Predator-prey dynamics and evolutionary defense tactics for marine bivalves

Persistence of prey species when faced with intense predation pressure is fostered by density-dependent survival and habitat features such as architecturally complex grasses or algae that furnish refugia from predation.

Infaunal bivalve molluscs, such as the thin-shelled clams Mya arenaria and Macoma balthica, are dominant species in soft-bottom estuarine and marsh systems and suffer heavy losses to epibenthic predators including the blue crab Callinectes sapidus  and various demersal fish in Chesapeake Bay.

Using this predator-prey system, we are conducting a series of experiments that test habitat-specific and density-dependent mortality for subtidal, soft-bottom, deep-burrowing prey, thereby enabling development of a conceptual model linking predator-prey dynamics, habitat structure, and evolutionary defense tactics for marine benthos. We are assimilating the most basic feature of predator-prey dynamics, the functional response, into a mechanistic model that incorporates the role of habitat and predator-prey dynamics in determining the major evolutionary defense tactics—armor and avoidance—of marine bivalves.