Andricus solitarius (Boyer de Fonscolombe, 1832)
on Quercus, agamous generation
Quercus robur, Raalte © Arnold Grosscurt: very young gall
section
older gall
section

Quercus sp., France, dépt. Ardennes, Givet, lieu-dit “Fort Condé”, leg Sébastien Carbonnelle © Stéphane Claerebout

Quercus robur, Dronten, de IJslander © Arnold Grosscurt

Quercus petraea, Belgium, prov. Hainaut, Thuin, Bois de la Frégène, early June: gall still quite young © Jean-Yves Baugnée

another specimen

same gall, opened; there is no differentiated gall chamber

Quercus robur, Ackerdijk © Ben van As (late August)

Quercus robur, Dronten; old gall, with gall of A. lignicolus © Arnold Grosscurt
gall
Mostly solitary pear-shaped gall, generally developed from an axil bud; the upper part drawn into a lang and slightly curved point. Fresh galls with much long, rust-red hair, but later the hairs disappear. At the base of the gall bud scales remain visible. May-September, mature in July.
host plants
Fagacae, monophagous
Quercus canariensis, frainetto, ilex, infectoria subsp. veneris, lusitanica, petraea, pubescens, pyrenaica, robur, suber.
on Quercus, sexual generation

Quercus robur, Belgium, prov. Antwerp, Retie, Prinsenpark © Carina Van Steenwinkel

the gall develops while the catkin is still immature

the catkin below the gall degenerates
gall
Catkin gall. Thin-walled, less than 3 mm, oval, smooth or short-hairy gall at the tip of an aborted catkin; at the foot some long hairs and failed anthers. Lengthwise two ridges run from bottom to tip, one at each side, meeting each other at the tip. Galls are mature in May.
host plants
Fagacae, monophagous
Quercuscerris, petraea, pubescens, pyrenaica, robur.
synonyms
Andricus occultus Tschek, 1871; villarubiae, Tavares, 1930.
inquilines
parasitoids, predators
Eupelmus azureus; Eurytoma brunniventris; Mesopolobus amaenus, mediterraneus, sericeus, tibialis; Ormyrus pomaceus; Sycophila biguttata; Torymus cerri.
references
Askew (1961b), Béguinot (2001c,f, 2002a, 2003a, 2006c, 2007b, 2008a, 2012a), Bellmann (2012a), Blanes-Dalmau, Caballero-López & Pujade-Villar (2017a), Buhr (1965a), Burton, Carbonnelle, Ellis & Schneider (2019a), Burton, Ellis & Schneider (2022a), Cerasa (2015a), Chinery (2011a), Cogolludo (1921a), Dauphin & Aniotsbehere (1997a), Eady & Quinlan (1963a), Gómez, Hernández Nieves, Garrido Torres, ao (2006a), de Vere Graham & Gijswijt (1998a), Groom (2011a), Hellrigl (2009a, 2010a, 2012a), Hellrigl & Bodur (2015a), Houard (1908a), Karaca & Katılmış (2020a), Katılmış & Kıyak (2008a), Kemal & Koçak (2010a), Kollár (2011a), Koops (2013a), Kwast (2012a, 2014a), Lambinon, Carbonnelle & Claerebout (2015a), Lambinon, Schneider & Chevin (2003a), Marković (2014a, 2015a), Melika (2006a), Melika, Csóka & Pujade-Villar (2000a), Nieves-Aldrey (1093a, 1084b, 2001a), Nieves-Aldrey, Gómez, Hernández Nieves & Lobo (2006a), Pujade-Villar (2005b), Pujade-Villar, Kwast, Thuroczy & Bellido (2002a), Redfern & Shirley (2011a), Roskam (2009a), Schneider (2016a), Shachar, Melika, Inbar & Dorchin (2018a), Stănescu (2009a), Tavares (1905a), Tomasi (2014a), Wiebes-Rijks (1976a), Williams (2010a).