How to Care for Diacamma rugosum | The Asian Bullet Ant Guide for Experts
Updated: 3 days ago
Diacamma rugosum, the Asian bullet ant, is one of the strangest ants you can keep: it has no queen at all. One mated worker lays every egg, and the rest of the colony hunts, cleans and cares for the brood.
The workers are quick, curious hunters in shiny ridged black armour. They are also an expert species, so this guide explains Diacamma rugosum care step by step, from the day your parcel arrives.
We have kept ants since 1997. Everything here comes from our own colonies and the care rules we use every single day.
👉 In a hurry? Download our free Diacamma rugosum care sheet (PDF) or open the Diacamma rugosum care sheet page for the key facts at a glance.
Diacamma rugosum at a Glance
Also known as: the Asian bullet ant
Origin: the tropical forests of South and South East Asia
Keeping level: Expert, adults only
Egg-layer: no queen; one mated worker (the gamergate) lays the eggs
Workers: 10 to 12mm, black, with a deeply ridged body
Colony: small, around 100 to 200 workers
Nest temperature: 24 to 28°C all year
Nest humidity: 50 to 80%
Workers before moving into a nest: 10+
Food: live prey, with a little honey as an extra
Winter: no hibernation, keep warm all year
Defence: a painful sting
Meet the Queenless Ant
Most ant colonies have a winged queen who flies out on a mating flight. Diacamma rugosum has none. Instead, one worker mates and becomes the colony's only egg-layer, called the gamergate.
Every Diacamma worker hatches with two tiny buds on its body, called gemmae. The gamergate keeps hers. On new workers, she bites them off, and without them a worker never becomes an egg-layer.
When a colony grows big enough, a group of workers can split away and start a new colony with a new egg-layer. If the gamergate dies, a newly hatched worker can take her place.
Despite the name, the Asian bullet ant is not a close relative of the real bullet ant from South America. The name comes from its size, its armour and its sting.
Workers hunt alone, and when one finds a big meal she leads a nestmate to it in a tandem run, one ant following right behind the other. It is wonderful to watch in the outworld.
Safety First
Diacamma workers have a painful sting. It usually causes short, local pain, but this is still an adults-only species. Never handle the ants and never let children open the setup.
Always use long tweezers when you feed or clean the outworld. Keep the lid closed and the PTFE band fresh.
When Your Ants Arrive
The most important step: leave the parcel completely unopened, exactly as it arrived, at room temperature for 5 hours. The ants must adjust to your home's temperature slowly, because abrupt temperature changes make ants seriously unwell.
After the 5 hours, check the egg-layer and workers are safe and sound. Then leave the colony in its original packaging, with the test tube still in its tin foil and wrapping.
Put it somewhere quiet and still, away from daily household activity. Normal daylight is fine, but never direct sunlight.
Give the colony 4 to 5 days of complete rest. The ants were fed before dispatch, so they need nothing from you. Use this time to set up and water the nest. 👉 Our step-by-step ant farm setup guide shows you exactly how.
Still workers after delivery are almost always delivery stress. Look at their antennae: moving antennae mean they are fine. Almost all recover within 4 to 5 days, and big ants like these can take a little longer.
Life in the Test Tube
The colony arrives with its egg-laying gamergate and workers together, so never split it up. Choose at least 10 workers with eggs, larvae or pupae laid inside that colony: the brood is your proof of a fertile egg-layer.
The egg-layer looks almost exactly like the other workers, so don't worry if you can't spot her. Fresh eggs and growing brood tell you she is there and well.
Keep the colony in its test tube until it has at least 10 workers. Moved earlier, the workers scatter in the bigger space and the egg-layer and brood are left unprotected. That can lead to colony failure.
These ants need warmth even in the test tube. If your room is cool, warm the tube with a heating cable at the cotton stopper end only. Never lay a test tube on a heat mat.
Moving Into the Ant Farm
When the colony is big enough, connect the test tube to the nest with the delivery tin foil still on. Leave it like that for 14 days.
Then slide the foil back about 1mm every day, until the tube is fully exposed to daylight. Bit by bit, the tube becomes the bright spot and the dark nest becomes the safe home.
If the ants haven't moved 2 days after the tube is fully exposed, wrap the foil back on, wait another fortnight and repeat the whole process. Moving in happens on the ants' own time: anywhere from a couple of days to 6 months.
Once the colony has moved, leave the old test tube connected for at least another 14 days. Ants sometimes leave a little brood behind.
The red filter and black cover stay on the nest all the time, so it is pitch dark inside. You can lift the black cover once a day for 2 to 3 minutes, ideally at night, and take the red filter off once a week for 2 to 3 minutes.
Take colony photos at most once a month. Every extra disturbance stresses the colony.
The Best Ant Farm for Diacamma rugosum
A Diacamma colony stays small, so a compact nest suits it perfectly and lets you see every ant. It must be well made, escape-proof and easy to keep warm and humid.
👉 Our top pick is the A7 Plus ant farm kit. Its pre-installed digital meter shows the nest temperature and humidity at a glance, which matters a lot for a tropical species that needs steady warmth and moisture.
