Lasius americanus

Woodland Lasius Ant

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Photo: Alex Abair, via Wikimedia Commons, licensed under CC BY 4.0.

🐜 At a glance

Origin: North America; shady woodland, logs, stones, leaf litter
Nest temperature: 21–25°C; heater at 24°C in cool homes; avoid overheating
Outworld temperature: 18°C night, up to 28°C day; by day like the nest or a degree or two cooler
Humidity: Nest 50–70%; outworld about 50%, never watered
Winter: Natural winter rest; steady 10°C only in a hibernation unit, or room temperature
Move to a nest: 10+ workers; 15–20 is better
Size: Queen about 7–9 mm; workers about 3–4 mm, dark brown to black
Colony: One queen per colony; thousands of workers when mature

A small, dark brown ant of shady North American woodland and a close cousin of the black garden ant. Hardy, busy and an easy, rewarding species.

Proteins: Protein Jelly (keep in the fridge) or Cricket Mash
Carbohydrates: organic Ant Honey or Ant Nectar, far better than sugar water or home-made mixes
Twice a week, small amounts, outworld only; remove leftovers after 2 days. Live food only for established colonies: scalded, cut in half, never for small colonies.

Distilled or purified water only. Never tap, rain or bottled mineral water, even boiled (mould and fungus).
Pipette a few drops through the watering hole; stop when 1–2 drops appear inside. About once a week, or when the meter drops below 50%.
Never water the outworld; keep it at about 50% humidity.

A7 Plus ant farm kit (built-in digital meter); A6 with Meter once the colony is big
Advanced Heating System Small 4W under one quarter of the nest, opposite the watering area, set to 24°C (in cool homes)
Daylight, never direct sunlight; away from windows, radiators, vibrations, speakers and kitchens
Escape risk: high. PTFE Fluon band on the top inner edge of the outworld lid, reapplied every 2–4 weeks

North American ant: not sold by Best Ants UK, may be illegal or impossible to import to the UK, and we don't encourage importing ants
Long known as Lasius alienus in America; a separate species found only in North America. Offer small sugar drops so tiny workers don't get stuck
Never release: it is not a UK ant. Can't keep it? See our ant adoption page

🚫 Never put ants in a fridge, shed or garage, and never expose them to abrupt temperature changes.
🚫 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 release ants into the wild. If you can no longer keep a colony, visit our ants adoption page and ask us whether we can adopt it.

📚 These care notes cover the essentials only. Please read the full ant farm setup guide and our Lasius americanus 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.