Ecological traits of Caribbean sea anemones and symbiotic crustaceans

In Caribbean coral reefs, many crustacean species associate with sea anemones, but only a few are anemone symbionts. We examined several ecological traits of 3 anemone species (Bartholomea annulata, Condylactis gigantea, Lebrunia danae) and their crustacean symbionts (6 species) on a coral reef at Puerto Morelos, Mexico. On average, C. gigantea was the largest and B. annulata the most abundant of the 3 anemone species. Season did not affect the density distribution of any species, whereas reef zone (back reef, fore reef, reef channels) significantly affected density and mean size of B. annulata and C. gigantea, but only density of L. danae. The probability of harboring crusta ceans increased with anemone size in all species, but varied with reef zone and season in B. annulata only. These patterns may be due to different microhabitat requirements, reproductive strategies, or photosynthetic plasticity of dinoflagellate endosymbionts among hosts, and different flow regimes among reef zones. Alpheus armatus and Ancylomenes pedersoni were strongly associated with B. annulata, and Periclimenes rathbunae with L. danae. Thor amboinensis and Mithraculus cinctimanus occurred more often in C. gigantea, while P. yucatanicus was more evenly associated with the 3 hosts. Only Ancylomenes pedersoni and T. amboinensis occurred in conspecific groups more often than expected by chance. Commensal complexes of up to 3 symbiont species occurred in all host species, with symbionts that typically used different parts of the host coexisting more frequently. These results provide a baseline to assess the potential influence of local and global anthropogenic stressors on anemone-crustacean symbioses.