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Ants are social insects and are made up of a head, thorax, petiole and abdomen and six legs. They live together in colonies of many individuals supporting at least one queen. They comprise three main castes which have different roles.
Workers: the vast majority of the population. They build and maintain the nest, care for the eggs and larvae, gather or hunt food, defend the nest and care for the queens.
Queens: mate with males, found colonies and lay eggs.
Males: their sole purpose is to mate with a queen.
The workers tend to be smaller than the queens and are all female but infertile. Occasionally though, they will lay eggs which are used as food. Before mating season in the summer, fertile male and female eggs are laid. These hatch into queens and males. The queens are usually larger and are winged but after their one mating flight they bite or rub off their wings and either make a new nest or return to an existing one to breed. The males are also winged but they die after their mating flight (hope it was worth it!). The mating flights occur in summer when the males and virgin queens take to the air in swarms and mate. The queen only needs to mate once to be able to lay eggs for her whole life.
The ants' eggs hatch into larvae which are completely helpless and are fed on liquid food. If they are the first workers born to a new colony the food is provided by the queen; if not, it is provided by other workers. Once there are enough workers to care for the young, the queen will do nothing but lay eggs. The larvae moult several times and finally form a cocoon called a pupa from which they hatch as a fully-formed adult. This happens in special chambers in the nest and there are different chambers for food, stages in development and for the queens.
Most native British species 'milk' aphids for the sweet liquid honeydew which they secrete. The ants stroke the aphids with their antennae to make them secrete the liquid. In return, the ants defend the aphids from predators and other competing insects. Other creatures live in ant nests; these include the white woodlouse and bristletail which eat the ants' waste and so are tolerated by the colony. Some small species of worm also help keep down mould and fungi in the nest.
The irritant substance in the sting of ants is formic acid, nowadays named systematically as methanoic acid. Formic acid was discovered in 1670 by Rey, who distilled red ants with water. Formic acid was named after the Genus name of red ants, and also occurs in the stinging hairs of nettles.
Ant swarms happen often in the summer and it was once believed that they were able to predict thunderstorms.
Some birds, such as jays, put ants in their feathers because they help to keep down mites.
If you have to eat ants, they must be cooked for at least six minutes before eating in order to destroy the poison.
Ants are the most common animal species found on the ground. Some scientists estimate that ants make up fifteen to twenty percent of the animal biomass in the world.
Main Ant Species in Britain
There are around fifty species of ant in Britain but not all are native. Greater varieties of species are found in the south as the climate is warmer for those introduced from abroad.
Black Ants (Lasius Niger)
These ants are the most commonly seen as they are likely to live in gardens and are the species most likely to invade human houses in search of food, although they will not usually live there. They are not in fact black but are dark brown in colour and the workers are about 4mm long, though the queen can be up to twice that. They nest underground and bring the mined-out soil to the surface which often forms a small flattish mound. Black ants are omnivorous and will bring back insects, fungi, seeds or honeydew to the nest for food.
Jet Black Ant (Lasius Fuliginosus)
These are black with yellow legs and heart-shaped heads and are about 5mm long. They nest in hedges and stumps and are mainly found in the south-east of England.
Yellow Meadow Ants (Lasius Flavus)
They are a pale yellow and the workers are about 3mm long. These ants build their nests underground in grassy areas, creating a mound above them, and are the most skilled nest-builders in Britain. This can be seen most spectacularly at the Defence Science and Technology Laboratory base in Porton Down. Here there are about three million yellow ant mounds with over 35 billion ants living in them, covering 20 species. It is one of the most important natural sites in Britain. The ants benefit from the short grass which makes sure the ant hills get enough sun to stay warm - some of the mounds are up to 100 years old. The yellow meadow ant also does the majority of its foraging underground, even farming aphids in the nest, and so it is rarely seen on the surface, except in the mating flights or if the nest is disturbed. However, yellow meadow ants are widespread around Britain, especially in the south of England.
Red Wood Ants (Formica Rufa)
These ants are orange in colour and have a darker head and abdomen. As the name suggests, they tend to live in woodland, often building their nests over tree stumps. They build very complex nests, most of which are above ground in a mound. The nests have ventilation passages and the entrances can be opened and closed by the workers to regulate the temperature. This system is so efficient that the temperature in the nest hardly differs from that of the surrounding soil. Where heat is needed, such as near the developing ants, some workers will 'sunbathe' to bring heat into those chambers. Wood ants hunt for food, particularly the larvae of other invertebrates such as the sawfly. The ants are capable of squirting formic acid from their abdomen in order to attack prey or to defend their nest. The wood ants Formica Aquilonia and Formica Lugubris are endangered.
