Hawaii is one of the few places on Earth believed to harbor no native ant species. The extreme isolation of the island chain has meant that ants may have never managed to arrive on their own. In fact, it is unclear whether Hawaii's native fauna includes social insects of any kind. Today, at least 57 ant species in 7 subfamilies and 24 genera have become established. This assemblage is unique in that nearly all of the species qualify as "tramps" - species with habits and life histories that make them exceedlingly good at moving about in conjunction with human activity. Among them are a majority of the world's most successful, and damaging, invasive species.
In addition to their effects on the resident arthropod communities, the ants of Hawaii are of interest because they provide a rare opportunity to study interspecific interactions among groups of species that have little or no shared evolutionary history. Although highly invasive species such as Linepithema humile, Pheidole megacephala and Anoplolepis gracilipes may dominate the scene, a fairly diverse array of other ants with differing habits and ecological strategies are also successful in the islands. These include highly active and common species (e.g. Paratrechina longicornis, Nylanderia spp. and Technomyrmex spp.), others that form small and inconspicuous colonies (such as Hypoponera spp. and Cardiocondyla spp.), as well as some highly specialized species (Strumigenys spp.). They occur in a wide variety of life zones, from sea level subtropical wet forest all the way up to subalpine shrubland and alpine desert at over 2800 m elevation.
The species list provided here includes all taxa known to occur in the islands, as well as those historically recorded that may still be present but are difficult to detect. Several conspicuous species that have not been seen in many decades are excluded.