Yellow meadow ant

Lasius flavus

Where it comes from

Range

Europe and across the Palaearctic, in grassland and meadows

Size

Workers 2–4 mm, queen 7–9 mm

Queens

One queen; founding queens often share a chamber at first

Keeping them

Diet

Sugar water and small insects

Founding

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

Brood development

Egg to worker in roughly 8–10 weeks at 23 °C

Nest

A dark, damp nest — cover it, because they hate the light

Wintering

5–10 °C

Lives underground and rarely forages in the open, so expect a quiet colony that wants a dark, damp nest more than a busy outworld.

Starting a colony

Lasius flavus queens fly in summer, usually in July or August, often on the same warm afternoons as Lasius niger. A queen that has dropped her wings has mated and is ready to dig in.

Set her up 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. Cover it completely, keep it at 20–24 °C and leave it alone. She is fully claustral and lives on her own reserves until her first workers arrive. At 23 °C, egg to worker takes roughly 8–10 weeks, and this is a slow species even by Lasius standards. A queen caught in summer often goes into her first winter with brood but no workers, and the first workers appear in spring. That is normal, not a failed queen.

In the wild, founding queens often dig in together. Whether they stay together once there are workers varies, so the safe choice is one queen per tube.

Feeding

In the wild Lasius flavus hardly ever forages above ground. It keeps root aphids in its tunnels, tending them, moving them to fresh roots and even looking after their eggs through the winter, and it lives mostly on their honeydew, with small soil insects for protein. In captivity that means a colony that will not come out to look for food the way Lasius niger does.

Put sugar water and small insects close to the nest entrance, or just inside it, and keep the portions tiny: a few fruit flies or a sliver of mealworm are plenty. Remove what is left after a day. In a damp nest, uneaten food goes mouldy fast, and mould is a bigger threat to this colony than hunger.

The nest

This is the species that most needs a dark, damp nest. The workers are small and pale with tiny eyes, they dry out easily and they avoid light. Cover the nest or keep it in a box, and keep most of it damp rather than just one corner. Humidity in the 60–80 % range suits it. Nests filled with soil or a sand-and-loam mix work well, since digging is what this ant does. Ytong and plaster work too, as long as they stay damp.

The outworld can be small. It will see little traffic, and a big empty arena is wasted on this species. It still needs a barrier on the walls, because the workers are only 2–4 mm long. In the wild these are the ants that build the grassy mounds in old pasture, mounds that can stand for decades. In a nest, a colony grows slowly at first and eventually reaches several thousand workers.

Hibernation

Lasius flavus needs a winter rest from November to February at 5–10 °C: a cellar, an unheated room or a fridge. Lower the temperature over a couple of weeks and stop offering insects. The main thing to watch is moisture. This species dries out faster than most, so check the water and the dampness of the nest every few weeks through the winter, and warm the colony up gradually in spring.

Common mistakes

• Expecting a busy outworld. A quiet setup is how this species lives, not a sign that something is wrong.
• Letting the nest dry out, especially over the winter.
• Leaving the nest uncovered.
• Food portions large enough to rot before they are eaten.
• Giving up on a founding queen who has no workers by autumn.

Questions keepers ask

Why do I never see them? Because they live underground. Lasius flavus forages through its own tunnels, among roots, and almost never in the open. Lift the cover of the nest and you will find them. Leave it on and you mostly won't.

How long until the first workers? About 8–10 weeks at 23 °C, and for a queen caught in summer, often not until after her first winter.

Does it need a heat mat? No. It is happy at room temperature, and extra heat mostly dries the nest out.

Is it a good first species? It is undemanding but quiet. If you want to watch ants forage, Lasius niger or Lasius emarginatus gives you more to see. If you like the idea of a calm colony in a dark nest, this one is easy to keep.

Check it yourself

• AntWiki: Lasius flavus

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

• Lasius emarginatus Two-coloured garden ant

  Central and southern Europe, the Caucasus and Asia Minor

  22–26 °C 50–65 %

  Beginner
• Lasius niger Black garden ant

  Across Europe and much of the Palaearctic

  21–25 °C 50–70 %

  Beginner
• Formica fusca Silky field ant

  Europe and northern Asia, in open woodland and clearings

  22–26 °C 50–70 %

  Beginner
• Temnothorax nylanderi Acorn ant

  Western and central Europe, in woodland leaf litter

  20–24 °C 50–60 %

  Beginner

All 21 species in the guide