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Any of various social insects of the family Formicidae, characteristically having wings only in the males and fertile females and living in colonies that have a complex social organization.
idiom:ants in (one's) pants Slang.
[Middle English amte, from Old English ǣmete.]
For more information on ant, visit Britannica.com.
Social Organization
All species show some degree of social organization; many species nest in a system of tunnels, or galleries, in the soil, often under a dome, or hill, of excavated earth, sand, or debris. Mound-building ants may construct hills up to 5 ft (1.5 m) high. Other species nest in cavities in dead wood, in living plant tissue, or in papery nests attached to twigs or rocks; some invade buildings or ships. Colonies range in size from a few dozen to half a million or more individuals. Typically they include three castes: winged, fertile females, or queens; wingless, infertile females, or workers; and winged males. Those ordinarily seen are workers. In some colonies ants of the worker type may become soldiers or members of other specialized castes.
Whenever a generation of queens and males matures it leaves on a mating flight; shortly afterward the males die, and each fecundated queen returns to earth to establish a new colony. The queen then bites off or scrapes off her wings, excavates a chamber, and proceeds to lay eggs for the rest of her life (up to 15 years), fertilizing most of them with stored sperm. Females develop from fertilized and males from unfertilized eggs. The females become queens or workers, depending on the type of nutrition they receive. The first-generation larvae are fed by the queen with her saliva; all develop into workers, which enlarge the nest and care for the queen and the later generations. It is thought that the production of males by the queen and the rearing of new queens by the workers may be controlled by hormonal secretions of all the members of the colony. There are many variations on the basic pattern of new colony formation. In some species the queen cannot establish a colony herself and is adopted by workers of another colony. Slave-making ants raid the nests of other ant species and carry off larvae or pupae to serve as workers; in a few slave-making species the adults cannot feed themselves.
Feeding Habits
Different species differ widely in their diets and may be carnivorous, herbivorous, or omnivorous. Members of some species eat honeydew from plants infested with aphids and certain other insects; others, called dairying ants, feed and protect the aphids and “milk” them by stroking. Harvester ants eat and store seeds; these sometimes sprout around the nest, leading to the erroneous belief that these ants cultivate their food. However, cultivation is practiced by certain ants that feed on fungi grown in the nest. Some of these, called leaf-cutter, or parasol, ants, carry large pieces of leaf to the nest, where the macerated leaf tissue is used as a growth medium for the fungus. Most leaf cutters are tropical, but the Texas leaf-cutting ant is a serious crop pest in North America. The army ants of the New World tropics and the driver ants of tropical Africa are carnivorous, nomadic species with no permanent nests. They travel like armies in long columns, overrunning and devouring animals that cannot flee their path; the African species even consume large mammals.
Beneficial and Harmful
Ants as a group are beneficial to humans. Their tunneling mixes and aerates the soil, in some places replacing the activity of earthworms. Many species feed on small insects that are serious crop pests. House pests among the North American ants include the yellowish pharaoh ant, the little black ant, the odorous house ant, the Argentine ant of warm climates, and the black carpenter ant. Carpenter ants tunnel in wood but do not feed on it. The fire ant, which has a painful bite, is a serious pest to humans and livestock in many parts of the South.
Classification
Ants are classified in the phylum Arthropoda, class Insecta, order Hymenoptera, family Formicidae.
Bibliography
See publications of the U.S. Dept. of Agriculture; E. O. Wilson, Insect Societies (1971) and, with B. Holldobler, The Ants (1990); G. E. Ball, ed., Taxonomy, Phylogeny, and Zoogeography of Beetles and Ants (1985); J. H. Sudd and N. R. Franks, The Behavioural Ecology of Ants (1987).
Ubiquitous insects, which, among other things, act as intermediate hosts for the trematode Dicrocoelium dendriticum and cestodes Raillietina spp.
How narrow is the vision that exalts the busyness of the ant above the singing of the grasshopper.
— Kahlil Gibran
Tutor's tip: Giving a chocolate-covered "ant" to your "aunt" (sister of one's mother or father) for her birthday is likely to be disastrous!
| Ants Fossil range: Cretaceous - Recent |
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 Meat eater ant feeding on honey
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Ants are eusocial insects of the family Formicidae and, along with the related families of wasps and bees, belong to the order Hymenoptera. They are a diverse group of more than 12,000 species, with a higher diversity in the tropics. They are known for their highly organized colonies and nests, which sometimes consist of millions of individuals. Individuals are divided into sub-fertile, and more commonly sterile, females ("workers"), fertile males ("drones"), and fertile females ("queens"). Colonies can occupy and use a wide area of land to support themselves. Ant colonies are sometimes described as superorganisms because the colony appears to operate as a unified entity.
