RESPIRAWON IN ANAX 3UNEUS DRURY (ODONATA: AESHNiDAE) Thesis for the Degree of M. & MICHIGAN STATE UNIVERSITY MICHAEL "F. PETITPREN . 1988 LID" ”‘Y THESIS Middné t6 Universit y ABSTRACT RESPIRATION IN ANAX JUNIUS DRURY (ODONATA: AESHNIDAE5 by Michael F. Petitpren A Gilson differential respirometer was employed to evaluate the influence of time of day, season, sex, weight, temperature, and life stage upon the oxygen consumption of the dragonfly, Anax Junius Drury. The respiratory rate of twelve individual naiads monitored over a 2“ hour period, six during the spring and six during the summer, showed no apparent diel or seasonal rhythm in metabolic rate. The oxygen consumption of immature female dragon- flies (ul/hr/individual) was significantly greater than that for the males at 13 and 20 C, but not significantly different at 27 and 3“ C. Sex did not significantly in- fluence the respiratory rate at 13, 20, 27, or 34 C when considered on a per gram basis. The per cent of ash material increased proportionally with the growth of dragonfly naiads. Naiads weighing 4 mg (dry wt) contained approximately three per cent inert material while 13 per cent inert material was recorded for naiads weighing 300 mg (dry wt). Oxygen consumption Michael F. Petitpren expressed either as a function of dry weight or ash free dry weight was not significantly different. Respiration was related to dry body weight by co- efficients of regression of 0.69, 0.79, 0.95, and 0.96 at 13, 20, 27, and 34 C, respectively. Respiration de- creased significantly with increasing dry weight at 13 and 20 C, but increased directly with dry weight at 27 and 3H 0. Increasing water temperature resulted in increased oxygen consumption. Q10 increased with increasing dry weight, but decreased in the upper range of the tempera- tures evaluated. It was not possible to delimit the specific in- stars for A. Junius immatures. Respiratory rate de- creased with growth at 13 and 20 C by coefficients of regression of 0.69 and 0.79, respectively. At 27 and 3M C the respiratory rate was not significantly altered during immature growth. Adult respiration was three times greater per unit gram weight when compared with naiad respiration at a comparable weight and temperature. RESPIRATION IN ANAX JUNIUS DRURY (ODONATA: AESHNIDAE) By ' } .313.“ Michael FJ‘Petitpren A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Entomology and the W. K. Kellogg Biological Station 1968 ACKNOWLEDGMENTS I am deeply indebted to my major professor, Dr. Allen W. Knight, of the W. K. Kellogg Biological Station, Michigan State University, for the guidance, encourage— ment, untiring help, invaluable suggestions, and financial support, throughout the duration of this study. Sincere thanks are extended to Dr. Gordon B. Guyer, Chairman of the Department of Entomology, Michigan State University, for making this work possible and for granting financial support through a departmental teaching assistant- ship during 1966 and 1967. I am grateful to the members of my guidance committee: Drs. Allen W. Knight; Gordon B. Guyer; Roland L. Fischer; Roger HOOpingarner; and Donald C. McNaught, for their perusal of the thesis. Also, I wish to thank Dr. William COOper for his criticisms on statistical aspects. It is with much appreciation that I acknowledge Mr. Harold L. Allen for many useful suggestions and valu- able drafting techniques, both of which aided in the com— pletion of this work. Also, a very special debt of gratitude is due Mr. Robert L. Lippson for having called to my attention many useful techniques applicable to the realm biological research. ii For his helpful assistance in securing needed equip- ment, I acknowledge Mr. Arthur Wiest. Further, I thank the W. K. Kellogg Biological Station, Michigan State University, for having provided the facilities and equipment required to carry out this study. Finally, to my parents, Mr. and Mrs. Francis E. Petitpren, I express my heartfelt gratitude for their deep understanding, patient encouragement, and loving interest, without which this thesis may never have been realized. This investigation was supported (in part) by Federal Water Pollution Control Administration Grant WP 01178-01. iii TABLE OF CONTENTS Page ACKNOWLEDGMENTS . . . . ii LIST OF TABLES . . . V LIST OF FIGURES . . . . . . Vi INTRODUCTION . . . . . . . . . . 