DIFFERENTIAL GROWTH OF MALE AND FEMALE URINOGENITAL SYSTEMS OF CARETTA-CARETTA, WITHIN THE SEX-DETERMINING PERIOD

The sex of loggerhead turtle embryos is determined by incubation temperature. We are interested in identifying temperature-dependent events during the development of the urinogenital system to more clearly define the "window" where sex is determined. Consequently, we have closely monitored the stages of whole embryo development in conjunction with the development of the urinogenital system. While an increase in constant incubation temperature shortens the length of the incubation period for Caretta caretta, the wet weight of whole embryos (set at the male- (26-degrees), pivotal- (28-degrees-C), and female- (32-degrees-C) determining temperatures) is very similar at each developmental stage. However, different growth patterns for the male and female urinogenital systems are found during the sex-determining period (stages 22-27) of embryogenesis. Thus, within this critical period, incubation temperature has a particular influence on the growth of urinogenital tissue.