Leaf cutter ants eat fungus to help them digest their food and for the nutrients the fungus supplies. Adult leaf cutter ants also cultivate the fungus and feed it to the growing ant larvae, which eat nothing else. The ants and the fungus have a symbiotic relationship, which means that they depend on each other for survival.
The fungus used by the ants only grows in leaf cutter colonies and cannot reproduce on its own. The ants cultivate the fungus underground by feeding it pieces of flowers and leaves, which they transport to a fungus-type garden.The fungus helps convert the leaves into carbohydrates.
The ants also use the cut leaves to make compost. They chew and fertilize them, weeding out any other plants in the garden. They cultivate the fungus much like a farmer cultivates crops. If a queen leaf-cutter ant leaves to form a new colony, she carries a piece of the fungus with her to begin a new garden. Different leaf cutter ant species use different types of fungus.
Leaf-cutter ants are prolific. Colonies often contain millions of individuals that can completely defoliate a full-sized tree in a single day. The colonies are made up of different classes of ants, including the queen, workers and drones.