How to Care for Veromessor pergandei | The Black Desert Harvester Ant Guide
Photo: peterwchen, via Wikimedia Commons, licensed under CC BY 4.0.
Glossy black workers marching out in long columns across the hottest deserts of North America: Veromessor pergandei, the black desert harvester ant, is a true seed specialist.
Its workers come in several sizes, from small minors to big-headed majors that crack seeds. This guide explains Veromessor pergandei care step by step, from a founding queen to a thriving seed-gathering colony.
We have kept ants since 1997, and the care rules here are the ones we use every day with our own harvester ants.
👉 In a hurry? Download our free Veromessor pergandei care sheet (PDF) or open the Veromessor pergandei care sheet page for the key facts at a glance.
Veromessor pergandei at a Glance
Also known as: the black desert harvester ant
Origin: the Mojave, Sonoran and Colorado deserts of the south-western United States and north-west Mexico
Keeping level: Beginner to intermediate (needs steady heating in the UK)
Queen: about 10 to 12mm
Workers: about 2.5 to 6mm, glossy black, in several sizes (minors to majors)
Colony: one or several queens, tens of thousands of workers when mature
Main food: seeds
Nest temperature: 26 to 30°C
Nest humidity: a steep gradient: seed store bone-dry at 10 to 30%, one damp brood corner at 50 to 70%
Workers before moving into a nest: 10 minimum, 15 to 20 recommended
Winter: no hibernation, never below 15°C
Water: never open water, a watering test tube only
Meet the Black Desert Harvester Ant
In the wild, Veromessor pergandei is one of the commonest ants of the Mojave and Sonoran deserts. It nests in open, sandy ground, often below sea level in places, in some of the hottest, driest land in North America.
Each nest has a crater with a large entrance, ringed by a pile of empty seed husks. The workers strip the husks off outside and carry the kernels down into granaries deep below.
Foragers leave the nest along a scent trail that can stretch for 40 metres, then fan out at the end to search for seeds one by one. In summer they forage in the cooler early morning, and in winter around midday.
Mature colonies can reach tens of thousands of workers. In some areas several queens start a colony together, and the colony usually ends up with just one queen once the first workers arrive.
Unusually, new queens and males fly in late winter and spring, from February to April, and the timing follows day length rather than rain.
Can You Keep Veromessor pergandei in the UK?
Veromessor pergandei is a North American ant, and Best Ants UK does not sell it. It may be illegal or impossible to bring into the UK, so please never try to import it, and never buy it from anyone offering to ship it here.
This guide is for keepers who live where the species is native and can keep it legally, and for anyone curious about harvester ants.
If you are in the UK and dream of harvesters, our Messor barbarus is a calm, hardy seed harvester, and much of this guide works for it too.
Watch our Messor barbarus care guide, filmed with our own 19-year-old harvester ant colony:
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 queen is safe and sound. Then leave the colony in its original packaging, with the test tube still in its tin foil and wrapping, somewhere quiet and still, away from daily household activity. Daylight is fine, 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 how.
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, and big harvester queens can take a little longer.
Life in the Test Tube
Keep the colony in its test tube until it has at least 10 workers. 15 to 20 is even better. Moved earlier, the workers often abandon the queen in the bigger space, and the colony can fail. The same rule applies to a queen on her own.
A founding queen still needs a little food. Once a week, give her a tiny drop of protein jelly, about half a grain of rice, on a small flat piece of tin foil inside the tube, next to the dry cotton stopper.
In our experience a fed queen raises her first workers faster and does far better afterwards. Keep her tube wrapped in its foil and disturb her as little as possible.
A desert queen needs warmth to lay. If your room is cool, use a heating cable at the cotton stopper end of the tube only, never near the water end. Never lay a test tube on a heat mat.
Moving Into the Ant Farm
When the colony is ready, 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. If the ants haven't moved 2 days later, wrap the foil back on, wait another fortnight and repeat. Moving in can take 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, as ants sometimes leave brood behind.
The red filter and black cover stay on the nest all the time. 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 once a month at most.
The Best Ant Farm for Veromessor pergandei
👉 For harvester ants we recommend the Angie ant farm starter kit, our harvester ant farm with a pre-installed digital meter. It shows the nest temperature and humidity at a glance, which matters a lot here, as too much water makes seeds sprout.
The A7 Plus ant farm, also with a pre-installed digital meter, is a great choice too. If you already have your ants, choose its Nest + Outworld option.
Place the ant farm in normal daylight, never direct sunlight. Avoid windows, radiators and heaters, vibrating surfaces, speakers and TVs, and rooms with strong smells such as the kitchen.
Temperature and Heating
Keep the nest at 26 to 30°C. Below about 26°C the queen may lay few eggs or none at all, and most UK homes are much cooler than that, so this species cannot thrive without gentle heating.
👉 We recommend the Advanced Heating System Small 4W. Its digital thermostat holds a steady warm spot. Set it to 28°C, the middle of the ideal range.
On a horizontal nest such as Angie or the A7 Plus, the heat mat goes under one quarter of the nest. On a vertical nest, it goes under half. Always put it on the side opposite the watering area, so the ants can choose their spot.
