Head-Body Temperature Differences in Free-Ranging Rubber Boas

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92 M. E. DORCAS AND C. R. PETERSON capture, and escape from predators. Given the physical characteristics of snakes and the tractability of many species for conducting both laboratory and field investigations, it is clear that studies of snakes can play an important role in developing a deeper understanding of the causes and consequences of regional temperature differences in reptiles. Acknowledgments.-We thank Jim Strawn and Patty Strawn for allowing us to conduct much of this research on their property and for directly assisting us with many logistic details. Michael McDonald assisted with making temperature measurements of some snakes. Mark Gerber allowed us to use his data on three snakes measured while he was road cruising. We thank J. Whitfield Gibbons, Justin D. Congdon, John R. Lee, Jane K. Distler, Julian C. Lee, and two anonymous reviewers for providing useful comments on the manuscript. This research was supported by awards from Sigma Xi, the American Museum (Theodore Roosevelt Memorial Fund), the Gaige Award of the American Society of Ichthyologists and Herpetologists, the Northwest Science Association, the Chicago Herpetological Society, the Graduate School and the Department of Biological Sciences at Idaho State University, and a National Science Foundation Doctoral Dissertation Grant IBN-9224230 to M. E. Dorcas (C. R. Peterson, sponsor). Data analysis and manuscript preparation were supported by Contract DE-AC09- 76SR00819 between the U.S. Department of Energy and the University of Georgia's Savannah River Ecology Laboratory. LITERATURE CITED BAKKEN, G. S. 1992. Measurement and application of operative and standard operative temperatures in ecology. Amer. Zool. 32:194-216. BERK, M. L., AND J. E. HEATH. 1975. Effects of preoptic, hypothalamic, and telencephalic lesions on thermoregulation in the lizard, Dipsosaurus dorsa- lis. J. Thermal Biol. 1:65-78. BLOCK, B. A., AND F G. CAREY. 1985. Warm brain and eye temperatures in sharks. J. Comp. Physiol. B 156:229-236. CAMPBELL, H. W. 1969. The effects of temperature on the auditory sensitivity of lizards. Physiol. Zool. 42:183-210. COBB, V. A. 1994. The thermal ecology of pregnancy in Great Basin Rattlesnakes (Crotalus viridis lutosus). Unpubl. Ph.D. Thesis. Idaho State Univ., Pocatello. CRAWFORD, E. C. JR., J. PALOMEQUE, AND B. J. BARBER. 1977. A physiological basis for head-body temperature differences in a panting lizard. DORCAS, M. E. 1995. Testing the coadaptation hypothesis: the thermoregulatory behavior and thermal physiology of the rubber boa (Charina bottae). Unpubl. Comp. Biochem. Physiol. 56A:161-163. DILL, C. D. 1972. Reptilian core temperatures: variation within individuals. Copeia 1972:577-579. Ph.D. Thesis, Idaho State Univ., Pocatello. FITCH, H. S. 1960. Autecology of the copperhead. Univ. Kansas Pub. Mus. Nat. Hist. 13:85-288. GRAVES, B. M., AND D. DUVALL. 1993. Reproduction, rookery use, and thermoregulation in free-ranging, pregnant Crotalus viridis viridis. J. Herpetol. 27:33- 41. GREGORY, P. T. 1990. Temperature differences between head and body in garter snakes (Thamnophis) at a den in central British Columbia. J. Herpetol. 24:241-245. HAMMERSON, G. A. 1977. Head-body temperature differences monitored by telemetry in the snake Masticophis flagellum piceus. Comp. Biochem. Physiol. 57:399-402. . 1979. Thermal ecology of the striped racer, Masticophis lateralis. Herpetologica 35:267-273. . 1987. Thermal behavior of the snake Coluber constrictor in west-central California. J. Therm. Biol. 12:195-197. . 1989. Effects of weather and feeding on body temperature and activity in the snake Masticophis flagellum. J. Therm. Biol. 14:219-224. HEATH, J. E. 1964. Head-body temperature differences in horned lizards. Physiol. Zool. 37:273-279. . 