Population Biology of Environmental Gender-Determination in Chrysemys picta

9629529 Janzen大多数动物的性别是由染色体决定的。 在几组脊椎动物中，性别是由胚胎发育期间经历的温度决定的。 本计画将探讨龟鳖自然族群中温度依赖性性别决定的生物学。 它将考虑如何蛋的大小，巢址选择，捕食影响后代的生存和性别比例。 将每年对筑巢的雌性进行随访，以研究巢址的一致性。 这个项目将有助于解释为什么有些动物的性别是由温度而不是染色体决定的。 这扩展了对自然种群中影响生育率和性别比例的因素的理解。 这个项目将展示栖息地利用和捕食者如何影响TSD动物的种群动态。 许多这样的物种濒临灭绝，这些信息可以帮助他们的保护。

9629529 Janzen For most animals gender is determined by the chromosomes. In several groups of vertebrate animals gender is determined by the temperature experienced during embryonic development. This project will investigate the biology of temperature-dependent sex determination (TSD) in a natural population of the turtle Chrysemys picta. It will consider how egg size, nest-site selection, and predation affect offspring survival and sex ratio. Nesting females will be followed from year to year to study nest-site consistency. This project will help explain why some groups of animals have their gender determined by temperature rather than by chromosomes. This extends understanding of what affects fertility and sex ratio in natural populations. This project will show how habitat use and predators affect population dynamics in animals with TSD. Many such species are endangered and this information can help their conservation.