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Leafcutter Ant (Atta cephalotes) Fact Sheet: Summary

Leafcutter Ant (Atta cephalotes) Fact Sheet

3 worker sizes of leafcutter ant, Atta cephalotes

Leafcutter Ant (Atta cephalotes)

Image credit: © San Diego Zoo Wildlife Alliance. All rights reserved.

 

Taxonomy

 

Kingdom: Animalia

Phylum: Chordata

Class: Insecta

Order: Hymenoptera

Family: Formicidae

Genus: Atta

Species: Atta cephalotes


 

Distribution & Status

Behavior & Ecology

Range

Southern Mexico to Brazil

Habitat

Intact and human-modified wet tropical forests in the Neotropics

IUCN Status

Not assessed

CITES Appendix

Not listed

Populations in the Wild

No global estimates. Considered wide-ranging and abundant.

Activity Patterns

Colonies may be active during the day and at night. Some colonies nocturnal only. Rain and daytime parasitism by phorid flies likely suppress daytime activity, while warmer air and soil temperatures increase activity.

Nests

Huge underground nest structures that house millions of workers and immature ants. Interconnected system of tunnels and ball-shaped chambers. Larvae develop in wooly, sponge-like fungus gardens. Waste removed from fungal gardens and stored in separate refuse chambers.

Social Structure

Colonial insect with complex division of labor. A single long-lived queen and millions of sterile workers live together in an enormous underground nest. Workers cut and carry leaf fragments, clean and mulch leaves, tend symbiotic fungus gardens, care for queen and many larvae/pupae, and defend the nest, together with soldiers. Newly hatched workers perform tasks inside the nest (some outside, e.g., trail clearing), with older workers mainly active outside the nest.

Communication

Atta foragers communicate acoustically via a “stridulation organ” and chemically by trail and alarm pheromones.

Diet

Fresh plant material, mainly leaves, used to cultivate a specialized species of fungus (Leucoagaricus gongylophorus) in underground nest chambers. Ants and the fungus are dependent on each other for survival. Larvae, pupae, and adults feed on liquids produced in fungus’ bulbous tip structures (gongylidia). Plant sugars (nectars, saps) also appear to play a role in forager diets.

Predators

Army ants prey on leafcutter ant brood young. Birds, bats, and ground mammals feed on Atta queens searching for a nest site after mating.

Reproduction & Development

Species Highlights

Breeding System

Typically, a single reproductive queen that mates with up to 5 males before founding a new colony. Most worker offspring sterile, but colony produces a few thousand reproductive females and males each year, which disperse to mate.

Mating

During nuptial flights, males mate with females and die the same day. Females that survive the dispersal period establish new colonies. Queens never mate again; use stored sperm to fertilize eggs, until death.

Egg Laying

Queen lays a small number of viable eggs to found colony. After a few years, as a diverse labor caste system becomes established, queen can lay more than 25,000 eggs per day, on average, which may add up to as many as 150 million daughters over a lifetime.

Care of brood young

Small workers tend the eggs, larvae, and pupae developing in fungus garden chambers. During colony founding, queen provides initial care of fungus, eggs, and larvae. Her offspring workers later take on all care duties, allowing the queen to continuously lay eggs.

Longevity

Atta cephalotes queens are among the longest-lived insects. May live 10–20 years, though average colony lifespan under natural conditions may be closer to about 8 years (more research needed to track survival of wild colonies).

Predators

Dispersing queens: birds, bats, and ground mammals (due to nutrient-rich gaster).
Brood young: army ants, possibly bullet ants.

