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top 10 words in brain distribution (in article): wear white century type skin black cut woman hair term |
top 10 words in brain distribution (in article): animal species breed male hunt human female size population bear |
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top 10 words in brain distribution (not in article): cat wolf dog wild lion elephant blade iron tiger steel |
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times more probable under pants 30 20 10 6 4 2.5 1.25 1 1.25 2.5 4 6 10 20 30 times more probable under ant (words not in the model) | |
| Trousers'" are an item of clothing worn on the lower part of the body from the waist to the ankles, covering both legs separately (rather than with cloth stretching across both as in skirts and dresses). Such items of clothing are often referred to as "'pants'" in countries such as Canada, South Africa and The United States. Additional synonyms include "'slacks'", "'kegs'" or "'kex'", "'breeches'" (sometimes) or "'breeks'". Historically, as for the West, trousers have been the standard lower-body clothing item for males since the 16th century; by the late 20th century, they had become prevalent for females as well. Trousers are worn at the hips or waist, and may be held up by their own fastenings, a belt, or suspenders (braces). Leggings are form-fitting trousers of a clingy material, often knitted cotton and lycra. Terminology. In North America, "pants" is the general category term, and "trousers" refers, often more formally, specifically to tailored garments with a waistband and (typically) belt-loops and a fly-front. For instance, informal elastic-waist knitted garments would never be called "trousers" in the U.S. Undergarments are called "underwear", "underpants", or "panties" (the last are women's garments specifically) to distinguish them from other pants that are worn on the outside. The term "drawers" normally refers to undergarments, but in some dialects, may be found as a synonym for "breeches", that is, trousers. In these dialects, the term "underdrawers" is used for undergarments. In Australia the terms "pants" and "trousers" are synonymous. In most parts of the United Kingdom, "trousers" is the general category term, and "pants" refers to underwear. In some parts of Scotland, trousers are known as "trews"; taken from the early Middle English "trouse", its plural developed into "trousers". Various people in the contemporary fashion industry use the word "pant" instead of "pants". This is grammatically incorrect. The word pants is a "plurale tantum", always in plural form much like the words scissors and tongs. The origin of pants is due to the use of two pieces of cloth in making it. Pant would actually mean just a single leg being covered with clothing. History. Nomadic Eurasian horsemen such as the Iranian Scythians, along with Achaemenid Persians, were among the first to wear trousers. In ancient China, trousers were only worn by soldiers. The first european appearance of trousers was in Hungary in the IX century. Men's clothes in Hungary in the 15th century consisted of a shirt and trousers as underwear, and a dolman worn over them, as well as a short fur-lined or sheepskin coat. At special occasions people wore gowns made of expensive materials, and these preferred by Pipo of Ozora too. Hungarian people had unique hair styles and wore high (fur) caps. Their trousers were simple in general, only their colour being unusual, but the dolman covered the greater part of the trousers. Trousers were introduced into Western European culture at several points in history, but gained their current predominance only in the 16th century, from a Commedia dell'Arte character named "Pantalone" (Italian word for Trousers). In England in the Twelfth century, the rustic were often seen in long garments to the ankle, rather like trousers, which are really glorified braies. Strangely enough, trouserlike garments, which became rare again in the thirteenth century, vanished during the fourteenth century and scarcely reappeared for six hundred years. The word itself is of Gaelic or Scots Gaelic origin, from the Middle Irish word "triubhas" (close-fitting shorts), however it is important to note that trews of the Early Industrial Period were in not trousers. Men's trousers. Trousers trace their ancestry to the individual hose worn by men in the 15th century (which is why trousers are plural and not singular). The hose were easy to make and fastened to a doublet at the top with ties called "points". It is important that at this point in time, these were not trousers, but trews, as can be seen in the 1746 painting by David Morier.. As time went by, the two hose were joined, first in the back then across the front, but still leaving a large opening for sanitary functions. Originally, doublets came almost to the knees, effectively covering the private parts, but as fashions changed and doublets became shorter, it became necessary for men to cover their genitals with a codpiece. By the end of the 16th century, the codpiece had been incorporated into the hose, now usually called breeches, which were roughly knee-length and featured a "fly" or "fall front" opening. During the French Revolution, the male citizens of France adopted a working-class costume including ankle-length trousers or pantaloons in place of the aristocratic knee-breeches. This style was introduced to England in the early 19th century, possibly by Beau Brummell, and supplanted breeches as fashionable street wear by mid-century. Breeches survived into the 1940s as the plus-fours or knickers worn for active sports and by young school-boys. Types of breeches are still worn today by baseball and American football players. Sailors may have played a role in the dissemination of trousers as a fashion around the world. In the 17th and 18th centuries, sailors wore baggy trousers known as "galligaskins". Sailors were also the first to wear jeans, trousers made of denim. These became more popular in the late 19th century in the American West, because of their ruggedness and durability. Women's trousers. Although trousers for women in western countries did not become fashion items until the later 20th century, women began wearing men's trousers (suitably altered) for outdoor work a hundred years earlier. Starting around the mid 19th Century, Wigan "pit brow