Ants have colonized almost every landmass on Earth. The only places lacking indigenous ant species are Antarctica, Greenland, Iceland, parts of Polynesia, the Hawaiian Islands, and other remote or inhospitable islands.[1][2] When all their individual contributions are added up, they may constitute up to 15 to 25% of the total terrestrial animal biomass.[3]
Termites, sometimes called white ants, are not closely related to ants, although they have similar social structures. Velvet ants, although resembling large ants, are wingless female wasps.
The Formicidae family belongs to the order Hymenoptera, which also includes sawflies, bees and wasps. Ants are a lineage derived from within the vespoid wasps. Phylogenetic analysis indicates that ants evolved from vespoids in the mid-Cretaceous period about 120 to 170 million years ago. After the rise of angiosperm plants about 100 million years ago, they diversified and assumed ecological dominance about 60 million years ago.[4][5][6] Several fossils from the Cretaceous are intermediate in form between wasps and ants, adding further evidence for wasp ancestry. Like other Hymenoptera, the genetic system found in ants is haplodiploidy.
In 1966 E. O. Wilson, et al. obtained the first amber fossil remains of an ant (Sphecomyrma freyi) from the Cretaceous era. The specimen was trapped in amber from New Jersey and is more than 80 million years old. This species provides the clearest evidence of a link between modern ants and non-social wasps. Cretaceous ants shared both wasp-like and modern ant-like characteristics.[7]
During the Cretaceous era, only a few species of primitive ants ranged widely on the super-continent Laurasia (the northern hemisphere). They were scarce in comparison to other insects (about only 1%). Ants became dominant after adaptive radiation at the beginning of the Tertiary Period. Of the species extant in the Cretaceous and Eocene eras, only 1 of approximately 10 genera is now extinct. 56% of the genera represented on the Baltic amber fossils (early Oligocene), and 96% of the genera represented in the Dominican amber fossils (apparently early Miocene) still survive today.[4]
Phylogenetic position of the Formicidae.[8]
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Ants are distinct in their morphology from other insects by having elbowed antennae, metapleural glands, and by having the second abdominal segment strongly constricted into a distinct node-like a petiole. Ants also have a narrow waist between their mesosoma (thorax plus the first abdominal segment, which is fused to it) and gaster (abdomen less the abdominal segments in the petiole). The petiole can be formed by one or two nodes (only the second, or the second and third abdominal segments can form it).
Ant bodies, like other insects, have an exoskeleton, an external covering that provides a protective casing around the body and a place to attach muscles, in contrast to the internal skeletal framework of humans and other vertebrates. Insects do not have lungs, but oxygen and other gases like carbon dioxide pass through their exoskeleton through tiny valves called spiracles. Insects also lack closed blood vessels but have a long, thin, perforated tube along the top of the body (called the "dorsal aorta") that functions like a heart in that it pumps hemolymph towards the head, thus creating some circulation of the internal fluids. Their nervous system consists of a ventral nerve cord running the length of the body, with several ganglia and branches along the way into each extremity.
The three main divisions of the ant body are the head, mesosoma and metasoma or gaster.
The head of an ant has many sensory organs. Ants, like most insects, have compound eyes with numerous tiny lenses attached together enabling them to detect movement very well. They also have three small ocelli (simple eyes) on the top of the head, which detect light levels and polarization.[9] Most ants have poor to mediocre eyesight and others are blind altogether. Some ants have exceptional vision though, including Australia's bulldog ant. Also attached are two antennae ("feelers") which are special organs that help ants detect chemicals. The antennae are used in communication, detecting pheromones released by other ants. The antennae are also used as feelers, aiding in their sensory input about what is in front of them. The head also has two strong jaws, the mandibles, used to carry food, manipulate objects, construct nests, and for defense. In some species a small pocket inside the mouth holds food for passing to other ants or their developing larvae.
The thorax of the ant is where all six legs are attached. At the end of each leg is a hooked claw that helps ants climb and hang onto things. Most queens and male ants have wings; queens shed the wings after the nuptial flight leaving visible stubs, a distinguishing feature of queens. Wingless queens (ergatoids) and males can also occur.