1966. Venous shunts in the cephalic sinuses of horned lizards. Physiol. Zool. 39:30-35. HUEY, R. B. 1982. Temperature, physiology, and the ecology of reptiles. In C. Gans and E H. Pough (eds.), Biology of the Reptilia. Vol. 12, pp. 25-91 Academic Press, New York. JOHNSON, C. R. 1973. Thermoregulation in pythons- II. Head-body temperature differences and thermal preferenda in Australian pythons. Comp. Biochem. Physiol. 45A:1065-1087. . 1975a. Head-body temperature thermal control, thermal preferenda, and voluntary maxima in the taipan, Oxyuranus scutellatus (Serpentes: Elapidae). Zool. J. Linn. Soc. London 56:1-12. 1975b. Thermoregulation in the Papuan-New Guinean boid and colubrid snakes, Candoia carinata, Candoia aspera and Boiga irregulatis. Zool. J. Linn. Soc. London 56:283-290. KLAUBER, L. M. 1972. Rattlesnakes: Their Habits, Life Histories, and Influence on Mankind. Vol. 1. University of California Press, Berkeley. LILLYWHITE, H. B. 1987. Temperature, energetics, and physiological ecology. In R. A. Seigel, J. T. Collins, and S. S. Novak (eds.), Snakes: Ecology and Evolutionary Biology, pp. 422-477. MacMillan, New York. PETERSON, C. R. 1982. Body temperature variation in free-living garter snakes (Thamnophis elegans va- grans). Unpubl. Ph.D. Thesis. Washington State Univ., Pullman. . 1987. Daily variation in the body temperatures of free-ranging garter snakes. Ecology 68:160-169. , AND M. E. DORCAS. 1992. The use of automated data acquisition techniques in monitoring amphibian and reptile populations. In D. R. McCullough and R. H. Barrett, (eds.), Wildlife 2001: Populations, pp. 369-378. Elsevier Applied Science, London.
HEAD AND BODY TEMPERATURES OF RUBBER BOAS ,A. R. GIBSON, AND M. E. DORCAS. 1993. Snake thermal ecology: the causes and consequences of body temperature variation. In R. A. Seigel and J. T. Collins, (eds.), Snakes: Ecology and Behavior, pp. 241-314. McGraw-Hill, New York. POUGH, F H., AND C. GANS. 1982. The vocabulary of reptilian thermoregulation. In C. Gans and F. H. Pough (eds.), Biology of the Reptilia. Vol. 12, pp. 17-23 Academic Press, New York. POUGH, F. H., AND W. N. MCFARLAND. 1976. A physical basis for head-body temperature differences in reptiles. Comp. Biochem. Physiol. 53A:301-303. REGAL, P. J. 1966. Thermophilic responses following feeding in certain reptiles. Copeia 1966:588-590. ,A. R. GIBSON, AND M. E. DORCAS. 1993. Snake thermal ecology: the causes and consequences of body temperature SPRAY, D. C., AND D. B. BELKIN. 1973. Thermal patterns in the heating and cooling of Iguana iguana variation. In R. A. Seigel and J. T. Collins, (eds.), Snakes: Ecology and Behavior, pp. 241-314. McGraw-Hill, New York. POUGH, F H., AND C. GANS. 1982. The vocabulary of reptilian thermoregulation. In C. Gans and F. H. Pough (eds.), Biology of the Reptilia. Vol. 12, pp. 17-23 Academic Press, New York. POUGH, F. H., AND W. N. MCFARLAND. 1976. A physical basis for head-body temperature differences in reptiles. Comp. Biochem. Physiol. 53A:301-303. REGAL, P. J. 1966. Thermophilic responses following feeding in certain reptiles. Copeia 1966:588-590. SPRAY, D. C., AND D. B. BELKIN. 1973. Thermal patterns in the heating and cooling of Iguana iguana Journal of Herpetology, Vol. 31, 31, No. 1, 1, pp. 93-98, 93-98, 1997 Copyright 1997 Society for the Study of Amphibians and Reptiles Postmetamorphic Development of Supernumerary Thyroid Glands in Pleurodeles waltl STEFANO GOZZO,1'4 ALESSANDRA TAGLIONI,' RITA CASET- TI,1 CLAUDIO BAGNOLI,2 AND VINCENZO MONACO,3 'IS- tituto di Medicina Sperimentale, Consiglio Nazionale delle Ricerche (CNR), 2Laboratorio di Parassitologia, Istituto Superiore di Sanita, and 3Dipartimento Ambiente, ENEA, Rome, Italy. During a study of histological material obtained from Pleurodeles waltl, our group observed an unexpected subdivision of thyroid tissue into more masses than has generally been reported for other species of amphibians (Gorbman, 1959; Gorbman and Bern, 1962; Gorbman, 1964; Norris, 1985a). In the present study, a description of these supernumerary thyroid aggregations of Pleurodeles waltl in various developmental stages is given. Moreover, the histological reaction