Ants have been farming fungi for around 50 million years – weeding, mulching and fertilising their crops. Fungus-farming ants originated in South America, spreading throughout the New World tropics, from Argentina to southern USA. One well-known example is the leafcutter ant (species in the Acromyrmex and Atta genera).
They build their fungus farms in sheltered underground nests, feeding them on chewed-up leaves. The fungi is the ant’s only food. Although benefiting from free food and protection, these species of fungi occasionally escape enslavement and become free-living.