1 MATERIALS AND METHODS . . . . 3 Description of Study Areas . . . . . . 3 Field and Laboratory Methods. . . . . . 5 Treatment and Calculation of Data . . . . 12 RESULTS. . . . . . . . . 15 Field Methods. . . . . l5 Respirometry . . . . . . . l5 Diel and Seasonal Effects. . . . . . 15 Influence of Sex. . . . . . . . . 19 Percentage of Ash Material . . . . . 26 Influence of Body Weight . . . . . . 33 Influence of Temperature . . . . . . 39 Influence of Life Stage . . . . AA DISCUSSION AND CONCLUSIONS . . . . . . 48 Field Methods. . . . . . . A8 Respirometry . . . 48 Influence of Light and Shaking Rate . . 48 Diel and Seasonal Effects. . . . . . A9 Influence of Sex. . . . . . . . . 53 Influence of Ash Material. . . . . . 55 Influence of Weight. . . . . . . . 57 Influence of Temperature . . . . . . 60 Influence of Life Stage . . 63 LITERATURE CITED. . . . . 66 APPENDIX . . . . . . . . 72 iv Table .1. LIST OF TABLES Page Chemical and Physical Determinations from Crum Park Pond (2 July to A September, 1966), Long Wodds Pond (13 July to A September, 1966), and Marrow Pond (28 July to 30 August, 1967). Data were Collected Between 0800 and 1900 . . . l6 Statistical-AnalysismCompaninguLogwaxyganm Consumption Between Male and Female Anax Junius Naiads at Different Temper— atures o o o o 0' o o o o o o 22 Statistical Analysis Comparing Log Oxygen Consumption (Per Gram Unit Weight) Be- tween Male and Female Anax Junius Nai- ads at Different Temperatures. . . . 25 Statistical Comparison Between Mean Log Oxygen Consumption (+ 95 Per Cent Confi- -dence Intervals) Expressed as Log Ash Free Dry Weight and as Log Dry Weight for Anax Junius Naiads. Comparison Based on lOOfmg Body Weight . . . . 26 Statistical Analysis Comparingithe Influ- ence of Log Dry Weight on Log Oxygen Consumption for Anax Junius Naiads Computed at Different Temperatures . . 36 Influence of Life Stage on the Log Oxygen Consumption of A. Junius Naiads (pl/g dry wt/hrT . A6 The Log Oxygen Consumption (ul/g dry wt/hr) of Four Anax Junius Adults . . A7 LIST OF FIGURES Figure l. Acclimation Apparatus Employed in Condi— tioning Anax Junius Naiads to Experi- mental Temperatures . . . . . 2. Diel and Seasonal Oxygen Consumption of Twelve Individual Anax Junius Naiads Determined at 20 C“ . . . 3. Comparison Between Male (A, C, E, and G) and Female (B, D, F, and H) Log Oxygen Consumption Compared at 13, 20, 27, and 34 C, Respectively, for Anax Junius Naiads . . . . . . . . . A. Comparison Between Male (A, C, E, and G) and Female (B, D, F, and H) Log Oxygen Consumption (Per Gram Unit Weight) for Anax Junius Naiads Compared at 13, 20, , an C, Respectively. . 5. Relationship Between Log Ash Free Dry Weight and Log Dry Weight for Anax Junius Naiads . . . . . . . 6. Change in the Per Cent Ash Free Dry Weight Relative to Increasing Dry Weight for Anax Junius Naiads. Regression Deter- mined from Equation Given in Figure 5 7. Relationship Between Log Oxygen Con- sumption and Log Ash Free Dry Weight for Anax Junius Naiads Compared at Different—Temperatures . . . . 8. Relationship Between Log Oxygen Con- sumption and Log Dry Weight for Anax %unius Naiads Compared at Different emperatures . . . . . . . . vi Page 17 20 23 27 29 31 3A Figure 9. Relationship Between Log Dry Weight and Log Oxygen Consumption Per Unit Weight for Anax iunius Naiads Compared at Different'Temperatures 10. Semi-log T-R Curve for Male (Broken Line) and Female (Solid Line) Anax Junius Naiads. Each Point Represents t e ean Q02 Based on Figure A Regressions. All Values Correéted to 100 mg Dry Wt 11. Relationship Between Q10 and Size (wt) for Anax lunius Naiads . vii Page 37 A0 A2 INTRODUCTION There is a wealth of information on the respiratory metabolism of economically important insects such as the cockroach, Periplaneta americana (L.); the flower beetle, Tribolium confusum Duval; the bee moth, Galleria mello- nella (L.); and the honey bee, Apis mellifera L. In contrast, one is generally struck by the paucity of in depth studies on the respiratory rates of numerous common aquatic insects. When the aquatic environment