Smallest ant species

The world's smallest ants are those in the genus Carebara. In Sri Lanka, Carebara bruni reaches a total length of 0.8–1.0 millimetres (0.31–0.39 inches), and in Fiji Carebara atomi has been measured over the same range.

Formally described in the early 1900s, this tiny cryptic group of ants inhabit leaf litter and soil, or nest in termite mounds, but little else is known of its ecology or distribution. There are around 250 species of Carebara ants, some of which are dimorphic, with soldiers and workers, some are monomorphic with one size of worker and some continuously polymorphic, which means that there is a range in sizes of workers from tiny to almost 5 millimetres (0.19 inches).

They are typically collected using a Winkler sampling method; soil and leaf litter is collected, sifted and hung up in white sheets for 24 hours, over which time tiny insects crawl outward toward a lighter environment and fall downward into a collecting jar. It is very difficult to see these ants in the soil and collect them by hand.