphorbiaceae

Malpighiales
Combretaceae

Juglandaceae

Fagaceae

Betulaceae

Fabaceae

Hamamelidaceae

Polygonaceae

Region
Nearctic
Nearctic
Nearctic
Nearctic
Nearctic
Nearctic
Nearctic
Nearctic
Nearctic
Nearctic
Nearctic
Nearctic
Nearctic
Nearctic
Nearctic
Nearctic
Nearctic

Eurosid I
Ranunculales Caryophylales Saxifragales Fabales Fagales
Ranunculaceae

Scolytus
species
aztecus
fagi
fiskei
laricis
monticolae
muticus
obelus
oregoni
piceae
praeceps
quadrispinosus
reflexus
robostus
subscaber
tsugae
unispinosus
ventralis

Pinaceae

Pinales

	
  

Table 2.6 (cont’d).
Pinopsida Angiosperms
Eudicots
Core Eudicots

	
  

Ulmaceae

Rhamnaceae

Cannabaceae

Rosales
Elaeagnaceae

Saliceae

Malpigaceae

Euphorbiaceae

Combretaceae

Juglandaceae

Fagaceae

Betulaceae

X
X
X

Malpighiales

Rosaceae

X

Fabaceae

Hamamelidaceae

Polygonaceae

Region
Neotropical
Neotropical
Neotropical
Neotropical
Neotropical
Neotropical
Paelarctic
Palearctic
Palearctic
Palearctic
Palearctic
Palearctic
Palearctic
Palearctic

Eurosid I
Ranunculales Caryophylales Saxifragales Fabales Fagales
Ranunculaceae

Scolytus
species
cristatus
dimidiatus
excavatus
mozolevskae
propinquus
proximus
carpini
ecksteini
ensifer
intricatus
japonicus
koltzei
laevis
mali

Pinaceae

Pinales

X
X
X

X
X
X
X
X

X
X

X
X

X
X

X
X
X

377	
  

X

X

X

X

X

X

X

	
  

Table 2.6 (cont’d).
Pinopsida Angiosperms
Eudicots
Core Eudicots

	
  

X

X
X

X

X

X

X
X
X
X
X
X

Ulmaceae

Rosaceae

Rhamnaceae

X

X
X

Cannabaceae

Rosales
Elaeagnaceae

Saliceae

Malpigaceae

Euphorbiaceae

Malpighiales
Combretaceae

X
X

Juglandaceae

Fagaceae

X

X
X

Fabaceae

X

X

Betulaceae

Hamamelidaceae

Polygonaceae

Region
Palearctic
Paelarctic
Palearctic
Palearctic
Palearctic
Palearctic
Palearctic
Palearctic
Palearctic
Palearctic
Paelarctic

Pinaceae

Scolytus
species
multistriatus
orientalis
pygmaeus
ratzeburgii
rugulosus
schevyrewi
scolytus
semenovi
sinopiceus
sulcifrons
triarmatus

Eurosid I
Ranunculales Caryophylales Saxifragales Fabales Fagales
Ranunculaceae

Pinales

X
X
X
X
X
X
X

X
X

378	
  

X
X

	
  
Table 2.6 (cont’d).

	
  

379	
  

Verbenaceae

Oleaceae

Caprifoliaceae

Region
Nearctic
Nearctic
Nearctic
Nearctic
Nearctic
Nearctic
Nearctic
Nearctic
Nearctic
Nearctic
Nearctic
Nearctic
Nearctic
Nearctic
Nearctic
Nearctic
Nearctic

Sapindaceae

Scolytus
species
aztecus
fagi
fiskei
laricis
monticolae
muticus
obelus
oregoni
piceae
praeceps
quadrispinosus
reflexus
robostus
subscaber
tsugae
unispinosus
ventralis

Malvaceae

Angiosperms
Eudicots
Eurosid II
Euasterid II
Malvales Sapindales Dipsacales Lamiales

Genera
Abies; Pseudotsuga
Fagus; Celtis
Pseudotsuga
Larix
Pseudotsuga
Celtis; Gleditisia
Abies
Pseudotsuga
Picea
Abies
Carya
Pseudotsuga
Abies
Abies
Tsuga
Pseudotsuga
Abies

	
  
Table 2.6 (cont’d).