is degraded by pol— lutants such as human and industrial wastes, insecticides, and heated effluents, the survival of important animal life is greatly threatened. Such degradation of the en— vironment is often reflected by changes in an organism's respiratory metabolism. Before the effects of pollutants on animal life can be assessed, it is first necessary to know the respiratory metabolism under "natural" environ- mental conditions. Consequently, the common dragonfly, Anax junius Drury, was selected as an experimental animal for the following reasons: (1) to advance knowledge on the respiratory metabolism of an aquatic insect under the influence of certain modifying agents; (2) to establish a base line of respiration upon which future studies on the effects of environmental modifiers of respiration might be ascertained; and (3) to contribute fundamental knowledge concerning the respiratory physiology of in— sects in general. As stated by Patton (1963): The greatest deficiency in the study of biological activity of chemicals is lack of de- tailed fundamental knowledge concerning the normal physiology of insects in general and test species in particular. The pressure of meeting emergencies in the field has, in many cases, caused the research to be guided into a head-on approach without the devotion of necessary time (and money) to the solu- tion of fundamental physiological problems that control the outcome of the experiments. This ap- proach is analagous to starting the construction of a masonary arch with the keystone. Successful understanding of the problems of chemical-bio- logical activity, resistance, and the ultimate goal of tailoring compounds to order will be achieved only after much time and effort have been expended on study of the fundamentals of the physiology and biochemistry of insects. There is no apparent shortcut to solution of the basic problems. MATERIALS AND METHODS Description of Study Areas The animals employed in respiratory studies were collected from three ponds in the vicinity of the W. K. Kellogg Biological Station, Hickory Corners, Michigan during the spring and summer of 1966-67. The ponds were selected because of their proximity and availability of populations of A. Junius. Crum Park Pond (T23 R9W S6) has a surface area of 0.65 hectares. The pond has a water depth ranging from 0.5 to 1.5 m and is dominated by water lily, Nymphaea sp.; bladderwort, Utricularia sp.; and sedge, Cargx sp. Approximately 25 per cent of the total A2A naiads tested were collected during 1966 among sedge along the pond's east shore. Long Woods Pond (TlS R9W 88), with an area of 1.0 hectare and originally intended for waterfowl management, is located within the confines of the W. K. Kellogg Bird Sanctuary. A canal 3 to 5 m wide and l m deep has been dredged around the peripheral two—thirds of the pond's northern border. Nearly half of the total test animals were obtained from a dense stand of yellow waterlily (Nuphar sp.) occurring within the canal area. The third collecting site, Marrow Pond, is located 100 meters NE of the W. K. Kellogg Biological Station and provided the only source of naiads during August and September, 1967. The pond is best described as a rather large (10 hectares) cattail-marsh with a central water lily region interspersed with areas of smartweed (Polygonum sp.) and purple-fringed riccia (Ricciocarpus O) p.). In addition to naiads, the adults tested were ob- tained from laboratory-reared immatures collected from Marrow Pond. Chemical and physical analyses of the pond waters were conducted periodically from 2 July through A September, C)\ 196 and 28 July through 30 August, 1967. Water analyses were performed in accordance with the methods set forth in Standard Methods for the Examination of Water and Waste- water (American Public Health Association 33431., 1965). Air and water temperatures were measured with a mercury thermometer. Dissolved oxygen was ascertained by the Azide Modification of the Winkler Method using 0.0125 N sodium thiosulfate solution as a titrant. Hydrogen ion concentration was assessed with a Beckman pH meter (Model M—2). Alkalinity was determined by titration with 0.02 N H2304, utilizing phenolpthalein and