The metasoma (the "abdomen") of the ant houses many important internal organs, including the reproductive organs. Many species of ants have stingers used for subduing prey and defending their nests.
The life of an ant starts with an egg. If the egg is fertilized, the ant will be female (diploid); if not, it will be male (haploid). Ants are holometabolous, and develop by complete metamorphosis, passing through larval and pupal stages (with the pupae being exarate) before they become adults. The larval stage is particularly helpless — for instance it lacks legs entirely – and cannot care for itself. The difference between queens and workers (which are both female), and between different castes of workers when they exist, is determined by the feeding in the larval stage. Food is given to the larvae by a process called trophallaxis in which an ant regurgitates food previously held in its crop for communal storage. This is also how adults distribute food amongst themselves. Larvae and pupae need to be kept at fairly constant temperatures to ensure proper development, and so are often moved around the various brood chambers within the colony.
A new worker spends the first few days of its adult life caring for the queen and young. After that it graduates to digging and other nest work, and then to foraging and defense of the nest. These changes are fairly abrupt and define what are called temporal castes. One theory of why this occurs is because foraging has a high death rate, so ants only participate in it when they are older and closer to death anyway. In a few ants there are also physical castes — workers come in a spectrum of sizes, called minor, median, and major workers, the latter beginning foraging sooner. Often the larger ants will have disproportionately larger heads, and correspondingly stronger mandibles. Such individuals are sometimes called "soldier" ants because their stronger mandibles make them more effective in fighting other creatures, although they are still in fact worker ants and their "duties" typically do not vary greatly from the minor or median workers. In a few species the median workers have disappeared, creating a sharp divide and clear physical difference between the minors and majors.
Most of the common ant species breed in the same way. Only the queen and breeding females have the ability to mate. Contrary to popular belief, some ant nests have multiple queens. The male ants, called drones, along with the breeding females emerge from pupation with wings (although some species, like army ants, do not produce winged queens), and do nothing throughout their life except eat and mate. At this time, all breeding ants, excluding the queen, are carried outside where other colonies of similar species are doing the same. Then, all the winged breeding ants take flight. Mating occurs in flight and the males die shortly afterward. The females that survive land and seek a suitable place to begin a colony. There, they break off their own wings and begin to lay eggs, which they care for. Sperm obtained during their nuptial flight is stored and used to fertilize all future eggs produced. The first workers to hatch are weak and smaller than later workers, but they begin to serve the colony immediately. They enlarge the nest, forage for food and care for the other eggs. This is how most new colonies start. A few species that have multiple queens can start a new colony as a queen from the old nest takes a number of workers to a new site and founds a colony there.
Ant colonies can be long-lived. The queens themselves can live for up to 30 years, while workers live from 1 to 3 years. Males, however, are more transitory, surviving only a few weeks.[10]
Ants survive the winter by going into a state of dormancy or inactivity. The forms of inactivity are varied and some temperate species have larvae that go into diapause while in others the adults alone pass the winter in a state of reduced activity. This does not happen in the tropics.[11]
Ants show a wide range of morphological differences between the castes. While in some species, these differences are small, they are large in others. In some ant species there can be several size variants within the worker castes.[12] Workers cannot mate; however, because of the haplodiploid sex-determination system in ants, workers of a number of species are able to lay unfertilized eggs leading to fully functional haploid males.
A group of ants called honeypot ants, have special workers called repletes who only store food for the rest of the colony, generally becoming immobile with greatly enlarged abdomens. In hot, dry places, like parts of Africa, North America, and Australia they are eaten and considered by some to be a great delicacy. In Australia, they are prized as a type of bushfood and considered a sweetmeat.
