Acromyrmex octospinosus
Temperature
24–28 °C
Humidity
70–90%
Colony size
10,000–50,000
Queen size
17–20 mm
Worker size
2–9 mm
Diet
Care Guide
Acromyrmex octospinosus is one of the most accessible leafcutter ants for hobbyists, although it remains a demanding species suited to advanced keepers. Native to Central America and northern South America, this medium-sized leafcutter shows clear polymorphism within the colony. The queen reaches 17–20 mm, while workers range from minute 2 mm minims that tend the fungus garden up to 9 mm majors that cut leaves and defend the colony. The eight characteristic spines on the thorax give the species its name.
The defining feature of Acromyrmex octospinosus, like all leafcutters, is its mutualistic relationship with a cultivated fungus. The ants do not eat plant material directly. Instead, workers cut fresh leaves, petals, and fruit pulp, carry them back to the nest, and process them into a substrate on which the fungus *Leucoagaricus gongylophorus* grows. The colony then feeds on swollen fungal structures called gongylidia. A newly mated queen carries a tiny pellet of fungus in her infrabuccal pocket and tends this starter garden alone until the first workers emerge.
Colonies are large by hobbyist standards, typically containing 10,000 to 50,000 individuals at maturity. While not as immense as their Atta cousins, they still require considerable space and produce a constant stream of organic waste that must be managed carefully.
Care difficulty
Keeping Acromyrmex octospinosus is rated advanced. The fungus is more demanding than the ants themselves — it requires stable temperature, high humidity, fresh plant matter daily, and protection from mold and mites. Beginners are best served by starting with a non-fungus species before tackling any leafcutter.
Housing
A proper setup requires a fungus chamber connected to a foraging arena, ideally through a transparent tube so you can monitor activity. Temperature should be held steadily between 24 and 28 °C, with humidity at 70–90 % around the fungus garden. Provide fresh leaves daily — rose, blackberry, oak, and bramble are reliable favorites — and supplement occasionally with fruit pulp and protein such as dried mealworms. Never use plants treated with pesticides.
First days after purchase
After arrival, place the founding queen and her fungus pellet in a small, dark, humid container at around 25 °C. Do not disturb her, and do not offer leaves until the first generation of workers is foraging. Keep the chamber spotlessly clean and check daily for any signs of mold on the garden, removing affected material immediately with sterile tweezers.