girls" scandalized Victorian society by wearing trousers for their work at the local coal mines. They wore skirts over their trousers and rolled them up to their waist to keep them out of the way. Although "pit brow lassies" worked above-ground at the pit-head, the task of sorting and shovelling coal was hard manual labour, so wearing the usual long skirts of the time would have greatly hindered their movements. Women working the ranches of the 19th century American West also wore trousers for riding, and in the early 20th century aviatrices and other working women often wore trousers. Actresses Marlene Dietrich and Katharine Hepburn were often photographed in trousers from the 1930s and helped make trousers acceptable for women. During World War II, women working in factories and doing other forms of "men's work" on war service wore trousers when the work demanded it, and in the post-war era trousers became acceptable casual wear for gardening, the beach, and other leisure pursuits. In Britain during the Second World War, because of the rationing of clothing, many women took to wearing their husbands' civilian clothes, including their trousers, to work while their husbands were away in the armed forces. This was partly because they were seen as practical garments of workwear, and partly to allow women to keep their clothing allowance for other uses. As this practice of wearing trousers became more widespread and as the men's clothes wore out, replacements were needed, so that by the summer of 1944 it was reported that sales of women's trousers were five times more than in the previous year. In the 1960s, André Courrèges introduced long trousers for women as a fashion item, leading to the era of the pantsuit and designer jeans and the gradual eroding of the prohibitions against girls and women wearing trousers in schools, the workplace, and fine restaurants. Pleats. Pleats just below the waistband on the front are typical of many styles of formal and casual trousers including suit trousers and khakis. There may be one, two, three, or no pleats, which may face either direction. When the pleats open towards the pockets they are called reverse pleats (typical of khakis and corduroy trousers) and when they open toward the zipper, they are known as forward pleats. Utilitarian or very casual styles such as jeans and cargo pants are flat-front (without pleats at the waistband) but may have bellows pockets. Cuffs. Most trouser legs are finished by hemming the bottom to prevent fraying. Trousers with cuffs ("turn-ups" in British English), after hemming, are rolled outward and sometimes pressed or stitched into place. The main reason for the cuffs is to add weight to the bottom of the leg, to help the drape of the trousers. Fly. A fly on clothing is a covering over an opening join concealing the mechanism, such as a zip, velcro or buttons used to join the opening. The term is most frequently applied to a short opening in trousers, shorts and other garments covering the groin, and to allow garments to be taken on and off with greater ease. Trousers have varied historically in whether or not they have flies. Originally, hose did not cover between the legs, which was hidden by a codpiece, and when breeches were worn, for example in the Regency period, they were fall-fronted (or broad fall). After trousers (pantaloons) were later invented later the fly-front (split fall) emerged. Later the panelled front returned as a sporting option, such as in riding breeches, but is now hardly used, flies being by far the most common fastening. Most flies now use a zip, though enthusiasts continue to wear button flies. Society. It is customary in the western world for men to wear trousers and not skirts or dresses. However, there are exceptions, such as the Scottish kilt and the Greek foustanella, worn on ceremonial occasions, as well as robes or robe-like clothing such as the cassocks, etc. of clergy and academic robes (both rarely worn in daily use today). (See also Men's skirts.) Based on Deuteronomy 22:5 in the Bible, some groups believe that women should not wear trousers, but only skirts and dresses. Among certain groups, low-rise, baggy trousers exposing underwear are in fashion, e.g. among skaters and in 1990s hip hop fashion despite its prison-based origins. This fashion is called sagging. "Cut-offs" are homemade shorts made by cutting the legs off trousers, usually after holes have been worn in fabric around the knees. This extends the useful life of the trousers. The remaining leg fabric may be hemmed or left to fray after being cut. Removing one's trousers in public is considered taboo. Law. In May 2004 in Louisiana, state legislator Derrick Shepherd proposed a bill that would make it a crime to appear in public wearing trousers below the waist and thereby exposing one's skin or "intimate clothing". The Louisiana bill was retracted after negative public reaction. In February 2005, Virginia legislators tried to pass a similar law that would have made punishable by a $50 fine: "any person who, while in a public place, intentionally wears and displays his below-waist undergarments, intended to cover a person's intimate parts, in a lewd or indecent manner". It is not clear whether, with the same coverage by the trousers, exposing underwear was considered worse than exposing bare skin, or that the latter was already covered by another law. It passed in the Virginia House of Delegates. However, various criticisms to it arose. For example, newspaper columnists and radio talk show hosts consistently said that since most people that would be penalized under the law would be young African-American men, the law would thus be a form of discrimination against them. Virginia's state senators voted against passing the law. Carol Broussard, mayor of Delcambre, said that he will sign the proposal unanimously passed by town councillors, so that wearing trousers that reveal one's underwear will lead to a $500 penalty and the risk of six months in jail. "If you expose your private parts, you'll get a fine," said Mr Broussard. He told the Associated Press that people wearing low-slung trousers are "better off taking the pants off and wearing a dress." Ted Ayo, town attorney, said that the new legislation would expand on existing indecent exposure laws in Louisiana: "This is a new ordinance that deals specifically with sagging pants. It's about showing off your underwear