Meeting Abstract

11.3  Saturday, Jan. 4 10:45  Here be dragons: Thermal ecology and biogeography of alligator lizards TELEMECO, R S*; ADDIS, E A; BRONIKOWSKI, A M; CORDERO, G A; POLICH, R L; Iowa State University; Gonzaga University; Iowa State University; Iowa State University; Iowa State University telemeco@iastate.edu

Important goals of modern biology are to understand how the geographic distributions of species are set. However, there is little consensus as to which organismal traits, life-history stages, or aspects of the environment are most limiting. To begin bridging this knowledge gap, we performed a series of experiments examining the thermal physiology of northern and southern alligator lizards (Elgaria coerulea and E. multicarinata). These lizards are ecologically similar, but E. coerulea exist at higher elevation and latitude (i.e. colder environments) than do E. multicarinata. Even so, previous work suggests that mean temperature does not differentially affect adults of these species. We examined the effects of biologically-relevant extreme temperatures on the stress physiology and mitochondrial functioning of adult lizards, and then the effects of incubation temperature on developing embryos. Cold temperatures elevated corticosterone in E. multicarinata, but not E. coerulea. In addition, mitochondrial respiration rates suggested that E.multicarinata have high aerobic scope at warm temperatures while E. coerulea have high aerobic scope at cold temperatures. Finally, E. multicarinata embryos could not tolerate developmental temperatures as cold as those tolerated by E. coerulea. Our results suggest that the affects of commonly experienced extreme temperatures on each life-history stage are important for setting thermal limits in alligator lizards. Generally, distribution models consider the effects of average temperature on adults only. Such models would not accurately predict the current or future geographic distribution of alligator lizards.