Scientists believe ants evolved from wasps in the Cretaceous Period, about 110 million years ago. Theearliest fossil ants have been found in North American amber, which has been dated at 94 million years old.
The ant fauna of Australia is especially large and diverse. World-wide, there are 16 subfamilies, about 300 genera and about 15,000 described species and subspecies. Thus Australia currently has representatives of two-thirds of the world’s ant subfamilies, one-third of its genera and, as far as we know, about 15% of its species.
After hatching from an egg, they begin life as larvae. The differentiation of the female castes (into queen and worker sub-castes) is largely determined by environmental factors such as:
The amount and quality of food;
Temperature ; and
Hormones produced by workers and the queen.
Males usually develop from unfertilised eggs.
Workers generally live one to three years depending on the species and climate.
Queens usually live much longer than the workers, some species having been kept in laboratory nests for up to 29 years.
Males generally live only for a few weeks and die within a day or two of leaving the nest on nuptial flights.
Most ants are general predators or scavengers. Solid prey, which is most often seen being carried by workers, is intended as food for the larvae.
Adult ants feed exclusively on liquid foods. They collect these liquids from:
While tending hemiptera (true bugs) and other insects; and
From plant glands on plants.
Returning foragers pass the liquid food to other adults, especially those that remain in the nest (such as the queen). Trophallaxis occurs when liquid food that is stored in the forager’s crop is regurgitated for nest mates on demand.
Ants are one of the few groups of animals which modify their immediate environment to suit their needs. They build often elaborate nests in a range of situations, sometimes expending huge amounts of energy in their construction. Only a handful of animals manufacture such elaborate and complex structures.While many ants form elaborate nests, those of other species are relatively simple. Many of the species found in rotten wood do little more than remove loose wood fibres to construct simple chambers for workers and brood. Others nest arboreally. Their nests are most frequently found in twigs, branches or the trunks of trees.
Ants are social insects which form small to large colonies. Communication between members of a colony is almost entirely chemical, with some tactile communication.
Ants use pheromones to:
Recognise colony members;
Mark trails to food/water sources;
Determine caste; and
Signal attack and defence.
Tactile communication is mainly used as requests for food between adults.
Some species, such as bulldog or bullants, are troublesome because they give painful stings, while the venom of jack-jumper or jumper ants can cause severe allergic reactions. Unlike bees that can only sting once, ants can sting multiple times. Others, such as meat and green tree ants, don’t sting but bite and then spray formic acid into the wound.
Some ants are nuisance pests when they make mounds, disturb paving or invade buildings.
Some introduced species are both nuisance and environmental pests, including:
Argentine ant (Linepithema humile);
red imported fire ant (Solenopsis invicta);
crazy ant (Anoplolepis gracilipes);
electric ant (Wasmannia auropunctatata); and
big headed ant or coastal brown ant (Pheidole megacephala).
Coastal Brown Ants (pheidole megacephala)
Ranging in color from yellow to brown, coastal brown ants are about 1.5-2.5 mm in length and tend to nest in soil along houses and in gardens. They prefer dry areas for nesting, where they will lay very small eggs and attack nearby food sources like meat, fruit and other sweet foods, and oily foods. As adults, they form three different castes within their colonies—winged males, winged females, and wingless workers. While winged males only exist to mate with females, the wingless workers are sterile and perform the duties of constructing and defending the nest and young, as well as supplying food. Winged females are the largest in size within the colony and are the reproductive queens.
Argentine Ants (linepithema humile)
On the smaller side and dark brown in color, Argentine ants are a non-swarming species of ant that reproduce in the spring and continue to increase in numbers until autumn. The nests are not easy to track as workers will travel long distances to find and retrieve food. Though they prefer sweet foods, they will also eat live and dead insects, meats, cereals, and fruit. These ants do bite, though they will not sting, so exercise a bit of caution if you notice them.
Black House Ants (ochetellus)
Shiny, black and a bit larger (between 2.5 and 3 mm), black house ants are most likely to spread diseases like salmonella for their tendency to scavenge in household kitchens and garbage. These ants are highly attracted to sweets and are even known to go through dog excrement to find food. Their larvae hatch as tiny white grubs that sometimes have a protective cocoon around them. To control these ants, the colony must be treated with exterminating agents.