of these structures to thiourea, a substance inhibiting thyroid hormones, was investigated to verify their reciprocal biochemical affinity in postmetamorphic animals. All the animals used in this study were collected from a breeding stock of Pleurodeles waltl maintained at the ENEA-Casaccia Center in Rome. The artificial breeding of this species began with the importation into Italy of 20 specimens from a locality near Granada in Spain in 1985. The larval stages were reared in an outdoor artificial pond (8 x 6 x 1 m). They were extensively exposed to sunlight and fed on Hyla tadpoles, insects, worms, daphnia, and other crustaceans. After metamorphosis, four During groups of five animals each were a study of histological material obtained from Pleurodeles waltl, our group observed an unexpected subdivision of thyroid tissue into more masses than has generally been reported for other species of amphibians (Gorbman, 1959; Gorbman and Bern, 1962; Gorbman, 1964; Norris, 1985a). In the present study, a description of these supernumerary thyroid aggregations of Pleurodeles waltl in various developmental stages is given. Moreover, the histological reaction of these structures to thiourea, a substance inhibiting thyroid hormones, was investigated to verify their reciprocal biochemical affinity in postmetamorphic animals. All the animals used in this study were collected from a breeding stock of Pleurodeles waltl maintained at the ENEA-Casaccia Center in Rome. The artificial breeding of this species began with the importation into Italy of 20 specimens from a locality near Granada in Spain in 1985. The larval stages were reared in an outdoor artificial pond (8 x 6 x 1 m). They were extensively exposed to sunlight and fed on Hyla tadpoles, insects, worms, daphnia, and other crustaceans. After metamorphosis, four groups of five animals each were 4 Present Address: Istituto di Medicina Sperimentale, CNR c/o AMB-PRO-TOSS, ENEA Casaccia, S. P. Anguillarese km 4 Present Address: Istituto di Medicina Sperimentale, CNR c/o AMB-PRO-TOSS, ENEA Casaccia, S. P. Anguillarese 1.3, 00060, Rome, Italy. km 1.3, 00060, Rome, Italy. and Ctenosaura hemilopha. Comp. Biochem. Physiol. 44A:881-892. VINCENT, T. 1975. Body temperatures of Thamnophis sirtalis parietalis at the den site. J. Herpetol. 9:252- and Ctenosaura hemilopha. Comp. Biochem. Physiol. 44A:881-892. VINCENT, T. 1975. Body temperatures of Thamnophis sirtalis parietalis at the den site. J. Herpetol. 254. WEBB, G. J. W., AND H. HEATWOLE. 1971. Patterns of heat distribution within the bodies of some Australian pythons. Copeia 1971:209-220. C. R. JOHNSON, AND B. T. FIRTH. 1972. Headbody temperature differences in lizards. Physiol. Zool. 45:130-142. WILKINSON, L. 1990. SYSTAT: the system for statistics. Systat, Inc., Evanston, Illinois. 9:252- 254. WEBB, G. J. W., AND H. HEATWOLE. 1971. Patterns of heat distribution within the bodies of some Australian pythons. Copeia 1971:209-220. C. R. JOHNSON, AND B. T. FIRTH. 1972. Headbody temperature differences in lizards. Physiol. Zool. 45:130-142. WILKINSON, L. 1990. SYSTAT: the system for statistics. Systat, Inc., Evanston, Illinois. Accepted: 30 October 1996. SHORTER COMMUNICATIONS 93 placed in separate aquaria (40 x 30 x 20 cm) containing 10 L of water, renewed weekly, and through which air bubbled. Two of the aquaria contained 0.16% of thiourea, also renewed weekly; the remaining aquaria were used for the controls. The animals were fed ad libitum on strips of beef twice weekly. After one year, these animals were killed and subjected to histological analysis. Ten newly hatched larvae, ten larvae aged 30 d, five specimens at metamorphic climax, ten control postmetamorphic specimens, and ten thiourea-exposed postmetamorphic specimens were used for histological studies. All the animals were anaesthetized in a humid, ether-saturated box and fixed for ten days in Dubosq-Brazil containing 37% formalin (Beccari and Mazzi, 1972). Body weight, total body length, snoutvent length, and the widest head