How to Care for Acromyrmex octospinosus | The Leafcutter Ant Guide
Updated: 3 days ago
Spiny, busy and brilliant gardeners: Acromyrmex octospinosus is one of the best-known leafcutter ants in ant keeping. The workers slice leaves with their sharp jaws and carry them home to feed a fungus garden, and the fungus feeds the colony.
Its colonies stay much smaller than the giant Atta leafcutters, so you can follow the whole farm up close. This guide explains Acromyrmex octospinosus care step by step, from arrival to a healthy fungus garden.
We have kept ants since 1997. Leafcutters are an expert species, so read this guide from A to Z before you begin.
👉 In a hurry? Download our free Acromyrmex octospinosus care sheet (PDF) or open the Acromyrmex octospinosus care sheet page for the key facts at a glance.
Acromyrmex octospinosus at a Glance
Origin: Central America, northern South America and the Caribbean
Keeping level: Expert
Queen: 12 to 13mm, light brown
Workers: 5 to 12mm, light brown, with spines on the back
Colony: several queens possible, often around 20,000 ants
Main food: fresh leaves for the fungus garden
Fungus chamber temperature: 24 to 28°C all year
Fungus chamber humidity: 80 to 90%
Waste area: dry, about 30 to 40% humidity
Moving in: straight into the setup after up to 5 hours of settling; always a whole colony with its fungus, never a lone queen
Winter: no hibernation, warm all year
Meet the Eight-Spined Leafcutter
Octospinosus means "eight spines". Look closely at a worker's back and you will find four pairs of spines. The ants are light brown and come in a range of sizes, from small fungus gardeners to larger leaf cutters.
In the wild, this leafcutter lives in rainforest and savanna. Its nests are earth nests with several chambers, smaller than Atta nests, and are sometimes found under wood or stones.
The workers have a clever trick. They carry helpful bacteria on their bodies that make natural antibiotics, which protect the fungus garden from disease.
Inside the nest, the ants chew leaves into a pulp and grow their fungus on it. The fungus forms small food bodies that the workers harvest for the queen and brood (the eggs, larvae and pupae). The workers also drink plant sap.
New queens fly out at the start of the rainy season. Each carries a small piece of fungus from her home nest to start a new garden, and a queen can live for up to about 15 years.
When Your Ants Arrive
Leafcutter colonies arrive in a fungus container, with the ants and their fungus garden together. Sometimes the ants come in a small container of their own and the fungus is supplied separately.
The most important step: leave the parcel completely unopened, exactly as it arrived, at room temperature for up to 5 hours. Leafcutters need this time to settle, because abrupt temperature changes make ants seriously unwell.
After that, open the parcel, check the queen is safe and sound, and transfer the colony into its setup straight away. Leafcutters must not wait in their travel container, so have the setup warm, humid and ready before the parcel arrives.
If the fungus came in its own container, place it gently in the fungus chamber or connect its container to it, then let the ants in right next to their garden. Move the fungus as little as possible, and never shake, tip or squeeze it.
🍃 Offer fresh, lightly misted leaves as soon as the ants are in their setup. The fungus garden needs them to keep growing.
Still workers or a motionless queen after delivery are almost always delivery stress. Look at the queen's antennae: moving antennae mean she is fine. Almost all recover within 4 to 5 days.
Don't worry if part of the fungus garden looks damaged. Losing up to a third of the fungus in transit is normal. With the right warmth, humidity and fresh leaves, the ants rebuild it.
Always a Colony, Never a Lone Queen
Leafcutters are only kept as a colony: the queen, her workers and their fungus garden, together. A queen on her own can't tend the fungus, and the fungus is the colony's only food.
Once the colony is in, leave the fungus garden to the ants. They move and rebuild it themselves, piece by piece. All you do is keep the conditions right and the leaves coming.
The Right Setup for Acromyrmex octospinosus
Best Ants UK doesn't offer an ant farm for leafcutters. Experienced keepers build a setup with three connected areas: a warm, humid fungus chamber, a foraging area (outworld) where you give the leaves, and a separate dry waste area.
The fungus chamber needs a digital humidity and temperature meter, because with leafcutters the humidity must be right every single day. Plan for more room in all three areas as the colony grows.
The ants carry used leaf pulp, old fungus and dead workers to the waste area. Empty it gently about once a week with long tweezers, before it smells or goes mouldy, and never put anything from it back into the fungus chamber.
Keep the fungus chamber dark. Lift its cover only briefly, about once a day for 2 to 3 minutes, ideally at night, and take colony photos once a month at most.
Place the setup in normal daylight, never direct sunlight. Avoid windows, radiators and heaters, vibrating surfaces, speakers and TVs, busy walkways and rooms with strong smells such as the kitchen.
Temperature and Heating
Keep the fungus chamber at 24 to 28°C, all year round. A UK home is cooler than that for most of the year, so these tropical ants need gentle, steady heating.
👉 We recommend the Advanced Heating System Small 4W, with its digital thermostat. Set it to 26°C and place it under one quarter of the fungus chamber, on the side away from where you add water, so the ants can choose where to sit.
Keep the outworld at 21 to 28°C. By day it should ideally match the fungus chamber or be a degree or two cooler. If the fungus chamber is heated, warm the outworld too. Never let the fungus chamber go above about 28°C or dry out.
