Pogonomyrmex occidentalis
Western Harvester Ant
Photo: Robert Webster / xpda.com, via Wikimedia Commons, licensed under CC BY-SA 4.0.
🐜 At a glance
Origin: Western USA, northern Mexico, southern Canada; grassland, sagebrush and open woodland
Nest temperature: 26–30°C; advanced Heating System Small at 28°C, under a quarter of the nest
Outworld temperature: 18°C night, up to 28°C day; by day like the nest or a degree or two cooler
Humidity: Nest 50–60%; outworld about 50%, never watered
Winter: 2–3 month rest at 17–18°C; never below 15°C; no rest in a queen's first year
Move to a nest: 10+ workers; 15–20 is better, a lone queen too
Size: Queen 12–14 mm; workers 6.5–10 mm, yellowish to reddish-brown
Colony: One queen; up to about 8,000 workers
📖 About this species
A harvester that builds a gravel-covered cone nest with a bare circle of ground around it. A North American ant with a very painful sting, not sold by Best Ants UK and possibly illegal or impossible to import to the UK.
🍯 Feeding
Seeds: our harvester seed mix is the main food, on tin foil or a feeding dish, never on the substrate (sprouted seeds are harmful)
Proteins: Protein Jelly once a week, for example every Monday (keep it in the fridge)
Carbohydrates: organic Ant Honey or Ant Nectar once a week on another day, for example every Thursday; far better than sugar water
Feed in the outworld only and remove leftover jelly and honey after 2 days. Founding queen: a tiny drop of protein jelly on tin foil once a week
Buy food only from established ant-keeping suppliers: bird seed, dried mealworms and pet-shop live food often carry blood-sucking mites
💧 Watering the nest
Distilled or purified water only, never tap, rain or mineral water, even boiled
Pipette a drop at a time through the watering hole: no more than 1 drop should leak into the nest; water when the meter drops below 50%
Never open water (they can drown): a watering test tube in the outworld, never a water dispenser; never water the outworld
🏠 Setting up the ant farm
Angie or A7 Plus ant farm, both with a pre-installed digital meter
Daylight, never direct sunlight; away from windows, radiators, vibration, speakers and kitchens
Escape risk: PTFE Fluon band around the top inner edge of the outworld lid, reapplied about every 4 weeks (every 2 weeks for 300+ ants); keep the lid closed
💡 Good to know
Very painful sting that can cause allergic reactions: adults only, never handle, use long tweezers
On arrival: parcel unopened for 5 hours, then 4–5 days of complete rest in its packaging
Some mounds stay in use for over 40 years. The workers are very defensive. New queens fly in July and August.
⭐ Golden rules | Never break these
🚫 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.
🛒 Recommended for this species
📚 These care notes cover the essentials only. Please read the full ant farm setup guide and our Pogonomyrmex occidentalis 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.