Worldwide spread of Cerapachys biroi (Hymenoptera: Formicidae: Cerapachyinae)
biogeography, Biological invasion, exotic species, island fauna
Cerapachys biroi FOREL, 1907 is a small, inconspicuous ant that has spread around the world through human commerce. To examine the worldwide distribution of C. biroi, we compiled and mapped specimen records from > 100 sites. We do- cumented the earliest known C. biroi records for 24 geographic areas (countries and island groups), including several for which we found no previously published records: Comoro Islands, Guadeloupe, Îles Éparses, Indonesia, Madagascar, the Seychelles, Turks & Caicos Islands, and the US Virgin Islands. All continental records of Cerapachys biroi come from Asia, where populations show notable geographic variation in morphology, suggesting that the species is native to this region. Conversely, the lack of obvious morphological variation among C. biroi specimens from outside mainland Asia suggests that C. biroi is exotic to these regions. Outside Asia, all records of C. biroi come from islands, possibly due to reduced competition with dominant ants in island habitats. Perhaps the many dominant native and exotic ant species in continental regions have prevented widespread establishment of C. biroi.