Ants communicate with each other through chemicals called pheromones, these signal messages are more developed in ant species than in other hymenopterans groups. Like other insects, ants smell with their long and thin antennae that are fairly mobile. The antennae have a distinct elbow joint after an elongated first segment; and since they come in pairs—rather like binocular vision or stereophonic sound equipment—they provide information about direction as well as intensity. Since ants spend their life in contact with the ground, the soil surface makes a good place to leave a pheromone trail that can be followed by other ants. In those species which forage in groups, when a forager finds food they mark a trail on the way back to the colony, and this is followed by other ants that reinforce the trail when they head back to the colony. When the food is exhausted, no new trails are marked by returning ants and the scent slowly dissipates. This behavior helps ants adapt to changes in their environment. When an established path to a food source is blocked by a new obstacle, the foragers leave the path to explore new routes. If successful, the returning ant leaves a new trail marking the shortest route. Successful trails are followed by more ants, and each reinforces the trail with more pheromone (ants will follow the heaviest marked trails). Home is often located by remembered landmarks in the area and by the position of the sun; ants' compound eyes have specialized cells that detect polarized light, used to determine direction. [13][14]
Ants use pheromones for other purposes as well. A crushed ant will emit an alarm pheromone which in high concentration sends nearby ants into an attack frenzy; and in lower concentration, merely attracts them. To confuse enemies, several ant species use "propaganda pheromones", which cause their enemies to fight amongst themselves.[15]
Pheromones are also exchanged mixed with food and passed in the trophallaxis, giving the ants information about one another's health and nutrition. Ants can detect what task group (e.g. foraging or nest maintenance) other ants belong to. When the queen stops producing a specific pheromone the workers raise new queens.
Some ants also produce sounds by stridulation using the gaster segments and also using their mandibles. They may serve to communicate among colony members as well as in interactions with other species.[16][17][18]
Ants attack others and defend themselves by biting and in many species, stinging, often injecting chemicals like formic acid. Bullet ants (the genus Paraponera), located in Central and South America, are considered to have the most painful sting among insects, although these are usually non-fatal. They are given the highest rating on the Schmidt Sting Pain Index. Jack jumper ants, Myrmecia pilosula, located in Australia have stings that cause fatality to a small number of people in the population, and cause hospitalizations each year.[19] A vaccine based on use of the venom extract to develop immunity has been developed.[20]
Fire ants, Solenopsis spp., are unique in having a poison sac containing piperidine alkaloids.[21]
Some ants of the genus Odontomachus are equipped with mandibles called trap-jaws. This snap-jaw mechanism, or catapult mechanism, is possible because energy is stored in the large closing muscles. The blow is incredibly fast, about 0.5 ms in the genus Mystrium. Before the strike, the mandibles open wide and are locked in the open position by the labrum, which functions as a latch. The attack is triggered by stimulation of sensory hairs at the side of the mandibles. The mandibles are also able to function as a tool for more finely adjusted tasks. Two similar groups are Odontomachus and Dacetini - examples of convergent evolution.
Apart from defense against larger threats, ants also need to defend their colonies against disease organisms. Some ant workers' role is to maintain the hygiene of the colony and their activities include undertaking or necrophory, the transport of dead nest-mates.[22] Oleic acid is identified as one compound released by dead ants that triggers undertaking behaviour in Atta mexicana.[23]
The nests are also protected from physical threats such as flooding by elaborate structures at the entrance or special chambers for escaping from flooding. Some arboreal species that live in plant hollows also have behavioural responses to flooding, where the workers drink the water and excrete it outside the nest.[24]
While many types of animals can learn behaviors by imitating other animals, ants may be the only group of animals besides primates and some other mammals in which interactive teaching behavior has been observed. Knowledgeable forager ants of the species Temnothorax albipennis directly lead naïve nest-mates to newly discovered food sources by the excruciatingly slow (and time-costly) process of tandem running. The follower thereby obtains knowledge that it would not have, had it not been tutored, and this is at the expense of its nest-mate teacher. Both leader and follower are acutely sensitive to the progress of their partner. For example, the leader slows down when the follower lags too far behind, and speeds up when the follower gets too close, while the follower does the opposite.[25]
Controlled experiments with colonies of Cerapachys biroi suggest that these ants can specialize based on their previous experience. An entire generation of identical workers was divided into two groups based on how the researchers controlled the outcome of food foraging. One group was continually rewarded with prey, while it was made certain that the other failed. As a result, members of the successful group intensified their foraging attempts while the unsuccessful group ventured out less and less. One month later, 'workers that previously found prey kept on exploring for food, whereas those who always failed specialized in brood care'[26]
While some ants form complex nests and galleries, other species are nomadic and do not build permanent structures. Various species may form subterranean nests or build them on trees. Nests can be found in the ground with craters or mounds around the entrance, under stones or logs, in logs, hollow stems, even acorns. The materials used for construction include soil and plant matter,[27] and they are highly selective of the nest site; Temnothorax albipennis will avoid sites with dead ants as these may be indicators of pests or disease. They are also quick to abandon established nest sites at the first sign of these threats.[28]
Some of the more advanced ants are the army ants and driver ants, from South America and Africa respectively. Unlike most species which have permanent nests, army and driver ants do not form permanent nests, but instead alternate between nomadic stages and stages where the workers form a temporary nest (bivouac) out of their own bodies. Colonies reproduce either through nuptial flights as described above, or by fission, where a group of workers simply dig a new hole and raise new queens. Colony members are distinguished by smell, and other intruders are usually attacked.