mixed bromcresol green- mcthyl red as indicators. Field and Laboratory Methods Naiads were collected by sweeping aquatic vege- tation with a heavy—duty triangular dip net, and subse- quently transported directly to the laboratory in a 10.A liter polyethylene pail containing pond water and vegetation. All animals were exposed to a similar pre—test history of 36 to A8 hours of starvation at a temperature (13, 20, 27, or 3A C) approximating that of the environ- ment at the time of collecting. Each animal was evalu— ltei only once at a single temperature for determination of oxygen consumption. Thus, all oxygen consumption ob— servations were made independently. Freshly collected, well aerated, filtered pond water was employed in the conditioning and evaluation of oxygen consumption. Handling of organisms was maintained at a minimum. Since dragonfly naiads are highly cannibalistic inder confined laboratory conditions, it was necessary to fabricate an acclimation apparatus for conditioning indi- vidual animals to experimental temperatures (Figure l). The apparatus was constructed by producing fifty goles .5 rows with 10 holes per row), 3.2 cm in diameter, into a piece of A0 cm x 20 cm x 3 cm styrofoam. Fiber- glass screen (# 18 mesh) was weaved, using smooth wire 520 gauge), into tubes 3.2 cm in diameter and 7.0 cm in Figure l, Acclimation apparatus employed in con- ditioning Anax ignius naiads to experi— mental temperatures. o 0" 3‘. .. .. C I Q Q q C .1 3 :Q“ 8 d C " \O“ ‘0' \Q‘S‘.‘ ... ‘ . length. The screen tubes were introduced into the holes in the styrofoam until the upper tube openings were flush with the upper surface of the styrofoam. The rough texture of the styrofoam held the screen tubes securely in place. Fiberglass screen (19 cm x 38 cm) was tied with monofilament line to the lower ends of the tubes. All materials used in the construction of the apparatus were non toxic. The acclimation apparatus was floated in a 15 liter laboratory aquarium filled to one-third capacity with freshly collected filtered (filter paper No. V100, folded, size H) pond water. The aquarium and apparatus (containing one naiad per chamber) was transferred to an Ambi-Lo variable temperature chamber (pre-set to experi— mental temperature) for approximately A8 hours prior to initial oxygen consumption measurements. A thermostatic water bath was employed for acclimations above ambient temperature. Escape of naiads was prevented,during the conditioning period,by placing a piece of fiberglass screen over the entire acclimation apparatus. An air source with two air stones ensured continuous oxygenation of the water during the conditioning phase. A Gilson Differential Respirometer (Gilson, 1963), Model No. GR 1A, was employed in the evaluation of im- mature and adult dragonfly respiration. The manometric techniques used were those outlined by Umbreit gt_gl. (196A). The reaction flasks used in oxygen consumption measurements were provisioned with a substrate of boiled brick fragments, freshly filtered pond water (filter paper Munktells No. 8, size J), and accordion-folded filter paper wick saturated with 0.2 ml of 20 per cent KOH. F1aSks of 7 ml, 15 ml, or 125 ml capacity were selected relative to the size of the naiads being tested. Adult respiration was measured in a specially constructed 1,250 m1 reaction vessel containing a sub- strate of four or five sticks. The 002 absorbent (KOH) was contained in the side arm of the flask to prevent interference with the animal's well-being. Each naiad, conditioned approximately A8 hours to the test temperature, was removed from the acclimation chamber and transferred to a flask containing filtered pond water. Precautions were taken to use flasks per- mitting liberal movement and complete emersion of test animals. End flasks (affixed to manometers 1 and 1A) were controls measuring pressure changes not resulting from dragonfly respiration. Changes registered by the controls were averaged and either added or subtracted, at five minute intervals,from individual dragonfly respiration. Flasks of equal size were used concomitantly whenever possible to equalize sensitivity to pressure change. 