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Common Spangle Gall Wasp

Common Spangle Galls ©Brian Eversham

Common spangle gall wasp

Scientific name: Neuroterus quercusbaccarum
The common spangle gall wasp produces a small, disc-shaped growth, or 'gall', on the undersides of oak leaves. Inside the gall, the larvae of the wasp feed on the host tissues, but cause little damage.

Species information

Statistics

Diameter of gall: 4mm

Conservation status

Common.

When to see

January to December

About

The common spangle gall wasp is a tiny wasp, Neuropterus quercusbaccarum, that causes a growth, or 'gall', on the underside of oak leaves in early autumn. It is common and widespread, and a single leaf can host up to 100 galls, each containing a single larva. The galls fall to the ground and can be seen around oak trees during autumn. The larvae continue to develop through the winter, and emerge as adults in April.

How to identify

The common spangle gall wasp produces a brown, disc-shaped gall on the undersides of oak leaves. You are more likely to see the galls than the adult gall wasps or the grubs. However, there are several similar, disc-shaped galls that grow on oak trees.

Distribution

Widespread.

Habitats

Did you know?

The common spangle gall wasp has two generations: the females that emerge in April from the previous autumn's oak-leaf galls, lay their eggs in oak catkins, creating hanging, round 'currant galls'. From June, a sexual generation emerge from the currant galls, ready to lay their eggs on oak leaves and start the cycle again.