Acromyrmex

Definition

A genus of New World leafcutter ants (Hymenoptera: Formicidae: Myrmicinae: Attini) comprising approximately 35 described species distributed from Mexico and the Caribbean through Central America to South America. Along with the genus Atta, Acromyrmex forms one of the two genera of advanced attines—fungus-growing ants that actively cut and collect fresh vegetation to cultivate symbiotic Leucoagaricus fungi as food. Colonies are typically smaller and more cryptic than those of Atta, often nesting in soil or rotting wood rather than constructing conspicuous soil mounds.

Etymology

New Latin, from Greek akron (tip, extremity) + myrmex (ant), perhaps alluding to the angular or pointed features of the head or mandibles in some species.

Example

Acromyrmex octospinosus workers forage nocturnally, cutting semicircular fragments from leaves of citrus, coffee, and other cultivated plants, making the species a significant agricultural pest in parts of Central America.

Related Terms

• Atta
• Attini
• leafcutter ant
• fungus-growing ant
• myrmecophyte
• symbiotic fungus
• Leucoagaricus

Usage Notes

Distinguished from the closely related genus Atta by morphological and behavioral traits: Acromyrmex workers have a pair of spines or teeth on the promesonotum (often four spines total), a more variable number of antennal segments, and typically smaller colony sizes with less conspicuous nest architecture. The two genera are the only attines that cut fresh vegetation; lower attines cultivate fungi on insect frass, dead vegetation, or other organic substrates. Species identification within Acromyrmex requires examination of thoracic spine configuration, mandibular dentition, and clypeal structure.