Meeting Abstract

49.3  Jan. 6  Predator-Induced Morphological Defenses In Marine Zooplankton: A Larval Case Study VAUGHN, Dawn ; Univ. of Washington, Friday Harbor Laboratories dvaughn@u.washington.edu

While there are numerous reports of predator-induced morphological defenses for benthic marine animals, freshwater zooplankton and freshwater larvae, at present there is an absence of studies demonstrating similar phenomena in adult marine zooplankton, and the planktonic larvae of marine organisms. Rarity of predator-induced morphological defenses in marine zooplankton would imply a difference in predation risks, whereas the presence of such plasticity in defenses would imply that risks are modified by developmental responses. This study reports a predator-induced change in defenses and vulnerability of a marine planktonic larva. Specifically, when reared in the presence of zoea larvae of Cancer spp., veliger larvae of the intertidal snail Littorina scutulata developed significantly smaller shell apertures and rounder shells than did cohort veligers reared in the absence of predator cues. Pair-wise predation trials demonstrated that veligers reared with caged zoeas throughout development had greater survival than predator-naive veligers during short-term exposure to zoeas. The results indicate that some marine larvae develop predator-induced morphological defenses and suggest that predators on marine larvae and other zooplankton are not so diverse as to preclude plasticity in development of defensive structures. This result introduces a range of testable hypotheses on developmental plasticity that reduces vulnerability of planktonic larvae and other marine zooplankton to predators.