Do latex and resin canals spur plant diversification? : re-examining a classic example of escape and radiate coevolution
The association between increased lineage diversification rates and the evolution of latex and resin canals is widely cited as a paradigmatic example of Ehrlich and Raven's 'escape-and-radiate' hypothesis of co-evolution. However, it has been nearly three decades since these plant defenses have been examined as key innovations, and updates to phylogenetic comparative methods, plant molecular systematics, and phenotypic data warrant a reassessment of this classic finding. I gathered data on latex and resin canals across 345 families and 986 genera of vascular plants and conducted a multi-scale test of the association between these traits and lineage diversification rates. At a broad scale (across clades), I used sister-clade comparisons to test whether 28 canal-bearing clades had higher net diversification rates than their canal-lacking sister clades. At a finer scale (within clades), I used ancestral state reconstructions and phylogenetic models of lineage diversification rates to examine the relationship between trait evolution and the timing of diversification rate shifts in two better-characterized clades - Araceae and Papaveraceae. At both scales of analyses, I found poor support for the predicted relationship between diversification and the evolution of latex and resin canals. This re-examination reveals that there is no longer strong evidence for latex or resin canals as general, consistently replicable drivers of species diversity across plants. However, I could not rule out a relationship in all groups, and therefore argue that theoretical and empirical work aimed at understanding ecological factors that condition 'escape-and-radiate' dynamics will allow for more nuanced tests of the hypothesis in the future.
Read
- In Collections
-
Electronic Theses & Dissertations
- Copyright Status
- In Copyright
- Material Type
-
Theses
- Authors
-
Foisy, Michael
- Thesis Advisors
-
Weber, Marjorie G.
- Committee Members
-
Lowry, David
Bradburd, Gideon
Conner, Jeff
- Date Published
-
2020
- Subjects
-
Coevolution
Vascular system of plants
Plant diversity
Plants--Evolution
Plant morphology
Plants--Variation
Evolution (Biology)
- Program of Study
-
Plant Biology - Master of Science
- Degree Level
-
Masters
- Language
-
English
- Pages
- vii, 68 pages
- ISBN
-
9798664757880
- Permalink
- https://doi.org/doi:10.25335/m1de-tm55