This study will test the hypothesis of escalation by examing the history of the naticid gastropod predator-prey system. Vermeij has suggested that increased severity of biologic hazards and, in turn, aptations to such hazards characterizes the Phanerozoic. This hypothesis is controversial and requires testing by systematic collection of data. We will analyze the development of the naticid predator-prey system in the context of this hypothesis of escalation. A comprehensive survey of Gulf Coastal Plain Cretaceous and Paleogene molluscan assemblages will be conducted within the theoretical framework of the Kitchell et al. (1981) energy maximization model of naticid predation. The survey will determine whether temporal trends in drilling frequencies occurred and whether naticid-prey interactions differed early in the history of the group compared to later. Temporal patterns in behavioral stereotypy (selectivity of drillhole site and prey size and species) and in relative effectiveness of predator and prey will be determined. Analysis of predation on and evolution of several prey lineages will explore and process of predator-prey evolution. We will examine whether escalation is a macroevolutionary phenomenon or occurs within lineages and (if it occurs) what processes are involved.
