Ecological Distribution, Demography and Behavioral Observations on Periclimenes Anthophilus, an Atypical Symbiotic Cleaner Shrimp

Ecology and social behavior of Periclimenes anthophilus were investigated on a near-shore reef habitat in Bermuda. Distributions and abundances of shrimps and the single species of host anemone (Condylactis gigantea) were determined by transect analysis. The shrimp population is not space limited since not all anemones were colonized. Analysis of field data confirmed that the shrimp population is randomly distributed with respect to available host habitat. Shrimps were aggregated (1-9 individuals), however, group size was not correlated with surface area of the host anemone. Although previously described as a cleaner, in 40 h of observation using SCUBA, no cleaning behavior was observed. Laboratory experiments indicate that P. anthophilus does not exhibit a strong social structure, No evidence of a dominance hierarchy, territoriality, or individual recognition was observed. Since shrimp recruit randomly to host anemones and social interactions are rare, population size seems to be limited largely by stochastic events (recruitment success and predation levels) and not regulated by intrinsic factors (social hierarchies or territoriality) as is commonly found in other anemone shrimp species.