Geographic Variation in Timekeeping Systems among Three Populations of Garter Snakes (Thamnophis sirtalis) in a Common Garden
Abstract Transduction of environmental cues into endocrine signals that synchronize physiology and behavior with optimal environmental conditions is central to an animal’s timekeeping system. Using a common garden approach, we investigated possible geographic variation in timekeeping systems by comp...
| Veröffentlicht in: | Physiological and Biochemical Zoology: Ecological and Evolutionary Approaches. - University of Chicago Press, 1999. - 81(2008), 6, Seite 810-825 |
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| Format: | Online-Aufsatz |
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2008
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| Zugriff auf das übergeordnete Werk: | Physiological and Biochemical Zoology: Ecological and Evolutionary Approaches |
| Schlagworte: | Biological sciences Behavioral sciences Business Social sciences Health sciences Physical sciences |
| Zusammenfassung: | Abstract Transduction of environmental cues into endocrine signals that synchronize physiology and behavior with optimal environmental conditions is central to an animal’s timekeeping system. Using a common garden approach, we investigated possible geographic variation in timekeeping systems by comparing 24‐h melatonin and corticosterone rhythms and reproductive behavior among three populations of garter snakes with very different life histories: red‐sided garter snakes (Thamnophis sirtalis parietalis) from Manitoba, Canada; red‐spotted garter snakes (Thamnophis sirtalis concinnus) from western Oregon; and eastern garter snakes (Thamnophis sirtalis sirtalis) from southern Florida. Melatonin and corticosterone cycles differed significantly among the three snake populations in a majority of the sampling periods. Population differences were observed across a wide range of acclimatization conditions and were themselves plastic (i.e., one snake population was not consistently different from the others). Changes in courtship behavior during emergence also varied significantly among populations. Our data support the hypothesis that endogenous timekeeping systems have evolved in the presence of unique environmental conditions. Further research is necessary to determine whether this geographic variation results from inherent genetic differences or whether it is a product of development. These studies provide insight into the evolution of timekeeping systems and may aid in understanding the potential effects of environmental perturbations on seasonal physiology and behavior. |
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| Beschreibung: | 1 Corresponding author. Present address: Center for Behavioral Neuroscience, Georgia State University, P.O. Box 3966, Atlanta, Georgia 30302; e‐mail: lutterschmidtgsu.edu . |
| ISSN: | 15375293 |
| DOI: | 10.1086/589900 |