size were measured after fixation. The anterior regions of the body were then removed, washed for two hours in tap water, and decalcified for two days in a solution composed of 85 parts distilled H20, 10 parts 37% formalin, and 5 parts formic acid. After decalcification, the pieces were again washed for six hours in running tap water and the picric acid was removed using a solution of 80% alcohol and 10% ammonium acetate. The samples were then dehydrated in alcohol, embedded in a mixture of 80% paraffin, 16% stearic acid, and 4% white beeswax, and sliced orthogonally to the animal's longitudinal axis into 15 ,um serial sections. All serial sections were stained with hematoxylin-eosin. The control group and the thiourea-exposed animals, one year after the metamorphosis, were compared in order to identify differences due to the treatment between body weight, total body length, snoutvent length, and widest head size. Data were subjected to one-way analysis of variance (ANOVA) to determine significant differences between group values. A differentiation of thyroid tissue into follicles was not observed in the newly-hatched larvae of Pleurodeles waltl. At the age of 30 d the larvae revealed two large pyriform thyroid organs located in the lower jaw, to the left and the right of the central musculature. They displayed wide follicles mostly containing col- placed loid with vacuoles, and a high density of red blood cells was observed within the interfollicular spaces. in separate aquaria (40 x 30 x 20 cm) containing 10 L of water, renewed weekly, and through which air bubbled. Two of the aquaria contained 0.16% of thiourea, also renewed weekly; the remaining aquaria were used for the controls. The animals were fed ad libitum on strips of beef twice weekly. After one year, these animals were killed and subjected to histological analysis. Ten newly hatched larvae, ten larvae aged 30 d, five specimens at metamorphic climax, ten control postmetamorphic specimens, and ten thiourea-exposed postmetamorphic specimens were used for histological studies. All the animals were anaesthetized in a humid, ether-saturated box and fixed for ten days in Dubosq-Brazil containing 37% formalin (Beccari and Mazzi, 1972). Body weight, total body length, snoutvent length, and the widest head size were measured after fixation. The anterior regions of the body were then removed, washed for two hours in tap water, and decalcified for two days in a solution composed of 85 parts distilled H20, 10 parts 37% formalin, and 5 parts formic acid. After decalcification, the pieces were again washed for six hours in running tap water and the picric acid was removed using a solution of 80% alcohol and 10% ammonium acetate. The samples were then dehydrated in alcohol, embedded in a mixture of 80% paraffin, 16% stearic acid, and 4% white beeswax, and sliced orthogonally to the animal's longitudinal axis into 15 ,um serial sections. All serial sections were stained with hematoxylin-eosin. The control group and the thiourea-exposed animals, one year after the metamorphosis, were compared in order to identify differences due to the treatment between body weight, total body length, snoutvent length, and widest head size. Data were subjected to one-way analysis of variance (ANOVA) to determine significant differences between group values. A differentiation of thyroid tissue into follicles was not observed in the newly-hatched larvae of Pleurodeles waltl. At the age of 30 d the larvae revealed two large pyriform thyroid organs located in the lower jaw, to the left and the right of the central musculature. They displayed wide follicles mostly containing col- loid with vacuoles, and a high density of red blood cells was observed within the interfollicular spaces.
Page 1 and 2: 00530 (paratype of A. komaii); Chia
Page 3 and 4: HEAD AND BODY TEMPERATURES OF RUBBE
Page 5: HEAD AND BODY TEMPERATURES OF RUBBE

Head-Body Temperature Differences in Free-Ranging Rubber Boas

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