How to Care for Paratrechina longicornis | The Longhorn Crazy Ant Guide
Photo: portioid, via iNaturalist, licensed under CC BY 4.0.
Paratrechina longicornis is the longhorn crazy ant: a tiny, dark ant with extra-long legs and antennae that dashes about in wild zigzags. It is one of the most widespread ants on Earth, carried around the world in cargo, plants and luggage.
It is fascinating to watch, but it is also a well-known pest. This guide explains Paratrechina longicornis care honestly and step by step, including how to keep every single worker inside its ant farm.
Paratrechina longicornis is a tropical tramp ant, and Best Ants UK does not sell it. It may be illegal or impossible to import into the UK, and we never encourage importing ants. This guide is for experienced keepers, and for anyone curious about this remarkable ant.
We have kept ants since 1997, and these are the care rules we use for our own colonies every day.
👉 In a hurry? Download our free Paratrechina longicornis care sheet (PDF), open the Paratrechina longicornis care sheet page or explore all our free ant care sheets.
Paratrechina longicornis at a Glance
Also known as: the longhorn crazy ant, black crazy ant or crazy ant
Origin: the Old World tropics, probably Africa or tropical Asia; now found in warm places worldwide
Sold by Best Ants UK: no, it is a tropical tramp ant and a known pest
Keeping level: Advanced (escape risk and pest status)
Queen: about 4 to 5mm, dark brown
Workers: about 2.5 to 3mm, all one size, dark brown to black with very long legs and antennae
Colony: many queens, often spread over several nests; thousands of workers when mature
Nest temperature: 24 to 28°C all year, best at around 26°C
Nest humidity: 50 to 70%
Workers before moving into a nest: 50+
Winter: no hibernation, keep warm all year
Escape risk: very high, so a fresh PTFE barrier and a tight lid are a must
A Pest Ant: Please Read This First
In warm countries the longhorn crazy ant is a common household and farm pest. In cooler countries it can only live indoors, in heated buildings and greenhouses. It has been found in heated premises in Britain for many years.
A colony has many queens, and a few queens with a handful of workers can walk off and start a new nest. That means a small escape can turn into an infestation in your home, and even your neighbours' homes.
So be honest with yourself before keeping this species. You need a well-sealed ant farm, a fresh PTFE barrier, a lid that is always closed and the time to check everything every week. If that sounds like too much, choose a UK native instead.
Meet the Longhorn Crazy Ant
In the wild, crazy ants live in disturbed, open places: gardens, beaches, rubbish, plant pots, under stones and logs, and in buildings. They are especially at home in dry, warm spots.
The workers forage in long, fast trails and find food quickly. They eat almost anything: dead insects, honeydew from aphids and scale insects, fruit, seeds and household scraps. They are also excellent at carrying big finds home as a team.
Its life story is unusual. There are no big mating flights. Winged males gather on the ground on warm, damp evenings and pair with young queens near the nest, and colonies spread by budding: queens leave with workers to start new nests close by.
Scientists have also found a rare kind of double cloning in this species: daughters are copies of their mother, and sons are copies of their father. That helps explain how such small, closely related groups can thrive.
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 queens 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, with no food. A good supplier feeds the ants before dispatch. Use this time to set up and water the nest. 👉 Our step-by-step ant farm setup guide shows you exactly how.
Still workers or a motionless queen after delivery are almost always delivery stress. Look at the antennae: moving antennae mean the ants are fine. Almost all recover within 4 to 5 days.
Life in the Test Tube
Crazy ant workers are tiny, so the colony must grow big in its test tube first. Keep it there until it has at least 50 workers. Moved earlier, the workers scatter in the bigger space and the colony can fail. The same rule applies to a queen on her own.
Colonies usually start as a small group of queens with workers, not a lone queen. If you ever have a queen on her own, give her a tiny drop of protein jelly once a week, 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 the colony does far better afterwards. Keep the tube wrapped in its foil and disturb it as little as possible.
Kept warm and well fed, this species grows fast. Brood takes roughly 3 to 5 weeks from egg to worker at around 26°C, and with several queens laying, numbers climb quickly.
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 Crazy Ants
Crazy ant workers are small, fast and determined. Their home must be well made and escape-proof, with tight-fitting connections. A young colony also feels safest in a small nest it can fill.
For tiny species we recommend the A7 Plus ant farm kit only (you will find the link at the end of this guide). Its small nest suits tiny workers, and its pre-installed digital meter shows nest temperature and humidity at a glance.
Place the ant farm in normal daylight, never direct sunlight. Avoid windows, radiators and heaters, vibrating surfaces, speakers and TVs, and above all the kitchen: strong smells upset the ants, and escaped ants head straight for food.
Temperature and Heating
This is a tropical ant, and warmth drives everything it does. Keep the nest at 24 to 28°C all year. The brood develops best at around 26°C, and in a cool nest the colony barely grows.
