Leaf-cutter ants

Description:

Common group of ants in the Sonoran Desert are the leaf-cutting or fungus-growing ants. Acromyrmex ants are related to the larger leaf-cutting ants of the tropical Americas. Acromyrmex versicolor is common in the Sonoran Desert. Its workers collect leaves and other plant parts to insert into fungus masses, which they grow in chambers deep within their underground nest. The fungus is completely dependent upon the ants for its care and propagation; the ants, in turn, eat a portion of the fungus as their sole source of solid food. Long columns of leaf-cutter ants search across the desert for plant matter for their fungus gardens when conditions permit in the fall and spring and on cool summer mornings; at other times, they remain underground.

Habitat:

Desert area alongside trail in Sabino Canyon.

Notes:

Leafcutters are not leaf eaters. They use the plant matter they gather on the surface as fertilizer to grow underground gardens of fungus, then they eat the fungus. The fungus has enzymes to digest the cellulose in the plant matter, but the ants don't. The underground fungus gardens are about the size of a softball. The fungus garden is started from a small “plug”of fungus brought by the queen from her home colony. Just before they fly out of the nest, when leaving to mate and begin a new colony, they go to the fungus garden, tuck some up under their mandibles and fly away.