Red-barbed ant
Formica rufibarbis
Where it comes from
- Range
- Europe from Portugal to western Siberia, on sandy grassland and heath
- Size
- Workers 4–7 mm, queen 8–10 mm
- Queens
- One to three queens
Keeping them
- Diet
- Sugar water and insects
- Founding
- Fully claustral — the queen needs no food until her first workers
- Brood development
- Egg to worker in roughly 5–7 weeks at 25 °C
- Nest
- A dry sandy nest with a big, sunlit outworld
- Wintering
- 5–10 °C
Sharp-eyed and very fast, and it sprays formic acid when annoyed. Common on the continent but critically endangered in Britain, so buy captive stock rather than digging a nest up.
Starting a colony
Formica rufibarbis lives on sandy grassland and heath, in warm, open, sunny places, and its queens fly in summer. On the continent it is a common ant. In Britain it survives at only a handful of sites and is critically endangered, so a queen found there should be left where she is. Anywhere else, a mated queen or a captive-bred colony is the way to start.
A founding queen goes into a test tube: water at the back behind a plug of cotton wool, the queen in the dry front half, and a loose plug at the opening. Cover it, keep it at 22–26 °C and leave it alone. She is fully claustral and lives on her own reserves until her first workers arrive. At 25 °C, egg to worker takes roughly 5–7 weeks. Wild colonies sometimes have two or three queens, but in a test tube one queen is the safe choice.
Feeding
This is a hunter. Formica rufibarbis has sharp eyes and is very fast, and much of what it eats in the wild it catches itself. It also collects honeydew. Give sugar water or diluted honey, and more protein than you would give a Lasius colony of the same size: fruit flies, crickets, cut mealworms, and live prey now and then if you want to see it hunt. Remove dead remains after a day.
The nest and the heat
Recreate a sunny sand bank: a dry nest, with only a small damp area, and a warm, bright outworld. A lamp over one end of the outworld or a heat mat under one end of the nest gives the colony a warm spot to choose. Never let direct sun fall on the nest itself, which heats a small setup far beyond what any ant survives. Sand or a sand-and-loam mix suits it, and so do Ytong and acrylic as long as most of the nest stays dry.
Colonies stay small, up to about 500 workers, so there is no need for a large nest. What it does need is a setup it cannot get out of. The workers are quick enough to be out of an open lid before you have noticed, and they climb smooth walls. A barrier along the top of the outworld — PTFE (Fluon) or a thin film of paraffin oil — and a habit of opening the setup only as far and as long as you need are what make this species manageable.
Hibernation
Formica rufibarbis needs a winter rest from October to March at 5–10 °C: a cellar, an unheated room or a fridge. Lower the temperature over a couple of weeks and stop offering insects. Check the water every few weeks through the winter, and warm the colony up gradually in spring.
Common mistakes
- Opening the outworld without a plan. A rufibarbis worker that gets out is very hard to catch.
- A nest that is damp throughout. This is an ant of dry sand.
- Feeding it like a Lasius colony, with too little protein.
- Direct sun on the nest.
- Collecting a queen in Britain, where the species is critically endangered.
Questions keepers ask
Why is it rated intermediate? Not because it is fragile. It is the speed and the temper: these are fast, alert ants that bite, spray formic acid and get out of a careless setup. With a sealed outworld and a warm, dry nest they are not hard to keep.
How do I tell it from Formica fusca? Formica fusca is dark all over. Formica rufibarbis has a red thorax. So does its close relative Formica cunicularia, though, and telling those two apart takes a magnifier and an identification key.
How long until the first workers? About 5–7 weeks at 25 °C, and longer when it is cooler.
Does it sting? No. It has no sting, but it bites and sprays formic acid, which stings a little in a cut and smells sharp. It is harmless to people.
Check it yourself
General guidance from the usual beginner references — treat it as a starting point, not as a rule your colony has agreed to.
Start a colony with this species
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