Ecological Observations on the Spinifex Ant, Ochetellus flavipes (Kirby) (Hymenoptera: Formicidae), of Australia's Northern Arid Zone

Ochetellus flavipes constructs covered runways across the surface of the ground by fastening grains of sand together with resin from spinifex grasses (Triodia and Plectrachne spp.), and travels inside the runways from its nests to the spinifex hummocks. the ants also build shelters from the same material enclosing mealybugs, Prorsococcus acanthodus, which are tended on spinifex by the ants. the ants occur patchily, and are known from less than 30 localities across a vast area of northern Australia. Topographic positions of these localities suggest that peculiarly favourable moisture conditions are necessary to support both mealybugs and attendant ants. Microclimatic conditions and thermal tolerances of the ants were assessed to investigate the possibility that the runways allow the ants to ameliorate their thermal environment, but the results do not support this notion. We suggest that the structures may serve as protection from predators and/or parasites.