Pheidole bicarinata

Big-Headed Ant

🐜 At a glance

Origin: 🌎 North America, from New Jersey to northern Florida and west to Utah and Nevada; sandy soils, lawns, fields and roadsides
Keeping level: Intermediate — tiny workers and a seed-and-protein diet
Queen: Sturdy, often darker than the workers
Workers: Minors about 2mm, majors a little over 3mm; clear yellow in the west to dark brown in the east
Founding: Fully claustral — do not feed the queen until workers arrive
Colony form: Single queen (monogyne); colonies usually stay at a few hundred workers
Nest temperature: 24–28°C in the warm area, heated on one side away from the water reservoir
Nest humidity: A moist brood area; keep the outworld dry
Workers before moving into a nest: 50–100, once they would fill about two-thirds of the new nest
Winter: Depends on where the colony comes from — see below

📖 About this species

A small North American big-headed ant with two worker castes: tiny minors and big-headed majors. It harvests seeds, which it may store in underground granaries, and also collects sweet plant secretions and tends aphids for honeydew. UK and European keepers are unlikely to find it legal or available — our Pheidole pallidula and Pheidole noda are the closest alternatives here.

🇺🇸 Not sold by Best Ants UK. US keepers can buy from Stateside Ants, which holds a USDA permit.

📦 When your ants arrive

⚠️ MOST IMPORTANT: leave the parcel completely unopened, exactly as it arrived, at room temperature for 5 hours. The ants must adjust to your home’s temperature gradually — 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 (test tube still in its tin foil and wrapping) in a quiet spot — in daylight, never direct sunlight — away from vibration and daily household activity.
😴 Give the colony 4 to 5 days of complete rest. The ants were fed before dispatch and need nothing from you during this time. Assemble and water the nest while you wait.
Still workers or a motionless queen after delivery are almost always delivery stress. Check the antennae: moving antennae means she is fine. Almost all recover within 4 to 5 days (a little longer for bigger queens).
Do not remove the black divider inside the test tube (between the two cotton stoppers) — it keeps the ants safe in transit. It has a hole, and the queen and all workers pass through it without any issue.
👑 A queen on her own: keep her test tube wrapped in its tin foil and undisturbed. She is fully claustral, so she needs no food until her first workers arrive.

🏠 Moving into the ant farm

Keep the colony in its test tube until it has 50 to 100 workers, and only move once they would occupy about two-thirds of the new nest. Moved earlier, the workers often abandon the queen in the larger space.
Connect the test tube to the nest with the delivery tin foil still on and leave it for 14 days. Then slide the foil back about 1mm every day until the tube is fully exposed to daylight.
If the ants have not moved in 2 days after the tube is fully exposed, wrap the foil back on, wait another fortnight and repeat the whole process — patience is the key. Moving in happens on the ants’ own time: anywhere from a couple of days to 6 months.
The red filter and black cover stay on the nest at all times — it is pitch dark inside. The black cover can come off once a day for 2 to 3 minutes (ideally at night); the red filter once a week for 2 to 3 minutes.
☀️ 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, strong smells such as the kitchen, and busy walkways. Keep a steady room temperature.

🍯 Feeding

👑 A founding queen needs no food until her first workers arrive.
🥩 Protein: Best Ants UK Protein Jelly, or pre-killed (frozen, then thawed) fruit flies, cut mealworms, or small crickets or roaches.
🍯 Sugars: a small drop of organic honey, or honey diluted with purified water, in a shallow dish.
🌾 Seeds: small grass or dandelion seeds, or our harvester seed mix, on a dry tin foil tray — never on damp substrate, because sprouted seeds are harmful.
Feed 2 to 3 times a week, adjusted to what the colony eats, in the outworld only. Remove leftovers within 24 to 48 hours.
🦗 Never feed live insects to a small colony. Use pre-killed prey only: freeze it, thaw it, then serve it in the outworld on a small tin foil tray.

💧 Watering the nest

💧 Use distilled or purified water only — never tap, rainwater or bottled mineral water, even boiled. They carry minerals and microbes that turn a nest green with mould. A litre of distilled water costs a few pounds and lasts over a year.
Water the nest with the pipette provided: pour slowly, a few drops at a time, through the watering hole, and stop as soon as 1 or 2 drops appear inside the nest — that is how you know it is done correctly. More than that is too much.
Once a week is usually right — slightly more in summer, less in winter. Never water the outworld.

🌡️ Temperature, heating and winter

Keep the warm area at 24–28°C with a heat mat on one side, near the front of the tube rather than the water reservoir.
Colonies from warm regions can stay active all winter. Colonies from cooler areas benefit from a winter rest: lower the temperature gradually over 2 to 4 weeks to a cool, stable, unheated room, then raise it gradually in spring.
Never use a fridge, and never make abrupt temperature changes.

🤩 Did you know?

Whether a larva becomes a major or a minor depends on juvenile hormone at a critical point in its final larval stage — shown in a 1981 study in Science by Diana Wheeler and Fred Nijhout.

⭐ Golden rules | Never break these

🚫 Never put ants in a fridge, and never expose them to abrupt temperature changes. Cold does not kill a colony instantly — the ants get sick and die over the following days — and prolonged cold near freezing damages the sperm a queen stores from her nuptial flight, so she may never lay fertile eggs again.
🚫 Never use gel ant farms, Ytong or concrete nests, or DIY nests.
🚫 Never use tap, rain or mineral water, even boiled.
🚫 Never move a colony into a nest too early, and never tip or shake ants out of their tube.
🚫 Never disturb the colony with tapping or handling — vibration stresses the queen and she can stop laying or eat her eggs.
☀️ Never keep the farm in the dark: ants need daylight for their circadian rhythm. Daylight yes — direct sunlight never.
🚫 Never release this species into the wild. If you can no longer keep it, visit our ants adoption page and ask us whether we can adopt it.

🛒 Recommended for this species

📚 These care notes cover the essentials only. Please read the full ant farm setup guide and our Pheidole bicarinata care guide from A to Z. Questions? Message us through our contact form and we will be happy to help. 💚

Written and reviewed by the Best Ants UK team, keeping ants since 1997.