in public". Mr. Broussard has received local criticism for the ordinance, with some Delcambre residents claiming that the proposal is racially motivated, due to the popularity of "sagging pants" among black hip-hop fans. However, he responded: "White people wear sagging pants, too." | A phylogeny of the extant ant subfamilies. "'Ants'" are social insects of the family "'Formicidae'", and along with the related wasps and bees, they belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. Today, more than 12,000 species are classified with upper estimates of about 14,000 species. They are easily identified by their elbowed antennae and a distinctive node-like structure that forms a slender waist. Ants form colonies that range in size from a few dozen predatory individuals living in small natural cavities to highly organised colonies which may occupy large territories and consist of millions of individuals. These larger colonies consist mostly of sterile wingless females forming castes of "workers", "soldiers", or other specialised groups. Ant colonies also have some fertile males called "drones" and one or more fertile females called "queens". The colonies are sometimes described as superorganisms because ants appear to operate as a unified entity, collectively working together to support the colony. Ants have colonised almost every landmass on Earth. The only places lacking indigenous ants are Antarctica and certain remote or inhospitable islands. Ants thrive in most ecosystems, and may form 15–25% of the terrestrial animal biomass. Their success has been attributed to their social organisation and their ability to modify habitats, tap resources, and defend themselves. Their long co-evolution with other species has led to mimetic, commensal, parasitic, and mutualistic relationships. Ant societies have division of labour, communication between individuals, and an ability to solve complex problems. These parallels with human societies have long been an inspiration and subject of study. Many human cultures make use of ants in cuisine, medication and rituals. Some species are valued in their role as biological pest control agents. However, their ability to exploit resources brings ants into conflict with humans, as they can damage crops and invade buildings. Some species, such as the red imported fire ant, are regarded as invasive species, since they have establish themselves in new areas where they may be accidentally introduced. Taxonomy and evolution. The family Formicidae belongs to the order Hymenoptera, which also includes sawflies, bees and wasps. Ants evolved from a lineage within the vespoid wasps. Phylogenetic analysis suggests that ants arose in the mid-Cretaceous period about 110 to 130 million years ago. After the rise of flowering plants about 100 million years ago they diversified and assumed ecological dominance around 60 million years ago. In 1966, E. O. Wilson and his colleagues identified the fossil remains of an ant ("Sphecomyrma freyi") that lived in the Cretaceous period. The specimen, trapped in amber dating back to more than 80 million years ago, has features of both ants and wasps. "Sphecomyrma" was probably a ground forager but some suggest on the basis of groups such as the Leptanillinae and Martialinae that primitive ants were likely to have been predators under the soil surface. During the Cretaceous period, only a few species of primitive ants ranged widely on the Laurasian super-continent (the northern hemisphere). They were scarce in comparison to other insects, representing about 1% of the insect population. Ants became dominant after adaptive radiation at the beginning of the Tertiary period. By the Oligocene and Miocene ants had come to represent 20–40% of all insects found in major fossil deposits. Of the species that lived in the Eocene epoch, approximately one in ten genera survive to the present. Genera surviving today comprise 56% of the genera in Baltic amber fossils (early Oligocene), and 92% of the genera in Dominican amber fossils (apparently early Miocene). Termites, though sometimes called "white ants", are not ants and belong to the order Isoptera. The termites are actually more closely related to cockroaches and mantids. The fact that ants and termites are both eusocial came about by Convergent evolution. Velvet ants look like large ants, but are wingless female wasps. Etymology. The word "ant" is derived from "ante" of Middle English which is derived from "æmette" and "emmett" of Old English and is related to the Old High German "āmeiza" from which comes "Ameise", the German word for ant. The family name "Formicidae" is derived from the Latin "formīca" ("ant") from which derived Portuguese "formiga", Spanish "hormiga", Romanian "furnică", French "fourmi", etc. Distribution and diversity. Ants are found on all continents except Antarctica and only a few large islands such as Greenland, Iceland, parts of Polynesia and the Hawaiian Islands lack native ant species. Ants occupy a wide range of ecological niches, and are able to exploit a wide range of food resources either as direct or indirect herbivores, predators and scavengers. Most species are omnivorous generalists but a few are specialist feeders. Their ecological dominance may be measured by their biomass, and estimates in different environments suggest that they contribute 15–20% (on average and nearly 25% in the tropics) of the total terrestrial animal biomass, which exceeds that of the vertebrates. Ants range in size from. Their colours vary; most are red or black, green is less common, and some tropical species have a metallic lustre. More than 12,000 species are currently known (with upper estimates of about 14,000), with the greatest diversity in the tropics. Taxonomic studies continue to resolve the classification and systematics of ants. Online databases of ant species, including AntBase and the Hymenoptera Name Server, help to keep track of the known and newly described species. The relative ease with which ants can be sampled and studied in ecosystems has made them useful as indicator species in biodiversity studies. Morphology. Ants are distinct in their morphology from other insects in having elbowed antennae, metapleural glands, and a strong constriction of their second abdominal segment into a node-like petiole. The head, mesosoma and metasoma or gaster are the three distinct body segments. The petiole forms 