Meeting Abstract
Some ectotherms have evolved remarkable adaptations for survival at cold temperatures, and cold-hardiness influences the distribution of many ectotherms at high latitudes. Hatchlings of some temperate aquatic turtles have been well-studied ecophysiological models for vertebrate cold tolerance because of their interesting subterranean overwintering behavior. After hatching from eggs, many temperate hatchlings remain in the terrestrial nest over winter, emerging the following spring. These turtles employ multiple strategies (supercooling and freeze tolerance) to survive subzero temperatures. Despite these remarkable adaptations, many hatchlings perish due to harsh abiotic conditions during winter. While the physiology of cold tolerance has been the focus of much research, important ecological considerations remain understudied. Here we present results from parallel multi-year observational studies of two painted turtle (Chrysemys picta) populations located in Nebraska and Illinois. We examine the intersection of maternal nest-site choice and abiotic conditions (snow cover, ambient temperature, etc.) on temperatures within painted turtle nests during winter, and the relationship between winter nest temperatures and sex-specific offspring mortality in those nests. Preliminary results suggest maternal nest-site choice has little influence on winter nest temperatures, whereas ambient temperature and snow cover are essential for predicting nest thermal environments and pre-emergence hatchling mortality. These findings suggest that estimates of mortality can be obtained during this life stage from weather data.
