Sublethal predation and regeneration in two onuphid polychaetes: patterns and implications.

We examined sublethal predation in the polychaete Diopatra cuprea, an important ecosystem engineer of intertidal and shallow subtidal marine sediments in the western Atlantic. D. cuprea commonly loses its antennae and portions of its anterior to predator attacks; these lost body portions are subsequently regenerated. We asked (i) if the intensity of sublethal predation differs for D. cuprea populations in Virginia versus Florida, (ii) if sublethal predation varies temporally in each region, and (iii) if sublethal predation influences activity and tube-building rates. Within Florida, we also drew comparisons between D. cuprea and the closely related onuphid Americonuphis magna. Surprisingly, we found that sublethal predation is more intense in Virginia than in Florida, likely making substantial contributions to secondary productivity. Within Florida, A. magna experienced more antennal loss than D. cuprea and is incapable of anterior regeneration. D. cuprea activity and tube-building rates are strongly influenced by anterior loss, but more subtly influenced by antennal loss. Given the observed rates of sublethal predation and population densities in Virginia versus Florida, sublethal predation is an important factor influencing D. cuprea populations and their associated communities.