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 (the second alone, or the second and third abdominal segments). Like other insects, ants have an exoskeleton, an external covering that provides a protective casing around the body and a point of attachment for muscles, in contrast to the internal skeletons of humans and other vertebrates. Insects do not have lungs; oxygen and other gases like carbon dioxide pass through their exoskeleton through tiny valves called spiracles. Insects also lack closed blood vessels; instead, they have a long, thin, perforated tube along the top of the body (called the "dorsal aorta") that functions like a heart, and pumps haemolymph towards the head, thus driving the circulation of the internal fluids. The nervous system consists of a ventral nerve cord that runs the length of the body, with several ganglia and branches along the way reaching into the extremities of the appendages. An ant's head contains many sensory organs. Like most insects, ants have compound eyes made from numerous tiny lenses attached together. Ants' eyes are good for acute movement detection but do not give a high resolution. They also have three small ocelli (simple eyes) on the top of the head that detect light levels and polarisation. Compared to vertebrates, most ants have poor-to-mediocre eyesight and a few subterranean species are completely blind. Some ants such as Australia's bulldog ant, however, have exceptional vision. Two antennae ("feelers") are attached to the head; these organs detect chemicals, air currents and vibrations; they are also used to transmit and receive signals through touch. The head has two strong jaws, the mandibles, used to carry food, manipulate objects, construct nests, and for defence. In some species a small pocket (infrabuccal chamber) inside the mouth stores food, so it can be passed to other ants or their larvae. All six legs are attached to the mesosoma ("thorax"). A hooked claw at the end of each leg helps ants to climb and hang onto surfaces. Most queens and male ants have wings; queens shed the wings after the nuptial flight, leaving visible stubs, a distinguishing feature of queens. However, wingless queens (ergatoids) and males occur in a few species. The metasoma (the "abdomen") of the ant houses important internal organs, including those of the reproductive, respiratory (tracheae) and excretory systems. Workers of many species have their egg-laying structures modified into stings that are used for subduing prey and defending their nests. Polymorphism. In the colonies of a few ant species, there are physical castes—workers in distinct size-classes, called minor, median, and major workers. Often the larger ants 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, although they are still workers and their "duties" typically do not vary greatly from the minor or median workers. In a few species the median workers are absent, creating a sharp divide between the minors and majors. Weaver ants, for example, have a distinct bimodal size distribution. Some other species show continuous variation in the size of workers. The smallest and largest workers in "Pheidologeton diversus" show nearly a 500-fold difference in their dry-weights. Workers cannot mate; however, because of the haplodiploid sex-determination system in ants, workers of a number of species can lay unfertilised eggs that become fully fertile haploid males. The role of workers may change with their age and in some species, such as honeypot ants, young workers are fed until their gasters are distended, and act as living food storage vessels. These food storage workers are called "repletes". This polymorphism in morphology and behaviour of workers was initially thought to be determined by environmental factors such as nutrition and hormones which led to different developmental paths; however, genetic differences between worker castes have been noted in "Acromyrmex" sp. These polymorphisms are caused by relatively small genetic changes; differences in a single gene of "Solenopsis invicta" can decide whether the colony will have single or multiple queens. The Australian jack jumper ant ("Myrmecia pilosula"), has only a single pair of chromosomes (males have just one chromosome as they are haploid), the lowest number known for any animal, making it an interesting subject for studies in the genetics and developmental biology of social insects. Development and reproduction. The life of an ant starts from an egg. If the egg is fertilised, the progeny will be female (diploid); if not, it will be male (haploid). Ants develop by complete metamorphosis with the larval stages passing through a pupal stage before emerging as an adult. The larva is largely immobile and is fed and cared for by workers. Food is given to the larvae by trophallaxis, a process in which an ant regurgitates liquid food held in its crop. This is also how adults share food, stored in the "social stomach", among themselves. Larvae may also be provided with solid food such as trophic eggs, pieces of prey and seeds brought back by foraging workers and may even be transported directly to captured prey in some species. The larvae grow through a series of moults and enter the pupal stage. The pupa has the appendages free and not fused to the body as in a butterfly pupa. The differentiation into queens and workers (which are both female), and different castes of workers (when they exist), is determined by the nutrition the larvae obtain. 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. It then graduates to digging and other nest work, and later to defending the nest and foraging. These changes are sometimes fairly sudden, and define what are called temporal castes. An explanation for the sequence is suggested by the high casualties involved in foraging, making it an acceptable risk only for ants that are older and are likely to die soon of natural causes. Most ant species have a system in which only the queen and breeding females have the ability to mate. Contrary to popular belief, some ant nests have multiple queens while others can exist without queens. Workers with the ability to reproduce are called "gamergates" and colonies that lack queens are then called gamergate colonies; colonies with queens are said to be queen-right. The winged male ants, called drones, emerge from pupae along with the breeding females (although some species, like army ants, have wingless queens), and do nothing in life except eat and mate. During the short breeding period, the reproductives, excluding the colony 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 afterwards. Females of some species mate with multiple males. Mated females then seek a suitable place to begin a colony. There, they break off their wings and begin to lay and care for eggs. The females store the sperm they obtain during their nuptial flight to selectively fertilise future eggs. 