Meeting Abstract
Parents increase their fitness by investing resources to offspring. However, such investment is often costly for parents, leading to tradeoffs. Furthermore, such tradeoffs should shift towards heavier investment to reproduction as females age and future reproductive opportunities decrease. Nests of aquatic turtles laid farther from water have higher survival than those laid closer to shore because nest predators often forage along environmental edges. However, the predation risk for adult females increases farther from water because water is used as refuge from terrestrial predators. Thus, females may balance investment in current offspring vs. maternal survival and future offspring. To test if investment varies depending upon perceived risk, we exposed 30 painted turtles (Chrysemys picta) to simulated predation during natural nesting attempts. We then allowed females to return and nest undisturbed, and compared the distance to water of nests laid before and after simulated predation. Unexpectedly, females did not vary distance to water in response to simulated predation. Regardless, nests laid after simulated predation were more likely to be depredated than those laid before simulated predation, suggesting females altered nest-site choice in ways we did not quantify. In addition, although older turtles nested almost twice as far from water as younger turtles, we found no evidence that age influenced maternal response to simulated predation. Our findings suggest perceived risk for mothers to predation influences nest-site choice and subsequently reduces offspring survival in C. picta. In addition, we provide a rare assessment of how plastic maternal investment might vary across reproductive life.
