Andricus foecundatrix

Andricus foecundatrix

Andricus foecundatrix is a parthenogenetic gall wasp which lays a single egg within a leaf bud, using its ovipositor, to produce a gall known as an oak artichoke gall, oak hop gall, larch-cone gall or hop strobile The gall develops as a chemically induced distortion of leaf axillary or terminal buds on pedunculate oak or sessile oak trees. The larva lives inside a smaller hard casing inside the artichoke and this is released in autumn. The asexual wasp emerges in spring and lays her eggs in the oak catkins. These develop into small oval galls which produce the sexual generation of wasps. A yew artichoke gall caused by the fly ''Taxomyia taxi'' also exists, but is unrelated to the oak-borne species. Previous names or synonyms for the species ''A. fecundator'' are ''A. fecundatrix'', ''A. pilosus'', ''A. foecundatrix'' , ''A. gemmarum'', ''A. gemmae'', ''A. gemmaequercus'', ''A. gemmaecinaraeformis'' and ''A. quercusgemmae''.

The scientific name is now once again ''Andricus foecundatrix''.
Andricus foecundatrix - Oak Artichoke Gall "Oak Artichoke" - A gall on oak caused by the gall wasp Andricus foecundatrix Andricus,Andricus foecundatrix,Cynipidae,Gall,Hymenoptera,Oak Artichoke,gall wasp


The wasps emerging from the oak artichoke galls will be female; and these females will go on to lay a solitary egg in the male flowers of the oaks, which will cause the formation of the 'hairy catkin galls.' The flies that arise form these galls are of both sexes and the cycle then starts again after they have mated and eggs are laid in the oak buds.

Once the oak artichoke gall has fallen to the ground the imago may leave the gall in the following spring, or may delay the emergence for 2–3 years. Galls may persist and exhibit opened scales curving outwards.


Mature galls are sometimes broken open by vertebrate predators to recover the larva or pupa.

A number of insect inquilines live harmlessly within the oak artichoke gall and some of these, as well as ''Andricus '' itself, are parasitised by insects referred to as parasitoids. Some fungi may infect and kill the ''A. fecundator'' larvae.

''Andricus curvator'', the causative agent of the 'collared-bud gall' shows a marked preference for depositing its eggs on buds already colonised by ''A. fecundator''. This may represent an early phase in the development of the inquiline mode of life.


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SpeciesA. foecundatrix
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