Integrating prey defensive traits: Contrasts of marine worms from temperate and tropical habitats

Marine worms are speciose and numerically prominent members of marine Communities where they play critical roles in trophic interactions and in affecting biogeochemical cycles. Despite the ecological importance of this group, little is known about their palatability to, and defenses against, consumers. In addition, most studies of prey defenses in marine organisms have focused on overt, sessile species: few studies have investigated more mobile and behaviorally complex species that could potentially be integrating predator deterrents with refuge use and other escape behaviors. To increase our understanding of consequences of defensive traits among mobile marine prey, we surveyed the palatability of 81 species of worms from the Caribbean and warm-temperate western Atlantic. Thirty-seven percent of the species were unpalatable. Worms with differentially exposed body portions commonly defended exposed feeding appendages with chemical or structural deterrents, while palatable and undefended bodies remained sheltered within structural refuges. Unpalatable worms tended to be brightly colored and sedentary, exposed to epibenthic predators, and to occupy hard substrates. Palatable worms tended to be drab, to live in structural refuges from consumers, to be mobile, and to inhabit unconsolidated sediments. Overall, taxonomy (Sabellidae and Terebellidae) and color were the traits most strongly associated with unpalatability. Unpalatable species appeared less constrained by predation and freer to forage for long periods on higher quality surface sediments or on other invertebrates at the sediment surface (thus, potentially influencing the distribution and abundance of other species). In contrast, palatable species appeared more constrained by predation risk. They fed on lower quality subsurface sediments and foraged at times or locations where consumers were less active. These ecological patterns may be generalized to other soft-bodied prey, Such as caterpillars, which show similar trends regarding palatability and lifestyle.