Meeting Abstract
Plestiodon skiltonianus and Plestiodon gilberti are two closely related skink species located in Western North and Central America. P. gilberti is thought to have evolved a larger body size from P. skiltonianus to deal with heat flux across the skin as it moved into warmer and more water restricting habitats. P. skiltonianus is usually found in cooler and higher elevation habitats while P. gilberti can be found in warmer and lower-elevation habitats. Both species can be found in areas of sympatry, however these areas are patchy and intermixed between areas of allopatry. This experiment was done to test inter/intraspecific physiological differences in sympatric and allopatric populations of both species. It was hypothesized that there would be significant physiological differences between all populations tested. To test physiological differences, burst sprint speed, critical maximum and minimum temperatures, and preferred temperature was taken. Respirometry (oxygen consumption rates, carbon dioxide production rates, and evaporative water loss rates) was performed at a range of temperatures both species experience in the field. Preliminary analyses show interspecific differences in optimal temperature, preferred temperature, and critical maximum and minimum temperatures, and evaporative water loss rates. These results suggest that moving into a more-xeric habitat resulted in a physiological shift along in P. gilberti with the increase in body size. Also, each species retains a physiological plasticity when sympatric and allopatric populations of the same species are compared.