Weaver ants (Oecophylla) build nests in trees by attaching leaves together, first pulling them together with bridges of workers and then sewing them together by pressing silk-producing larvae against them in alternation.
Leafcutter ants (Atta and Acromyrmex) feed exclusively on a special fungus that lives only within their colonies. They continually collect leaves which they cut into tiny pieces for the fungus to grow on. There are different sized castes specially suited to finer and finer tasks of cutting and chewing the leaves and tending to the garden. Leaf cutter ants are sensitive enough to adapt to the fungi's reaction to different plant material, apparently detecting chemical signals from the fungus. If a particular type of leaf is toxic to the fungus the colony will no longer collect it. The ants grow the fungus because it produces special structures called gongylidia which are fed on by the ants. They create antibiotics on their exterior surfaces with the aid of symbiotic bacteria, and subsist entirely on this farming of the fungus.
Desert ants Cataglyphis fortis make use of visual landmarks in combination with other cues to navigate.[29]
In the absence of visual landmarks, Sahara desert ants have been shown to navigate by keeping track of direction as well as distance travelled, like an internal pedometer that keeps tracks of how many steps they take, and use this information to find the shortest routes back to their nests.[30]
Worker ants generally do not grow wings and reproductive females remove theirs after their mating flights in order to begin their colonies. Therefore, unlike their wasp ancestors, most ants travel by walking.
The more cooperative species of ants sometimes form chains to bridge gaps, whether that be over water, underground, or through spaces in arboreal paths. Some species also form floating rafts that help them survive floods. They may also have a role in colonization of islands.[31]
Some ants are even capable of leaping. A particularly notable species is Jerdon's jumping ant, Harpegnathos saltator. This is achieved by synchronized action of the mid and hind pair of legs.[32]
Polyrhachis sokolova, a species of ant found in Australian mangrove swamps, can swim and lives in nests that are submerged underwater. They make use of trapped pockets of air in the submerged nests.[33]
There are several species of gliding ant including Cephalotes atratus. In fact this may be a common trait among most arboreal ants. Ants with this ability are able to direct the direction of their descent while falling.[34]
Not all ants have the same kind of societies. The Australian bulldog ants are among the biggest and most primitive of ants. The individual hunts alone, using its large eyes instead of its chemical senses to find prey. Like all ants they are social, but their social behavior is poorly developed compared to more advanced species. An Australian bulldog ant, Myrmecia pilosula, has only a single pair of chromosomes and males have just one chromosome as they are haploid.
Some species of ants are known for attacking and taking over the colonies of other ant species. Others are less expansionist but nonetheless just as aggressive; they attack colonies to steal eggs or larvae, which they either eat or raise as workers/slaves. Some ants, such as the Amazon ants, are incapable of feeding themselves, and must rely on captured worker ants to care for them. In some cases ant colonies may have other species of ants or termites within the same nest.[35]
The pavement ant is famous for its urge to increase its territory. In early spring, colonies attempt to conquer new areas and often attack the nearest enemy colony. These result in huge sidewalk battles, sometimes leaving thousands of ants dead. Because of their aggressive nature, they often invade and colonize seemingly impenetrable areas.
