Disturbance and reattachment behavior of sea anemonesCalliactis tricolor (Le Sueur): Temporal, textural and chemical mediation.

Two hermit crabs,Dardanus venosus (Milne-Edwards) andPagurus pollicaris Say, have evolved mutualistic symbiotic relationships with sea anemones,Calliactis tricolor (Le Sueur). Anemones live on gastropod shells occupied by the crabs. Both partners are thought to participate in the transfer of the anemone to the crab's shell. However, neither species invariably exhibits transfer behavior when in contact with the other symbiont. Factors influencing transfer activity ofC. tricolor were studied. Anemone attachment is stimulated by disturbance and is time dependent. Anemones attached to shells more frequently immediately after the anemone was disturbed. Assays testing surface texture and surface composition showed that attachment activity of the sea anemone is dependent upon the organic matrix of the shell and is enhanced by texture. Attachment by anemones to shells with organic matrix removed is reduced, but is stimulated by adsorption of complex odor mixtures. Anemones respond to odor mixtures that signal food to crabs and to odor mixtures that stimulate shell investigation and shell switching in crabs. Thus,C. tricolor participates in shell transfer activity after disturbance. Behavior of the anemone is cued by texture and chemicals, including chemical mixtures that cause hermit crabs to change shells.