Predators, Inquilines, Parasitoids and Fungi
Mature galls are sometimes broken open by vertebrate predators to recover the larva or pupa. Woodpeckers, such as the lesser spotted woodpecker(Dendrocopus minor), as well as other birds or squirrels have been suggested. In territory of former Czechoslovakia, both Bank voles and yellow-necked mice feed on larvae and pupae extracted from Oak marble galls.
A number of insect inquilines live harmlessly within the oak marble gall and some of these, as well as Andricus itself, are parasitised by insects referred to as parasitoids. The chalcid wasp Torymus nitens is an example of a parasitoid in oak marble galls. The presence of these inquilines and parasites is often visible on older galls by the presence of fine exit-holes, smaller than that of the gall wasp itself.
A gall can contain the cynipid wasp as the host that made the gall; up to 5 species of inquilines (Ceroptres clavicornis, Synergus gallaepomiformis, S. pallidipennis, S. reinhardi and S. umbraculus) eating the hosts food; as well as up to 13 parasitoid species (Eurytoma brunniventris, Sycophila biguttata, S. variegata, Megastigmus dorsalis, M. stigmatizans, Torymus geranii, T. auratus, Caenacis lauta, Hobbya stenonota, Mesopolobus amaenus, M. fasciiventris, M. sericeus, Eupelmus urozonus) living on the host, inquilines and each other.
Many old galls bear numerous dark brown excrescences, due to the fungus Phoma gallorum.
Read more about this topic: Andricus Kollari