Temperature-Induced Changes in Hatching Size of a Tropical Snail Occur During Oogenesis and Can Persist for Several Weeks.

AbstractIt is accepted that temperature affects offspring size in ectotherms. However, the processes that result in temperature-induced changes are not well understood. We sought to determine when temperature changes during development induce changes in hatching size and how long hatchlings reflect the previous thermal experiences of their mother. Juveniles of the common tropical slipper snail Crepidula cf. marginalis were collected at Playa Venado, Panama; were raised in the laboratory at either 24 °C or 28 °C, temperatures experienced in nature; and were reciprocally moved between the two temperatures. In the first experiment, the animals were moved immediately after oviposition to determine whether temperatures experienced during oogenesis or embryogenesis contribute to differences in hatching size. The second experiment transplanted animals between the same two temperatures after the first brood hatched. The subsequent three broods were measured to determine how long the legacy of the first temperature persists. We found that (i) the temperature the mother experienced during oogenesis significantly affects hatching size, whereas the temperature experienced during embryogenesis does not; and (ii) hatching size is impacted for at least two broods after a change in temperature (≥17 days). These results show that hatching size is a legacy of temperatures experienced prior to oviposition and that this legacy does not persist for more than two brooding cycles. It remains unclear whether this rapid response to environmental temperature is adaptive or the result of a physiological constraint on oogenesis. Understanding the process whereby temperature influences offspring size will provide insight into the potential for organisms to respond to temperature changes and, ultimately, climate change.