Chemically mediated effects of injured prey on behavior of both prey and predators

Abstract

Abstract We examined the behavioral responses of aquatic snails (prey) and two species of crayfish (predators) following exposure to chemical cues from injured snails. Snail survival rates and crayfish capture rates were compared between cued treatments and controls. Snails (Physa gyrina) responded to chemical cues by significantly increasing refuge use (i.e. moving to the waterline, floating or crawl-out behavior). Despite their responses, use of refugia did not influence survival rates. Crayfish species differed in their responses to these same chemicals. Orconectes juvenilis became more active (including increased movements across the substrate and reaching up sides of aquaria). In contrast, the activity levels of Procambarus clarkii did not significantly change. Nevertheless, P. clarkii captured snails in less time than O. juvenilis, regardless of whether injured-snail cue was present, and the presence of these cues did not significantly influence capture times for either crayfish species. This study provides strong evidence that injury-released chemical cues can elicit behavioral responses from both conspecific prey and their predators, but found no benefits of response for either prey or predators. The complex interplay of effects makes it difficult to draw simple, general insights about the benefits of the responses for either participant during a predator-prey interaction.