Place the ant farm in normal daylight, never direct sunlight: the sun can overheat a nest within minutes. Avoid windows, radiators and heaters, vibrating surfaces, speakers and TVs, and rooms with strong smells such as the kitchen.
Temperature and Heating
Diacamma rugosum comes from the tropics, so keep the nest at 24 to 28°C every day of the year. A UK home is too cool for them for most of the year.
👉 The Advanced Heating System Small 4W holds the nest steady with its digital thermostat. Set it to about 26°C, the middle of their range.
The heat mat goes under one quarter of the nest only, on the side opposite the watering area. The ants can then pick the spot they like best. Never heat the whole nest.
Warm the outworld too, because a big gap between nest and outworld confuses the ants. Aim for at least 21°C overnight, rising to about 28°C by day, ideally matching the nest or a degree or two cooler.
Water and Humidity
Keep the nest humidity at 50 to 80%. Use distilled or purified water only. Never use tap water, rainwater or bottled mineral water, even boiled: they cause mould and fungus, which is deadly for ants.
Water the nest with the pipette provided. Pour slowly, a few drops at a time, through the watering hole. Stop as soon as 1 or 2 drops appear inside the nest. That is how you know it is done correctly.
Warm nests dry out faster, so check the meter often. Water about once a week, a little more in summer and a little less in winter, and always as soon as the nest humidity drops below 50%.
Never water the outworld. Keep it at about 50% humidity, like an average UK home. A watering test tube in the outworld gives the workers a safe drink.
Feeding Your Diacamma Colony
Diacamma rugosum is a true hunter with a big need for protein, and live prey is its main food. It will not thrive on jelly or honey alone. Even a young colony needs live prey, sized so a single worker can overpower it.
🥩 Give small live crickets, flightless fruit flies or small cockroach nymphs, twice a week, in the outworld only. Give the prey alive: the workers find it, sting it and carry it home, and that hunt is the best part to watch.
Never scald live prey for these ants. Remove any uneaten prey and the remains after 2 days to stop mould.
🍯 As a small extra, put a tiny drop of our 👉 organic ant honey or 👉 Ant Nectar in the outworld about once a week. Both are far better than sugar water or home-made mixes.
Now and then you can offer a tiny piece of peeled grape, no bigger than a grain of rice. Take away what is left after 2 days.
Keep Mites Out of Your Colony
Blood-sucking mites are one of the biggest dangers for any ant colony, and they are not rare. Live food is the main risk for a hunter: in our experience about half of the live food sold in pet shops or online carries mites.
Mites also arrive with bird seed from local shops and with dried mealworms, which are useless as ant food anyway. Buy live prey only from established, reputable suppliers, and check it for mites before it goes in.
At Best Ants UK we clean our foods in several ways before dispatch, check every colony twice a month, and check each colony again before it leaves us.
Now and then, look at your ants with a magnifying glass. Tiny white or reddish specks on their joints and legs, together with ants dying fast, are a warning sign of blood-sucking mites.
Stopping Escapes
Diacamma workers are fast, very active and always exploring, so escape prevention is a must. 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 a small colony of 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, because it foams. Roll it gently in your hands instead. Keep the lid closed at all times, except for the moment you add food.
Winter Care
Diacamma rugosum has no winter rest. It comes from a climate that stays warm all year, so keep the nest at 24 to 28°C through every UK winter.
Cold doesn't kill a colony at once. The ants get sick and die over the following days, so never let them cool down. Never put ants in a fridge, shed or garage, and avoid any abrupt temperature change.
Kept warm, the colony stays active, so keep giving live prey twice a week in winter. If the ants eat less, simply give less.
Can I Release My Diacamma Colony?
No. These are tropical ants and could never survive outside in the UK. 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
Does Diacamma rugosum have a queen?
No. There is no winged queen in this species. One mated worker, called the gamergate, lays all the eggs. A colony always comes with its egg-layer and workers together, so never split it up.
Is Diacamma rugosum good for beginners?
No. It is an expert species for adult keepers. It needs steady tropical warmth, live prey, a good escape barrier and care around its sting. For a first colony, Lasius niger or Messor barbarus is a far better start.
Do Asian bullet ants sting?
Yes. The workers have a painful sting, which usually causes short, local pain. Never handle them, keep the lid closed and always use long tweezers in the outworld.
What temperature does Diacamma rugosum need?
Keep the nest at 24 to 28°C all year. In a UK home that means an Advanced Heating System set to about 26°C under one quarter of the nest, with a warm outworld too.
What do Diacamma rugosum eat?
Live prey is their main food: small crickets, flightless fruit flies and small cockroach nymphs, given alive. A small drop of organic honey or Ant Nectar and, now and then, a rice-grain piece of peeled grape are welcome extras.
How many workers before moving Diacamma rugosum into a nest?
At least 10 workers. Moved earlier, the workers scatter in the bigger space and the egg-layer and brood are left unprotected, which can lead to colony failure.
How big does a Diacamma rugosum colony get?
Small. A colony usually has around 100 to 200 workers. That makes it a great species to watch closely in a compact nest.
Ready for a Queenless Colony?
👉 Find Diacamma rugosum colonies in our shop, and watch one of the most unusual ants in the world up close.
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