Geographic variation in the critical thermal minimum of the green anole, Anolis carolinensis (sauria:Iguanidae), along a latitudinal gradient

Abstract

1. 1. Critical thermal minimum (CTMin) tests were conducted on adult male green anoles ( Anolis carolinensis) collected in central Florida, southern Georgia and eastern Tennessee. 2. 2. CTMin was determined on the afternoon of capture to obtain a temperature range from which a laboratory acclimation temperature could be extracted. After being held in the laboratory at 25 ± 2°C for 14–18 days, lizards were cold-acclimated to 9°C for 48 hr prior to CTMin retesting. 3. 3. The Tennessee population was significantly more cold resistant than the Florida and Georgia populations, suggesting a genetic basis for the variation noted.