Meeting Abstract
The choice of oviposition site often has strong effects on offspring survival. The risk of predation of nest sites and the proximity of nest sites to suitable offspring habitat can influence this decision. Yet, how offspring dispersal ability might interact with such factors to influence maternal investment strategies is unclear. In aquatic turtles, terrestrial nests laid farther from shore often have higher survival because nest predators (e.g., raccoons) tend to forage along environmental edges. However, offspring from eggs deposited farther inland must migrate a greater distance to water upon emergence from their nests. To explore this tradeoff in light of offspring dispersal ability, we collected and measured the body size of 428 hatchling common snapping turtles (Chelydra serpentina) from 15 nests. We released the turtles 25 m, 62.5 m, and 100 m from a drift fence and subsequently monitored survival, time to fence, and orientation during overland dispersal. Not surprisingly, survival decreased with dispersal distance and no selection on body size was evident for hatchlings dispersing from 25 or 62.5 m. However, survival increased with body size for hatchlings dispersing from 100 m. Thus, because larger offspring are less affected by long dispersal distances, females producing large eggs can oviposit farther from water to maximize nest survival while also permitting offspring a reasonable chance to survive overland dispersal. These findings suggest that offspring dispersal ability can be an important factor influencing maternal investment strategies.
