Effects of adult and egg predators on hatching plasticity of the pulmonate limpet

Abstract In response to predation risks during the embryonic period, prey animals from various taxonomic groups acquire plasticity in hatching time. In theory, the predators of the adult prey as well as the egg predators can influence hatching time. Similarly, not only the embryos but also the parents of the prey can regulate hatching time. However, research on the effects of adult and egg predators and factors that influence egg-hatching time is limited. To the best of our knowledge, no study has explored this phenomenon in marine invertebrates under natural conditions. In this study, we investigated the effects of life stage-specific predators (i.e., adult and egg predators) on the hatching time of the pulmonate limpet (Siphonaria sirius) on an intertidal rocky shore. Although the presence of predators of adult prey did not affect the prey hatching time, the presence of egg predators accelerated their hatching. Moreover, the presence of egg predators following egg-laying accelerated hatching time. This indicates that embryos, rather than their parents, determine hatching time in response to their own predation risk. Siphonaria sirius is likely to have evolved plasticity in hatching time in response to high but fluctuating egg predation risk.