Andricus Kollari
Oak marble galls develop as a chemically induced distortion of leaf buds on pedunculate oak (Quercus robur), or sessile oak (Quercus petraea) trees, caused by the parthenogenetic gall wasp (Andricus kollari, (Hartig, 1843)) which lays eggs within leaf buds using their ovipositor. The Turkey oak (Quercus cerris), introduced into Britain in 1735, is required for the completion of the life cycle of the gall. The oak marble gall is frequently confused with the oak apple gall, caused by another gall wasp, Biorhiza pallida. Oak marble galls are also known as the bullet gall, oak nut or Devonshire gall. Synonyms for the species are Cynips kollari, Andricus quercusgemmae, A. hispanicus, A. minor, A. indigenus and A. circulans.
Read more about Andricus Kollari: The Physical Appearance of The Gall, Life-cycle and Arrival in Britain, Gall Forming Insects, Predators, Inquilines, Parasitoids and Fungi, Uses of Oak Marble Galls, Infestations of Oak Marble Galls