Investigations on symbioses between shrimp and sea anemones

Periclimenes yucatanicus, P. pedersoni, and Thor sp. were nonrandomly distributed among three anemone species at different sites off southern Florida. Host selection tests showed that P. yucatanicus had a strong preference for one anemone, which could explain its field abundance with this same species. Host location tests showed that both Periclimenes species used chemical cues to detect their anemones--visual information seemed unimportant. Laboratory predation trials showed that shrimp survived significantly longer with an anemone than without in the presence of predatory fishes. The acclimation behavior of Periclimenes was described to analyze the protection mechanism. Legs and antennae were in frequent contact with the anemone, but the other body regions rarely contacted the tentacles. Additionally, antennae were used frequently to direct tentacles away from these other body regions. Coating of high contact areas with anemone mucus and avoidance of tentacles with other areas may be the method of protection.