10 After the flasks were lowered into the water bath, light was subdued by tapping a cloth securely over the respirometer. Flasks werecscillatedslowly (8A cycles per minute) for 90 minutes before initiating measurements. The 90 minute period was necessary to equilibrate gas and liquid phases and permit animals to recover from handling and adjust to the experimental conditions. The hydrogen ion concentration (pH) of the pond water was determined at various times before and after experimental evaluation. The changes in pH were in all cases considered negligible. Oxygen consumption values were recorded at five minute intervals throughout a one—hour test period. Each test organism was subjected to four one-hour replicate oxygen consumption evaluations. The barometric pressure was noted at the beginning of each evaluation. At the termination of an experiment the test organisms were removed from the flasks, killed in hot water, and placed in a drying oven for 2A hours at 10A C. Organisms were transferred from the drying oven to a desiccator, containing CaCO for a two—hour period. 3, Dry weights were determined to the nearest 0.1 mg. Measurements of total body length, head capsule width, labium width and length, and meso-thoracic wing sheath length were determined to the nearest 0.1 mm utilizing a vernier caliper. Total body length was 11 measured from the distal end of the clypeus to the distal end of the epiproct; head capsule width from the most lateral points of the eyes; labium length from the distal points on the appressed moveable hooks of the lateral lobes to the proximal end of the mentum and labium width from the proximal ends of the opposite lateral lobes (labium terminology from Whedon, 1927); and wing sheath length from the mid—dorsal point of attachment to the most distal point of development. Whenever possible sex was determined by inspection of the ventral side of the ninth abdominal segment; females possessed ovipositors, males did not. See Appendix I for weight, linear measure— ment, and sex determinations. Fifty—four oven dried specimens of various sizes were ashed to determine the relative percentage of ash material (cuticle, labium, endoskeleton, etc.) to oven dry body weight. Vycor tubes were washed, heated in a muffle oven approximately six hours at 520 C, removed, cooled, desiccated, and weighed to 0.1 mg accuracy on a Mettler balance. Tubes not deviating more than 0.1 mg from previous weights were provisioned with an oven dried specimen of known weight, placed in a muffle oven for one hour at 520 C, removed, cooled, desiccated, and re- weighed to 0.1 mg accuracy. The weight of the ash subtracted from the dry weight of the organism equaled 12 the specimen's ash free dry weight. The percentage of ash free dry weight was determined by the equation: P = (d-a/d) (100) where P = per cent ash free dry weight; d = oven dry weight (mg); and a = weight of ash (mg). Treatment and Calculation of Data The oxygen consumption rates reported herein are representative of animals undergoing free, but moderate activity. The rates of oxygen consumption were computed utilizing various body weights as follows: (1) "Oxygen Consumption (ul/hr/individual" or "02 consumption;" (2) ”Oxygen Consumption (pl/g dry wt/hr)" or "002;" and (3) "Oxygen Consumption (ul/g ash free dry wt/hr)" or "ash Q02." The values obtained in each oxygen consumption evaluation were plotted on arithmetic grid paper (10 mm 4. La 0 the cm), over a one—hour period, at five minute inter— vals. A line was fitted by inspection and the oxygen consumption rate computed for a 20 minute interval (be— tween the 20 and A0 minute interval) and extrapolated on the basis of an hour. Micrometer readings of oxygen consumption were given digitally in microliters. To convert to standard conditions, corrections were made for the following: 3. 13 Water bath temperature in degrees C = t. Operating pressure (usually the same as barometric pressure) = Pb (3 is subtracted to compensate for the specific gravity of Hg at room temperature). Pressure of water vapor = PW The microliter readings were multiplied by the following to give microliters of dry gas at 760 millimeters Hg: multiplying factor = where: 273 760 (273) (Pb-3-PW) H0mLHa Aoov snapshoaeoe .oomH ocm com: cmmspmc ompomHfiOU one; mums .Aemmfi .pmsw:< om 0p Ease wmv ocom scenes new .Aooma .ponEmemm a on mazw mav ncod mooo: wcoq Awwma .LmnEmemm : 0p masw my ocom xama Esau Song mcofipmcfiegmpmo HmOszca one HonEmsolo.H mgm<5 17 Figure 2. Diel and seasonal oxygen consumption of twelve individual Anax junius naiads determined at 20 C. l8 mmEEDm come ooh ooh con con. 08. 