Water and Humidity
Keep the fungus chamber at 80 to 90% humidity. If the fungus dries out, the colony starves. Use distilled or purified water only. Never use tap water, rainwater or bottled mineral water, even boiled: they cause mould.
Add water with a pipette, a few drops at a time, to the damp part of the fungus chamber, away from the fungus. Never let water drip onto the fungus itself, and never let it stand in puddles.
With a digital meter in the fungus chamber, water whenever the fungus chamber falls below 80%. Leafcutters need much more humidity than most ants, so check the meter every day.
Never water the outworld; keep it at about 50% humidity. Keep the waste area dry, at about 30 to 40%. The only water in the outworld is a fine mist on the leaves just before feeding.
Feeding Your Leafcutter Colony
🍃 Fresh leaves are the main food, every day. The ants cut them and feed them to the fungus. Bramble (blackberry), raspberry, rose, box, elder, lime (linden) and oak leaves all work well. Mist them lightly first, never soak them.
Only use leaves free from pesticides and road dirt. Never use staghorn sumac, which is toxic to the fungus. Remove old, dried-out leaves after 2 days, before mould can start.
🍎 Flowers and small pieces of apple, orange, banana or grape are welcome extras. Put fruit on a piece of tin foil or in a 👉 small feeding dish in the outworld.
Our dried Dandelion Leaves, Rose Petals and Blue Mallow Flowers are also safe for the fungus. Fresh leaves stay the main food, so alternate the dried ones with fresh leaves every other day. Use oat flakes only in an emergency.
🍯 Now and then, a tiny drop of our 👉 organic ant honey or 👉 Ant Nectar on tin foil gives the workers extra energy. Both are far better than sugar water or home-made mixes.
🥩 Leafcutters don't need protein jelly or insects. Their fungus makes the protein the queen and brood need.
Think ahead for the UK winter. Bramble often keeps its leaves through a mild winter, and box stays green all year, so find a clean, pesticide-free source before the cold months.
Keep Mites Out of Your Colony
Blood-sucking mites are a threat to every ant colony, and they are not rare. They often arrive with bird seed from local shops and off-licences, dried mealworms, and live food from pet shops or online, where about half carries mites.
Leafcutters don't need any of those foods. Buy ant food only from established, reputable ant-keeping suppliers. At Best Ants UK we clean our foods before dispatch, check every colony twice a month, and check each colony again before it leaves us.
Now and then, look at your queen with a magnifying glass. Tiny white or reddish specks on her joints and legs, together with ants dying fast, are a warning sign of blood-sucking mites.
Stopping Escapes
Acromyrmex workers explore constantly and climb well. Paint a band of 👉 PTFE Fluon escape barrier around the top inner edge of the outworld lid. The ants slip off it and can't climb out.
PTFE wears off as the ants keep testing the same spots. For up to about 100 ants, reapply it roughly every 4 weeks. For 300 to 500 ants or more, reapply it about every 2 weeks. Never shake the bottle; roll it gently instead.
Winter Care
Acromyrmex octospinosus has no winter rest. Keep the fungus chamber at 24 to 28°C and keep feeding fresh leaves all winter long.
From autumn to spring the heating system does the hard work. Never put ants in a fridge, shed or garage, and avoid any abrupt temperature change. Cold doesn't kill a colony at once: the ants get sick and die over the following days.
Can I Release My Leafcutter Ants?
No. A colony raised indoors won't survive outside. If you ever can't keep your colony any more, 👉 visit our ant adoption page and let us know. We'll see whether we can take it in.
Frequently Asked Questions | FAQ
Is Acromyrmex octospinosus good for beginners?
No, it is an expert species. Its colonies stay smaller than Atta, but the fungus garden still needs steady warmth, very high humidity and fresh leaves every day. Start with a beginner species such as Lasius niger or Messor barbarus first.
What do Acromyrmex octospinosus eat?
They cut fresh leaves and flowers to feed their fungus garden, and the fungus feeds the colony. Bramble, raspberry, rose, box, elder and lime (linden) leaves work well, with small pieces of fruit as extras.
Can I keep an Acromyrmex octospinosus queen on her own?
No. Leafcutters are only kept as a colony with its fungus garden. A queen on her own can't tend the fungus, and the fungus is the colony's only food.
What temperature do Acromyrmex octospinosus need?
Keep the fungus chamber at 24 to 28°C all year, and the outworld at 21 to 28°C. In most UK homes that means an Advanced Heating System under one quarter of the fungus chamber, set to 26°C.
Do Acromyrmex octospinosus hibernate?
No. They are tropical ants with no winter rest. Keep them warm, humid and supplied with fresh leaves all year round.
How big does an Acromyrmex octospinosus colony get?
Far smaller than Atta. A mature colony reaches about 20,000 ants, which makes it one of the more manageable leafcutters for experienced keepers.
Do Acromyrmex octospinosus sting?
No, they have no sting, but they can bite hard. Never handle them, and keep the outworld lid closed.
Start Your Own Leafcutter Colony
👉 Find Acromyrmex octospinosus colonies in our shop and check availability, then watch your own spiny gardeners tend their fungus farm.
Print this guide and keep it next to your leafcutter setup. 👉 Keep the essentials close and explore all our free ant care sheets.
