Upper Thermal Limits and Thermal Preferenda for Three Sympatric Species of Anolis

Abstract

Three species of south Florida anoles, Anolis carolinensis, A. distichus, and A. sagrei, can be grouped on a phylogenetic basis with carolinensis and distichus in one group and sagrei in another. They can also be grouped ecologically with carolinensis and sagrei in a group and distichus in the other. Mean preferred temperatures were determined for all 3 species. A. sagrei (33.3 C) and carolinensis (34.0 C) were found to be similar, and both were significantly different from distichus (31.0 C). Critical thermal maxima were determined for all three species. As with mean preferred temperatures, distichus was significantly different from sagrei and caro- linensis, while the latter two were not significantly different from each other. Both thermal char- acteristics are influenced more by ecology than by phylogeny. CTM shifted with a 10 C shift in temperature of previous acclimation. With animals acclimated at 20 C and 30 C, the shifts were from 38.6 C to 40.6 C for distichus, from 40.8 C to 41.9 C for carolinensis, and from 40.5 C to 41.9 C for sagrei. CTM is a better thermal character than MPT for interspecific comparisons, be- cause of the lack of behavioral modification and the known effect of acclimation.