SOLOMON, Scott E; MIKHEYEV, Alexander S; The University of Texas at Austin; The University of Texas at Austin: The Ant Fauna of Cocos Island, Costa Rica

Island communities are often the subject of ecological research because they are generally less complex than otherwise similar continental habitats. Relatively small and isolated islands are expected to have the simplest communities, and are thus ideal systems for investigating community ecological patterns and processes; indeed, these systems have been the focus of a rich literature in island biogeography that has developed during the last 50 years. One of the taxa commonly used in island biogeographic studies are ants, due in part to their ubiquity and relative ease of collection. Widespread human disturbances on most islands, however, renders difficult the study of natural island communities. We conducted a systematic survey of the ants of Cocos Island, Costa Rica, a 24 km2 volcanic island 500 km off the Pacific coast of Central America that has never had a long-term human settlement. We recorded the presence of 16 ant species, almost all of which appear to have been transported to the island by humans. One species, Wasmannia auropunctata, is well-known as a tramp species that often outcompetes native fauna; the distribution and behavior of this species on Cocos Island, however, is atypical. The patterns revealed by this survey suggest that even islands that have had minimal human presence may have very disturbed communities, and therefore the conclusions that can be drawn based on their analysis may need to be reconsidered.