Ants identify kin and nestmates through their scents, a hydrocarbon-laced secretion that coats their exoskeletons. If an ant is separated from its original colony, it will eventually lose the colony scent. Any ant that enters a colony with a different scent than that of the colony will be attacked.[36] (See also Kin selection)
| Region | Number of species [27] |
|---|---|
| Neotropics | 2162 |
| Nearctic | 580 |
| Europe | 180 |
| Africa | 2500 |
| Asia | 2080 |
| Melanesia | 275 |
| Australia | 985 |
| Polynesia | 42 |
There is a great diversity among ants and their behaviors. They range in size from 2 to about 25 mm (about 0.08 to 1 inch). Their color may vary; most are red or black, but other colors can also be seen, including some tropical groups with a metallic luster. (See also ant genera). Numerous species of ant continue to be added in present times and taxonomic studies continue to resolve the classification and systematics of ants. Online databases of ant species include AntBase and the Hymenoptera Name Server.[37]
Ants have been used as indicator species in biodiversity studies.[38][39]
Ants associate with a wide range of species in many ways. They form mutualisms with other insects, plants, and fungi. They parasitize each other. They are preyed upon by many animals and even certain fungi. Because their nests are such hospitable places, many species of arthropods sneak in and integrate themselves in various ways to the ant's daily lives.
Aphids secrete a sweet liquid called honeydew which they exude in the process of feeding from plants. The sugars can provide a high-energy food source, which many ant species collect. In some cases the aphids secrete the honeydew specifically in response to the ants tapping them with their antennas. The ants in turn keep predators away and will move the aphids around to better feeding locations. Upon migrating to a new area, many colonies will take new aphids with them, to ensure that they have a supply of honeydew in the new area. Ants also tend mealybugs to harvest their honeydew. Mealybugs can become a serious pest of pineapple if ants are present to protect mealybugs from natural enemies.[40][41]
Myrmecophilous (ant-loving) caterpillars of the family Lycaenidae (e.g., blues, coppers, or hairstreaks) are herded by the ants, led to feeding areas in the daytime, and brought inside the ants' nest at night. The caterpillars have a gland which secretes honeydew when the ants massage them. Some caterpillars are known to produce vibrations and sounds that are sensed by the ants.[42] Some caterpillars have evolved from being ant-loving to ant-eating and these myrmecophagous caterpillars secrete a pheromone which makes the ants think that the caterpillar's larva is one of their own. The larva will then be taken into the ants' nest where it can feed on the ant larvae.
Fungus-growing ants that make up the tribe attini, including leafcutter ants, actively cultivate certain species of fungus in the Leucoagaricus or Leucocoprinus genera of the Agaricaceae family. In this ant-fungus mutualism, both species depend on each other for survival. The ant Allomerus decemarticulatus has evolved a tripartite association with their host plant Hirtella physophora (Chrysobalanaceae), and a sticky fungus which is used to trap their insect prey.[43]
Lemon ants make devil's gardens by
selectively killing surrounding plants and leaving a pure patch of lemon ant trees Duroia hirsuta.[44] Many trees have extrafloral
Flies in the Old World genus Bengalia (Calliphoridae) are kleptoparasites and predators on ants and often snatch prey or brood from the adult ants.[46] Wingless and legless females of the Malaysian phorid fly Vestigipoda myrmolarvoidea live in the nests of ants of the genus Aenictus and are cared for by the ants.[46]
Many species of birds show a peculiar behaviour called anting that is as yet not fully understood. Here birds may rest on ant nests or pick and drop ants onto their wings and feathers, presumably to rid themselves of ectoparasites.
A fungus, Cordyceps, infects ants, causing them to climb up plants and sink their mandibles into the plant tissue. The fungus kills and engulfs the ant and produces its fruiting body. It appears that the fungus alters the behavior of the ant and uses the ant to help disperse its spores.[47]
Some South American frogs in the genus Dendrobates feed primarily on ants and the toxins on their skin may be derived from the ants.[48]
Brown bears (Ursus arctos) have been found to feed on ants, with as much as 12%, 16%, and 4% of their fecal volume in spring, summer, and autumn, respectively being made up of ants.[49]
Many species of mammals such as anteaters, pangolins and several marsupial species in Australia have special adaptations for living on a primary diet of ants. These adaptations include long sticky tongues to pick the ants and strong claws to break into the ant nests. Some South American birds such as the antpittas are also ant predators.
Ants are useful for clearing out insect pests and aerating the soil. The use of weaver ants in citrus cultivation in southern China is one of the oldest known uses of biological control.[27] On the other hand, they can become annoyances when they invade homes, yards, gardens and fields. Carpenter ants damage wood by hollowing it out for nesting.
In some parts of the world large ants, especially army ants, are said to be used as sutures by pressing the wound together and applying ants along it. The ant in defensive attitude seizes the edges in its mandibles and locks in place. The body is then cut off and the head and mandibles can remain in place, closing the wound.[50]
Some species, called killer ants, have a tendency to attack much larger animals during foraging or in defending their nests. Attacks on humans are rare, but the stings and bites can be quite painful and in large enough numbers can be disabling.