Palearctic
Palearctic

mali

Verbenaceae

koltzei
laevis

Oleaceae

Palearctic

Caprifoliaceae

japonicus

	
  

Region
Neotropical
Neotropical
Neotropical
Neotropical
Neotropical
Neotropical
Paelarctic
Palearctic
Palearctic
Palearctic

Sapindaceae

Scolytus
species
cristatus
dimidiatus
excavatus
mozolevskae
propinquus
proximus
carpini
ecksteini
ensifer
intricatus

Malvaceae

Angiosperms
Eudicots
Eurosid II
Euasterid II
Malvales Sapindales DipsacalesLamiales

Palearctic

Genera
X Lonchocarpus; Heteropterys; Clematis, Petrea
Lonchocarpus; Rhamnus
Pterocarpus
Inga; Lonchocarpus
Lonchocarpus
Carpinus; Ostrya; Fagus; Corylus; Quercus;
Ulmus; Zelkova
Ulmus; Prunus; Zelkova
Ostrya; Castanea; Parrotia; Ulmus; Quercus;
Zelkova; Populus; Salix; Aesculus; Sorbus;
Betula; Fagus
Prunus; Pyrus; Ulmus; Zelkova; Malus;
Lonicera; Acer
Tilia
Ulmus; Alnus; Corylus; Fagus; Quercus; Tilia;
malus; Prunus; Pyrus; Acer
Malus; Prunus; Pyrus; Cotoneaster; Crataegus;
Sorbus; Ulmus

X

X
X
X

X

X

380	
  

	
  

Table 2.6 (cont’d).

Palearctic

semenovi
sinopiceus
sulcifrons
triarmatus
sinopiceus
sulcifrons
triarmatus

Palearctic
Palearctic
Palearctic
Paelarctic
Palearctic
Palearctic
Paelarctic

X
X
X

X

381	
  

Verbenaceae

Palearctic

scolytus

Oleaceae

Palearctic

schevyrewi

Caprifoliaceae

rugulosus

	
  

Region
Palearctic
Paelarctic
Palearctic
Palearctic

Sapindaceae

Scolytus
species
multistriatus
orientalis
pygmaeus
ratzeburgii

Malvaceae

Angiosperms
Eudicots
Eurosid II
Euasterid II
Malvales Sapindales Dipsacales
Lamiales

Genera
Ulmus
Ulmus, Zelkova
Ulmus; Carpinus; Fagus; Quercus; Prunus; Olea
Betula; Ulmus; Carpinus; Corylus; Prunus;
Zelkova; Populus; Juglans; Salix; Fraxinus
Malus; Pyrus; Prunus; Amelanchier; Crataegus;
Sorbus; Cotoneaster; Cydonia; Mespilus
Ulmus; Salix; Eleagnus; Caragana; Prunus;
Armeniaca; Caragana; Persica
Ulmus; Quercus; Amalygdalus; Fraxinus;
Juglans; Corylus
Ulmus; Malus
Picea
Ulmus; Quercus
Ulmus
Picea
Ulmus; Quercus
Ulmus

	
  

Table 2.7. Estimates of clade ages in millions of years ago (mya) and 95% highest posterior density (HDP) ranges generated using a
Bayesian relaxed molecular clock in BEAST with fossil calibrations of the oldest Scolytini at 100 mya (A) and 120 mya (B).

	
  

382	
  

	
  
Table 2.1. Scolytini genera, diversity, distribution, feeding habits and common host families.

Genus

Species
count

Distribution

Feeding
habit

# Conifer
feeders

Common hosts

Camptocerus

31

Neotropical

fungus

0

Burseraceae, Lauraceae

Ceratolepsis

6

Neotropical

phloem

0

Myristicaceae

Cnemonyx

22

Neotropical

phloem

0

Burseraceae, Clusiacae,
Euphorbiaceae

Loganius

19

Neotropical

phloem

0

Euphorbiaceae

Scolytopsis

6

Neotropical

phloem

0

Combretaceae

Scolytus

44

Neotropical

phloem

0

Fabaceae

Scolytus

21

Nearctic

phloem

18

Scolytus

62

Palearctic

phloem

4

Total

	
  

211

22

353	
  

Pinaceae, Cannabaceae,
Fagaceae, Juglandaceae
Ulmaceae, Rosaceae,
Betulacae, Fagacae,
Sapindaceae, Julandaceae,
Malvaceae, Pinaceae

Figure 2.1. Bayesian tree derived by analysis of data set I with all genes treated as a single partition with GTR+I+ Γ. Posterior
probabilities are listed above nodes (** ≥ 95, * ≥ 90).