83 1 q _ 4 u u 4‘ 1 A— d u —‘ d d — J u — q d _ d on .8 .8. 353: wizu... 7!. . .oz .25.: mi: 11. . h- . on. L .A- ‘ q — < - .— 4 — 1 — q — . — u - n\\.§lll¢ll|olll\\\\1| IQIII {I‘ll/(\AIJI .8. 322.: mix: 7!. $238 34: I .9. L .8. Q . cum I _ _ . _ _ _ _ _ om 7!] \\OII \bll4\\)1IJllu|‘||uou.\||Orllloll \\\9I10L ( 11:... < .00. 3528 magma 1!. - 102 352.3 mi: .11. m . .8. ‘\l\/<\\|l\/luk.o- :5 22:. 00no OOON GEN 000. can. OON. OO¢O qldA‘ - — - d d — u u d d u — d d — 1 fi 2 100 .ON 0v \ I \ I )I ’/’(\\\Q\ J" I‘\ ( I/ \\ I! < .oa :5 mt magma 7!. 3... on. mi: I H To. 1 — q u — q q — - d — A u — A q — q 1 1T 1 low low 0/\/\/\Ill\/\j a 2.53. 345... V... U Se 2; 34: .I... on -Ow L 0? I00 or! \‘\\.7/ \\\9IlI// x7156 .. If \9/ \ ( , \ Lso. 9.: I... ( A 3: 345... 1 .8. 2.... 2.. mi: I OZEdm N39AXO NOIldWflSNO 3 (Ionpwpuvm/Irf) 19 Influence of Sex The comparison of O2 consumption and QO2 between male and female dragonfly naiads was determined by test- ing the homogeneity of comparable coefficients of re- gression (b's) for males and females (Figure 3) (Steel and Torrie, 1960). Having met the assumption of a random sample drawn from a normal population, the level of significance was set at 5 per cent and the hypotheses tested: (a) HO: bf — bm = O (b) H1: bf - bm # 0 where bm = male coefficient of regression; and bf = female coefficient of regression. Female dragonflies showed a significantly greater oxygen consumption rate (per individual) at 13 and 20 C, but 0 consumption was not influenced by sex at 27 and 2 3A C (Figure 3 and Table 2). When oxygen consumption was expressed on the per unit weight basis, no sex difference was evident at any comparable temperature (Figure A and Table 3). In general, male dragonflies (A. junius) tend to weigh more than females; however, the weight difference was not significant. T. a. 3 n. n... .3.. 3.5 2 7 Au... 3 t a. a. C. .2 a. .w. o .2 34¢ a. :. ... C . E 8.: 2 (pl/hr/individual) CONSUMPTION OXYGEN IOO 21 r r : MALE L loo y- 0.2637 + 0.6827 log: n- 38 100: A ° )- b r I- '0 1 1 1 1 11L11 1 1 L IO I00 5 MALE " log y' 0530? + 0.6872 log: n '56 I00 : L— IO : I ’- 0 ' 20C ' 1 11111111 1 [JALILLL 1 1 I I0 100 b A. : MALE _ 35/ _ log y - 0.2456 + 0947.9 I001: 11- 45 I00 : L— . E IO : 27C ' 1 11111111 1 11111111 1 L1 I I0 I00 I- I, [ MALE .2 : log y - 03960 + 09439 log; / ,. n- 42 /! . /' ' - / ,/.'I. _ (3 .4 . I y” u / I U ‘9 1 ,1 . t 34 C 1 1 411L1 #1 1 1 1 11 1 1 L 1 I IO I00 I00 F1 2 FEMALE ' loqu 0.2105 + 0.7124 qux n- 35 I. IOO: 10 10 E FEMALE " log y I 0.3455 + 0.7720 log: _ n I 44 j/ 100 5 ' .4" 1; o b I0 : 5 20C ‘ 1 1111l111 1 11111111 1 LL 1 10 100 E FEMALE ,H, * log y . 0.2390 + o 9664 loaf-fit - n ‘50 /'/ ,V / I00 : /' .. F 11 °/‘ ' .. [f/fi. IO : / I ’- a h 276 | 1 1 11114111 1 11111111 1 1 1 l 10 100 C FEMALE : log ,1 03809 +09712 qul n - 56 DRY WEIGHT (mg) .Hm>ma moo.o the pa pchoaoaemamee .Hm>ma mo.o was as pehoaeaewams .Aoofifiaow pwop omHHMp ozpv mo.o n moCMOHchme mo Ho>oa Umpaooo¢ 22 H empdmooh moa.H mmo.o am Hem.o mam.o am emphases mmH.H mmo.o Hm oom.o sam.o Am empomnmw Aefimm.= mmo.o mm mse.o smm.o om emuomnmh *Hmm.m mao.o mm mas.o mmm.o ma u on 1 an ”om A smm .A.e an en .QEmwowpaxm H.mmA3pmnmmsmp pcmpommao on human: msfinmd xmc< madame one came consumn coHpoEszoo commxo woa wcHnmasoo mammamcm Hmofipmfipwpmll.m mqmma Umpamoo< H uwpamoom :om.o1 mo~.o :m moo.o :mo.o 3m ompamoom :Hm.o1 mmm.o Hm mmo.o amo.o Em umpamoom Hmo.o1 moo.o mm mmm.o mmm.o om umpgmoom pm:.H1 mao.o mm omm.o Hmm.o ma 4 o u up 1 En n u Qmm .m.