Synergus gallaepomiformis

A member of the family Cynipidae, this wasp is actually an inquiline of other cynipid wasps. In fact it is incapable of forming a gall of its own so acts as an inquiline. This is basically a wasp that lays its egg into an existing gall at an early stage to share the same food store as the gall causer. Although the causer is not directly targeted, the fight for food resource can sometimes cause the death of the gall causer, especially if the inquiline is sharing the same cavity as the causer.

The common gall hosts of this species are; Andricus albopunctatus agamic, A. aries agamic, A. callidoma agamic, A. curruptrix agamic, A. curvator sexual, A. grossulariae sexual, A. kollari agamic, A. lignicola agamic, A. quadrilineatus agamic, A. quercuscalicus agamic, A. quercusramuli sexual, A. seminationis agamic, A. solitarius agamic, Aphelonyx cerricola agamic, Biorhiza pallida sexual, Cynips quercusfolii sexual, Neuroterus anthracinus agamic, N. quercusbaccarum sexual, N. tricolor sexual and Trigonaspis megaptera sexual. The flight times for this wasp are from mid january through to october.

Parasitoids of S. gallaepomiformis are; Torymus flavipes.

The female form A wasp measures in at 1.4-2.9mm with an average of 2.3mm.
The head is dark yellow to brown but always with a brown vertex. The eyes are large, brown and edged with yellow. The ocelli are small and chestnut. The antennae are deep yellow throughout the 14 segments with a short pedice, and the third segment straight.
The pronotal carina is present on the black thorax, and the straw coloured tegulae lead to the wings which are clear and hairy with pale yellow veins, along with a closed radial cell. The legs are predominatly yellow brown with dark and glossy coxae and femora.
The gaster (abdomen) starts off dark brown but tapers to yellow brown. It is not punctate.

The male form A is 1.1-2.4mm averaging at 1.8mm in length.
The head is a rich, deep yellow with a brown vertex, strongly contrasting with its dark mid sized eyes and small brown ocelli. The antennae consist of 15 segments and are deep yellow with a slight taper with a short pedicel and the third segment bent.
The thorax is again black and the pronotal carina is present. The tegulae are straw coloured and the wings are transparent with mid grey/brown hairs and pale yellow veins, with a closed radial cell. The legs are a rich deep yellow which shade to a rich deep brown. The hind coxae is darker and glossy, with some brown on the front ones.
The glossy gaster is dark brown with paler colouring underneath, and is not punctate.

The female form B wasp measures in at 1.1-2.4mm with an average of 2.3mm.
The head is dark with dark mid sized eyes and the ocelli are small and chestnut. The antennae are deep yellow throughout the 14 segments with a short pedicel and the third segment bent.
The pronotal carina is present on the black thorax, and the straw coloured tegulae lead to the wings which are clear and hairy with pale yellow veins, along with a closed radial cell. The legs are yellow and brown with darker, high gloss rear coxae and some brown on the front coxae, otherwise rich, deep yellow which shades to a rich brown.
The gaster (abdomen) is glossy, dark brown with paler underneath. It is not punctate.

The male form B is 1.1-2.4mm averaging at 1.8mm in length.
The head is dark with mid sized dark eyes and small chestnut ocelli. The antennae consist of 15 segments and are deep yellow with a slight taper with a short pedicel and the third segment bent.
The thorax is again black and the pronotal carina is present. The tegulae are straw coloured and the wings are transparent with mid grey/brown hairs and pale yellow veins, with a closed radial cell. The legs are yellow and brown with darker, high gloss rear coxae and some brown on the front coxae, otherwise rich, deep yellow which shades to a rich brown.
The glossy gaster is dark brown with paler colouring underneath, and is not punctate.

More detailed descriptions and identification keys are available from Robin Williams at the British Plant Gall Society.

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