Epibionts on Arenaeus cribrarius (Brachyura: Portunidae) from Brazil

Mean prevalence and intensity of infestations by epibionts were evaluated in Arenaeus cribrarius (Lamarck, 1818), based on monthly samplings (May/1991 to April/1993), in Ubatuba, Brazil. Bryozoans were quantified in terms of colony numbers and barnacles by the number of specimens. Prevalence of infestation was determined in 1,914 individuals of A. cribrarius and assessed with respect to sex, maturity stage and season. No significant interaction was detected between epibionts and biological host factors. Males showed a higher infestation rate by Chelonibia patula (Ranzani, 1818) when compared to mature non-ovigerous females, yet Octolasmis lowei Darwin, 1851 infestation was associated to adult crabs. The ovigerous females of A. cribrarius showed a higher prevalence of infestation than males and non-ovigerous females, with lower infestations being recorded during winter. A synchrony between the life cycle of the epibionts and their hosts was evident and promotes the continuity of the former in the area.