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Being Efficient Despite Adversity. How Do Lizards Do It?
Volume 16, Number 41: 9 October 2013

First of all, Valdecantos et al. (2013) note that "temperature has a great impact on ectotherms, affecting physiological, behavioral and life history traits such as reproductive timing (Zug et al., 2001; Labra and Bozinovic, 2002), reproductive mode (Shine, 2004), growth rate, survivorship (Huey, 1982), locomotion (Hertz et al., 1983; Angilleta et al., 2002) and diet (Espinoza et al., 2004)." And they state, in this regard, that late 20th-century global warming "has been suggested as a potential threat for lizards at a global scale," citing Sinervo et al. (2010).

Not willing to give earth's lizards up to this potential threat so readily, the four Argentine researchers studied four related species - Liolaemus irregularis, L. albiceps, L. multicolor, and L. yanalcu - that inhabit high-elevation desert areas in Northwestern Argentina, Northern Chile and Southwestern Bolivia, working both in the laboratory and at four sites near San Antonio de los Cobres in Salta, Argentina, where they measured body temperatures (Tb), air temperatures (Ta), soil temperatures (Ts), operative temperatures in the field (Te) and preferred body temperatures (Tpref) for all four species. And what did they find?

Valdecantos et al. report that all four species, "despite living at high elevation and harsh climatic conditions," were able to "behaviorally or physiologically thermo-regulate to achieve body temperatures close to their preferred temperatures." And in discussing this finding further, they conclude, "as proposed by Labra et al. (2009)," that "many species are conservative in some aspects (e.g. Tpref), yet labile in others (e.g. Tb), thus "allowing them to inhabit a wide range of environments," even those that would appear to be outside their range of habitability.

Sherwood, Keith and Craig Idso

Angilleta Jr., M.J., Niewiarowski, P.H. and Navas, C.A. 2002. The evolutions of thermal physiology in ectotherms. Journal of Thermal Biology 27: 249-268.

Espinoza, R.R., Wiens, J.J. and Tracy, C.R. 2004. Recurrent evolution of herbivory in small, cold-climate lizards: breaking the ecophysiological rules of reptilian herbivory. Proceedings of the National Academy of Sciences USA 101: 16,819-16,824.

Hertz, P.E., Huey, R. and Nevo, E. 1983. Homage to Santa Rita: thermal sensitivity of sprint speed in agamid lizards. Evolution 37: 1075-1084.

Huey, R.B. 1982. Temperature, physiology, and the ecology of the reptiles In: Gans, C. (Ed.), Biology of the Reptilia, Vol. 12. Wiley, New York, New York, USA, pp. 25-91.

Labra, A. and Bozinovic, F. 2002. Interplay between pregnancy and physiological thermoregulation in Liolaemus lizards. Ecoscience 9: 421-426.

Labra, A., Pienar, J. and Hansen, T.F. 2009. Evolution of thermal physiology in Liolaemus lizards: adaptation, phylogenetic inertia, and niche tracking. American Naturalist 174: 204-220.

Shine, R. 2004. Does viviparity evolve in cold climate reptiles because pregnant females maintain stable (not high) body temperature? Evolution 58: 1809-1818.

Sinervo, B., Mendez-de-la-Cruz, F., Miles, D.B., Heulin, B., Bastiaans, E., Villagran-Santa Cruz, M., Lara-Resendiz, R., Martinez-Mendez, N., Calderon-Espinosa, M.L., Meza-Lazaro, R.N., Gadsden, H., Avila, L.J., Morando, M., De la Riva, I.J., Sepulveda, P.V., Rocha, C.F.D., Ibarguengoytia, N., Puntriano, C.A., Massot, M., Lepetz, V., Oksanen, T.A., Chapple, D.G., Bauer, A.M., Branch, W.R., Clobert, J. and Sites, J.W. 2010. Erosion of lizard diversity by climate change and altered thermal niches. Science 328: 894-899.

Valdecantos, S., Martinez, V., Lobo, F. and Cruz, F.B. 2013. Thermal biology of Liolaemus lizards from the high Andes: Being efficient despite adversity. Journal of Thermal Biology 38: 126-134.

Zug, G.R., Vitt, L.J. and Caldwell, J.P. 2001. Herpetology. An Introductory Biology of Amphibians and Reptiles. Second Edition. Academic Press, San Diego, California, USA. 630 pp.