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North American Animals - mamals, birds, reptiles, insects
Oak apple gall wasp (Biorhiza pallida)
Biorhiza pallida Galle an Quercus robur, Wiesbaden, Hessen, Germany
Photograph by Fritz Geller-Grimm. Some rights reserved. (view image details)
Underside of early pupa of Biorhiza pallida
Photograph by Siga. Some rights reserved. (view image details)
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 FACTSDescription
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.
woodland or parkland and other areas where oak trees are found
larvae feed on the tissue inside the oak galls
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.
found in Europe and North America