Neuroterus quercusbaccarum - Gall on Oak flower

The common spangle gall on the underside of leaves and the currant gall on the male catkins or occasionally the leaves, develop as chemically induced distortions on pedunculate oak, or sessile oak trees, caused by the cynipid wasp ''Neuroterus quercusbaccarum'' which has both agamic and bisexual generations.