EDWARDS, D.R.*; WOODIN, S.A.: Should worms of a feather stink together? The effects of prey density and aggregation on predator deterrence

SHOULD WORMS OF A FEATHER STINK TOGETHER? THE EFFECTS OF PREY DENSITY AND AGGREGATION ON PREDATOR DETERRENCE. D.R. Edwards* and S.A. Woodin. University of South Carolina, Columbia. deirdre@sc.edu Halogenated hydrocarbons are widespread among hemichordates and polychaetes in temperate sedimentary environments. The bromophenols produced by some larger (>3cm in length) macroinfauna act as predator deterrents. However, many of the infaunal organohaline producers are small (<1cm in length), especially in relation to the bite size of their common predators. The ability of these small organisms to deter predators may be dependent not only on the production of deterrent compounds by individuals, but on the structure of the surrounding community. In this study, we examine whether patches of small individuals with such compounds are less palatable to infaunal predators than patches of individuals without, and whether deterrence is dependent on prey density. Spot (Leiostomus xanthurus), mummichogs (Fundulus heteroclitus) and grass shrimp (Paleomonetes sp.) were offered patches of small (1-2 mm³) cubes of surimi with and without bromophenols. The cubes were offered at a high density (100 cubes/0.01 m²), low density (30 cubes/0.01 m²), and an aggregated low density (30 cubes divided into 6 1cm² patches). Results of these choice experiments demonstrate that, at least for some predators, bromophenols are effective predator deterrents for small prey, and that this effect increases with density and aggregation.