Meeting Abstract

84.3  Friday, Jan. 7  Decoupling Intrinsic and Behavioral Maternal Effects on Phenotypic Variation in Hatchling Turtles: Insights from a Cross-fostering Experiment in the Field WARNER, D.A.*; MITCHELL, T.S.; JANZEN, F.J.; Iowa State University; Iowa State University; Iowa State University dwarner@iastate.edu

Identifying the relative contributions of genetic, maternal and environmental factors to generating phenotypic variation is critical for evaluating how phenotypic traits may evolve in response to selection. Offspring phenotypes are a result of parental effects (genetic and non-genetic sources) and the environmental conditions experienced by embryos. In this study, we employed a cross-fostering experiment using eggs of the painted turtle (Chrysemys picta) to evaluate the contributions of clutch (i.e., maternal identity) and maternally-chosen nest site to variation in embryo development, hatchling morphology and performance during hatchling migration to water. Because hatchling C. picta overwinter in nests, we used a double-cross-fostering design to decouple the effects of the summer nest (during egg incubation) from those of the winter nest. Maternal identity and summer nest contributed substantially to variation in incubation duration, egg water uptake and offspring morphology. Maternal identity contributed to the variation in all post-winter hatchling variables, but the effects of the summer and winter nest site varied among traits. The impact of summer nest on hatchling mass did not persist through winter and most of the variation in post-winter body mass was due to the winter nest site regardless of maternal identity or pre-winter body size. Both summer and winter nest sites contributed to variation in mass loss during the overwinter period, but only the winter nest affected mass loss during spring migration to water. Adaptive nest-site choice in this system must involve complex interactions between summer and winter nest conditions.