ORAL PRESENTATION (abstract)
Many studies have shown the efficacy of dorid nudibranch's chemical defenses in laboratory systems, but these investigations often neglect predators encountered in the field and the possibly defensive calcareous spicules. I investigated the defenses of Cadlina luteomarginata (Chromodorididae) against common Pacific Northwest generalist predators from four phyla. Spicule investment in C. luteomarginata is heavier in the mantle than in the foot, rhinophores, or gills, consistent with a defensive role. In bioassays, no predator consistently consumed C. luteomarginata. Nudibranch extracts deter feeding from two Cancer crabs, while spicules have no effect. Only a combination of extracts and spicules significantly deterred feeding by Anthopleura elegantissima (Anthozoa). Differences in response between predators suggest nudibranchs may require a variety of defenses to deter the range of generalist predators in the field.
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