Selected body temperatures of seven species of Chilean Liolaemus lizards

Selected body temperature (Tsel) was determined for seven species of Liolaemus lizards, under laboratory conditions. The objectives were to establish if there are intra- and interspecific differences in Tsel, and if these differences would be correlated with the thermal environments naturally experienced by the lizards. To analyze intraspecific differences in Tsel, I collected individuals of each species from different localities or during different months of the year. Lizards were placed in a thermal gradient without biotic or abiotic factors that would prevent thermoregulation, and their Tsels were recorded. No intraspecific differences were observed in Tsel for six of the seven species studied. However, there were interspecific differences in Tsel, and these were positively correlated with the minimum air temperature recorded during the capture period of lizards. It is not clear if this correlation actually represent an adaptive response because this argument depends on level of analysis. At the intraspecific level, lizards did not appear to exhibit an adaptive response to thermal conditions, whereas at the interspecific level lizards appeared to be responding to thermal factors in their physical environment. Results suggest that different factors are involved in the thermal biology of the species studied, at macro and microevolutionary scales. Further studies in this area may help to understand the evolution of the thermal biology of Liolaemus species.