Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from vespoid wasp ancestors in the Cretaceous period. More than 13,800 of an estimated total of 22,000 species have been classified. They are easily identified by their geniculate (elbowed) antennae and the distinctive node-like structure that forms their slender waists.
Atta is a genus of New World ants of the subfamily Myrmicinae. It contains at least 17 known species.
Leafcutter ants, a non-generic name, are any of 47 species of leaf-chewing ants belonging to the two genera Atta and Acromyrmex. These species of tropical, fungus-growing ants are all endemic to South and Central America, Mexico, and parts of the southern United States. Leafcutter ants can carry twenty times their body weight and cut and process fresh vegetation to serve as the nutritional substrate for their fungal cultivates.
Fungus-growing ants comprise all the known fungus-growing ant species participating in ant–fungus mutualism. They are known for cutting grasses and leaves, carrying them to their colonies' nests, and using them to grow fungus on which they later feed.
The Texas leafcutter ant is a species of fungus-farming ant in the subfamily Myrmicinae. It is found in Texas, Louisiana, and north-eastern Mexico. Other common names include town ant, parasol ant, fungus ant, cut ant, and night ant. It harvests leaves from over 200 plant species, and is considered a major pest of agricultural and ornamental plants, as it can defoliate a citrus tree in less than 24 hours. Every colony has several queens and up to 2 million workers. Nests are built in well-drained, sandy or loamy soil, and may reach a depth of 6 m (20 ft), have 1000 entrance holes, and occupy 420 m2 (4,500 sq ft).
Weaver ants or green ants are eusocial insects of the family Formicidae. Weaver ants live in trees and are known for their unique nest building behaviour where workers construct nests by weaving together leaves using larval silk. Colonies can be extremely large consisting of more than a hundred nests spanning numerous trees and containing more than half a million workers. Like many other ant species, weaver ants prey on small insects and supplement their diet with carbohydrate-rich honeydew excreted by small insects (Hemiptera). Weaver ant workers exhibit a clear bimodal size distribution, with almost no overlap between the size of the minor and major workers. The major workers are approximately 8–10 mm (0.31–0.39 in) in length and the minors approximately half the length of the majors. Major workers forage, defend, maintain, and expand the colony whereas minor workers tend to stay within the nests where they care for the brood and 'milk' scale insects in or close to the nests.
The pharaoh ant is a small (2 mm) yellow or light brown, almost transparent ant notorious for being a major indoor nuisance pest, especially in hospitals. A cryptogenic species, it has now been introduced to virtually every area of the world, including Europe, the Americas, Australasia and Southeast Asia. It is a major pest in the United States, Australia, and Europe.
Atta sexdens is a species of leafcutter ant belonging to the tribe Attini, native to America, from the southern United States (Texas) to northern Argentina. They are absent from Chile. They cut leaves to provide a substrate for the fungus farms which are their principal source of food. Their societies are among the most complex found in social insects. A. sexdens is an ecologically important species, but also an agricultural pest. Other Atta species, such as Atta texana, Atta cephalotes and others, have similar behavior and ecology.
The ant–fungus mutualism is a symbiosis seen between certain ant and fungal species, in which ants actively cultivate fungus much like humans farm crops as a food source. There is only evidence of two instances in which this form of agriculture evolved in ants resulting in a dependence on fungi for food. These instances were the attine ants and some ants that are part of the Megalomyrmex genus. In some species, the ants and fungi are dependent on each other for survival. This type of codependency is prevalent among herbivores who rely on plant material for nutrition. The fungus’ ability to convert the plant material into a food source accessible to their host makes them the ideal partner. The leafcutter ant is a well-known example of this symbiosis. Leafcutter ants species can be found in southern South America up to the United States. However, ants are not the only ground-dwelling arthropods which have developed symbioses with fungi. A mutualism with fungi is also noted in some species of termites in Africa.
Acromyrmex is a genus of New World ants of the subfamily Myrmicinae. This genus is found in South America and parts of Central America and the Caribbean Islands, and contains 33 known species. Commonly known as "leafcutter ants" they comprise one of the two genera of advanced attines within the tribe Attini, along with Atta.
Atta cephalotes is a species of leafcutter ant in the tribe Attini. A single colony of ants can contain up to 5 million members, and each colony has one queen that can live more than 15 years. The colony comprises different castes, known as "task partitioning", and each caste has a different job to do.
Atta colombica is one of 47 species of leafcutter ants. This species is part of the Attini tribe.
Atta mexicana is a species of leaf-cutter ant, a New World ant of the subfamily Myrmicinae of the genus Atta. This species is from one of the two genera of advanced attines within the tribe Attini.
Acromyrmex versicolor is known as the desert leafcutter ant. A. versicolor is found during the summer months in the Colorado and Sonoran deserts when there is precipitation. They form large, distinctive nest craters that are covered with leaf fragments. Living and dead leaves are collected by workers and used to cultivate fungus gardens. Each colony can have multiple queens, if they do this is a practice called polygyny, and each queen has her own batch of “starter” fungus. This species does not sting.
Lenomyrmex is a Neotropical genus of ant in the subfamily Myrmicinae.
Symmetry breaking of escaping ants is a herd behavior phenomenon observed when ants are constrained to a cell with two equidistant exits and then sprayed with an insect repellent. The ants tend to crowd one door more while trying to escape, there by decreasing evacuation efficiency.
Escovopsis is a genus of seven formally acknowledged parasitic microfungus species that rely on other fungi to be their hosts. This genus formally circumscribed with a single identified species in 1990; in 2013 three other species were added.
Escovopsis aspergilloides is a species of fungus that was rediscovered in 1995 by mycologists Keith A. Seifert, Robert A. Samson and Ignacio Chapela. Escovopsis aspergilloides co-exist in a symbiotic relationship with attini ants - fungus-growing ants. The highly evolved, ancient ant-fungus mutualism has become a model system in the study of symbiosis. In spite of this, the genus Escovopsis was not proposed until 1990 and the first two species were not formally described until the 1990s: E. weberi by Muchovej and Della Lucia in 1990 E. aspergilloides by Seifert, Samson and Chapela in 1995.
Cartwrightia is a genus of scarab found in Latin America. It was named and circumscribed in 1958 by Federico Islas Salas. As of 2017, three species are recognized: C. intertribalis, C. cartwrighti, and C. islasi. They can be found in the nests of leafcutter ants or in dung.
Leucoagaricus gongylophorus is a fungus in the family Agaricaceae which is cultivated by certain leafcutter ants. Like other species of fungi cultivated by ants, L. gongylophorus produces gongylidia, nutrient-rich hyphal swellings upon which the ants feed. Production of mushrooms occurs only once ants abandon the nest. L. gongylophorus is farmed by leaf cutter ant species belonging to the genera Atta and Acromyrmex, amongst others.
