Meeting Abstract

P1.71  Tuesday, Jan. 4  The effect of egg capsule clustering on embryonic survival in the dogwhelk Nucella lapillus WHITE, CF*; ALLEN, JD; College of William and Mary; College of William and Mary cfwhite@email.wm.edu

Observations of several species from a taxonomically diverse group of amphibians, reptiles, arachnids, coleopterans, lepidopterans and molluscs have suggested that clustering of eggs is a survival strategy through which rates of predation or desiccation are decreased. The dogwhelk Nucella lapillus is an intertidal predatory snail that deposits egg capsules under intertidal rocks in clusters of up to 1000 capsules. These benthic egg capsules are then left to develop undefended for up to four months. This study investigated the adaptive significance of clustering eggs capsules by manipulating cluster size in the field over a five week span. In this study and previous work it was found that capsules themselves provide little direct protection against predators. However, it was found that clustering of egg capsules is beneficial and significantly reduces predation relative to uniformly spaced egg capsules. Similarly, it appears that encapsulation alone is an ineffective means to prevent desiccation induced mortality in the embryos. However, this study found that clustering of capsules significantly reduced mortality due to desiccation. Overall, clustering increased survival among egg capsules and the increase in survival was roughly proportional to cluster size. In addition we conducted laboratory predation trials to identify potential predators on N. lapillus egg capsules. We found that lobsters, green crabs and rock crabs all consumed N. lapillus capsules in the lab but hermit crabs did not.