	
  

383	
  

Figure 2.1 (cont’d).

	
  

384	
  

Figure 2.1 (cont’d).

	
  

385	
  

Figure 2.1 (cont’d).

	
  

386	
  

Figure 2.1 (cont’d).

	
  

387	
  

Figure 2.1 (cont’d).

	
  

388	
  

Figure 2.1 (cont’d).

	
  

389	
  

Figure 2.1 (cont’d).

	
  

390	
  

Figure 2.1 (cont’d).

	
  

391	
  

Figure 2.2. Bayesian tree derived by analysis of data set II with all genes treated as a single partition with GTR+I+ Γ. Posterior
probabilities are listed above nodes (** ≥ 95, * ≥ 90).

	
  

392	
  

Figure 2.2 (cont’d).

	
  

393	
  

Figure 2.2 (cont’d).

	
  

394	
  

Figure 2.2 (cont’d).

	
  

395	
  

Figure 2.2 (cont’d).

	
  

396	
  

Figure 2.2 (cont’d).

	
  

397	
  

Figure 2.2 (cont’d).

	
  

398	
  

Figure 2.2 (cont’d).

	
  

399	
  

Figure 2.3. Bayesian tree derived by analysis of data set III with three data partitions COI, 28S and (ArgK+CAD) with GTR+I+ Γ.
Posterior probabilities are listed above nodes (** ≥ 95, * ≥ 90).

	
  

400	
  

Figure 2.3 (cont’d).

	
  

401	
  

Figure 2.3 (cont’d).

	
  

402	
  

Figure 2.3 (cont’d).

	
  

403	
  

Figure 2.3 (cont’d).

	
  

404	
  

Figure 2.3 (cont’d).

	
  

405	
  

Figure 2.3 (cont’d).

	
  

406	
  

Figure 2.3 (cont’d).

	
  

407	
  

Figure 2.3 (cont’d).

	
  

408	
  

Coptonotus

Scolytus

Ceratolepsis
Loganius

Cnemonyx

Camptocerus

Figure 2.4. Ancestral state reconstruction of feeding habit among the Scolytini calculated by likelihood estimation with the Mk-1
model over the analysis II consensus tree topology (Figure 2.2). Taxa known to bore into sapwood are marked in black and taxa
known to mine the phloem are marked in white.

Wood-Boring
Phloem

	
  

	
  
	
  
	
  
	
  
	
  
	
  

409	
  

Coptonotus

Scolytus
Neotrpoical

Scolytus
Palearctic

Scolytus
Palearctic
Scolytus
Nearctic

Scolytus
Nearctic

Ceratolepsis
Loganius

Cnemonyx

Camptocerus

Figure 2.5. Ancestral state reconstruction of host-use among the Scolytini calculated by likelihood estimation with the Mk-1 model
over the analysis II consensus tree topology (Figure 2.2). Only most common host family was scored for each species. Only those taxa
with host records were scored.
	
  

Unknown
Burseraceae

Pinaceae
Burseraceae
Ulmaceae
Rosaceae
Fabaceae
Juglandaceae
Cannabaceae
Betulaceae
Fagaceae
Myristicaceae
Clusiaceae
Euphorbiaceae
Malvaceae
Unknown

Pinaceae

Ulmaceae

	
  

	
  

410	
  

Picea
Abies
Pseudotsuga
Larix
Tsuga
Angiosperm

411	
  

Scolytus
Neotrpoical

Scolytus
Palearctic

Scolytus
Nearctic

Scolytus
Palearctic

Scolytus
Nearctic

Figure 2.6. Ancestral state reconstruction of conifer-feeding Scolytus by host genus, calculated by likelihood estimation with the Mk1 model over a pruned analysis II consensus tree topology (Figure 2.2) with non-Scolytus genera removed. Only coniferous genera
were scored for each species while angiosperm feeders are marked in black.

Figure 2.7. Maximum clade credibility tree (in part) for Scolytini based on the minimum age
Bayesian analysis (analysis A). 95% confidence intervals for the ages of clades indicated with
blue bars. Numbers correspond to clades listed in Table 2.8. ** denotes the Quaternary period
and * denotes the Pliocene epoch.

