Formicinae

These are some of the most common ants in Australia and can be found everywhere, often in large numbers. Many seem to feed principally upon nectar and other plant exudates, directly or indirectly via Homoptera, while others are general scavengers, foraging on the ground or on vegetation. They can be found at all times of the day and night. Nests are usually fairly large, with hundreds or thousands of workers, and range from small and cryptic to large and obvious. They are generally in soil but some species are associated with rotten wood while a few are arboreal (nesting in hollows in tree trunks or branches). Workers are generally active and fast moving and many will defend their nests vigorously, attacking intruders with their large mandibles and formic acid sprays.

Species of formicines are found world wide and are second only to the Myrmicinae in numbers of species, with over 3700 described species and subspecies and 49 genera. In Australia there are just over 400 described species and subspecies in 21 genera, with many species yet to be described. Of the 19 genera, six are found only in Australia. For relationships among these genera see Phylogeny of Formicinae.

Identification
The mesosoma is attached to the gaster by a single distinct segment, the petiole. The gaster is smooth, without constrictions between the segments. The sting is absent and the tip of the gaster has a small circular opening (an acidopore) which is often surrounded by a ring of short hairs. Species of Formicinae are most often confused with species of the subfamily Dolichoderinae because both have a single segmented petiole, lack a sting and are often similar in overall body size and shape. This is especially true for the smaller species such as those in Plagiolepis. However, formicines can always be separated from dolichoderines because the tip of the gaster has a small circular opening while all dolichoderines have a slit-like opening.

Distribution and Habitats
Australian distribution

