Abstract
A unique foraging behavior of the carnivorous polychaete Halla okudai (Lysaretidae) is described in detail. Living bivalves, Ruditapes philippinarum were supplied to adult H. okudai, which were burrowing in sandy sediment in aquariums. The foraging behavior was divided into 4 stages ; responding, searching, handling, and feeding. Responding and searching were considered to be dependent on the olfactory sense, and searching was significantly responsible for the variation in total foraging time. Handling was performed by inhibiting the escape of the bivalve and then opening its shell while secreting a jelly-like material. Bivalve size (23.8-26.3mm shell length) showed a significant correlation to handling time, which ranged from 0.87 to 6.67hr. During feeding, the ploychaete continued to secrete the jelly-like material, which was different in hue from that secreted during handling.