1

150.0

125.0

100.0

75.0

Mesozoic
Cretaceous

Paleoce

412	
  

Figure 2.7 (cont’d).

9

8
6
7
3
1

5

4
2

100.0

75.0

50.0

esozoic

25.0

Cenozoic

taceous

Paleogene
Paleocene

413	
  

Eocene

Ne
Oligocene

Mioc

6
7
Figure 2.7 (cont’d).

3

1

0.0

5

4
2

75.0

50.0

25.0

0.

Cenozoic
Paleogene
Paleocene

Eocene

414	
  

Neogene
Oligocene

Miocene

**
*

Scolytus fi

Scolytus la

10

Scolytus u

Scolytus p

Figure 2.7 (cont’d).

Scolytus o
Scolytus m

Scolytus o
Scolytus ts

Scolytus re

Scolytus ro

Scolytus s

Scolytus ru

Scolytus s
Scolytus la
Scolytus m
Scolytus ra
Scolytus s
Scolytus tr
Scolytus s
Scolytus q

Scolytus m

Scolytus fa
Scolytus s
Scolytus e

9

8

Scolytus m

6
7
3
1

00.0

Scolytus p
Scolytus c
Scolytus in
Scolytus s
Scolytus ja
Scolytus k

Scolytus e
Scolytus c
Scolytus d
Scolytus p
Scolytus e
Scolytus p
Scolytus m
Ceratolep
Ceratolep
Ceratolep
Camptoce

Camptoce

Camptoce

Camptoce
Camptoce
Camptoce
Camptoce
Camptoce
Camptoce
Camptoce

5

Cnemonyx

4

Camptoce
Camptoce
Camptoce
Cnemonyx
Cnemonyx
Loganius f
Loganius o
Loganius g
Coptonotu

2
415	
  
75.0

50.0

25.0

0.0

Figure 2.7 (cont’d).

Scolytus praeceps

Scolytus obelus
Scolytus aztecus
Scolytus ventralis
Scolytus fiskei
Scolytus laricis

10

Scolytus unispinosus
Scolytus piceae
Scolytus oregoni
Scolytus monticolae
Scolytus oregoni
Scolytus tsugae
Scolytus reflexus
Scolytus robustus
Scolytus subscaber
Scolytus rugulosus
Scolytus sinopiceus
Scolytus laevis
Scolytus mali
Scolytus ratzeburgii
Scolytus scolytus
Scolytus triarmatus
Scolytus sulcatus
Scolytus quadrispinosus
416	
  

Scolytus muticus

Scolytus robustus
Scolytus subscaber
Scolytus rugulosus
Figure 2.7 (cont’d).

Scolytus sinopiceus
Scolytus laevis
Scolytus mali
Scolytus ratzeburgii
Scolytus scolytus
Scolytus triarmatus
Scolytus sulcatus
Scolytus quadrispinosus
Scolytus muticus
Scolytus fagi
Scolytus semenovi
Scolytus ensifer

9

Scolytus pygmaeus
Scolytus carpini
Scolytus intricatus
Scolytus schevyrewi
Scolytus japonicus
Scolytus koltzei
Scolytus multistriatus

7

Scolytus ecksteini
Scolytus cristatus
Scolytus dimidiatus
Scolytus propinquus
Scolytus excavatus
Scolytus proximus
Scolytus mozolevskae
Ceratolepsis insignis
Ceratolepsis amazonicus
Ceratolepsis amazonicus
Camptocerus suturalis
Camptocerus noel
Camptocerus aeneipennis
417	
  
Camptocerus aterrimus
Camptocerus pseudoangustior
Camptocerus latipillis

Scolytus multistriatus
Scolytus ecksteini
Scolytus cristatus
Scolytus dimidiatus
Scolytus propinquus
Scolytus excavatus
Scolytus proximus
Scolytus mozolevskae
Ceratolepsis insignis
Ceratolepsis amazonicus
Ceratolepsis amazonicus
Camptocerus suturalis

Figure 2.7 (cont’d).

