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.
Fungus-growing ants
A still-winged fungus-growing alate
An Atta colombica queen surrounded by workers in a fungus garden
Different sizes of Atta insularis workers demonstrating the common polymorphism of higher attines
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.
Atta colombica queen
Until the first generation of the new colony is born and matures, the queen will have to cultivate the fungus herself. When a queen is establishing a new colony, she brings a fungal cultivar from her previous colony and lays her eggs around it. Once the eggs mature, she retires from cultivating and continues to lay as many as 20,000 eggs to establish the rest of the colony.
Atta, "higher attine" ants and their cultivar fungus