DO LOW INCUBATION TEMPERATURES YIELD FEMALES IN PAINTED TURTLES

The sex of painted turtles (Chrysemys picta) is determined by the incubation temperature of the egg. At high temperatures (> 30-degrees-C), all females are produced, with a transition to all males at most lower temperatures (24-27-degrees-C). However, two of three previous studies have reported that some females also result when incubation temperatures are low (20-22-degrees-C). In this study C. picta eggs were incubated at low temperatures (21.5 and 22.5-degrees-C); however, macroscopic and histological examination of both embryos and hatchlings did not confirm these reports. Thus, C. picta has, at least typically, the pattern of sex determination that is most common among the genera to which it is most closely allied.