Solenopsis

This genus consists of, broadly, three sets of species. The first consists of large, polymorphic species commonly called "fire ants" (S. geminata, S. invicta and relatives). They are free-living, form enormous colonies in open soil sometimes with a mound of loose dirt around the nest entrance, forage on the surface of the ground for seeds, living and dead insects and assorted other foods, and sting like the dickens. The Red Imported Fire Ant (S. invicta) belongs to this group.

The second group (the subgenus Diplorhoptrum) are commonly known as thief ants. The workers are extremely tiny, monomorphic and often live in close proximity to larger ants and termites. When nesting with other ants or termites, they act as "thief ants", raiding the host's nests for food. While most "Diplos" nest in open soil or under rocks some are arboreal. In some cases 3 or 4 Solenopsis nests have been found in a single Myrmecia nest.

The third set of species are social parasites of other ants. While the first two sets form natural groups (are monophyletic) this set is an artificial assemblage of unrelated species.



Worker of Solenopsis from New South Wales.

Identification
The antennae are 10 segmented (including the scape) and have a 2 segmented club. The front margin of the clypeus just above the mandibles has a single central elongate hair or seta. The rear face of the propodeum is rounded or with at most low, rounded ridges or protuberances, but never with teeth, spines or thin flanges.

Workers of Solenopsis are most often confused with workers of Carebara. They can be separated by the single central hair on the front margin of clypeus (paired hairs are present in Carebara) and the rounded rear face of the propodeum (spines, teeth or flanges are present in Carebara). Solenopsis may also be confused with smaller species of Monomorium. In this case, the distinctly 2-segmented club will allow the identification of Solenopsis.

Distribution and Habitats
Australian distribution

Regional Species Lists

 * Australia

Keys to Species

 * Australia