Cynips quercusfolii Linnaeus, 1758
Quercus, agamous generation
Quercus robur, Hungary, Kimle, 4.ix.2017 © László Érsek
larva in opened gall
Quercus robur, Belgium, prov. Hainaut, Comines, 6.viii.2019 © Martin Windels
galled lead, upper side
gall at the underside; see note below
two more galls

Quercus robur, Bergen aan Zee, 2.ix.2012

Generally the galls remain attached to the leaf until autumn, then drop with the leaf to the ground, but sometimes the galls drop spontaneously (?) already in late summer.

Hollandsche Rading: opened gall; the gall is soft and juicy

the small larval chamber

Wolfheze, 6.x.2007: hibernation as imago in a gall that has fallen to the ground

Nieuwendam, 8.ix.2012: extremely heavy infestation of a small tree in the bank of a main highway
Gall
Galls from July till October, mature in August.
host plants
Fagaceae, monophagous
Quercus frainetto, macranthera, petraea, pubescens, pyrenaica, robur.
Rarely also Q. cerris.
inquilines
notes
Normally the surface of the gall si completely smooth, but galls with a tuberculare surface do occur as well. Redfern & Shirley write that this occur in galls on Quercus petraea, but this cannot be the complete explanation. The statement by Buhr thit is exclusively concerns parasitised galls needs confirmation.
Quercus, sexual generation

Quercus petraea, Belgium, prov. Namur, Couvin, Frasnes © Stéphane Claerebout: group of dormant buds with two young galls

Quercus petraea, Belgium, East Flanders, Geraardsbergen, Overboelare-Planken @ Bart Uitterhaegen: as the galls grow older, the colour changes from reddish to dark purple
gall
The sexual generation makes egg-shaped, velvety galls of about 2 mm on resting buds; initially they are red. Contrary to Cynips longiventris, at the base of the gall remnants of bud scales are visible.
host plants
Fagaceae, monophagous
Quercus frainetto, x hispanica, infectoria, petraea, pubescens, pyrenaica, robur.
Rarely also Q. cerris.
synonyms
Dryophanta folii Hartig, 1840; D. scutellaris Olivier, 1781; D. flosculi (Giraud, 1868); D. taschenbergi (von Schlechtendal, 1870).
parasitoids, predators
Aprostocetus aethiops; Bootanomyia dorsalis; Eupelmus barai; Eurytoma brunniventris; Mesopolobus fasciiventris. fuscipes, sericeus; Ormyrus nitidulus; Sycophila biguttata; Torymus auratus, cerri, cyaneus, macrurus.
notes
In the agamous generation there is a significant preference for the larger leaves (Giertych ao, 2013a).
references
Abras, Fassotte, Chandelier & Cavelier (2008a), Andersen & Fjellberg (1977a), Askew (1961b), Béguinot (2002a,e,f,g,h, 2003a, 2006a,c, 2007b, 2012a), Bellmann (2012a), Blanes-Dalmau, Caballero-López & Pujade-Villar (2017a), Cerasa (2015a), Chinery (2011a), Cogolludo (1921a), Coulianos & Holmåsen (1991a), Dauphin & Aniotsbehere (1997a), Dietrich (2016a), Eady & Quinlan (1963a), Ecott (2012a), Fusu (2017a), Giertych, Jagodziński & Karolewski (2013a), Gómez, Hernández Nieves, Garrido Torres, ao (2006a), Groom (2011a), Guzicka, Karolewski & Giertych (2017a), Hellrigl (2009a, 2010a, 2012a), Hellrigl & Bodur (2015a), Houard (1908a), Ilie & Marinescu (2011a), Jankiewicz, Dyki, Machlatiska & Dubert (2017a), Karaca & Katılmış (2020a), Katılmış & Kıyak (2008a), Kemal & Koçak (2010a), Kollár (2007a, 2011a), Koops (2013a), Kwast (2012a, 2014a), Lambinon, Carbonnelle & Claerebout (2015a), Lambinon, Schneider & Chevin (2003a), Lehmann & Hannover (2016a), Marković (2014a, 2015a), Melika (2006a), Melika, Csóka & Pujade-Villar (2000a), Mete & Demirsoy (2012a), Nieves-Aldrey (2001a), Pellizzari (2010a), Popescu (2003a), Redfern & Shirley (2011a), Roques, Cleary, Matsiakh & Eschem (2017a), Roskam (2009a), Schimitschek (1939a), Tomasi (2003a, 2012a, 2014a), Williams (2010a).