ECOLOGICAL OBSERVATIONS ON THE SPINIFEX ANT, OCHETELLUS FLAVIPES (KIRBY) (HYMENOPTERA, FORMICIDAE), OF AUSTRALIA NORTHERN ARID ZONE

Ochetellus flavipes constructs covered runways across the surface of t he ground by fastening grains of sand together with resin from spinife x grasses (Triodia and Plectrachne spp.), and travels inside the runwa ys from its nests to the spinifex hummocks. The ants also build shelte rs from the same material enclosing mealybugs, Prorsococcus acanthodus , which are tended on spinifex by the ants. The ants occur patchily, a nd are known from less than 30 localities across a vast area of northe rn Australia. Topographic positions of these localities suggest that p eculiarly favourable moisture conditions are necessary to support both mealybugs and attendant ants. Microclimatic conditions and thermal to lerances of the ants were assessed to investigate the possibility that the runways allow the ants to ameliorate their thermal environment, b ut the results do not support this notion. We suggest that the structu res may serve as protection from predators and/or parasites.