This report documents the ongoing invasion of the Tokelau atolls by
the long-legged ant, Anoplolepis gracilipes (Jerdon). These ants were collected
from two of the three Tokelau atolls. On the island of Fenua Fala of Fakaofo
Atoll, long-legged ants appear to be a recent arrival and occur in only a small
area around one of the two 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 long-legged ants were 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. Long-legged ants 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.