Long-legged ants (Anoplolepis gracilipes) have invaded Tokelau, changing the composition and dynamics of ant and invertebrate communities

*[This report documents the ongoing invasion of the Tokelau atolls by the long-legged ant, Anoplolepis gracilipes (Jerdon). These ants were collected from 2 of the 3 Tokelau atolls. On the island of Fenua Fala of Fakaofo Atoll, A. gracilipes appears to be a recent arrival and occur in only a small area around one of the 2 ports. Most of the inhabited islands of Vao and Motuhuga on Nukunonu Atoll have been invaded, in addition to several of the uninhabited, forested islands. Despite this ant having been previously recorded from at least one island of Fakaofo and Nukunonu, these appear to be new invasions. Densities of up to 3,603 A. gracilipes per pitfall trap were caught per 24 hr. A significant reduction in ant species diversity was observed with increasing A. gracilipes densities. Densities of this ant were not uniformly high, perhaps due to variation in food availability. Prey such as crabs, ant colonies, and other insects were directly observed being attacked, and A. gracilipes was observed to feed on honeydew produced by high densities of aphids, mealybugs, and scale insects on a variety of plants. Interspecific competition was investigated as an additional mechanism for the successful invasion. A. gracilipes found and removed bait faster than the dominant resident ant species, Paratrechina longicornis (Latreille), in forested areas of Nukunonu Island, though needing smaller numbers of recruits to achieve this result. This A. gracilipes invasion is of serious concern for the biodiversity of Tokelau and probably many of the other Pacific islands where these ants have invaded. Boats are certainly a carrier of ants to these islands because while traveling on the boat for this study one of us (P.J.L) recorded the presence of the species Monomorium minutum Mayr, P. vaga, and T. bicarinatum in just 4 small potted plants being moved to Nukunonu during November 2002.]