Leaf-cutting Ants

Acromyrmex

Classification

Phylum: Arthropoda
Subphylum: Hexapoda
Class: Insecta
Order: Hymenoptera
Superfamily: Formicoidea
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Subtribe: Attina
Genus: Acromyrmex

Pronunciation

How to pronounce Acromyrmex: /ˌæk.roʊˈmɜː.mɛks/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Images

Acromyrmex octospinosa var. pallida by the Smithsonian. Used under a CC0 license.

Acromyrmex (Acromyrmex) octospinosus volcanus by the Smithsonian. Used under a CC0 license.

Acromyrmex octospinosus by the Smithsonian. Used under a CC0 license.

Acromyrmex insinuator by the Smithsonian. Used under a CC0 license.

Acromyrmex octospinosus inti by the Smithsonian. Used under a CC0 license.

Summary

Acromyrmex is a genus of leafcutter ants found throughout the New World, notable for their complex social structure and advanced mutualistic relationships with fungi. They play a vital role in their ecosystems and can impact agriculture negatively.

Physical Characteristics

Acromyrmex species are dark red in color, with well-defined body parts including a head, thorax, and abdomen. They typically have four pairs of spines on the thorax and a rough exoskeleton. They possess jointed antennae and have compound eyes, but their eyesight is poor. The abdomen contains two stomachs and important glands for digestion and communication.

Identification Tips

Distinguished from the related genus Atta by having four pairs of thoracic spines and a rough upper exoskeleton.

Habitat

Primarily found in desert habitats of the southwestern United States and various ecosystems in the New World tropics and subtropics.

Distribution

Found throughout South America, parts of Central America, México, and the Caribbean Islands; one species occurs in the southwestern United States.

Diet

Leafcutter ants cut fresh vegetation to feed a specialized fungus that grows in their nests; the fungus serves as their primary food source.

Life Cycle

Winged males and females engage in a nuptial flight, after which females mate and found a new colony. A small number of queens survive to establish nests.

Reproduction

Queens can mate with multiple males during a nuptial flight, accumulating sperm to start a colony. They take a section of fungus to start their own gardens.

Ecosystem Role

Acromyrmex ants play a crucial role in the ecosystem as decomposers and as part of an ant-fungus mutualism, actively cultivating fungi that depend on them for survival.

Economic Impact

Can be agricultural pests, particularly in tropical and subtropical regions, by defoliating crops and damaging farmland.

Cultural Significance

In Central America, leafcutter ants are commonly known as 'wee wee' ants, referring not to their size but to a local term.

Collecting Methods

Trap sometimes used to catch foraging workers.
Nest excavation can be done to observe colony structure.

Preservation Methods

Preservation in ethanol for genetic studies.
Drying and mounting for taxonomic identification.

Evolution

Acromyrmex has evolved a mutualistic relationship with specific fungi (genus Leucocoprinus) and a symbiotic bacterium that provides antimicrobials, which is a complex evolutionary advancement in social insects.

Similar Taxa

Atta (another genus of leafcutter ants).

Misconceptions

Not all Acromyrmex species are pests; their ecological role is more complex involving symbiosis with fungi and bacteria.