Most UK homes are cooler than that for much of the year. 👉 The Advanced Heating System Small 4W holds a steady warm spot with its digital thermostat. Set it to 26°C.
The heat mat goes under one quarter of the nest only, on the side opposite the watering area, so the ants can choose their spot. Never heat the whole nest.
Warm the outworld too, because a big gap between nest and outworld confuses the ants. Aim for at least 20°C overnight, up to 28°C by day, ideally matching the nest or a degree or two cooler.
Water and Humidity
Keep the nest humidity at 50 to 70%. 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.
Water about once a week. A heated nest dries out faster, so check the meter often and water as soon as the nest humidity drops below 50%.
Never water the outworld. Keep it dry, at about 50% humidity, like an average UK home. A watering test tube in the outworld gives the workers a safe drink.
Feeding Your Crazy Ants
Crazy ants are hungry and eat a wide range of foods. Feed twice a week, in small amounts, in the outworld only. Remove leftovers after 2 days to stop mould.
🍯 For energy, give our 👉 organic ant honey or 👉 Ant Nectar, which has even more carbohydrates than honey. Both are far better than sugar water or home-made mixes. Offer small drops, as tiny workers can get stuck in a big one.
🥩 For the queens and brood, give 👉 Protein Jelly or 👉 Cricket Mash. Keep protein jelly in the fridge at all times. Growing colonies need more protein in summer.
Serve food on a small piece of tin foil or in a 👉 small feeding dish, so leftovers are easy to lift out.
Live food, such as crickets or locusts, is only for big, established colonies, never small ones. Always scald it first: wearing gloves, hold it with tweezers in just-boiled water (above 90°C, no longer bubbling) for 10 to 15 seconds.
Then cut it in half only, and serve it in the outworld.
Keep Mites Out of Your Colony
Blood-sucking mites are one of the biggest dangers for any ant colony, 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 before dispatch, check every colony twice a month, and check each colony again before it leaves us.
Now and then, look at your queens 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
With this species, escape-proofing matters more than anything else. 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. Once the colony reaches 300 to 500 ants or more, which happens quickly with this species, reapply it about every 2 weeks.
Never shake the bottle, because it foams. Roll it gently in your hands instead.
Keep the outworld lid closed at all times, and check every tube and connection each week. Workers this small use gaps you can barely see.
For extra safety, many keepers of tramp ants stand the whole ant farm inside a larger, smooth-sided plastic box with its own PTFE band. Any escapee is then caught before it reaches your home.
If ants ever do escape, never spray them. Sprays make these ants scatter and split into new nests. Professional pest controllers use slow-acting baits that the workers carry home.
Winter Care
Paratrechina longicornis is a tropical ant with no winter rest at all. Keep the nest at 24 to 28°C right through every UK winter, with the heating system running, and never let the colony get cold.
Never put ants in a fridge, shed or garage, and avoid any abrupt temperature change. The colony may slow down a little in winter anyway, because its biological clock can't be tricked.
If the ants eat less in winter, give a little less, but never guess. At 22 to 26°C, give about half the summer amount, still twice a week.
Can I Release My Crazy Ants?
Never. A tropical ant can't live outdoors here, but escaped crazy ants can settle inside heated buildings and become a pest. Never release them, and never let any escape.
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 Paratrechina longicornis good for beginners?
No. The ants are hardy, but the colony grows fast, the workers are tiny and very quick, and escaped ants can become a real pest in a home. It is for experienced keepers only. For a first colony, a UK native such as Lasius niger is far better.
Can I buy Paratrechina longicornis in the UK?
Best Ants UK does not sell Paratrechina longicornis. It is a tropical tramp ant and a known indoor pest, and it may be illegal or impossible to import into the UK. We never encourage importing ants.
Why is it called the crazy ant?
The workers run fast in sudden zigzags, changing direction all the time, as if they had no idea where they were going. Their very long legs and antennae give them the name longhorn crazy ant.
How many workers before moving Paratrechina longicornis into a nest?
At least 50 workers, whether the colony has one queen or several. The workers are only about 2.5 to 3mm long, so a smaller colony is lost in an ant farm.
What temperature do Paratrechina longicornis need?
Keep the nest at 24 to 28°C all year. Most UK homes are cooler, so use an Advanced Heating System set to 26°C under one quarter of the nest. Never let the colony get cold.
Do Paratrechina longicornis hibernate?
No. This tropical ant has no winter rest at all. Keep the heating on right through the winter and never put the ants in a fridge, shed or garage.
What if my crazy ants escape?
Act fast, but never spray them: sprays make these ants split up into new nests. Professional pest controllers use slow-acting baits. Good escape-proofing from day one is the best protection.
Ready to Keep Ants the Safe Way?
👉 Whatever species you keep, start with the A7 Plus ant farm kit. Its small nest suits tiny workers, its pre-installed digital meter shows temperature and humidity at a glance, and if you already have your ants, choose its Nest + Outworld option.