© up En QEmMo pmxm H.mmL:pmthEmp pammmmMHU pm mumamc mswczfi.xmc¢.mfim80m Ucm mama Cmmzumn Auswamz was: Edam hmav coauaezmcoo cmwzxo woa wQHLMQEoo mflmzawcm Hmoapmflumum11.m mqm¢e 26 Percentage of Ash Material The relationship between ash free dry weight and dry weight is presented in a double logarithmic plot (Figure 5). Initial growth is associated with a low percentage of ash material which decreases subsequently as size increases (Figure 6). Hence, naiads weighing u mg (dry weight) contain approximately 97 per cent ash free dry material in contrast to 87 per cent in indi- viduals weighing 300 mg. There is no significant difference between oxygen consumption expressed either as Q02 (Figure 9) or as ash Q02 (Figure 7); (the statistical comparison between Q02 and ash Q02 is given in Table u). TABLE 4.--Statistical comparison between mean log oxygen consumption (1 95 per cent confidence intervals) expressed as log ash free dry weight and as log dry weight for Anax Junius naiads. Comparison based on 100 mg body weight. Expt Mean Log Respiration ( l/g/hr) Temp . (C) Log Ash Free Dry Wt n Log Dry Wt 13 2.6677 : 0.3160* (73) 2.63u9 : 0.3162 20 2.9286 i 0.3101 (119) 2.8989 1 0.3108 27 3.2u98 i 0.311” (10“) 3.1791 : 0.3146 31 3.3627 1 0.3147 (100) 3.3131 1 0.3146 *Overlapping of confidence limits at any comparable temperature is taken to indicate no significant differ- ence. 27 Figure 5. Relationship between log ash free dry weight and log dry weight for Anax Junius naiads. ASH FREE DRY WEIGHT (mg) 28 log y = -0.00IO + 0.9767 Iogx n = 54 1111'] I00 [llllll I IIIIIII | 1 1 llLllll 1 11L|1111 L11 I IO IOO DRY WEIGHT (mg) 29 Figure 6.» Change in the per cent ash free dry weight relative to increasing dry weight for Anax Junius naiads. Regression determined from equation given in Figure 5. 3O d uni ‘ fl .1 q —I q d 1 1 1 1 1 1 00 10 ¢ N o 00 10 a} as as as m 00 1H9|3M A80 338:! HSV .LNBOHSd IOO IO (mo) DRY WEIGHT 31 Relationship between log oxygen con— sumption and log ash free dry weight for Anax lunius naiads compared at different temperatures. a: Eon; 32 0.. _O. .00. 4 u add u — u a _ — - — — d u — - oo- 0 en 00. .c - .32 35.0 + momma u x no. H quiwu 93 w4<2 U . n 000. % o o 900 o 0 0 0M 00 o o 0 Away“. SD ow» 0 >00 m H 1 06M 0 d 00m. 00 M o 000 090 o o 1 0800 O o O o o o o o O l 0.. _o. _OO. 4 4 2:31. a _ :Z.. _ _ OO. 0 ON 3. w H 00%00 o ofWoWo e co 0 H11 1%. Manner . a u 0 0M 00 000009/W1va/Q 0 1 000— B% 000 0000 ouoooo M o 0 o / m... c 1 .32 32.0 1 Noah . a no. w1_<_2wu_ nco MAS). 11111 >mo mum“. Imd 9. .o. .oo. _ _ :_.~__ _ :__«__ _ _ 09 0 NN l 8 u % o M o o o H o o 1 COO— SMO 0..) 00a 0% OOOOOWO 00 0 do 0 LE 0 O \r 4‘ 8 O 0 O % o 0 0 0 m 1 0%0 o o u g . vo. . c .33 good 1 memun u > oo. 1 m4<2mm uco M1322 H O_. _O. — _ -—« a d d A — a 00— on. I; o H 000. 2. u .32 33.0 I 2.36 n x no. m._<_2mn_ uco w._<_2 c 1 111J NOLLlenSNOO NBOAXO (111/1111 hp 0911 1.150 b/lrf) 33 The decreased 002 with increasing dry weight may be explained, in part, by the progressive increase in the percentage of ash material directly related to growth. Influence of Body Weight To ascertain the influence of body weight (dry wt), log 02 consumption was regressed against log dry weight at different temperatures (Figure 8) and tested by the hypotheses: Log oxygen consumption was related to log dry weight by coefficients of regression of 0.69, 0.79, 0.95, and 0.96 at l3, 20, 27, and 3“ C, respectively (Figure 8). The null hypothesis (Ho:b=l) was rejected at 13 and 20 C but accepted at 27 and 3“ C (Table 5) indicating that log oxygen consumption significantly decreased with increasing log dry weight at 13 and 20 C but not at 27 and 39 C. Figure 9 shows log oxygen consumption calculated on a per unit weight basis. These data indicate that oxygen consumption is significantly influenced by body weight at 13 and 20 C but not at 27 and 3A C. 3“ Figure 8. Relationship between log oxygen con— sumption and log dry weight for Anax junius naiads compared at different temperatures. 35 oo. 3.... 59...; oo. 1 c .32 8.3.0 + otnd . a of o. J 1 11111 00. 5%. H.442“: uco MES: H oo_ o. _ q ———..:j _ —:__u_ a q _ oo~ 1 M ”.o. .. u 00 m H . uoo. 3mm.w\ow% m: .. c - .32 32.0 + _o_n.o . x no. m4<2mu uco w4<2 111111 >mo oo— q q - -—qud- d u u-qqddq - d — ohm . 1 m u o_ L n oo. 0... . co. 1 c - 2.0.3 .32 63.0 + 93.6 1 a o... M . minim... 2:. ”.352 u o_ o. L 1 U .1. 1 oo. ms... .32 300.0 + Ecmd . a mo. w4<2mm uco M125. NOIldWflSNOO N39AXO (Ionpwpuvm/Irf) 36 .Aomflaqu pmmp omHfiMp ozpv mo.o n mocmoflwflcwflm mo H6>6H ompmmoo 000 0 0 o 0.6“ o a“ 0 G q 00 1 D0“ 0 o o o 00 0%0 O o 1. o_. _o. _oo. 0 d u —__‘__d _ ___._q__ _ OO— 6 06 u 89 6:1 c 1 .32 38.0 1 Sow.