7

Camptocerus noel
Camptocerus aeneipennis
Camptocerus aterrimus
Camptocerus pseudoangustior
Camptocerus latipillis
Camptocerus coccoformus
Camptocerus mallopterus
Camptocerus pilifrons
Camptocerus costatus
Cnemonyx rugulosus
Camptocerus auricomus
Camptocerus niger
Camptocerus opacicollis
Cnemonyx exiguus
Cnemonyx vismiacolens
Loganius flavicornis
Loganius opacus
Loganius gracilens
Coptonotus cyclopus

25.0

cene

0.0

Neogene

**
418	
  

Miocene

*

Figure 2.8. Maximum clade credibility tree (in part) for Scolytini based on the maximum age
Bayesian analysis (analysis B). 95% confidence intervals for the ages of clades are indicated
with blue bars. Numbers correspond to clades listed in Table 2.8. ** denotes the Quaternary
period and * denotes the Pliocene epoch.

1

150.0

190.0

125.0

Mesozoic
Jurassic

Creta

419	
  

Figure 2.8 (cont’d).

1

100.0

75.0

Mesozoic
Cretaceous

420	
  

Figure 2.8 (cont’d).

8
6
7

5

4
3

2

75.0

50.0

25.0

Cenozoic
Paleogene
Paleocene

Eocene

421	
  

Oligocene

Scolytus subscaber
Scolytus rugulosus
Scolytus sinopiceus
Scolytus laevis
Scolytus ratzeburgii
Scolytus mali
Scolytus scolytus
Scolytus triarmatus
Scolytus sulcatus
Scolytus quadrispinosus

Figure 2.8 (cont’d).

Scolytus muticus
Scolytus fagi
Scolytus semenovi
Scolytus ensifer
Scolytus pygmaeus
Scolytus carpini
Scolytus intricatus
Scolytus schevyrewi
Scolytus japonicus
Scolytus koltzei
Scolytus multistriatus

9

8

Scolytus ecksteini
Scolytus cristatus
Scolytus dimidiatus
Scolytus propinquus
Scolytus excavatus
Scolytus proximus
Scolytus mozolevskae

7

Camptocerus suturalis
Camptocerus noel
Camptocerus aeneipennis
Camptocerus pseudoangustior
Camptocerus aterrimus
Camptocerus latipillis
Camptocerus coccoformus
Camptocerus mallopterus
Camptocerus pilifrons
Camptocerus costatus
Cnemonyx rugulosus
Camptocerus auricomus
Camptocerus niger
Camptocerus opacicollis
Cnemonyx exiguus
Cnemonyx vismiacolens
Ceratolepsis amazonicus
Ceratolepsis amazonicus
Ceratolepsis insignis
Loganius flavicornis
Loganius opacus
Loganius gracilens
Coptonotus cyclopus

25.0

0.0

Cenozoic

Paleogene
Eocene

Neogene
Oligocene

Miocene

422	
  

**
*

Figure 2.8 (cont’d).

Scolytus praeceps
Scolytus obelus
Scolytus aztecus
Scolytus ventralis
Scolytus fiskei
Scolytus laricis

10

Scolytus unispinosus
Scolytus piceae
Scolytus oregoni
Scolytus monticolae
Scolytus oregoni
Scolytus tsugae
Scolytus reflexus
Scolytus robustus
Scolytus subscaber
Scolytus rugulosus
Scolytus sinopiceus
Scolytus laevis
Scolytus ratzeburgii
Scolytus mali
Scolytus scolytus
Scolytus triarmatus
Scolytus sulcatus
Scolytus quadrispinosus
Scolytus muticus

9

8

Scolytus fagi
Scolytus semenovi
Scolytus ensifer
Scolytus pygmaeus
Scolytus carpini
Scolytus intricatus
Scolytus schevyrewi
Scolytus japonicus
Scolytus koltzei
Scolytus multistriatus
Scolytus ecksteini
Scolytus cristatus
Scolytus dimidiatus
Scolytus propinquus
Scolytus excavatus
Scolytus proximus
Scolytus mozolevskae

7

Camptocerus suturalis
Camptocerus noel

423	
  

Camptocerus aeneipennis
Camptocerus pseudoangustior
Camptocerus aterrimus
Camptocerus latipillis
Camptocerus coccoformus
Camptocerus mallopterus

Figure 2.8 (cont’d).

