Andricus seminationis (Giraud, 1859)
on Quercus
Quercus robur, Biddinghuizen, Spijkbos, 15.v.2021 © Arnold Grosscurt
Quercus robur, Belgium, prov. Antwerp, Meerhout, Keyfheide, 9.v.2015 © Carina Van Steenwinkel: the axis of the inflorescence is swollen and malformed, but the galls are yet to appear
Quercus robur, Belgium, prov. Limbourg, Maasmechelen, 12.v.2018 © Carina Van Steenwinkel: young galls
Quercus robur, Belgium, prov. Antwerp, Meerhout, Keyfheide, 9..v.2015 © Carina Van Steenwinkel: older galls – unstalked, presumably parasitised
Quercus robur, Belgium, prov. Antwerp, Balen, Scheps, 7.vi.2015 © Carina Van Steenwinkel: mature galls
detail
Quercus spec., Belgium, prov. Limbourg, Nieuwerkerken, Schelfheide, 12.x.2019 © Carina Van Steenwinkel: old (date!), parasitised gall

Quercus robur, België, prov. Namen, Étang de Virelles, 9.vi.2015 © Stéphane Claerebout

detail
Quercus robur, Loenen (Gld), 1.vi.2017 © Arnold Grosscurt: older gall
another specimen
leaf gall (from Houard, 1908a)
gall
Catkin gall, rarely leaf gall. Generally the gall is preceded by a strong, often angular swelling of the axis of the catkin. Days later the gall itself appears. The fresh gall is green, slender fusiform, 6-8 mm long, ribbed lengthwise. The young gall has short but obvious, downwards directed hairs, that later disappear. The gall stands on a stalk of c. 5 mm (except when parasitised). Often several galls in a male catkin. As a leaf gall the gall is attached to the leaf margin. Galls in May-June; the wasps emerge in the spring of the second year.
hostplants
Fagaceae, monophagous
Quercus petraea, pubescens, robur.
notes
Only the agamous generation is known.
references
Béguinot (2003a), Bellmann (2012a), Buhr (1965a), Burton, Ellis & Schneider (2022a), Chinery (2011a), Dauphin & Aniotsbehere (1997a), Eady & Quinlan (1963a), Hellrigl (2009a), Hellrigl & Bodur (2015a), Houard (1908a), Koops (2013a), Kwast (2012a, 2014a), Lambinon, Schneider & Chevin (2003a), Meika (2006a), Melika, Csóka & Pujade-Villar (2000a), Redfern & Shirley (2011a), Roskam (2009a), Tomasi (2014a), Wiebes-Rijks (1976a), Williams (2010a).