Листорезы: жизнь и колонии муравьев-грибоводов.

Any of 47 species of leaf chewing ants

Leafcutter ants, a non generic name, are any of 47 species of leaf chewing ants belonging to the two genera Atta and Acromyrmex, within the tribe Attini. 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 (leaves, flowers, and grasses) to serve as the nutritional substrate for their fungal cultivates. Acromyrmex and Atta ants have much in common anatomically; however, the two can be identified by their external differences. Atta ants have three pairs of spines and a smooth exoskeleton on the upper surface of the thorax, while Acromyrmex ants have four pairs and a rough exoskeleton. The exoskeleton itself is covered in a thin layer of mineral coating, composed of rhombohedral crystals that are generated by the ants. Next to humans, leafcutter ants form some of the largest and most complex animal societies on Earth. In a few years, the central mound of their underground nests can grow to more than across, with smaller radiating mounds extending out to a radius of , taking up and containing eight million individuals. Once on the ground, the female loses her wings and searches for a suitable underground lair in which to found her colony. The success rate of these young queens is very low, and only 2.5% will go on to establish a long lived colony. To start her own fungus garden, the queen stores bits of the parental fungus garden mycelium in her infrabuccal pocket, which is located within her oral cavity. Colonies are generally founded by individual queens haplometrosis. Because colonies with multiple queens over the lifespan of the colony have been found by a large number of investigators by Weber 1937, Jonkman 1977, Huber 1907, Moser & Lewis 1981, Mariconi & Zamith 1963, Moser 1963, and Walter et al 1938 it is believable that some colonies have multiple foundresses termed pleometrosis. Their fungi produce nutritious and swollen hyphal tips (gongylidia) that grow in bundles called staphylae, to specifically feed the ants. Leucoagaricus gongylophorus is the most commonly documented fungi farmed by higher attine ant species.

Leafcutter ants have very specific roles in taking care of the fungal garden and dumping the refuse. Waste management is a key role for each colony's longevity. The necrotrophic parasitic fungus Escovopsis threatens the ants' food source and thus is a constant danger to the ants. The waste transporters and waste heap workers are the older, more dispensable leafcutter ants, ensuring the healthier and younger ants can work on the fungal garden. The Atta colombica species, unusually for the Attine tribe, have an external waste heap. Waste transporters take the waste, which consists of used substrate and discarded fungus, to the waste heap. Once dropped off at the refuse dump, the heap workers organise the waste and constantly shuffle it around to aid decomposition. A compelling observation of A. colombica was the dead ants placed around the perimeter of the waste heap. In addition to feeding the fungal garden with foraged food, mainly consisting of leaves, it is protected from Escovopsis by the antibiotic secretions of Actinomycetota (genus Pseudonocardia). This mutualistic micro organism lives in the metapleural glands of the ant. Actinomycetota are responsible for producing the majority of the world's antibiotics today.

When the ants are out collecting leaves, they are at risk of attack by some species of phorid flies, parasitoids that lay eggs into the crevices of the worker ants' heads. Often, a minim will sit on a worker ant and ward off any attack. Also, the wrong type of fungus can grow during cultivation. Escovopsis, a highly virulent fungus, has the potential to devastate an ant garden, as it is horizontally transmitted. Escovopsis was cultured, during colony foundation, in 6.6% of colonies. However, in one to two year old colonies, almost 60% had Escovopsis growing in the fungal garden. Nevertheless, leafcutter ants have many adaptive mechanisms to recognize and control infections by Escovopsis and other micro organisms. The most common known behaviors rely on workers reducing the number of fungal spores by grooming, or removing an infected piece of the fungus garden and throwing it away at the waste dump (described as weeding).

Leafcutter ants use chemical communication and stridulation (substrate borne vibrations) to communicate with each other.

Leafcutter ants prefer disturbed habitats, likely due to higher concentrations of pioneer plant species. These are more attractive food sources because pioneer plants have lower levels of secondary metabolites and higher nutrient concentrations than the shade tolerant species that will come later.

In some parts of their range, leafcutter ants can be a serious agricultural pest, defoliating crops and damaging roads and farmland with their nest making activities.