Geoffrey C. Trussell
Salvatore J. Genovese, Philip O. Yund
Date of Award
Master of Science
Department or Academic Unit
College of Arts and Sciences. Department of Biology.
injury, non-consumptive, predator-prey, prey state, shell, trait-mediated
Ecosystem management, Predatory animals--Ecology
Non-consumptive effects exerted by predators on their prey can have far reaching implications for the structure of ecological communities and functioning of ecosystems. In addition to risk cues detected from nearby predators, physiological state of individual prey animals may influence the sign and magnitude of trait-mediated indirect interactions. Using a tri-trophic intertidal food web, I tested the influence of prey state as represented by injury history on behavior and resource allocation in an intermediate prey species, the marine snail Nucella lapillus. Despite the presence of shell injury in natural populations of this and other intertidal gastropods, injured N. lapillus showed no differences in feeding rate, energy assimilation efficiency or growth in morphological traits relative to uninjured conspecifics. I also compared the relative influence of predator risk cue and prey physiological state on the combined indirect effect of predators in this system. Predation risk cues account for the great majority of reductions in resource and energy consumption while physiological prey state has negligible influence. Although repaired shells were significantly weaker when tested in compression than uninjured shells, injury status did not influence mortality in snails exposed to predation in the field. These data indicate that predation risk is a major driver of resource consumption and community effects while prey state as represented by shell injury makes little contribution.
Timothy Robert Dwyer
Dwyer, Timothy Robert, "Predator risk cues and prey physiological state in an intertidal food web" (2009). Biology Master's Theses. Paper 10. http://hdl.handle.net/2047/d20000639
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