Fungus-growing ants collect food for their fungus from the area surrounding their nests. The picture below shows workers of an Atta leaf-cutter ant cutting leaf fragments.

The material the fungus-growing ants use as food for the fungus depends on the species of ant. The lower attines use a variety of materials, including grasses, fallen leaves, insect fæces and dead insects. The higher attines tend to use only plant material, and sometimes insect fæces while the leaf-cutter ants use material collected from living plants. While leaf-cutter ants in the genus Atta are cutting the leaves they produce high-pitched vibrations which may aid in allowing them to break through the tough leaf surface, although recent research at the University of Würzburg now suggests that they may have a different function. While the worker ants are cutting plants they also drink the sap that emerges from the cut edges. This is the major source of energy for the worker ants. Large leaf-cutter ant colonies can do a lot of damage to the plants on which they forage, often completely defoliating them. Hence leaf-cutter ants are pests in many agricultural systems in the neotropics.

The damage to the plant on the right was caused by a large colony of Atta leaf-cutting ants in less than half an hour