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 Oak apple gall wasp (Biorhiza pallida)




Oak apple gall wasp | Biorhiza pallida photo
Biorhiza pallida Galle an Quercus robur, Wiesbaden, Hessen, Germany

Photograph by Fritz Geller-Grimm. Some rights reserved.  (view image details)

Oak apple gall wasp | Biorhiza pallida photo
Underside of early pupa of Biorhiza pallida

Photograph by Siga. Some rights reserved.  (view image details)

Oak apple gall wasp | Biorhiza pallida photo
oak apples are caused by the cynipid gall wasp species Biorhiza pallida

Photograph by David Lally. Some rights reserved.  (view image details)

OAK APPLE GALL WASP FACTS

Description
The Oak apple gall wasp larvae produces galls on oak tree buds. The adult wasp is a small brown insect with long fifteen-segmented antennae, and transparent wings with dark veins. Females have an ovipositor which they use for laying eggs in oak buds. The galls are pink or red, before turning brown, and may grow to about four centimetres in diameter with dry and paper like texture. Biorhiza pallida has a complicated life cycle, with a spring generation that develops inside oak galls, and a summer generation that overwinters as larvae in the soil and emerges in spring.

Size
about 5mm

Environment
woodland or parkland and other areas where oak trees are found

Food
larvae feed on the tissue inside the oak galls

Breeding
The female wasp lays eggs in oak tree leaf buds which causes a swelling in the leaf tissue. When the larvae hatch they secretes fluid that causes the formation of the gall. The larvae fed on the gall and there may be numerous larvae inside a single gall. The adult wasps emerge from the galls two or three months after laying.

Range
found in Europe and North America

Classification
Class:Insecta
Order:Hymenoptera
Family:Cynipidae
Genus:Biorhiza
Species:pallida
Common Name:Oak apple gall wasp