Range Expansion and Local Population Increase of the Exotic Ant, Pheidole Obscurithorax, in the Southeastern United States (Hymenoptera: Formicidae)

The exotic ant, Pheidole obscurithorax Naves, is currently expanding its range and increasing in local density in the southeastern United States. We describe new county records from 5 states and local density increases along roadside transects in the Tallahassee, Florida area. The patchy distribution suggests that this species is being transported to new localities by people. Throughout its introduced range, this species is largely confined to highly disturbed habitats, such as lawns and roadsides and frequently co-occurs with the introduced fire ant, Solenopsis invicta Buren. Locally, although the maximum density of nests per unit area has not changed since 2002, the total area occupied, and the total number of nests of P. obscurithorax is much greater. Beyond these data, little is known of the biology of this species.