The outworld can cool to about 18°C overnight and warm up to 28°C by day. By day it should ideally match the nest or be a degree or two cooler. If the nest is heated, warm the outworld too.
Water and Humidity
Never keep the whole nest at one humidity. Give it a steep gradient: a bone-dry seed store at 10 to 30%, and one damp brood corner by the watering area at 50 to 70%. Watering the whole nest ruins the seed store: seeds sprout and mould, and the colony can collapse. Use distilled or purified water only, never tap water, rainwater or bottled mineral water.
Water the nest about once a week with the pipette provided. Pour very slowly, a drop at a time, through the watering hole. With harvesters, be extra careful: no more than 1 drop should leak into the nest.
Water only the brood corner, a little sooner in summer and later in winter. If the whole colony crowds into the damp corner, it is too dry: water it straight away. If seeds near the water start to sprout, you are watering too much.
Never water the outworld. Keep it dry, at about 50% humidity, like an average UK home.
Harvester ants must never have open water, because they can drown in it. Give them a watering test tube in the outworld, not a water dispenser.
Feeding Your Harvester Ants
🌾 Seeds are the main food. Give our 👉 harvester ant seed mix. Start with a small pinch and give more as the colony grows and collects it. Fresh seeds help the colony keep growing instead of sitting on an old store.
Always put the seeds on a piece of tin foil or in a 👉 small feeding dish in the outworld. Never put them straight on the substrate: damp seeds sprout, and sprouted seeds are harmful to the colony.
🥩 Once a week, for example every Monday, give a little 👉 Protein Jelly. The queen and brood need it to grow. Keep protein jelly in the fridge at all times.
🍯 Once a week on another day, for example every Thursday, offer our 👉 organic ant honey or 👉 Ant Nectar, which has even more carbohydrates than honey. Keepers find this species takes little sugar, but both are far better than sugar water.
Feed in the outworld only, and remove leftover jelly and honey after 2 days to stop mould.
Keep Mites Out of Your Colony
Blood-sucking mites are one of the biggest dangers for harvester ants, and they are not rare. They often arrive with bird seed from local shops and off-licences, dried mealworms (useless as ant food), and live food from pet shops or online, where about half carries mites.
Buy ant food only from established, reputable ant-keeping suppliers. 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.
A home freezer won't kill all the mites in seeds, so never rely on it. We freeze our seeds below -60°C in a special freezer before they reach you.
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
A big harvester colony has thousands of busy foragers, so escape-proofing 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 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; roll it gently instead.
Winter Care
Veromessor pergandei doesn't need a cold hibernation, and well-heated colonies can keep growing all year. Many queens still slow down for a few months in winter, because the biological clock can't be tricked. A quieter spell at around 20°C is fine.
Harvesters are sensitive to cold: 15°C is the absolute minimum, and 17°C or above is safe. If the room drops below 17°C, set the heater's thermostat to 17°C: it switches on at 16°C and off again at 17°C.
We never give a queen a winter rest in her first year: keep her at her normal warmth. Never put ants in a fridge, shed or garage, and never move them from a warm room straight into a cold one.
Feed less in winter, but never guess. At 17 to 22°C, give about a third of the summer amount. At 22 to 26°C, give about half.
Can I Release My Harvester Ants?
No. A colony raised indoors won't survive outside, and this species doesn't belong in the wild here. 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 Veromessor pergandei good for beginners?
It is one of the easier harvesters to keep where it is native, but in a UK home it needs steady heating to grow. With a heater and careful watering, a patient beginner can manage it.
Can I buy Veromessor pergandei in the UK?
Best Ants UK does not sell this species. It is a North American desert ant, and it may be illegal or impossible to import into the UK. We never encourage importing ants. Messor barbarus is a similar harvester that is kept and sold legally in the UK.
What do Veromessor pergandei eat?
Seeds are their main food. Add Protein Jelly once a week and organic honey or Ant Nectar once a week on another day, even though many colonies show little interest in sweets. Always feed in the outworld only.
How many workers before moving Veromessor pergandei into a nest?
At least 10 workers, and 15 to 20 is even better. The same rule applies to a queen bought on her own: she stays in her test tube until she has raised enough workers.
What temperature do Veromessor pergandei need?
Keep the nest at 26 to 30°C. Most UK homes are cooler than that, so use the Advanced Heating System Small set to 28°C under one quarter of a horizontal nest, opposite the watering area.
Do Veromessor pergandei hibernate?
No. They don't need a cold hibernation and can grow all year. The colony may slow down for a few months in winter. Never let it drop below 15°C, and keep it at 17°C or above to be safe.
Do Veromessor pergandei sting?
They have a small sting but rarely use it, and they are not known as a danger to people. They can give a little bite. As with every ant, never handle them.
Start Your Own Harvester Ant Colony
Print this guide and keep it next to your ant farm. In the UK, the easiest way to enjoy seed-gathering ants is a colony of Messor barbarus.
👉 Ready to start? Our A7 Plus ant farm kit has a pre-installed digital meter and a Nest + Outworld option, and it makes a superb home for harvester ants. 👉 Explore all our free ant care sheets.
