All ants everywhere belong to the family group Formicidae and are closely related to wasps and bees. There are thousands of different species of ants worldwide and over 3 000 species in Australia. However, there are only a few of these that pose a problem to humans. In Queensland, the two that are most likely to be seen in homes, businesses and other buildings are the Black Ant and the Coastal Brown Ant.

black house ant

Identifying Characteristics

All ants have a distinct, narrow “waist”. The black ant is 2.5 to 3mm long, black in colour (surprise). The coastal brown ant is light brown in colour, dimorphic with small minor workers (1.5 to 3mm) and larger (3.5 to 4.5mm) major workers with very large, darker heads. Males have wings; females have wings until mating then remain the reproductive queen ant. Worker ants are sterile and exist to serve the colony while soldiers protect the nest from predators. Larvae are a whitish grub that narrows towards the end.

Life Stages

The queen lays the eggs which develop into larvae then pupa and finally adult. The reproductive queen of the colony can live for many years, but the life span of the others is approx. 1 year.


The Black Ant rarely nests in the soil, preferring instead the outdoors next to paths, rockeries and in crevices. However it does nest indoors in wall cavities, ceilings, doors etc. The Coastal Brown Ant generally nests in the soil with nest openings under rocks, between pavers or even in the open.


Sweet foods will draw the Black Ant but they will also eat plants, seeds and fats, while the Coastal Brown Ant prefers fatty substances but will also eat similar foods if necessary, as well as meats, fruit and honeydew from aphids. The Blank Ant needs moisture and this is the main reason they invade the wet areas in homes.

Detrimental Effects to Humans and Property

Both species are more a nuisance to humans than a danger. However, the Coastal Brown Ant has been known to damage electrical wiring such as hot water systems. Both species leave trails which can be unsightly, and the debris and droppings from nests inside the house need constant cleaning.

Eradication/Control Mechanisms

Because ants live together in colonies, and the eradication of the queen will destroy the colony, using their foraging instinct to take contaminated matter back to the nest is an excellent control mechanism. Barrier treatments to keep the ants separated from the food source are also successful, and often a combination of the two will provide the perfect solution.

The team at Bob Gunn Termite Solutions are trained, experienced and licensed to advise on the best method for ant control, and will offer a solution that suits each individual circumstance.

Ant proof your home with treatments that work, call us today on 07 3286 9877.