Quercus robur, Belgium, prov. Antwerp, Mol, 30.iv.2015 © Carina Van Steenwinkel

beginning gall

ripe gall; the remnant of the loculi still clearly recognisable

one week later

Quercus robur, Belgium, prov. Antwerp, Mol, 26.iv.2020 © Carina Van Steenwinkel: four anthers with young galls; the galls develop in the purplish tissue between the two dark green pollen chambers; neither the pollen chambers nor the grey filament participate in the galling.

opened gall with larva

another specimen

Quercus robur, Belgium, prov. Antwerp, Keyfheide-Meerhout, 1.v.2015 © Carina Van Steenwinkel: the galls may be quite numerous

Quercus robur, Spain, A Coruña, Cesuras, 11.iv.2009 © Jordi Montobbio

3.iv.2012: another specimen

The agamous generation makes a tiny unilocular gall, hardly over one milimeter, in the connective of a stamen. Initially the anthers remain well distinguishable.

host plants

Fagaceae, monophagous

Quercus faginea, lusitanica, petraea & subsp. iberica, pubescens, pyrenaica, robur.

Preference for Q. pubesccens.

on Quercus; sexual generation

Quercus robur (from Houard, 1908a)

Quercus robur, Belgium, prov. Antwerp, Meerhout, de Hutten 24.iv.2015 © Carina Van Steenwinkel: occupied gall

Quercus robur, Belgium, prov. Antwerp, Balen, 26.iv.2015 © Carina Van Steenwinkel: vacated galls

Quercus robur, Belgium, prov. Antwerp, Mol, Galbergen, 28.iv.2015 © Carina Van Steenwinkel: the bud scales participate in the gall formation

Quercus robur, Dronten, Roggebotsebos, 4.iv.2020 © Arnold Grosscurt: the gall is (still) completely hidden by the bud scales

in transverse section they turn out as two, succulent, galls

Quercus robur Belgium, prov. Namur, Étang de Virelles, 9.vi.2015 © Stéphane Claerebout

Quercus robur, Spain, A Coruña, Cesuras, 8.iv.2009 © Jordi Montobbio

opened gall with pupa

Quercus robur, Spain, A Coruña, O Pino, 10.iv.2009 © Jordi Montobbio: vacated gall

Quercus robur, Schiedam, Pr. Beatrixpark, 21.iv.2012 © Ben van As

gall

About 1 cm long pale green gall, at the tip of a young shoot, consisting of an already unfolding leaf bud (generally a terminal bud). The bud scales participate in the gall, often only their ultimate tips remain brown and scarious. The wall is thin and encloses a spacious gall chamber. The development starts in early spring and is so fast that sometimes galls are already vacated before the foliage is unfolded. The gall matures in May; then it starts to shrivel and remains recognisable only by the distorted bud.

host plants

Fagaceae, monophagous

Quercus petraea, pubescens, pyrenaica, robur.

synonyms

Neuroterus aprilinus Giraud, 1859; N. petioliventris (Hartig, 1840); N. schlechtendali Mayr, 1870.

references

Béguinot (2000b, 2002a, 2003b, 2007b), Bellmann (2012a), Blanes-Dalmau, Caballero-López & Pujade-Villar (2017a), Buhr (1965a), Chinery (2011a), Dauphin & Aniotsbehere (1997), Eady & Quinlan (1963a), Ecott (2012a), Hellrigl (2009a, 2010a), Hellrigl & Bodur (2015a), Houard (1908a), Katılmış & Kıyak (2008a), Koops (2013a), Kwast (2012a, 2014a), Melika (2006a), Melika, Csóka & Pujade-Villar (2000a), Nieves-Aldrey (2001a), Nieves-Aldrey, Gómez, Hernández Nieves & Lobo (2006a), Redfern & Shirley (2011a), Roskam (2009a), Tavares (1905a), Vilarrubia Garet (1956a), Williams (2010a).