The Masai of Africa had an abiding respect for the Siafu ants, voracious predators that consume a large amount of insects and are welcomed for the benefit they bring to farmers, as they will eliminate all pests from a crop and quickly move on.
In South Africa, ants are used to help harvest rooibos, Aspalathus linearis, the small seeds of which are used to make a herbal tea.[51]
Ants and their larvae are eaten in different parts of the world. The eggs of two species of ants are the basis for the dish in Mexico known as "escamoles". They are considered a form of insect caviar and can sell as high as $40 USD per pound because they are seasonal and hard to find. In the Colombian department of Santander, hormigas culonas (lit.: "fatass ants") Atta laevigata are toasted alive and eaten.[52] This tradition has come down from the native Guanes. In parts of Thailand, ants are prepared and eaten in various ways. Khorat ant eggs and diced flying ants are eaten as an appetizer. Weaver ant eggs and larvae as well as the ants themselves may be used in a Thai salad, yum (ยำ), in a dish called yum khai mod daeng (ยำไข่มดแดง) or red ant egg salad, a dish that comes from the Issan or north-eastern region of Thailand. Weaver ant queens may also be eaten live, at the time of nest initiation.
Charles Thomas Bingham notes that in parts of India, and throughout Burma and Siam, a paste of the green weaver ant, Oecophylla smaragdina, is served as a condiment with curry. Saville Kent, in the Naturalist in Australia wrote "Beauty, in the case of the green ant, is more than skin-deep. Their attractive, almost sweetmeat-like translucency possibly invited the first essays at their consumption by the human species." Mashed up in water, after the manner of lemon squash, "these ants form a pleasant acid drink which is held in high favor by the natives of North Queensland, and is even appreciated by many European palates."[53]
John Muir, in his First Summer in the Sierra notes that the Digger Indians of California ate the tickly acid gasters of the large jet-black carpenter ants. The Mexican Indians eat the replete workers, or living honey-pots, of the honey ant (Myrmecocystus).[53]
Modern society considers the ant a pest,[54] and due to the adaptive nature of ant colonies, eliminating them is nearly impossible. Pest control with regard to ants is more a matter of controlling local populations than eliminating an entire colony. Attempts to control ant populations of any kind are temporary solutions.
Typical ants that are classified as pests include pavement ants (otherwise known as the sugar ant), Pharaoh ants, carpenter ants, Argentine ants, and the red imported fire ant. Control of species populations are usually done with bait insecticides, which are either in the form of small granules, or as a sticky liquid that is gathered by the ants as food and then brought back to the nest where the poison is inadvertently spread to other members of the brood — a system that can severely reduce the numbers in a colony if used properly. Boric acid and borax are often used as insecticides that are relatively safe for humans. With the recent insurgence of the red imported fire ant, a tactic called broadcast baiting has been employed, by which the substance (usually a granule bait designed specifically for fire ants) is spread across a large area, such as a lawn, in order to control populations. Nests may be destroyed by tracing the ants' trails back to the nest, then pouring boiling water into it to kill the queen. This works in about 60% of the mounds and needs about 14 litres (3 gallons) per mound.[55]
Ants that tend other insects can indirectly cause pest infestations. Many homopteran insects that are considered as horticultural pests are controlled by the use of grease rings on the trunks of the trees. These rings cut off the routes for ants and make the pest species vulnerable to parasites and predators.
Myrmecologists study ants both in the laboratory and in their natural conditions using a number of tools and techniques. Ants are model organisms for the study of sociobiology and the testing of hypotheses such as those based on the theories of kin selection or evolutionarily stable strategies. Ant colonies can be reared or temporarily maintained in specially constructed glass frames for study purposes.[56] For certain kinds of studies it is necessary to identify specific individual ants through the study period and this is achieved by use of colour marking techniques.[57] The use of endoscopes to observe ants inside their nest tunnels is another technique that has been used in the field.
The successful techniques used by ant colonies has been widely studied especially in computer science and robotics to produce distributed and fault-tolerant systems for solving problems. This area of biomimetics has led to studies of ant locomotion, search engines which make use of foraging trails and fault tolerant storage and networking algorithms.[58] (See also Langton's ant and ant colony optimization.)
