Ants (Family Formicidae)

green-head ant A green-head ant carries off a wattle seed that is specially designed to be spread by ants. The white part, called an elaiosome, is full of fat. It attracts ants who take the seed back to their nest. Caterpillar of an Imperial Hairstreak Butterfly, Jalmenus evagoras, and a leafhopper are tended and protected by Iridomyrmex gracilis ants The caterpillar of an Imperial Hairstreak Butterfly, Jalmenus evagoras, and a leafhopper are tended and protected by Iridomyrmex gracilis ants. In return they supply the ants with a sugary secretion.

All ants belong to the family Formicidae and together with wasps and bees belong to the Order Hymenoptera. There are lots of different ant species. In Australia alone there may be more than 3000 different species of ants, but so far only around 1300 have been scientifically named.

Ants are social insects that live in colonies. Their colonies are perennial, meaning they survive from one year to the next. The size of a colony depends on the species of ant. They range from a few tens or hundreds of individuals to several millions.

Many people regard ants as pests. Some species come inside houses looking for food or water. A few can even live indoors, nesting in wall cavities and ceiling spaces or sometimes inside electrical appliances. Outdoors their nesting activities can destabilise paved areas and play havoc with lawns, playing fields and golf courses.

Ant stings can be very painful but are usually short-lived. However, people who are sensitive to ant venoms can suffer severe allergic reactions. In the worst cases stings can be life-threatening, but deaths are rare.

Finally, a few introduced ant species are among the worst environmental pests. These invasive species can build up in huge numbers and affect native plants and animals.

In spite of their bad reputation ants play very important roles in the environment. They are major predators of other insects and invertebrates and some are important seed feeders. Conversely, ants provide an important food source for many animals including other insects and spiders as well as many reptiles, birds and mammals.

Many species of ants nest in the ground and their excavations help to turn and aerate the soil. Their tunnelling also helps rainfall to penetrate the soil.

Some plant species have seeds that are specially designed to be spread by ants. Australia has more plant species with seeds that are spread by ants than anywhere else in the world.

Ants also form close relationships with many other animals and plants. Some plant species grow special cavities in which particular ant species nest. In return the ants attack insects and other animals that try to feed on the plant. These close relationships between ants and plants are not very common in Australia compared to other tropical countries.

The caterpillars of some butterfly species are tended and protected by ants. In a few rare cases the butterfly caterpillars live within ant nests and feed on ant larvae. Australia has more species of these 'predatory' butterflies that anywhere else in the world.

Learn more about Australian ants

CSIRO’s ‘Ants Down Under’ is an excellent site providing information on the biology, identification and distribution of Australian ants.

The Australian Ants. 2000. Their Biology and Identification. Monographs on Invertebrate Taxonomy Series Volume 3. S. Shattuck, CSIRO publishing.

Ants of Brisbane. 2007. Burwell, C.J. Queensland Museum, Brisbane. 68 pages.

Tetraponera punctulata ants gang up on a moth caterpillar. Ants are major predators of other insects.Funnel ant, Aphaenogaster longiceps, nest entrances stand out against a burnt landscape. In many environments ants move more soil than earthworms.

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