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Department 1

Environmental Studies


DeAngelis et al. (1985) have described a model of the evolutionary response of bivalve prey to size-selective naticid snail predation. The model analyzed "the allocation of bivalve energy among reproduction, overall growth in size, and supplementary growth in shell thickness" (p. 818). Using parameter values for Polinices duplicatus as the predator and Mercenaria mercenaria as the prey, the model predicted three optimal strategies for bivalves faced with naticid predation: (1) delayed reproduction with energy diverted into rapid growth in order to reach a size refuge; (2) early reproduction, possibly with some extra shell thickness; and (3) greatly increased shell thickness for deterring predator attacks. This model and an earlier one (DeAngelis et al. 1984) are elaborations on a general qualitative model for bivalve prey (Seed and Brown 1978). [excerpt]