“ . a 32 1 “342m“. 6:6 m1_<.2 n 00. 000. 00. 0.. _0. .00. m — q—-—- q a. - _ j-_-—4 — u d 0 hm a .. H 16 o o 0 o n $0 0 OOOOOWO My 0 “0% We 0 006000 0000 0 0 80d 0 Q 1.: 6°C 1 “$0 0 000 o 0 a 1 n8 o o . 3.1.. 1 .36. 6660.6 I 3.66.... 1 3 36. 1 m4<2wm can M122 u 0.. .0. _ _ —__d—_ _ d a .36. mommd I mm_N.n m3": x00. mgdimm uco win—2 1111 000. NOLLdWOSNOO NBSAXO (IN/1M Mp 5/110 39 ,Influence of Temperature The effect of temperature on 002 is demonstrated in a temperature-respiration curve (T—R curve), (Figure 10), and expressed quantitatively, relative to dry body weight, utilizing van't Hoff's (188M) Q10 approximation (Figure 11). Q10 is the increase in reaction velocity caused by a 10 C rise in temperature. The value is calculated with data obtained over any temperature range from the general formula: 10(log kl - 10g k2) 1 2 where kl and R2 are the velocities at tl ant t2, re— spectively (Hoar, 1966). The Q10 approximation in thermobiological reactions is about two (Prosser and Brown, 1961). Yet, for meaning- ful comparisons of the effects of temperature on the rates of various biological processes, the rates of reaction must be compared for the same temperature interval (Giese, 1961). At all comparable temperature intervals the 010 of .2- junius increased directly with body weight (Figure ll). However, Q10 variance, in relation to increasing dry weight, was less at the higher temperature intervals (Figure 11; D and E). Between 27—3H C the Q10 change Figure 10. 40 Semi—log T—R curve for male (broken line) and female (solid line) Anax Junius naiads. Each point represents the mean 002 based on Figure A regressions. All values were corrected to 100 mg dry wt. £11 FEMALE ‘34 2.2.3 0.. 20_.rn:znmzoo zm0>x0 I00 27 20 TEMPERATURE (C) I3 42 Figure 11. Relationship between Q10 and size (wt) for Anax Junius naiads. Q1. 43 lI-IO C IS-ZTC B I00 200 20-276 C I00 200 20-34 C 27-34C E 4 1— r ""‘ MALE 3 - °—-° FEMALE 2 ‘ --- ..... 1131 | _ °—-° FEMALE 1 1 l 1 4 o 1 l 1 l l L 100 200 300 0 I00 200 300 DRY WEIGHT (mg) AM was nearly independent of weight. In general, 0 values 10 decreased inversely with temperature. Although male and female A. Junius naiads responded to temperature change by showing generally parallel in- creases in Q10 values, a certain difference was noted. Based on Figure ll, males showed less increase in meta- bolic rate at low temperature intervals (l3-20 and l3—27 C) than females, but a significant increase at the higher temperature intervals. Influence of Life Stage An attempt was made to delimit individual instars by regressing head capsule width, total body length, meso- wing sheath length, labium length, labium width, and oven dry body weight in different combinations. The meso-wing sheath length regressed against oven dry body weight ap— peared to give the best possible instar separation, but was still too variable to be of definitive value. Conse- quently instars were not deemed definable. However, based on th studies of Calvert (l93U) and Macklin (196A) it was apparent that the dragonfly naiads utilized as test organisms in the present study were in their sixth through fourteenth (terminal) instars. It seems that instars are definable, with certainty, only if reared from egg to adult. Naiads nearing the terminal instar showed a decrease in oxygen consumption at 13 and 20 C, but 45 appeared to maintain a relatively constant rate at 27 and 34 C (Table 6). Adult respiration (Table 7) at 30 C was about three times greater when compared to naiads of similar weight and at comparable temperatures (27 and 31 C). A6 .606560 u m mm0mE n z * wmm.m omm.m mmm.m mwm.m 6mm.m mum.m mmm.m mmm mm0.m 0m0.m mm0.m 6m0.m m00.m m©0.m m60.m 060 om6.m Hom.m OHm.m omm.m omm.m oom.m mom.m mam oam.m mm:.m mmm.m wam.m mmm.m mpm.m How.m mam .6 066.6 660.0 666.0 666.6 .00 .m :wH.m wma.m mom.m mmm.m mm .m omm.m mmm.m wHH.m mmH.m om .m mm6.m 6m6.m 6mm.m omm.m m0 .0 z .0 z 1.0 2 .6 z .0 z .6 *2 08 0.03 6m:.m mmm.m 630.6 666.0 666.0 666..0 16666w6e Amev u£w063 mum mod .Apgxpz 000 m\010 600 6 .0 c mSHCSm x60< mo co0meSmcoo Q6m00o wo0 600 Co 60606 6000 mo 66:63002011.w m0m