Ants are very common minded citizens of the insect world. They have kings, queens and immature stages back in the nest. The ones you usually find foraging through your kitchen, your garden and around your back door are the workers and maybe some soldiers. Some ants have painful stings but mainly they are pests because so many of them turn up uninvited at your home.
Winged males and females reproduce and leave a mature colony to set up on their own in a moist and secure crevice. They drop their wings and produce eggs which hatch into larvae and pupae that have to be tended and fed by the ‘royal’ couple. The young become sterile female adults or workers and they soon take over the operation, defence and extension of the nest and forage for food.
Later on, some species, such as the Coastal Brown and Singapore Ants, develop big headed soldiers or majors (also sterile females) that specialise in defending the colony. Argentine and Pharaoh ant colonies have many queens and millions of workers in an enormous conglomeration of interlocking nests.
Adults have elbowed antennae , a thorax and a globular abdomen with a sting on the tip. The eggs, larvae and pupae are usually white and immobile; often these can be seen being carried by workers to a new nesting site.
Of the thousands of different species of ants in Australia only a few are considered pests in and around our buildings. Individual size seems to be relevant to pest status. The large bull ants, trigger ants, sugar ants, meat ants and even the greenhead ants are of minor consequence if you’re not a keen gardener or you haven’t been stung. These ants seldom come inside buildings. It’s the small bland and brown ants (up to 5mm long) that develop large, hard to find colonies that are of the most concern.
They can undermine pavers and the root zones of plants, they can damage and short-circuit electrical components, enough to cause fires, and they can transfer viral, fungal and bacterial plant diseases while removing the sweet secretions from aphids, bugs and scale insects.
If it can possibly be considered to be food, there is a species of ant that will take whatever it is back to their nest. There’s a fairly loose generalisation that brown ants prefer protein and black ants prefer carbohydrates and that brown ants are more likely to nest in the building and blank ants outside. Just don’t count on it. It is also said that a surge in ant numbers and black ants moving their young and nest up into a building is a good indicator of rain. Don’t count on that either.
Although ants have comparatively powerful jaws and they do bite, the pain comes from the hypodermic sting or from venom sprayed from the tip of the abdomen over the bitten area. Large painful welts are almost instantaneous and allergic reactions have caused deaths.