Acorn ant

Temnothorax nylanderi

Where it comes from

Range

Western and central Europe, in woodland leaf litter

Size

Workers 2–3 mm, queen 3–4 mm

Queens

Usually one queen

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 6–8 weeks at 22 °C

Nest

A hollow acorn, a walnut or a very small nest — they want it tight

Wintering

7–11 °C

A whole colony fits inside one acorn, which makes this the species to keep when you have no room for a formicarium. It never outgrows the shelf you put it on.

Starting a colony

Temnothorax nylanderi lives in the leaf litter of woodland, in hollow acorns, beech nuts and dead twigs. Its queens fly in summer and are tiny, only 3–4 mm long, so a founding queen is easy to overlook.

House her in a small 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 room temperature, and leave it alone. At 22 °C, egg to worker takes roughly 6–8 weeks. A colony with a dozen workers by its first winter has made a good start.

Feeding

Everything about this species is small, including its appetite. Half a fruit fly or a small piece of cricket is a meal for a young colony, and a single drop of sugar water or diluted honey on a scrap of foil lasts several days. Feed a little, once or twice a week, and remove leftovers after a day. Overfeeding is the easiest way to grow mould in a nest this small.

The nest

Temnothorax wants it tight. A whole colony lives in a cavity the size of an acorn, and in a nest with more room than that it does not feel at home. A small test tube with a narrow entrance works. So does a hollow acorn or walnut with a small hole drilled in it, or a nest of two glass plates held a couple of millimetres apart, which lets you see every ant and every larva. Whatever you choose, keep it moderately damp rather than wet, at room temperature, with no heat mat.

Put the nest in a small box that serves as the outworld, with a water tube and a barrier along the top. The workers are 2–3 mm long, but they are calm and slow, so escapes are less of an issue than with other small ants. Colonies rarely grow beyond a few hundred workers, so the setup stays small for good.

Hibernation

Temnothorax nylanderi needs a winter rest from October to March at 7–11 °C: a cellar, an unheated room or a fridge set not too cold. Lower the temperature over a couple of weeks, stop offering insects and check the water every few weeks, because in a nest this small, drying out happens fast. Warm them up gradually in spring.

Common mistakes

• A nest that is far too large.
• Food portions sized for a bigger species.
• A nest that is wet rather than damp.
• Skipping the winter rest.
• Expecting a big colony. A few hundred workers is a large one.

Questions keepers ask

Can I really keep them in an acorn? Yes. A hollow acorn with a small entrance hole, placed in a little box with a water source, is close to how they live in the wild. You will see less of the colony than in a glass nest, but the ants will be at home.

What if the nest goes bad? Offer a better cavity nearby and they will often move by themselves. Moving house is something this genus is good at: its close relatives are the ants biologists use to study how a colony chooses a new home.

How long until the first workers? About 6–8 weeks at 22 °C, and longer when it is cooler.

Is it a good first species? Yes, especially if you have little room. It is calm, small and easy to care for. If you want a busier colony to watch, try Lasius niger.

Check it yourself

• AntWiki: Temnothorax nylanderi

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

• Formica fusca Silky field ant

  Europe and northern Asia, in open woodland and clearings

  22–26 °C 50–70 %

  Beginner
• Lasius emarginatus Two-coloured garden ant

  Central and southern Europe, the Caucasus and Asia Minor

  22–26 °C 50–65 %

  Beginner
• Lasius flavus Yellow meadow ant

  Europe and across the Palaearctic, in grassland and meadows

  20–24 °C 60–80 %

  Beginner
• Lasius niger Black garden ant

  Across Europe and much of the Palaearctic

  21–25 °C 50–70 %

  Beginner

All 21 species in the guide