Technomyrmex jocosus

Technomyrmex jocosus is a distinct and very widespread species that forages extensively in leaf litter, in dead trees and under the bark of fallen trees, on shrubs and low vegetation, and on trunks and branches of standing trees. It sometimes enters houses in Australia (Steven O. Shattuck (ANIC), pers. com.) and a series from Sydney University see below) was collected in a laboratory building. Worker-queen intercastes occur in this species, as do ergatoid males. (Bolton 2007)

Identification
Bolton (2007) - A member of the T. pallipes complex in the Technomyrmex albipes group. The cephalic pilosity of jocosus most closely resembles that of Technomyrmex cheesmanae and the four species related to Technomyrmex quadricolor. However, in all of these the longest setae on the dorsum of the head (in profile located just anterior to the posterior margin), and the longest on the first gastral tergite, are all distinctly longer than the maximum diameter of the eye. In addition, quadricolor and its relatives all have the head unsculptured, smooth and highly polished, and have the eyes located more posteriorly.

Heterick (2009) - Very similar to the better-known exotic Technomyrmex albipes but can readily be differentiated through its shinier, less sculptured head capsule and different arrangement of erect setae on the frons.

Distribution based on Regional Taxon Lists
Australasian Region: Australia, Lord Howe Island, New Zealand, Norfolk Island.

Biology
Heterick (2009) - Occurs in the SWBP, where it is something of a nuisance in some Perth suburbs and, occasionally, in country towns. Outside of houses, workers are most often seen trailing on fence-lines or on tree trunks. Within the central SWBP the species can also be found in disturbed areas such as parkland but does not appear able to penetrate large areas of native vegetation. However, further south, where it may be indigenous, the author has found T. jocosus in enormous numbers on karri and tingle trees near Pemberton, and in Banksia woodland west of Albany.

Nomenclature

 *  jocosus. Technomyrmex jocosus Forel, 1910b: 56 (w.) AUSTRALIA. See also: Bolton, 2007a: 114.

Worker
Bolton (2007) - TL 2.5 - 3.1, HL 0.64 - 0.70, HW 0.60 - 0.66, SL 0.58 - 0.64, PW 0.40 - 0.43, WL 0.81 - 0.90 (12 measured). Indices: CI 90 - 95, SI 94 - 102, OI 25 - 29, EPI 74 - 80, DTI 126 - 135.

With head in profile the dorsum behind the clypeus with numerous pairs of setae: frontal carina with 3 - 4 setae; dorsum above eye with 2 - 4 pairs; dorsum behind level of posterior margin of eye with 2 - 3 pairs; posterior margin usually with an additional short seta on each side, close to the comers. All of these setae are distinctly shorter than the maximum diameter of the eye. With head in full-face view the moderately sized eyes are located just in front of the midlength of the sides, their outer margins just touch or just break the outline of the sides; posterior margin has a slight median indentation. Shagreenate-punctulate sculpture of dorsal head fine and superficial. Number of setal pairs on mesosoma: pro not urn 2 - 4; mesonotum 1 - 3; propodeal dorsum 0; lateral margins of propodeal declivity 1 - 2. Mesonotal dorsum in profile evenly convex. Propodeal dorsum short, junction of dorsum and declivity angular but blunt, in absolute profile not sharply angled. Gastral tergites 1 - 4 each with numerous setae present; longest setae on the first gastral tergite are shorter than the maximum diameter of the eye. Head, mesosoma, petiole and gaster uniform blackish brown to black. Middle and hind coxae, femora and tibiae the same colour as the mesosoma and gaster or fractionally lighter; tarsi dull yellow.

Type Material
Syntype workers, Australia: Victoria, Yarra District (Froggatt) [examined].



Determination Clarifications
Bolton (2007) - This is probably the species that Shattuck (1999) had in mind when he wrote that they, “enter through small cracks and, on finding a suitable food source, form distinct trails with many workers travelling between their nest sites and the food source”; jocosus is probably also the “black house ant” of Clark (1941). A series from Bicheno, Tasmania was collected from “light fixtures in caravan”. An earlier reference to ants nesting in electric switches in New Zealand (Little, 1984) probably also refers to this species. T. jocosus is most likely the New Zealand species referred to as Technomyrmex albipes by Brown (1958). He wrote that the species is largely confined to urban areas in the North Island and around Nelson in the South Island. He added that it forms long foraging files and can become a serious pest both indoors and in gardens and orchards.