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 new colonies start in most species. Species that have multiple queens may have a queen leaving the nest along with some workers to found a colony at a new site, a process akin to swarming in honeybees. Ant colonies can be long-lived. The queens can live for up to 30 years, and workers live from 1 to 3 years. Males, however, are more transitory, and survive only a few weeks. Ant queens are estimated to live 100 times longer than solitary insects of a similar size. Ants are active all year long in the tropics but, in cooler regions, survive the winter in a state of dormancy or inactivity. The forms of inactivity are varied and some temperate species have larvae going into the inactive state (diapause), while in others, the adults alone pass the winter in a state of reduced activity. Communication. Ants communicate with each other using pheromones. These chemical signals are more developed in ants than in other hymenopteran groups. Like other insects, ants perceive smells with their long, thin and mobile antennae. The paired antennae provide information about the direction and intensity of scents. Since most ants live on the ground, they use the soil surface to leave pheromone trails that can be followed by other ants. In species that forage in groups, a forager that finds food marks a trail on the way back to the colony; this trail is followed by other ants, these ants then reinforce the trail when they head back with food to the colony. When the food source is exhausted, no new trails are marked by returning ants and the scent slowly dissipates. This behaviour helps ants deal with changes in their environment. For instance, when an established path to a food source is blocked by an obstacle, the foragers leave the path to explore new routes. If an ant is successful, it leaves a new trail marking the shortest route on its return. Successful trails are followed by more ants, reinforcing better routes and gradually finding the best path. Ants use pheromones for more than just making trails. A crushed ant emits an alarm pheromone that sends nearby ants into an attack frenzy and attracts more ants from further away. Several ant species even use "propaganda pheromones" to confuse enemy ants and make them fight among themselves. Pheromones are produced by a wide range of structures including Dufour's glands, poison glands and glands on the hindgut, pygidium, rectum, sternum and hind tibia. Pheromones are also exchanged mixed with food and passed by trophallaxis, transferring information within the colony. This allows other ants to detect what task group ("e.g.", foraging or nest maintenance) other colony members belong to. In ant species with queen castes, workers begin to raise new queens in the colony when the dominant queen stops producing a specific pheromone. Some ants produce sounds by stridulation, using the gaster segments and their mandibles. Sounds may be used to communicate with colony members or with other species. Defence===. Ants attack and defend themselves by biting and, in many species, by stinging, often injecting or spraying chemicals like formic acid. Bullet ants ("Paraponera"), located in Central and South America, are considered to have the most painful sting of any insect, although it is usually not fatal to humans. This sting is given the highest rating on the Schmidt Sting Pain Index. The sting of Jack jumper ants can be fatal, and an antivenin has been developed. Fire ants, "Solenopsis" spp., are unique in having a poison sac containing piperidine alkaloids. Their stings are painful and can be dangerous to hypersensitive people. Trap-jaw ants of the genus "Odontomachus" are equipped with mandibles called trap-jaws, which snap shut faster than any other predatory appendages within the animal kingdom. One study of "Odontomachus bauri" recorded peak speeds of between 126 and 230 h (78 143 mph), with the jaws closing within 130 microseconds on average. The ants were also observed to use their jaws as a catapult to eject intruders or fling themselves backwards to escape a threat. Before the strike, the ant opens its mandibles extremely widely and locks them in this position by an internal mechanism. Energy is stored in a thick band of muscle and explosively released when triggered by the stimulation of sensory hairs on the inside of the mandibles. The mandibles also permit slow and fine movements for other tasks. Trap-jaws are also seen in the following genera: "Anochetus", "Orectognathus", and "Strumigenys", plus some members of the Dacetini tribe, which are viewed as examples of convergent evolution. In addition to defence against predators, ants need to protect their colonies from pathogens. Some worker ants maintain the hygiene of the colony and their activities include undertaking or "necrophory", the disposal of dead nest-mates. Oleic acid has been identified as the compound released by dead ants that triggers undertaking behaviour in "Atta mexicana". Nests may be protected from physical threats such as flooding and over-heating by elaborate nest architecture. Workers of "Cataulacus muticus", an arboreal species that lives in plant hollows, respond to flooding by drinking water inside the nest, and excreting it outside. Learning. Many animals can learn behaviours by imitation but ants may be the only group apart from mammals where interactive teaching has been observed. A knowledgeable forager of "Temnothorax albipennis" leads a naive nest-mate to newly discovered food by the excruciatingly slow process of tandem running. The follower obtains knowledge through its leading tutor. Both leader and follower are acutely sensitive to the progress of their partner with the leader slowing down when the follower lags, and speeding up when the follower gets too close. Controlled experiments with colonies of "Cerapachys biroi" suggest that individuals may choose nest roles based on their previous experience. An entire generation of identical workers was divided into two groups whose outcome in food foraging was controlled. 