Foraging and Reproductive Ecology of Intertidal Gastropods

• Main Author: White, Connor
• Format: Text
• Language: English
• Published: W&M ScholarWorks 2011
• Subjects: Gastropods; Marine; Trophic Interactions; Trait Mediated; Biology; Dogwhelk; Nucella lapillus
• Online Access: https://scholarworks.wm.edu/honorstheses/385; https://scholarworks.wm.edu/context/honorstheses/article/1394/viewcontent/WhiteConnor2011.pdf

Gastropods are a diverse and abundant class of molluscs found in all of the world's oceans. In this thesis, I explore how predation affects two ecologically similar species of marine gastropods performing two essential activities: foraging and reproduction. First, I examined whether the Atlantic oyster drill, Urosalpinx cinerea, a common predator in the mid-Atlantic adjusted its foraging behavior in the presence of predatory crabs. I found that oyster drills do not reduce the number of oysters consumed nor do they alter the location in which they drill through an oyster shell in the presence of blue crabs. However, oyster drills did preferentially drill through the dorsal right quadrant of oyster shells. Preferential drilling of oyster shells is a novel result that contradicts prior claims in the literature. Second, I investigated whether the oviposition strategy of the dogwhelk, Nucella lapillus, acts to reduce predation and desiccation mortality. Here, as in previous work, I found that egg capsules themselves provide little direct protection against predators. However, the clustering of egg capsules in large groups does provide a significant benefit by reducing predation relative to uniformly spaced egg capsules. Similarly, it appears that encapsulation alone is an ineffective means of preventing desiccation-induced mortality in the embryos. However, clustering of capsules significantly reduced mortality due to desiccation. Overall, clustering increased survival of egg capsules and the increase in survival was roughly proportional to cluster size. Taken together, these two experiments suggest that predators may influence oviposition but not foraging in intertidal gastropods.