Acclimation of Two Shrimps of the Genus Periclimenes to Sea Anemones

Through an acclimation behavior, Periclimenes rathbunae Schmitt and Periclimenes anthophilus Holthuis and Eibl-Eibesfeldt acquire protection from the tentacles of their respective host sea anemones, Stoichactis helianthus (Ellis) and Condylactis gigantea (Weinland). Laboratory experiments have shown that after a period of isolation from the host these shrimps lose their protection from nematocysts. Unacclimated (=unprotected) shrimps were stung by anemones with and without shrimps living with them, while acclimated (=protected) shrimps were not stung by anemones, with or without shrimps.