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. A month later, the successful foragers continued in their role while the others moved to specialise in brood care. Nest construction. Complex nests are built by many ants, but other species are nomadic and do not build permanent structures. Ants may form subterranean nests or build them on trees. These nests can be found in the ground, under stones or logs, inside logs, hollow stems or even acorns. The materials used for construction include soil and plant matter, and ants carefully select their nest sites; "Temnothorax albipennis" will avoid sites with dead ants, as these may indicate the presence of pests or disease. They are quick to abandon established nests at the first sign of threats. The army ants of South America and the driver ants of Africa do not build permanent nests, but instead alternate between nomadism and stages where the workers form a temporary nest (bivouac) from their own bodies, by holding each other together. Weaver ant ("Oecophylla" spp.) workers build nests in trees by attaching leaves together, first pulling them together with bridges of workers and then inducing their larvae to produce silk as they are moved along the leaf edges. Similar forms of nest construction are seen in some species of "Polyrhachis". Food cultivation. Most ants are generalist predators, scavengers and indirect herbivores, but a few have evolved specialised ways of obtaining nutrition. Leafcutter ants ("Atta" and "Acromyrmex") feed exclusively on a fungus that grows only within their colonies. They continually collect leaves which are taken to the colony, cut into tiny pieces and placed in fungal gardens. Workers specialise in tasks according to their sizes. The largest ants cut stalks, smaller workers chew the leaves and the smallest tend the fungus. Leafcutter ants are sensitive enough to recognise the reaction of the fungus 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 feed on structures produced by the fungi called "gongylidia". Symbiotic bacteria on the exterior surface of the ants produce antibiotics that kill bacteria that may harm the fungi. Navigation. Foraging ants travel distances of up to from their nest and usually find their way back using scent trails. Some ants forage at night. Day foraging ants in hot and arid regions face death by desiccation, so the ability to find the shortest route back to the nest reduces that risk. Diurnal desert ants ("Cataglyphis fortis") use visual landmarks in combination with other cues to navigate. In the absence of visual landmarks, the closely related Sahara desert ant ("Cataglyphis bicolor") navigates by keeping track of direction as well as distance travelled, like an internal pedometer that counts how many steps they take in each direction. They integrate this information to find the shortest route back to their nest. Several species of ants are able to use the Earth's magnetic field. Ants' compound eyes have specialised cells that detect polarised light from the Sun, which is used to determine direction. Locomotion. Worker ants do not have wings and reproductive females lose their wings after their mating flights in order to begin their colonies. Therefore, unlike their wasp ancestors, most ants travel by walking. Some species are capable of leaping. For example, Jerdon's jumping ant ("Harpegnathos saltator") is able to jump by synchronising the action of its mid and hind pairs of legs. There are several species of gliding ant including "Cephalotes atratus"; this may be a common trait among most arboreal ants. Ants with this ability are able to control the direction of their descent while falling. Other species of ants can form chains to bridge gaps over water, underground, or through spaces in vegetation. Some species also form floating rafts that help them survive floods. These rafts may also have a role in allowing ants to colonise islands. "Polyrhachis sokolova", a species of ant found in Australian mangrove swamps, can swim and live in underwater nests. Since they lack gills, they breathe in trapped pockets of air in the submerged nests. Cooperation and competition. Not all ants have the same kind of societies. The Australian bulldog ants are among the biggest and most basal (primitive) of ants. Like virtually all ants they are eusocial, but their social behaviour is poorly developed compared to other species. Each individual hunts alone, using its large eyes instead of its chemical senses to find prey. Some species (such as "Tetramorium caespitum") attack and take over neighbouring ant colonies. Others are less expansionist but just as aggressive; they invade colonies to steal eggs or larvae, which they either eat or raise as workers slaves. Extreme specialists among these slave-raiding ants, such as the Amazon ants, are incapable of feeding themselves and need captured workers to survive. Ants identify kin and nestmates through their scent, which comes from hydrocarbon-laced secretions that coat their exoskeletons. If an ant is separated from its original colony, it will eventually lose the colony scent. Any ant that enters a colony without a matching scent will be attacked. Parasitic ant species enter the colonies of host ants and establish themselves as social parasites; species like "Strumigenys xenos" are entirely parasitic and do not have workers, but instead rely on the food gathered by their "Strumigenys perplexa" hosts. This form of parasitism is seen across many ant genera, but the parasitic ant is usually a species that is closely related to its host. A variety of methods are employed to enter the nest of the host ant. A parasitic queen can enter the host nest before the first brood has hatched, establishing herself prior to development of a colony scent. Other species use pheromones to confuse the host ants or to trick them into carrying the parasitic queen into the nest. Some simply fight their way into the nest. A conflict between the sexes of a species is seen in some species of ants with the reproductives apparently competing to produce offspring that are as closely related to them as possible. The most extreme form involves the production of clonal offspring. An extreme of sexual conflict is seen in "Wasmannia auropunctata", where the queens produce diploid