Incubation temperature influences sex-steroid levels in juvenile red-eared slider turtles, Trachemys scripta, a species with temperature-dependent sex determination

Incubation temperature determines gonadal sex in the red-eared slider turtle, Trachemys scripta. However, little is known about the long-term effects of incubation temperature on traits other than gonadal sex in this species. To investigate the hy-pothesis that incubation temperature (independent of gonadal sex) influences sex steroid levels after hatching, we incubated eggs of the red-eared slider turtle at three temperatures (26, 28.6, and 318C). We then measured plasma levels of dihydro-testosterone, estradiol, progesterone, and testosterone in 6-wk-old males from 268C and 28.68C eggs, and in 6-wk-old females from 28.68C and 318C eggs. We found that dihydrotestosterone levels were not influenced by incubation temperature or gonad-al sex. However, progesterone levels were significantly higher in males from 268C eggs than in males from 28.68C eggs. In con-trast, testosterone levels did not differ between males from 268C versus males from 28.68C eggs, but they were significantly high-er in females from 28.68C than in females from 318C eggs. Pro-gesterone and testosterone levels did not differ between males and females from 28.68C eggs. Temperature also influenced es-tradiol levels in both sexes, but the effects were enigmatic. We conclude that incubation temperature has lasting effects on sex steroid levels even after hatching