Population differences in effects of fish on Physa integra refuge use

Abstract

Prey populations exposed to different sets of predators often adopt distinct antipredator behaviors. We investigated the refuge use of a freshwater pulmonate snail, Physa integra, in the presence and absence of fish predators. Over 80% of snails in sites with fish used refuge, while only 50% used refuge in sites without fish. Snails in sites with fish were also significantly smaller than snails in sites without fish. In a laboratory experiment, the presence of fish did not alter the habitat use of snails collected from a no-fish site, whereas snails collected from a site with fish used refuge when exposed to predation risk. These results support the hypothesis that P. integra exhibit local behavioral adaptations to their predator regime.