daughters by thelytokous parthenogenesis and males produce clones by a process where a diploid egg loses its maternal contribution to produce haploid males that are clones of the father. Relationships with other organisms. The spider "Myrmarachne plataleoides" (here a female) mimics weaver ants to avoid predators. Ants form symbiotic associations with a range of species, including other ant species, other insects, plants, and fungi. They are preyed on by many animals and even certain fungi. Some arthropod species spend part of their lives within ant nests, either preying on ants, their larvae and eggs, consuming the ants' food stores, or avoiding predators. These inquilines can bear a close resemblance to ants. The nature of this ant mimicry (myrmecomorphy) varies, with some cases involving Batesian mimicry, where the mimic reduces the risk of predation. Others show Wasmannian mimicry, a form of mimicry seen only in inquilines. Aphids and other hemipteran insects secrete a sweet liquid called honeydew when they feed on plant sap. The sugars in honeydew are a high-energy food source, which many ant species collect. In some cases the aphids secrete the honeydew in response to the ants' tapping them with their antennae. The ants in turn keep predators away and will move the aphids between feeding locations. On migrating to a new area, many colonies will take the aphids with them, to ensure a continued supply of honeydew. Ants also tend mealybugs to harvest their honeydew. Mealybugs can become a serious pest of pineapples if ants are present to protect mealybugs from their natural enemies. 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 produce vibrations and sounds that are perceived by the ants. Other caterpillars have evolved from ant-loving to ant-eating: these myrmecophagous caterpillars secrete a pheromone that makes the ants act as if the caterpillar is one of their own larvae. The caterpillar is then taken into the ants' nest where it feeds on the ant larvae. Fungus-growing ants that make up the tribe Attini, including leafcutter ants, 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 three-way association with the host plant "Hirtella physophora" (Chrysobalanaceae), and a sticky fungus which is used to trap their insect prey. Lemon ants make devil's gardens by killing surrounding plants with their stings and leaving a pure patch of lemon ant trees ("Duroia hirsuta"). This modification of the forest provides the ants with more nesting sites inside the stems of the "Duroia" trees. Some trees have extrafloral nectaries that provide food for ants, which in turn protect the plant from herbivorous insects. Species like the bullhorn acacia ("Acacia cornigera") in Central America have hollow thorns that house colonies of stinging ants ("Pseudomyrmex ferruginea") that defend the tree against insects, browsing mammals, and epiphytic vines. Isotopic labelling studies suggest that plants also obtain nitrogen from the symbiotic ants. In return, the ants obtain food from protein-lipid Beltian bodies. Another example of this type of ectosymbiosis comes from the "Macaranga" tree, which has stems adapted to house colonies of "Crematogaster" ants. Many tropical tree species have seeds that are dispersed by ants. Seed dispersal by ants or myrmecochory is widespread particularly in Africa and Australia. Some plants in fire-prone grassland systems are particularly dependent on ants for their survival and dispersal. Many ant-dispersed seeds have special external structures, elaiosomes, that are sought after by ants as food. A convergence, possibly a form of mimicry, is seen in the eggs of stick insects. They have an edible elaiosome-like structure and are taken into the ant nest where the young hatch. Ants prey on and obtain food from a number of social insects including other ants. Some species specialise in preying on termites ("Megaponera" and "Termitopone") while a few Cerapachyinae prey on other ants. Some termites form associations with certain ant species to keep away other predatory ant species.The tropical wasp "Mischocyttarus drewseni" coats the pedicel of its nest with an ant-repellant chemical. It is suggested that many tropical wasps may build their nests in trees and cover them to protect themselves from ants. Stingless bees ("Trigona" and "Melipona") use chemical defences against ants. Flies in the Old World genus "Bengalia" (Calliphoridae) prey on ants and are kleptoparasites, snatching prey or brood from the mandibles of adult ants. 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. The fungus "Cordyceps" infects ants, causing them to climb up plants and sink their mandibles into plant tissue. The fungus kills the ant, grows on its remains, and produces a fruiting body. It appears that the fungus alters the behaviour of the ant to help disperse its spores. Strepsipteran parasites also manipulate their ant host to climb grass stems, to help the parasite find mates. A nematode ("Myrmeconema neotropicum") that infects canopy ants ("Cephalotes atratus") causes the black coloured gasters of workers to turn red. The parasite also alters the behaviour of the ant, and makes them carry their gasters high. The conspicuous red gasters are mistaken by birds for ripe fruits such as "Hyeronima alchorneoides" and eaten. The droppings of the bird are collected by other ants and fed to their young leading to the further spread of the nematode. South American poison dart frogs in the genus "Dendrobates" feed mainly on ants, and the toxins in their skin may come from the ants. Several South American antbirds follow army ants to feed on the insects that are flushed from cover by the foraging ants. This behaviour was once considered mutualistic, but later studies show that it is instead kleptoparastic, with the birds stealing prey. Birds indulge in a peculiar behaviour called anting that is as yet not fully understood. Here birds rest on ant nests, or pick and drop ants onto their wings and feathers; this may remove ectoparasites. Anteaters, pangolins and several marsupial species in Australia have special adaptations for living on a diet of ants. These adaptations include long, sticky tongues to capture ants and strong claws to break into ant nests. Brown bears ("Ursus arctos") have been found to feed on ants, and about 12%, 16%, and 4% of their faecal volume in spring, summer, and autumn, respectively, is composed of ants. Relationship