Scolytus praeceps
Scolytus obelus
Scolytus aztecus
Scolytus ventralis
Scolytus fiskei
Scolytus laricis

10

Scolytus unispinosus
Scolytus piceae
Scolytus oregoni
Scolytus monticolae
Scolytus oregoni
Scolytus tsugae
Scolytus reflexus
Scolytus robustus
Scolytus subscaber
Scolytus rugulosus
Scolytus sinopiceus
Scolytus laevis
Scolytus ratzeburgii
Scolytus mali
Scolytus scolytus
Scolytus triarmatus
Scolytus sulcatus
Scolytus quadrispinosus
Scolytus muticus

9

424	
  

Scolytus fagi
Scolytus semenovi
Scolytus ensifer
Scolytus pygmaeus
Scolytus carpini
Scolytus intricatus
Scolytus schevyrewi
Scolytus japonicus
Scolytus koltzei

Scolytus reflexus
Scolytus robustus
Scolytus subscaber
Figure 2.8 (cont’d).

Scolytus rugulosus
Scolytus sinopiceus
Scolytus laevis
Scolytus ratzeburgii
Scolytus mali
Scolytus scolytus
Scolytus triarmatus
Scolytus sulcatus
Scolytus quadrispinosus
Scolytus muticus
Scolytus fagi
Scolytus semenovi
Scolytus ensifer
Scolytus pygmaeus
Scolytus carpini
Scolytus intricatus
Scolytus schevyrewi
Scolytus japonicus
Scolytus koltzei
Scolytus multistriatus

9

Scolytus ecksteini
Scolytus cristatus
Scolytus dimidiatus
Scolytus propinquus
Scolytus excavatus
Scolytus proximus
Scolytus mozolevskae

7

Camptocerus suturalis
Camptocerus noel
425	
  

Camptocerus aeneipennis
Camptocerus pseudoangustior
Camptocerus aterrimus

Scolytus ecksteini
Scolytus cristatus
Scolytus dimidiatus
Scolytus propinquus
Scolytus excavatus
Scolytus proximus
Scolytus mozolevskae

Figure 2.8 (cont’d).

Camptocerus suturalis
Camptocerus noel
Camptocerus aeneipennis
Camptocerus pseudoangustior
Camptocerus aterrimus
Camptocerus latipillis
Camptocerus coccoformus
Camptocerus mallopterus
Camptocerus pilifrons
Camptocerus costatus
Cnemonyx rugulosus
Camptocerus auricomus
Camptocerus niger
Camptocerus opacicollis
Cnemonyx exiguus
Cnemonyx vismiacolens
Ceratolepsis amazonicus
Ceratolepsis amazonicus
Ceratolepsis insignis
Loganius flavicornis
Loganius opacus
Loganius gracilens
Coptonotus cyclopus

426	
  

APPENDIX C:
Tables and Figures for Chapter 3	
  

427	
  

Figure 3.1. Ceratolepsis diagnostic characters including the shape and setae on the antennal club
and funicle (A), the apical margins of the meso- and metathoracic tibiae unnamed with
supplemental denticles (B), the shape of the mesosternum (C) and the slightly impressed frons in
both sexes (D).

428	
  

Figure 3.2. Ceratolepsis jucundus lateral (A) and dorsal view (B).

429	
  

Figure 3.3. Scolytus rabagliatus male, 3.0-3.2 mm long, lateral (A) and dorsal view (B).

430	
  

Figure 3.4. Scolytus rabagliatus female, 2.0-3.0 mm long, lateral (A) and dorsal view (B).

431	
  

Figure 3.5. Scolytus rabagliatus male venter posterior (A) and posterior oblique (B); female
venter posterior (C) and posterior oblique (D).

432	
  

Figure 3.6. Scolytus rabagliatus male head anterior (A) and anterior oblique (B); female head
anterior (C) and anterior oblique view (D).

433	
  

LITERATURE CITED

434	
  

LITERATURE CITED
Aguirre-Planter É, Jaramillo-Correa JP, Gómez-Acevedo S, Khasa DP, Bousquet J, Eguiarte LE
(2012) Phylogeny, diversification rates and species boundaries of Mesoamerican firs
(Abies, Pinaceae) in a genus-wide context. Molecular Phylogenetics and Evolution 62:
263-274.
The Angiosperm Phylogeny Group (2009) An update of the angiosperm phylogeny group
classification for the orders and families of flowering plants: APG III. Botanical Journal
of the Linnean Society 161: 105–121.
	
  
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