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 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 similar mutualism with fungi is also noted in termites within the subfamily Macrotermitinae which are widely distributed throughout the Old World tropics with the highest diversity in Africa.
The banded sugar ant, also known as the sugar ant, is a species of ant native to Australia. A member of the genus Camponotus in the subfamily Formicinae, it was described by German entomologist Wilhelm Ferdinand Erichson in 1842. Its common name refers to the ant's liking for sugar and sweet food, as well as the distinctive orange-brown band that wraps around its gaster.
Myrmecia inquilina is a species of ant endemic to Australia in the subfamily Myrmeciinae, first discovered in 1955 and described by Athol Douglas and William Brown Jr. in 1959. These ants are large, measuring 21.4 millimetres (0.84 in). During the time of its discovery, Douglas and Brown announced M. inquilina as the first social parasite among the primitive subfamilies, and today it is one of the two known Myrmecia species to have no worker caste. Two host species are known, Myrmecia nigriceps and Myrmecia vindex. Aggression between M. inquilina and its host species does not occur, and colonies may only produce M. inquilina brood months after the inquiline queens begin to lay their eggs. Queens eat the colony brood or trophic eggs, and other Myrmecia species may kill M. inquilina queens if they reject them. Due to its restricted distribution and threats to its habitat, the ant is "vulnerable" according to the IUCN Red List.
Sericomyrmex is a genus of fungus-growing ants in the subfamily Myrmicinae.
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.
Mycocepurus smithii is a species of fungus-growing ant from Latin America. This species is widely distributed geographically and can be found from Mexico in the north to Argentina in the south, as well as on some Caribbean Islands. It lives in a variety of forested habitats and associated open areas. Two studies published in 2009 demonstrated that some populations of the species consist exclusively of females which reproduce via thelytokous parthenogenesis. A detailed study found evidence of sexual reproduction in some populations in the Brazilian Amazon. Accordingly, M. smithii consists of a mosaic of sexually and asexually reproducing populations. In asexual populations all ants in a single colony are female clones of the queen. Inside the colony, the ants cultivate a garden of fungus grown with pieces of dead vegetable matter, dead insects, and insect droppings.
Cyphomyrmex is a genus of fungus-growing ants found primarily in South and Central America. However, some species do come up to the southern portion of North America. They grow a variety of fungi in the tribe Leucocoprineae. Most fungal gardens are grown in small nodules, some species to cultivate entire mycelium, though. Colonies are monogynous and are relatively small with about 100 workers on average.
Apterostigma is a genus of New World ants of the subfamily Myrmicinae. Two species have been described from fossils preserved in Dominican amber, while the others are extant. They are fungus-growing ants, though, unlike the majority of other species in Attini who grow Lepiotaceae, some species have begun cultivating Tricholomataceae.
Myrmecocystus mexicanus is a species of ant in the genus Myrmecocystus, which is one of the six genera that bear the common name "honey ant" or "honeypot ant", due to curious behavior where some of the workers will swell with liquid food until they become immobile and hang from the ceilings of nest chambers, acting as living food storage for the colony. Honey ants are found in North America, Australia, and Africa. Ant species belonging to the genus Myrmecocystus reside in North America. M. mexicanus in particular is found in the southwestern United States and parts of Mexico.
Megalomyrmex mondabora is a Neotropical species of ants in the subfamily Myrmicinae. Known from Costa Rica. In Costa Rica this species occurs in wet forest habitats, typically in mature rainforest. Collections are from sea level to 800 m elevation on the Atlantic slope of the Cordillera Volcanica Central, Cordillera de Talamanca, and Cordillera de Guanacaste. It is a specialized nest parasite of attines and is found most often in nests of Cyphomyrmex cornutus. It cohabits with C. cornutus in their nests, feeding on both host brood and the host's fungal symbiont.
Megalomyrmex mondaboroides is a Neotropical species of ant in the subfamily Myrmicinae. Megalomyrmex mondaboroides occurs in lowland wet forest habitats in Panama and Costa Rica. Colonies have been collected in the nests of small attines, primarily Cyphomyrmex costatus and Apterostigma goniodes. In Costa Rica a worker was collected in a Winkler sample of sifted leaf litter.
Megalomyrmex adamsae is a Neotropical species of ants in the subfamily Myrmicinae. Megalomyrmex adamsae, known from Panama, is very similar to M. symmetochus, known from Costa Rica to Panama.
Megalomyrmex wettereri is a Neotropical species of ants in the subfamily Myrmicinae. Megalomyrmex wettereri is known from two lowland rainforest sites: Barro Colorado Island in Panama and La Selva Biological Station in Costa Rica.
Megalomyrmex silvestrii is a Neotropical species of ants in the subfamily Myrmicinae. Megalomyrmex silvestrii is widespread in the mainland Neotropics from Mexico to northern Argentina. This species occurs in moist to wet forest habitats, from sea level to 1100 m elevation. It nests in small chambers in rotten wood or opportunistically in other small cavities in the soil. Colonies have been found in small attine nests and alone, suggesting it is a facultative predator of small Attini.
An ergatoid is a permanently wingless reproductive adult ant or termite. The similar but somewhat ambiguous term ergatogyne refers to any intermediate form between workers and standard gynes. Ergatoid queens are distinct from other ergatogyne individuals in that they are morphologically consistent within a species and are always capable of mating, whereas inter caste individuals, another class of ergatogynes, often are not. Ergatoids can exhibit wide morphological differences between species, sometimes appearing almost identical to normal workers and other times being quite distinct from both workers and standard queens. In addition to morphological features, ergatoids among different species can exhibit a wide range of behaviors, with some ergatoids acting only as reproductives and others actively foraging. Ergatoid queens have developed among a large number of ant species, and their presence within colonies can often provide clues on the social structures of colonies and as to how new colonies are founded. Without wings, almost all species of ants that solely produce ergatoid queens establish new colonies by fission.
Mycocepurus castrator is a species of parasitic ant, in the genus Mycocepurus, native to Brazil. Described in 2010, the species is a workerless and obligate parasite of the related ant Mycocepurus goeldii. It is known only from Rio Claro, Brazil, and has only been found in nests of M. goeldii.
Novomessor ensifer is a species of ant endemic to Mexico. A member of the genus Novomessor in the subfamily Myrmicinae, it was first described by Swiss entomologist Auguste Forel in 1899. N. ensifer was originally a part of the genus Aphaenogaster until a recent phylogenetic study concluded that Novomessor was genetically distinct and should be separated. The ant is a medium-sized species, measuring 5.5 to 10 millimetres. The ant is ferruginous-colored in some certain parts of the body, and small workers (nanitics) in incipient colonies are noticeably different in color and body structure.
Electromyrmex is an extinct genus of ants in the formicid subfamily Dolichoderinae. The genus contains a single described species, Electromyrmex klebsi and is known from a group of Middle Eocene fossils which were found in Europe.
