DISTURBANCE AND REATTACHMENT BEHAVIOR OF SEA-ANEMONES CALLIACTIS TRICOLOR (LE SUEUR) - TEMPORAL, TEXTURAL AND CHEMICAL MEDIATION

Two hermit crabs, Dardanus venosus (Milne-Edwards) and Pagurus pollica ris Say, have evolved mutualistic symbiotic relationships with sea ane mones, Calliactis tricolor (Le Sueur). Anemones live on gastropod shel ls occupied by the crabs. Both partners are thought to participate in the transfer of the anemone to the crab's shell. However, neither spec ies invariably exhibits transfer behavior when in contact with the oth er symbiont. Factors influencing transfer activity of C. tricolor were studied. Anemone attachment is stimulated by disturbance and is time dependent. Anemones attached to shells more frequently immediately aft er the anemone was disturbed. Assays testing surface texture and surfa ce composition showed that attachment activity of the sea anemone is d ependent upon the organic matrix of the shell and is enhanced by textu re. Attachment by anemones to shells with organic matrix removed is re duced, but is stimulated by adsorption of complex odor mixtures. Anemo nes respond to odor mixtures that signal food to crabs and to odor mix tures that stimulate shell investigation and shell switching in crabs. Thus, C. tricolor participates in shell transfer activity after distu rbance. Behavior of the anemone is cued by texture and chemicals, incl uding chemical mixtures that cause hermit crabs to change shells.