Ochetellus glaber (Mayr 1862)

Compiled by Warwick Don & Richard Harris

Biostatus: Introduced

Classification

Family:	Formicidae
Subfamily:	Dolichoderinae
Tribe:	Dolichoderini
Genus:	Ochetellus
Species:	glaber

Common name(s)

Black house ant (Andersen 2002)

Synonyms (WWW4)

Hypoclinea glabra Mayr, Iridomyrmex glaber (Mayr)

Valid subspecies

Glaber clarithorax (Forel)

Origin

According to Shattuck (1999), Ochetellus comprises 10 described species and subspecies, several ranging south from Japan in an arc which includes the Philippines, Fiji, New Caledonia and Australia (which has four species and subspecies). The United States possesses one introduced species. New Zealand, too, has an introduced species, Ochetellus glaber, which occurs also in Australia, the probable country of origin. The earliest record for New Zealand appears to be a winged female collected at Whangarei Falls (Northland) in 1927, and records show it was well established here by the late 1940s. It has been intercepted at ports on numerous occasions.

Distribution

Since its establishment, O. glaber has spread to most parts of the North Island and to urban Nelson. It has been found in both urban and rural areas. It seems to show a strong preference for exploiting the margin between forest and scrub, judging by the large number of samples of the ant recorded in this habitat.

General Description

Identification

The front margin of the clypeus in the genus is broadly and shallowly concave (it bears a central projection in the related genus, Iridomyrmex ). The metanotal groove is a narrow notch in the relatively flat surface of the mesosoma. The rear face of the propodeum is generally concave. The petiolar node is thin, vertical, not inclined forward and is expanded laterally.

Diagnostic features of the worker

Length 2.0 to 2.5 mm; antennae 12-segmented; mandibles with 8 teeth and 1 or 2 denticles; petiolar scale rounded and forming an even arch dorsally; colour shiny black or brown.

[Ochetellus glaber] head. Image: Erin Prado (Specimen code: CASENT0178874). www.antweb.org Image — Ochetellus glaber head. Image: Erin Prado (Specimen code: CASENT0178874). www.antweb.org

Ochetellus glaber profile. Image: Erin Prado (Specimen code: CASENT0178874). www.antweb.org

[Ochetellus glaber] dorsal view. Image: Erin Prado (Specimen code: CASENT0178874). www.antweb.org Image — Ochetellus glaber dorsal view. Image: Erin Prado (Specimen code: CASENT0178874). www.antweb.org

Biology

Only a few details of the biology of this species are known. O. glaber is well adapted for living in open or semi-open habitats in this country, nesting under stones or in dry fallen logs. Often found in domestic gardens; occasionally workers enter houses. They form conspicuous files on tree trunks in their search for honeydew and small insects and may nest aboreally, having often been seen trailing into holes in trees, fenceposts and flax flower stems (RJH pers. obs.).

Pest Status

Do not sting. In Australia, the genus is reported as "often foraging in houses where they show a preference for fluids and sweets" (WWW4). Not noted as a major house pest in New Zealand, although commonly collected in urban gardens and occasionally from houses. Commonly collected at forest and scrub margins (Harris et al. 2002) but impact in native habitats unknown. As it is an arboreal species it will likely occupy very different habitats from native ant species, none of which nest above the ground.