Hayes F. E. 2007. Decapod crustaceans associating with the sea urchin Diadema antillarum in the Virgin
Islands. Nauplius 15:81-85.
Abstract.--The association of decapod crustaceans with the long-spined urchin Diadema antillarum was studied at 18 sites in the Virgin Islands during 2002-2003. At least eight species of decapods, including three previously unreported species, associated facultatively with D. antillarum. The decapods probably benefit by increased protection from the urchin�s long spines whereas the urchin is probably unaffected. Of 1,800 D. antillarum examined, 115 (6.4%) hosted one or more decapods with an average of 0.09 individuals per urchin. Of 164 individual decapods observed, the grapsid crab Percnon gibbesi was the most common species (48.8% of all individuals), followed by unidentified hermit crabs (Paguridae; 30.5%), the arrow crab Stenorhynchus seticornis (11.0%), the banded coral shrimp Stenopus hispidus (5.5%), the spiny lobster Panulirus argus (2.4%), the porcelain crab Petrolisthes galathinus (0.6%), and an unidentified spider crab (possibly Mithraculus sp.; 0.6%). In addition, a green clinging crab Mithrax sculptus moved from an urchin Tripneustes ventricosus to a D. antillarum. The frequency of decapods associating with D. antillarum in the Virgin Islands was about five times lower than on some islands in the southeastern Caribbean Sea. The environmental factors responsible for geographic variation remain unknown. Because long-term temporal trends in the association of decapods with urchins may be linked to large-scale population dynamics of D. antillarum, the populations of both urchins and their decapod associates should be monitored.
Key words.--crustacean-echinoderm associations, Caribbean Sea, crustacea, decapods, Diadema antillarum, Virgin Islands |
