The Caribbean region is considered a threatened biodiversity hotspot because of its high levels of biotic endemism and widespread habitat destruction. On Caribbean islands, as elsewhere in the world, ants are a critical component of virtually every terrestrial ecosystem. Nonetheless, the ants of most Caribbean islands remain poorly known. Here, we reviewed historical accounts, compiled published and unpublished ant records, and collected new specimens to document the diversity of ants on the Caribbean island of Barbados, including summary accounts for each species. We expected Barbados to have a relatively depauperate native ant fauna with few endemic species because of high isolation, young age, flat terrain, and high degree of habitat destruction. Furthermore, we expected to find many exotic ants, introduced throughout a long history of international commerce dating back to the 1600s.

Our investigations increased the list of ant taxa known from Barbados to 69 (46 New World and 23 Old World). Of these, 62 are represented among specimens we collected, and seven are New World species only known from earlier records. We found that Barbados has fewer New World ant species and more Old World ant species than are known for Grenada and St. Vincent, two neighboring Caribbean islands of similar size. Most of the New World ant species in Barbados are continuously distributed from South American and Trinidad, through the Lesser Antilles and are probably native (i.e., predating human arrival). Some New World species in Barbados, however, may be exotics introduced through human commerce, as are all Old World ant species present. Six previously recorded New World species that we did not find may now be extinct in Barbados. These include Atta cephalotes lutea and Crematogaster brevidentata, the only two ant taxa thought to be endemic to Barbados, each collected just once >110 years ago.