Negro ant (Formica Fusca)
This is another type of wood ant, but is black in colour. It is mainly found in southern and central England. The worker can be up to 6mm long. These ants tend to make their nests under rotting logs and there are rarely more than 1000 in a colony. Similar is the Formica Lemani, but this can live further north and at higher altitudes.
Slave-making Ants, or Blood-red Ants (Formica Sanguinea)
Slave-making ants are the largest native species in Britain. These are also a type of wood ant, but they do not make mounds for their nests. The slave-making occurs in two ways. A queen will go to a nest of another formica ant and kill the queen, taking the nest over and using the workers to bring up her eggs. The original kind of ant will eventually die out without the queen to reproduce for them. Another way in which the slave-making occurs is that workers from a slave-making ant colony will raid other nests of their larvae and pupae and raise them as auxiliary workers. These ants are only found in small areas of south-east England and north-east Scotland.
Turf Ant (Tetramorium Caespitum)
Dark brown in colour, this ant lives in the south and east of England under stones in heath land. The worker is about 3mm long. It is a stinging ant living in colonies of up to 30,000. They apparently bury their food in mounds of soil.
Red Ant (Myrmica Ruginodis, Sabuleti and Rubra)
Red ants live throughout the British Isles and the worker is about 6mm long. They can have a painful sting, but it should be noted that they will only do this if they think they're about to get eaten. They tend to live in fairly small colonies of only 300 individuals. The sabulti farmed the caterpillar of the Large Blue butterfly, keeping it in the nest and letting it eat ant larvae in return for milking it. The caterpillar gives off a scent which makes the ants believe it is one of their larvae. When the caterpillar matures it leaves the nest. These butterflies became extinct in Britain in 1979: to changed farming practices led to the decline of the ant which was vital to its life-cycle.
Ants of the World
Some ants already have their own Entries on h2g2:
There are several species of leaf-cutter ant. The best known, Atta sexdens, is an animal of the tropical rainforest.
Members of the Solenopsis genus, fire ants are named after the fiery pain and burn-like effects of their stings.
Pharaoh's Ants are yellow in colour and were introduced to Britain from tropical climates.
Weaver Ants (Oecophylla Smaragdina)
Weaver ants are one of the most fascinating species. They are reddish-brown in colour and live in trees and fields across India, south-east Asia and Australia. Unlike any other ants they use fresh leaves to build their nests. Chains of workers pull the leaves into place where they are sealed by silk produced by the ants' own larvae. The colony may have several nests but the queen lives in one only. They are carnivorous, but will also eat nectar which plants such as the Sea Hibiscus (Hibiscus Tiliceaus) and Great Morinda (Morinda Citrifolia) produce. These plants secrete the nectar so that the ants will protect them from leaf-eating insects and animals.
Army Ants (Eciton Burchelli)
Unusually, army ants do not have permanent nests. For a time, they wander nomadically and when a nest is needed the workers form it with their bodies. Sometimes new colonies are started by workers simply beginning a new nest and raising a queen.
Honeypot Ants (Myrmecocystus Mexicanus)
Honeypot ants are found in the hot, dry places of Africa, North America and Australia. They have a special caste of workers called 'repletes' whose function is to store food in their large abdomen, and are regarded as a delicacy in some areas. This adaptation means that the ants can survive in drought when food is scarce.
Bull, Soldier or Bulldog Ants (Myrmecia Gulosa)
These are found in Australia and get their name from their habit of grabbing hold of objects with their mandibles and hanging on. Bulldog ants have a red head and thorax and a dark abdomen. Their nests are underground, but a small mound is created above them and soldiers guard the entrance. They are the largest ants at between 8-10mm, and have a painful sting in the abdomen which can cause an allergic reaction. Their sight is good and if disturbed they will run straight for the cause of the disruption. They only have small colonies and are not as highly developed as other ant species. The adults mainly eat honeydew and nectar, but the larvae are carnivorous and so the workers hunt insects to feed them.
Jumper or Hopper Ants (Myrmecia Pilosula)
Jumper ants are found in Australia; they build mounds up to 20cm high and the tunnels can be a metre deep. A disturbed ant can perform a series of 5cm jumps to escape. They eat honeydew and get protein to feed the larvae by hunting insects which they sting then carry back to the nest.
Argentine Ant (Iridomyrmex Humilis)
Argentine ants are about 2mm long and light brown in colour. They were imported into Britain, where they can only survive in heated buildings, and America in the late 19th Century. They have spread across north and south America, and also occur in Africa. In America they have succeeded in driving away native species from any territories they invade. They are even disrupting the ecosystem, as some creatures depend on native ants for food, for example the horned lizard. Argentine ants have many queens in a colony - as many as one for every 125 workers. They rarely swarm and they usually mate in the nest.