European thief ant

Solenopsis fugax

Where it comes from

Range

Europe, North Africa and the Middle East

Size

Workers 1.5–3 mm, queen 6–7 mm

Queens

Often several queens

Keeping them

Diet

Insects, seeds and sugar water

Founding

Fully claustral — the queen needs no food until her first workers

Brood development

Egg to worker in roughly 4–6 weeks at 25 °C

Nest

Fine galleries, damp nest, dry outworld — and no standing water to drown in

Wintering

10–15 °C

At 1.5 mm the workers walk out of almost any setup, so an escape barrier is not optional. Despite the genus, this is a native European ant and not one of the fire ants on the EU list.

Starting a colony

Solenopsis fugax queens fly in late summer and early autumn, often in huge numbers. The queens are far larger than their workers: 6–7 mm, against 1.5–3 mm for a worker. A wingless queen has mated.

House her in 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. She is fully claustral and lives on her own reserves until her first workers arrive. Keep the tube dark at 22–26 °C and leave it alone. At 25 °C, egg to worker takes roughly 4–6 weeks, quick for a European species. Before you see the first workers, think about how you will keep them in: they are smaller than almost anything else you can keep.

How it lives

In the wild Solenopsis fugax is a thief ant. It digs fine tunnels into the walls of larger ants' nests and steals their brood to eat, and a chemical in its venom helps keep the much larger hosts at bay. In captivity it needs no other ants: it lives perfectly well on insects, seeds and sugar.

Feeding

Give small pieces of insect — fruit flies, a cut cricket or mealworm — whenever there is brood, a few small seeds, and sugar water or diluted honey. The workers are so small that an open drop of liquid can drown them. Offer sugar water soaked into a piece of cotton wool or tissue instead, and do the same with the water supply. Remove insect remains after a day.

The nest

Give it fine galleries in a damp nest and a dry outworld. A plaster or Ytong nest with narrow tunnels works, and so does a nest filled with fine soil. Standing water anywhere in the setup is a hazard.

Most of the work goes into keeping them in. The smallest workers get through ventilation mesh that holds larger species, around tubing and under lids. Use the finest mesh you can find, check every seam, and put a barrier — PTFE (Fluon) or a thin film of paraffin oil — along the top of the outworld. A colony grows to tens of thousands of workers, so the setup will need to grow too.

Hibernation

Solenopsis fugax rests from November to February at 10–15 °C: a cool room or an unheated hallway rather than a fridge. Lower the temperature over a couple of weeks, stop offering insects and check the water every few weeks. Warm them up gradually in spring.

Common mistakes

• Open drops of water or sugar water, which drown the workers.
• Ventilation mesh that is too coarse.
• A setup with any unchecked seam or gap.
• Food pieces too big for the colony to deal with before they go mouldy.
• Wintering it as cold as a northern species.

Questions keepers ask

Is this a fire ant? It belongs to the same genus, but no. Solenopsis fugax is a native European ant. The fire ants that are banned in the EU are different species, from the Americas.

Does it need other ants to steal from? No. Stealing brood is how it lives in the wild, but in a nest it does fine on insects, seeds and sugar.

How long until the first workers? About 4–6 weeks at 25 °C, and longer when it is cooler.

Is it a good first species? Not really. It is not hard to feed, but keeping workers this small inside the setup takes care and experience. For a small species that is easier to contain, try Temnothorax nylanderi.

Check it yourself

• AntWiki: Solenopsis fugax

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

Similar species

• Camponotus herculeanus Hercules carpenter ant

  Northern Europe, Asia and North America, in conifer forest

  20–25 °C 50–70 %

  Intermediate
• Camponotus ligniperda Brown-black carpenter ant

  Central and northern Europe, in and under dead wood

  22–26 °C 50–70 %

  Intermediate
• Formica rufibarbis Red-barbed ant

  Europe from Portugal to western Siberia, on sandy grassland and heath

  22–26 °C 50–70 %

  Intermediate
• Manica rubida European red mountain ant

  Central and southern Europe, the Near East and Georgia, at 400–2,200 m

  20–24 °C 50–70 %

  Intermediate

All 21 species in the guide