Quercus cerris, Denmark © Simon Haarder: the acorn is not notably modified …

… but contains several young gall chambers

gall

The interior of an acorn has become hard and is partly or entirely transformed into a mass of gall chambers; exteriorly the acorns hardly show any change. The development of the wasps in the gall takes at 3-8 years.

hostplants

Fagaceae, monophagous

Querus cerris.

on Quercus, sexual generation

gall

Gall chambers under the bark on unchanged one-year twigs; only the eventual appearance of exit holes betrays their presence. See Callirhytis spec..

hostplants

Fagaceae, monophagous

Quercus robur.

synonyms

Callirhytis hartigi Förster, 1869; C. erythrostoma Dettmer (1933) A third species, viz. C. erythrosoma Dettmer (1933) also generally is taken as a synonym of erythrocephala, but this is doubted by Pujade-Villar ao (2005a).

references

Bellmann (2012a) Dauphin & Aniotsbehere (1997a), Eady & Quinlan (1963a), Groom (2011a), Melika (2006a), Nieves-Aldrey (1992a), Pujade-Villar, Barbotin, Folliot & Melika (2005a), Redfern & Shirley (2011a), Roskam (2009a), Williams (2010a).