Huberia striata (Fr. Smith 1876)
Striated ant (Ferro et al. 1977)
Synonyms (Valentine & Walker 1991 )
Tetramorium striatum Smith, Huberia striata var . rufescens Forel, Hubertia striata (Smith)
Regarded as endemic to New Zealand. With H. brounii belongs to New Zealand’s only endemic ant genus.
Distribution (see map)
Widespread, it occurs on both main islands, Stewart I., and some offshore islands. It appears to be far less prevalent in Northland than elsewhere.
Features of the genus are: antennae 11-segmented with a weakly 4-segmented club; clypeus with a median longitudinal groove; propodeum armed with a pair of sharp spines; areas of striation (fine lines) on the head and mesosoma; gaster smooth and shining.
Diagnostic features of the worker
Length 4.5 - 5 mm; metanotal groove more deeply impressed than in H. brounii; dorsal surface of head smooth and shining, sides of head longitudinally striate; dorsal surfaces of mesosoma, petiole (two nodes), gaster, smooth and shining; body less obviously striate overall than in H. brounii; colour reddish-yellow to black.
Probably attains its greatest density in beech forests of the South Island, nesting in soil under stones or in rotting logs on the forest floor. However, nests can also be found in more open bush country, such as in the Okuku Pass area of inland Canterbury, as well as entirely in the open, surrounded by grass, though still close to the forest edge. H. striata has also been seen nesting at high altitudes.
Colonies can be large (hundreds or thousands of workers), due mainly to a tendency for colony branching and the formation of groups of supplementary nests or “super-colonies”. Disturbance of a nest evokes an immediate aggressive response and the rapid removal of brood to lower levels.
An odour trail pheromone is produced in the poison gland, a gland associated with the sting (Blum 1966).
Often associates closely with another endemic ant species, Discothyrea antarctica (Moore 1940), and with plant-sucking homopterans. Moore strongly suspects that D. antarctica (particularly the active queens) occupies galleries in the nests of H. striata in order to prey on mites parasitising the Huberia workers. The association between the two ant species appears to be purely opportunistic on the part of D. antarctica.
Root-feeding aphids, scale insects (coccids) and mealy bugs (pseudococcids) have been observed inhabiting the nests of H. striata and being tended by the ants for their sweet excreta. W.W.Smith (1896) found a large yellow coccid, Dactylopius arecae Maskell [now called Chlorizococcus arecae (Maskell)] in colonies of the ant at Ashburton and elsewhere on the Canterbury Plains. At Mt Somers he observed D. poae Maskell [now called Balanococcus poae (Maskell)], a large slate-coloured pseudococcid, associated with this ant. He noted that the pseudococcid and a species of woolly aphid were a great attraction, the ant workers ensuring a clear passage alongside the homopteran-infested roots so as to facilitate “milking”.
Readily sampled in pitfalls and attracted to protein baits.
We have had reports of people being stung (multiple times) at sites within native forests; likely where nests have been distributed. Those stung reported pustules forming at the site of the sting.