Atta mexicana
Temperature
24–28 °C
Humidity
75–90%
Colony size
500,000–3,000,000
Queen size
20–23 mm
Worker size
1.5–18 mm
Diet
Care Guide
Atta mexicana is the Mexican leafcutter, ranging across much of Mexico and into parts of the southwestern United States. The queen reaches 20–23 mm, slightly smaller than her tropical cousins but still impressive. Workers are dramatically polymorphic, from 1.5 mm minims tending the fungus to 18 mm soldiers defending the colony. Mature colonies number 500,000 to 3,000,000 individuals — large by any standard but more manageable than the truly massive A. cephalotes or A. sexdens colonies.
Like all leafcutters, A. mexicana cultivates a symbiotic fungus that the colony feeds. Workers cut leaves, flowers, and fruit, carry them along well-established trails, and process them into a substrate for the fungal garden. The colony then feeds on gongylidia produced by the fungus. The queen carries a starter pellet of fungus from her natal nest during her mating flight.
In its natural range A. mexicana is adapted to a slightly drier, more seasonal climate than its rainforest relatives, which gives it marginally more tolerance for fluctuating humidity in captivity.
Care difficulty
Expert. While slightly more forgiving than A. cephalotes or A. sexdens, this remains an extremely demanding species best suited to keepers with prior leafcutter experience.
Housing
A modular system of fungus chambers, foraging arenas, and waste chambers is essential. Maintain temperature between 24 and 28 °C with humidity at 75–90 % around the garden. Offer a daily supply of fresh, untreated leaves — rose, bramble, oak, hibiscus — supplemented with apple, banana, and occasional dried protein such as mealworms. Avoid any plant material that may have been exposed to insecticides or fungicides.
First days after purchase
Place the founding queen and her fungus pellet in a small, dark, humid chamber at around 25 °C and leave her completely undisturbed. Do not open the container, do not offer leaves until the first generation of workers is actively foraging, and inspect daily only by visual check for mold or contamination. The founding stage is the riskiest part of leafcutter keeping and demands maximum patience.