An Intercontinental Analysis of Climate-Driven Body Size Clines in Reptiles: No Support for Patterns, No Signals of Processes
- 643 Downloads
Climatic gradients impose clinal selection on animal ecological and physiological performance, often promoting geographic body size clines. Bergmann’s rule predicts that body size increases with decreasing environmental temperatures given the need to retain body-heat through adjustments of body-mass-to-surface-area ratio. This prediction generally holds for endotherms, but remains controversial for ectotherms. An alternative interpretation, the ‘resource rule’, suggests that food abundance, primary productivity and precipitation (which, unlike temperature, do not necessarily correlate with geography), drive body size clines. We investigate geographic variation in body size within 65 species of lizards and snakes (squamates) based on an intercontinental dataset (6,500+ specimens belonging to 56 Israeli species, and multiple populations of nine Liolaemus species from Argentina and Chile). Bergmann’s rule is only rarely supported by our data (in four species, 6 %), whereas six species (9 %) follow its converse (hence, it is unsupported in 94 % of cases). Similarly, size increases with resource abundance in only 12 species (18 %). Therefore, although neither of the rules is supported, factors suggested by the resource rule are better predictors of body size than temperature. Surprisingly, we show that some measures of the extent of a species’ climatic envelope do not affect the likelihood of it showing a size-climate relationship. We conclude that negative size-temperature associations are an exception rather than a generality among squamates.
KeywordsMacroecology Bergmann’s rule Resource rule Climatic variability Geographic variation in body size Lizards Snakes Liolaemus
We thank Erez Maza for invaluable help resolving the correct geographic origin of species in the TAUM, and Anat Feldman and Stanislav Volynchic for valuable discussion. We are also grateful to referee’s and editor’s comments that greatly improved our manuscript. D.P.-D. thanks the Leverhulme Trust and a University of Lincoln Faculty Starting Funding for financial support. D.P.D. dedicates this paper to Natalia Feltrin, a young Argentinean ecologist, and a good friend, who devoted her career to the study of Liolaemus lizards, and who recently passed away in a road accident. Her life was interrupted on her way to her Ph.D viva. Natalia’s work will be greatly remembered and appreciated.
- Amarello, M., Nowak, E. M., Taylor, E. N., Schuett, G. W., Repp, R. A., Rosen, P. C., et al. (2010). Potential environmental influences on variation in body size and sexual size dimorphism among Arizona populations of the western diamond-backed rattlesnake (Crotalus atrox). Journal of Arid Environments, 74, 1443–1449.CrossRefGoogle Scholar
- Bar, A., & Haimovitch, G. (2011). A field guide to reptiles and amphibians of Israel. Israel: Pazbar.Google Scholar
- Bergmann, C. (1847). Ueber die Verhaltnisse der warmeokonomie der thiere zu ihrer grosse. Gottinger Studien, 3, 595–708.Google Scholar
- Blackburn, T. M., & Gaston, K. J. (2003). Macroecology. Concepts and consequences. Oxford: Blackwell.Google Scholar
- Cei, J. M. (1993). Reptiles del noroeste, nordeste y este de la Argentina. Herpetofauna de las selvas subtropicales, puna y pampas (p. 947). Torino: Museo Regionale di Scienze Naturali di Torino.Google Scholar
- Feldman, A. & Meiri, S. (2013). Length-mass allometry in snakes. Biological Journal of the Linnean Society (In Press).Google Scholar
- Frankenberg, E., & Werner, Y. L. (1992). Egg, clutch and maternal sizes in lizards: Intra- and interspecific relations in near-eastern Agamidae and Lacertidae. Herpetological Journal, 2, 7–18.Google Scholar
- Goldberg, S. R. (2012a). Reproduction in Kotschy’s gecko Mediodactylus kotschyi (Squamata: Gekkonidae) from the Greek Islands and Israel. Herpetological Bulletin, 119, 15–18.Google Scholar
- Iverson, J. B. (1982). Adaptations to herbivory in Iguanine lizards. In G. M. Burghardt, & A. S. Rand (Eds.), Iguanas of the world. Their behaviour, ecology and conservation. New Jersey: Noyes Publications. (pp. 60–76).Google Scholar
- King, G. (1996). Reptiles and herbivory. New York: Chapman and Hall.Google Scholar
- Meiri, S. (2010). Length-weight allometries in lizards. Journal of Zoology, 281, 218–226.Google Scholar
- Meiri, S., Bauer, A. M., Chirio, L., Colli, G. R., Das, I. Doan, T. M., Feldman, A., Castro-Herrera, F., Novosolov, M., Pafilis, P., Pincheira-Donoso, D., Powney, G., Torres-Carvajal, O., Uetz, P., & Van Damme, R. (2013). Are lizards feeling the heat? A tale of ecology and evolution under two temperatures. Global Ecology and Biogeography (In Press). doi: 10.1111/geb.12053.
- Mendelssohn, H. (1963). On the biology of the venomous snakes in Israel, Part I. Israel Journal of Zoology, 12, 143–170.Google Scholar
- Pincheira-Donoso, D., Fox, S. F., Scolaro, J. A., Ibargüengoytía, N., Acosta, J. C., Corbalán, V., et al. (2011). Body size dimensions in lizard ecological and evolutionary research: Exploring the predictive power of mass estimation equations in two Liolaemidae radiations. Herpetological Journal, 21, 35–42.CrossRefGoogle Scholar
- Pincheira-Donoso, D., & Núñez, H. (2005). Las especies chilenas del género Liolaemus. Taxonomía, sistemática y evolución. Publicación Ocasional del Museo Nacional de Historia Natural de Chile, 59, 1–487.Google Scholar
- Pincheira-Donoso, D., Scolaro, J. A., & Sura, P. (2008b). A monographic catalogue on the systematics and phylogeny of the South American iguanian lizard family Liolaemidae (Squamata, Iguania). Zootaxa, 1800, 1–85.Google Scholar
- Tracy, C. R. (1999). Differences in body size among chuckwalla (Sauromalus obesus) populations. Ecology, 80, 259–271.Google Scholar
- Uetz, P. (2012). The Reptile Database. Available at http://www.reptile-database.org. Accessed 31 Mar 2012.
- Webb, T. J., & Gaston, K. J. (2003). On the heritability of geographic range sizes. American Naturalist, 166, 129–135.Google Scholar