White-footed House Ants (technomyrmex difficilis)
These dark brown to black-colored ants are noticeably different from other species for their distinct, white feet. These ants do not bite or sting, but they colonize in large numbers and can even spread one colony into several smaller, satellite colonies. Trees are an ideal nesting area for this species for the loose bark and plant debris close to them, but they will also occupy tunnels and galleries created by termites. Indoors, they will almost always be found near where food is stored or prepared, so finding them in pantries would not be unusual. They are strongly attracted to sweet foods and plant nectars. Unlike other species, both the winged AND wingless males mate with females, though the wingless males are capable of mating multiple times where winged males will only mate once before they die.
Bulldog Ants (mymecia)
Usually red or black, these ants are quite sizable and often range between 18 and 20 mm. Unlike most species of ants, these are rather aggressive and can attack when their nests are disturbed. They have a stinger which will not remain in their attack victims (allowing them to sting repeatedly) but is very painful to humans. These ants live outdoors in bushy areas and are rarely seen indoors. They feed on other insects, plant nectar and fruit. Like many other species of ant, there is a caste system to their colonies—worker ants, soldier ants, the Queen and the Male, whose job it is to mate with the Queen.
Fire Ants (solenopsis spp)
Copper-brown with dark brown abdomens, fire ants are large ants with distinctive two-segment antennae that very much resemble clubs in their appearance. The males range anywhere from 3.2 to 6.4 mm in length, while the Queen is usually the largest at 1.4 cm long. Fire ants swarm and mate in mid- to late summer—the males usually die after mating. Their workers will forage for a wide range of food, from dead animals and insects to sweet foods like fruit. The Queen will lay as many as 125 eggs in the spring and when larvae hatch, they will feed on secretions from her salivary glands. These ants are aggressive pests within agricultural and urban communities, often found both indoors and outdoors.
Black Garden Ants (lasius niger)
Usually found outdoors, below slabs of pavement and near sunlit building sides, garden ants are an exceptionally common species of ant with a nest that can be easily identified by a small exit hole surrounded by finely ground soil. They are black in color and workers are usually around 4-5 mm long. The Queen is, as usual with many ant species, much larger and can reach 15 mm in total length. These ants are not aggressive and do not sting or bite. Eggs usually hatch in the spring and worker ants are the primary members of the colony forage for food and protect the nest.
Ghost Ants (tapinoma melanocephalum)
The name of the ghost ant is attributed to its pale, and often translucent abdomen. Their heads are darker, making them a bit more visible, and they are roughly 1.5 mm long. They feed on greasy food in addition to sweets when they are found indoors. When they are found outdoors, they are often found eating sweet foods like melon. Because they can be found both indoors and outdoors, their nesting habits are varied. Indoors, they prefer small spaces and are often drawn to moist, damp areas like kitchens and bathrooms. Outdoors, they’re likely to be seen in planters or flower pots, or under loose bark on the ground. The colonies breed continuously and can occupy many different sites for nesting.
Pavement Ant (tetramorium caespitum)
The dark brown or black pavement ant is a smaller species noted for the two spines on their backs. The winged pavement ants can sometimes be mistaken for termites. This species of ant is one that is most commonly seen during the spring and summer months. Their colonies are most often found near water, but look under large rocks, wooden boards, or other outdoor items as well to identify if it is their habitat. They are capable of moving through plumbing and electrical wires and they most often invade homes at night to look for food. Their diet is inclusive of any food that humans eat and they will even eat pet food.
Pharaoh’s Ant (monomorium pharaonis)
The Pharaoh’s ant, yellow-brown to brown in coloring with black eyes, is a small ant that lives in multi-queen colonies. The queens and mating males both have wings that are reddish in color. The males’ wings fall off after mating. Swarming can take place at any time of year. These ants have sophisticated trails and they are often associated with heating systems. They like humid conditions and will often build colonies there. When their colonies are disturbed, Pharaoh’s ants can split into multiple new colonies. These ants have a high-protein diet, often feeding on meat, animal blood and fats, or other dead insects.