with humans. Ants perform many ecological roles that are beneficial to humans, including the suppression of pest populations and aeration of the soil. The use of weaver ants in citrus cultivation in southern China is considered one of the oldest known applications of biological control. On the other hand, ants can become nuisances when they invade buildings, or cause economic losses. In some parts of the world (mainly Africa and South America), large ants, especially army ants, are used as surgical sutures. The wound is pressed together and ants are applied along it. The ant seizes the edges of the wound in its mandibles and locks in place. The body is then cut off and the head and mandibles remain in place to close the wound. Some ants of the family Ponerinae have toxic venom and are of medical importance. The species include "Paraponera clavata" ("Tocandira") and "Dinoponera" spp. (false "Tocandira"s) of South America and the "Myrmecia" ants of Australia. In South Africa, ants are used to help harvest rooibos ("Aspalathus linearis"), which are small seeds used to make a herbal tea. The plant disperses its seeds widely, making manual collection difficult. Black ants collect and store these and other seeds in their nest, where humans can gather them "en masse". Up to half a pound (200 g) of seeds can be collected from one ant-heap. As food. 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 for as much as USD 40 per pound (USD 90 kg) because they are seasonal and hard to find. In the Colombian department of Santander, "hormigas culonas" (roughly interpreted as "large-bottomed ants") "Atta laevigata" are toasted alive and eaten. In areas of India, and throughout Burma and Thailand, a paste of the green weaver ant ("Oecophylla smaragdina") is served as a condiment with curry. 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. 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". In his "First Summer in the Sierra", John Muir 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"). As pests. Some ant species are considered pests, and because of the adaptive nature of ant colonies, eliminating the entire colony is nearly impossible. Pest management is therefore a matter of controlling local populations, instead of eliminating an entire colony, and most attempts at control are temporary solutions. Ants classified as pests include the pavement ant, yellow crazy ant, sugar ants, the Pharaoh ant, carpenter ants, Argentine ant, odorous house ants, red imported fire ant and European fire ant. Populations are controlled using insecticide baits, either in granule or liquid formulations. Bait is gathered by the ants as food and brought back to the nest where the poison is inadvertently spread to other colony members through trophallaxis. Boric acid and borax are often used as insecticides that are relatively safe for humans. Bait may be broadcast over a large area to control species like the red fire ant that occupy large areas. Nests of red fire ants may be destroyed by following the ants' trails back to the nest and then pouring boiling water into it to kill the queen. This works in about 60% of the mounds and requires about per mound. In science and technology. Myrmecologists study ants in the laboratory and in their natural conditions. Their complex and variable social structures have made ants ideal model organisms. Studies on ants have tested hypotheses in ecology, sociobiology and have been particularly important in examining the predictions of theories of kin selection and evolutionarily stable strategies. Ant colonies can be studied by rearing or temporarily maintaining them in formicaria, specially constructed glass framed enclosures. Individuals may be tracked for study by marking them with colours. The successful techniques used by ant colonies have been studied 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 that make use of "foraging trails", fault-tolerant storage and networking algorithms. In culture. Ants have often been used in fables and children's stories to represent industriousness and cooperative effort. They are also mentioned in religious texts. In the Book of Proverbs in the Bible, ants are held up as a good example for humans for their hard work and cooperation. Aesop did the same in his fable The Ant and the Grasshopper. In parts of Africa, ants are considered to be the messengers of the gods. Ant bites are often said to have curative properties. The sting of some species of "Pseudomyrmex" is claimed to give fever relief. Some Native American mythology, such as the Hopi mythology, considers ants as the very first animals. Others use ant bites in initiation ceremonies as a test of endurance. Ant society has always fascinated humans and has been written about both humorously and seriously. Mark Twain wrote about ants in his "A Tramp Abroad". Some modern authors have used the example of the ants to comment on the relationship between society and the individual. Examples are Robert Frost in his poem "Departmental" and T. H. White in his fantasy novel "The Once and Future King". The plot in French entomologist and writer Bernard Werber's "Les Fourmis" science-fiction trilogy is divided between the worlds of ants and humans; ants and their behaviour is described using contemporary scientific knowledge. In more recent times, animated cartoons and 3D animated movies featuring ants have been produced include "Antz", "A Bug's Life", "The Ant Bully", "The Ant and the Aardvark", "Atom Ant", and there is a comic book superhero called Ant-Man. From the late 1950s through the late 1970s, ant farms were popular educational children's toys in the United States. Later versions use transparent gel instead of soil allowing greater visibility. In the early 1990s, the video game SimAnt, which simulated an ant colony, won the 1992 Codie award for "Best Simulation Program". Ants are also quite popular inspiration for many science-fiction creatures, such as the Formics of "Ender's Game", the Bugs of "Starship Troopers", the giant ants in the film "Them!", and ants mutated into super intelligence in "Phase IV". In strategy games, ant-based species often benefit from increased production rates due to their single-minded focus, such as the Klackons in the "Master of Orion" series of games or the ChCht in "Deadlock II". These characters are often credited with a hive mind, a common misconception about ant colonies. |