Thermal profiles and performance curves of two Agamid lizards at different elevations in Taiwan

Background/Question/Methods Several recent reviews have indicated that thermal environment changes, such as warming, may have irreversible impacts on heliothermic species. Particularly, the potential of adaptation by a lizard species to different thermal environments has been debated. In this study, we test if lizard species maintain similar thermal characteristics in different thermal environments by comparing the thermal profiles and thermal performance curves between two populations of Japalura swinhonis from lowland and mid-altitude. We measured lizard sprint speed at 6 temperatures to calculate performance breadth (B₈₀) and thermal optimum (T_o). We also measured thermal tolerance limits (CT_max, CT_min), preferred temperature (T_set) and field body temperature (T_b). 

Results/Conclusions The results showed that B₈₀ of mid-altitude population is significant wider than that of lowland population; B₈₀ of female is significant wider than that of male. T_o, T_b and CT_max of mid-altitude population are significant lower than lowland ones. Thermal tolerance range of male is significant wider than that of female. There is no significant difference in T_set between altitudes or sexes. Overall, our results reveal that J. swinhonis exhibits different thermal characteristics in different altitudes, and support the labile view regarding the evolution of thermal physiology in lizards. The specifics of our findings will contribute to the understanding of the impacts of thermal environment changes on heliothermic species.