Technomyrmex jocosus Forel 1910

Compiled by Warwick Don & Richard Harris 2005. Updated Darren Ward 2009

Biostatus: Introduced

Classification

Family:	Formicidae
Subfamily:	Dolichoderinae
Tribe:	Dolichoderini
Genus:	Technomyrmex
Species:	jocosus

Common name(s)

White-footed house ant

Synonyms (WWW5 )

Origin

The first record for New Zealand appears to be a single male collected in Nelson in 1921. This species was misidentified by Brown (1958a) as Technomyrmex albipes. In a worldwide revision of the genus, Bolton (2007) discovered that the New Zealand specimens were not T. albipes but T. jocosus (an Australian species). Subsequent checking of specimens in NZAC and other samples from around the country has only identified T. jocosus as being present in New Zealand.

Distribution

In this country it has become well established, both outdoors and indoors, in northern and eastern regions of the North Island (including northern offshore islands), Waikato, and Wellington and Nelson provinces. Further south (Christchurch and Dunedin) it appears to be restricted to indoors. The genus has been intercepted at ports on many occasions, particularly in association with cut flowers.

General Description

Identification

The mandibles have 7–10 large teeth and 2–15 denticles. The front margin of the clypeus has a broad, shallow concavity in the middle, or has a distinct central notch. The petiolar scale is reduced or absent.

Diagnostic features of the worker

Length 3.0 to 3.4 mm; antennae 12-segmented; mandibles with 10 teeth and numerous denticles; petiolar node is flattened; colour of body black or dark brown, legs pale.

[Technomyrmex jocosus] head. Image: Erin Prado (Specimen code: CASENT0178864). www.antweb.org Image — Technomyrmex jocosus head. Image: Erin Prado (Specimen code: CASENT0178864). www.antweb.org

Technomyrmex jocosus profile. Image: Erin Prado (Specimen code: CASENT0178864). www.antweb.org

[Technomyrmex jocosus] dorsal view. Image: Erin Prado (Specimen code: CASENT0178864). www.antweb.org Image — Technomyrmex jocosus dorsal view. Image: Erin Prado (Specimen code: CASENT0178864). www.antweb.org

Biology

Technomyrmex is one of only a few ant genera that (in some species) exhibit a remarkable male and female polymorphism. Three types of female are to be found in a colony: (1) queens — winged females; (2) intercastes — wingless females that have a spermatheca (a storage receptacle for sperm); (3) workers — wingless females with no spermatheca. Dealate queens (previously winged females) are rare or absent within a colony.

Reproduction of established colonies is performed by intercastes inseminated by wingless males from the same colony. The winged females (potential queens) and the winged males copulate outside the nest only after the nuptial flight. New colonies are founded by dealate queens, but they are eventually supplanted by intercastes. Thus, inbred wingless reproductives allow the enlargement and budding of colonies, often resulting in the formation of huge polydomous colonies (single colonies that occupy more than one nest) containing millions of individuals.

In New Zealand, T. jocosus has been found nesting in rotting logs, under loose bark and in soil under stones. This species exploits forested and open habitats. Technomyrmex species are general scavengers, form long foraging trails and often enter houses in search of food and water. Workers can be recognised by their habit of raising the abdomen while in motion.

Nests are often in dry sites off the ground outdoors (e.g. in rotten wood, under loose bark on trees) and in wall cavities of buildings (Deyrup et al. 2000).

Pest Status

Can reach very high densities in buildings and are difficult to control (baits typically not effective as not transferred between workers, so large quantities needed to control nests). Workers frequently forage indoors and form trails indoors or outdoors. Farm sap-sucking Homoptera (Samways et al. 1982). Commonly collected in forest but their impact in native habitats is 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.