Feature Facts

  • Atta leafcutter ant colonies comparable in social complexity with honeybees and African fungus-growing termites; referred to as “superorganisms”
  • Sophisticated division of labor and reproductive caste systems; single breeding queen can have more than 5 million workers that forage and cooperatively care for developing brood
  • Queen, workers, and brood live in a vast subterranean nest complex with hundreds of interconnected fungus garden chambers
  • Workers harvest and process enormous amounts of fresh plant matter to cultivate a specialized fungus as their almost exclusive food source
  • Foragers travel along well-maintained trails; routes between nest and harvest sites marked with potent pheromones
  • Small workers sometimes ride on leaf fragments being transported back to nest by larger workers to help deter parasitic flies that lay eggs in the necks of larger foragers
  • Extensive leaf processing occurs below ground, sometimes taking 12 hours to cut, clean, mulch, and add the material to fungus garden in a pre-digested state
  • Use chemical secretions, antimicrobial compounds, bacterial biofilms, gardening behaviors, and strict waste disposal practices to maintain their garden system (unique to each colony)
  • When starting new colonies, young queens carry a small tuft of fungus during mating flight; queen lives off her body reserves and does not feed on fungus until first workers raised
  • Atta cephalotes: a dominant and ecologically important species in tropical America, especially in rainforests and forest-edge ecosystems
  • Considerable impact on plant communities and forest structure; an “ecosystem engineer”
  • Atta considered a severe pest in agricultural and urban areas

About This Fact Sheet

For detailed information, click the tabs at the top of this page.

 

© 2022 San Diego Zoo Wildlife Alliance

 

How to cite: Leafcutter Ant (Atta cephalotes) Fact Sheet. c2022. San Diego (CA): San Diego Zoo Wildlife Alliance; [accessed YYYY Mmm dd]. http://ielc.libguides.com/sdzg/factsheets/leafcutter-ant.
(note: replace YYYY Mmm dd with date accessed, e.g., 2019 Dec 31)

 

Disclaimer: Although San Diego Zoo Wildlife Alliance makes every attempt to provide accurate information, some of the facts provided may become outdated or replaced by new research findings. Questions and comments may be addressed to library@sdzwa.org.

Acknowledgments

Many thanks to the scientists who served as expert content reviewers for this fact sheet. All reviewers have investigated the biology of leafcutter ants and other eusocial insects.


Thank you to Prof. Jacobus J. (Koos) Boomsma (University of Copenhagen) for helping with content review of this fact sheet. Prof. Boomsma has authored more than 300 research articles on social evolution in insects and topics related to ant mating systems, genomics, conflict-cooperation dynamics, ant-fungus mutualism, and more. Boomsma has conducted fieldwork on fungus-growing ants for 25 years.


Thank you to Dr. Pepijn W. Kooij (São Paulo State University) for reviewing the Diet & Feeding section of this fact sheet. Dr. Kooij studies fungus-ant symbiosis, including aspects of fungus evolution and growth, garden cultivation, nest hygeine and fungal pathogens, ant communication, and ant digestion and nutrition.


Thank you to Dr. Alejandro G. Farji-Brener (Laboratorio de Investigaciones en Hormigas, Bariloche, Argentina) for reviewing the Behavior & Ecology section of this fact sheet. Dr. Farji-Brener has studied leafcutter ants for three decades, conducting research on ant foraging behavior, ecology, communication, ant-phorid parasitism, and management planning.


Thank you to Dr. Ted R. Schultz (Smithsonian National Museum of Natural History) for reviewing the Evolutionary History content of this fact sheet. Dr. Schultz is the world's leading expert on the evolution, systematics, and phylogeny of attine ants.


Thank you to Prof. Boris Baer (University of California Riverside) for reviewing the Mating content in this fact sheet. Prof. Baer has published extensively on social insect reproduction, investigating breeding systems, immunity and pathogens, anatomy, and sexual selection.


Thank you to Prof. Jonathan Z. Shik (University of Copenhagen) and Prof. Ulrich G. Mueller (University of Texas Austin) for answering questions related to Atta biology, evolution, reproduction, and behavior.

Harvesting in the Tree Canopy

Two leafcutter ants carry a fragment of green fern

Two leafcutter ants carry a fragment of green fern.

Atta cephalotes is a dominant and ecologically important species in the tropical Americas, especially in rainforests and forest-edge ecosystems.

They harvest most plant matter from the tree canopy.

Image credit: © San Diego Zoo Wildlife Alliance. All rights reserved.

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