Carebara

Minor workers of Carebara are some of the smallest ants in the world, often barely exceeding 1 mm in overall length and sometimes being as small as 0.75 mm long. They nest in soil, either in the open or under rocks and logs, and in leaf litter and rotten wood. Workers are often found in leaf litter. They are also commonly found in or near the nests of other species of ants or termites. When associated with other ants or termites they form small chambers attached to the nests of their hosts, foraging into their nests where they prey on brood and/or eggs. When encountered by their hosts, Carebara workers are ignored and seldom attacked.



Worker of C. norfolkensis from Norfolk Island.

Identification
The antennae have 9 or 11 segments (including the scape) and a 2 segmented club. The upper surface of the head is smooth or uniformly sculptured and lacks grooves for the reception of the antennae when at rest (antennal scrobes are absent). The clypeus has a pair of longitudinal ridges or sharp angles immediately below the antennal sockets which separate the central region from the lateral regions (clypeus longitudinally bicarinate). The eyes are sometimes reduced to a single facet (ommatidium) which is only slightly differentiated from the surrounding integument. The rear face of the propodeum is armed with teeth or spines which vary from short and angular to long and thin, or occasionally the propodeum has thin, elongate flanges which run from just above the insertion of the petiole upwards to near the propodeal angle. The workers are very small (overall body length less than 1.5 mm) and with distinct majors and minors but without intermediates (dimorphic). In most species, the major workers have small horns on the upper surface of the head near the rear margin.

Minor workers of Carebara are similar to Solenopsis workers, but may be separated by the paired hairs on the front margin of the clypeus (a single central hair is present in Solenopsis) and the presence of spines, angles or flanges on the rear face of the propodeum (this face is smooth in Solenopsis).

Distribution and Habitats
Australian distribution

Regional Species Lists

 * Australia

Keys to Species

 * Australia