DESCRIPTION
This small ant is yellow-brown in colour with well-developed black eyes. Workers tend to be 1.5-2mm long, while the male is slightly larger at 3mm long and is a darker black colour with wings. The Queen is 3.6-5mm long, she is dark red and winged.
Widely distributed across Australia, they need warm, humid conditions which mean that in temperate lands they are confined to buildings and often found infesting hospitals.
The insects locate themselves in the fabric of buildings (wall voids, windows etc.) or in plants and sterile supplies. They can spread through service ducts (e.g. heating and electrical conduits). The ants forage for water around sinks and areas of condensation.
Pharaoh ants are a major hazard in hospitals, where their small size means they can access wounds, driplines, and instrumentation, causing the spread of infection and electrical interference.
behaviour
There are several queens in one nest (polygenic). Winged Pharaoh ants do not fly. The queens are interchangeable, so colonies survive indefinitely. Disturb, rather than destroy the nest, and there is a strong likelihood that you will encourage a new colony.
These social insects live in colonies from a few dozen to 300,000 ants. The ants can survive low temperatures for prolonged periods where the workers continue to forage for food.
Inside a Pharaoh’s ant nest. Thousands of workers care for the eggs, larvae and pupae. Pharaoh’s ants have multiple queens – three are visible in the picture, including one unmated queen with wings. The black-bodied winged insect in the centre is a male. Pharaoh’s ants do not rely on flight of the reproductives for dispersal – instead new colonies bud off from established ones, with workers carrying brood to new locations. This makes them a highly successful pest species.
habits
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The Pharaoh ant is polygynous, meaning its colonies contain many queens (up to 200).
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An individual colony normally contains 1,000–2,500 workers but a high density of nests gives the impression of massive colonies.
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Elimination and control are made difficult because multiple colonies can also consolidate into smaller colonies and be unaffected by a baiting program only to repopulate when baiting is withdrawn.
