INCUBATION-TEMPERATURE AFFECTS THE BEHAVIOR OF ADULT LEOPARD GECKOS (EUBLEPHARIS-MACULARIUS)

The leopard gecko has temperature-dependent sex determination (TSD); f emales are predominantly produced when incubated at 26 degrees C (100% ), 30 degrees C (70%), and 34 degrees C (95%), whereas males are predo minantly produced at 32.5 degrees C (75%). Exogenous estradiol can ove rride the effect of temperature on sex determination. To compare tempe rature-determined females with hormone-determined females, eggs from t he male-biased temperature were treated with estradiol benzoate during incubation. As adults, animals from a male-biased incubation temperat ure were more likely to exhibit aggression than animals from female-bi ased incubation temperatures. Furthermore, females from a male-biased incubation temperature tended to be less attractive than females from female-biased temperatures. Hormone-determined females were both attra ctive and aggressive. This suggests that incubation temperature is an important developmental determinant of adult aggressiveness and attrac tiveness. The 26 degrees C animals ovariectomized on the day of hatch exhibited more frequent aggression and were unreceptive to males, indi cating that postnatal ovarian hormones also play a role in adult socio sexual behaviors. The parallel between incubation temperature and intr auterine position in laboratory mammals is discussed.