a1 University Marine Biological Station, Millport, Isle of Cumbrae, Scotland, KA28 OEG
Columbus crabs, Planes minutus (L.) (Crustacea: Brachyura) are often found on the postero-ventral surfaces of sea turtles, particularly the loggerhead Caretta caretta (L.) (Testudines: Cheloniidae). There has been a general acceptance of a hypothesis that the crabs feed upon turtle faeces. However, evidence is presented here to demonstrate that Planes has a ‘cleaning’ role, feeding on other epibionts (e.g. barnacle cyprids, parasitic amphipods) during daylight hours. At night it is likely that the crabs feed on neustonic animals (e.g. euphausids). The species is also cannibalistic.