The fungus civilisation
Atta sexdens is one of the most impressive ants in the world. Native to the tropical forests of South America, it cuts tree leaves to cultivate a symbiotic fungus in its underground nest. It’s this fungus, not the leaves themselves, that is its exclusive food source.
Wild Atta colonies can have several million workers and dig underground nests of more than 50 m² with hundreds of chambers. It’s one of the largest known animal civilisations.
Atta is not recommended for most keepers. You must maintain 80-95% humidity, a stable temperature of 25-28°C, provide fresh leaves every day (rose, raspberry, mulberry, privet leaves), and monitor the health of the symbiotic fungus, which can die and take the colony with it. Material costs and daily maintenance time are high.
The fungus cycle
The queen carries a fragment of fungus from her parent nest during the nuptial flight, in a special mouth pocket. She replants it in her new nest after settling in and feeds it with her own droppings, then her trophic eggs, before raising her first workers.
The workers cut the leaves into pieces, carry them to the nest, and chew them into pulp to inoculate it with the fungus. The fungus grows on this pulp and produces structures called gongylidia that the ants graze on.
Extreme polymorphism
An Atta colony has up to 7 different worker castes: from the 2 mm minor (fungus gardener) to the 15 mm major (a soldier with large mandibles). Each has a precise role. Atta’s polymorphism is one of the most extreme in the animal kingdom.
In the wild, Atta colonies can consume up to 10-15% of the plant biomass of a forest area. They are the “cattle” of the Amazon rainforest, major recyclers and soil engineers.
Keeping
Reserved for seasoned experts with a large terrarium (>100 L), an automatic humidification system, and a willingness to provide fresh leaves daily. Slow growth in the first year, then explosive: be ready to double the terrarium size every 6 months after 2 years.
Large 100L terrarium with lid
The minimum format to start an Atta colony. Plan for expansion.
Ultrasonic humidifier
Maintaining 80-95% humidity requires an active device, especially in winter.
Frequently asked questions
- How big is Atta sexdens?
- Queen: 20-25 mm — Workers: 2-15 mm (highly polymorphic).
- How long does a Atta sexdens queen live?
- A Atta sexdens queen lives approximately 15-20 years.
- How does Atta sexdens found a colony?
- Foundation type: Claustral (fungus) — Polygynous: No.
- What does Atta sexdens eat?
- Diet: Symbiotic fungus.
- Does Atta sexdens need a diapause (hibernation)?
- Diapause: None (tropical).
- What temperature and humidity does Atta sexdens require?
- Temperature: 24-28°C — Humidity: 80-95%.
- How large does a Atta sexdens colony grow?
- Colony size: 100,000-5,000,000+.
- Is Atta sexdens suitable for beginners?
- Difficulty level: 5/5 (expert).
Sources & references
Authoritative references for further reading on Atta sexdens:
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