Plagiotrochus quercusilicis (Fabricius, 1798)

on Quercus, agamous generation

gall

Fusiform, woody, very multilocular swelling of the twigs, up to 1.5 x 3 cm in size. The development of the galls may take two or three years.

hostplants

Fagaceae, narrowly monophagous

Quercus coccifera, ilex.


on Quercus, sexual generation

Plagiotrochus quercusilicis: galls on Quercus coccifera

Quercus coccifera, Spain, Cataluña, Corçà (Àger), Ermita de Mare de Déu de la Pertusa © Jean-Yves Baugnée

Plagiotrochus quercusilicis: galls on Quercus coccifera

gall seen from the side

Plagiotrochus quercusilicis: galls on Quercus ilex

Quercus ilex, Britain, Essex, Colchester © Maria Fremlin

Plagiotrochus quercusilicis FM gall on Quercus coccifera

Quercus coccifera; this galling of the axis of the male catkin originally was considered a distinct species viz. P. fusifex (from Houard, 1908a).

Plagiotrochus quercusilicis: old gall on Quercus ilex male inflorescence

October image of this type of gall, Portugal, Charneca da Caparica, Mata Nacional dos Medos © Maria Fremlin

gall

Multilocular, eventually red swelling of the lamina, equally strongly protruding at both sides. The small leaves of Q, coccifera are almost entirely galled, leaving only the spiny leaf margins. Also the axis of the male catkins may turn into a shiny bright red sausage, with the remnants of the flowers attached to the outside.

hostplants

Fagaceae, narrowly monophagous

Quercus coccifera, ilex, rotundifolia.

distribution within Europe

According to (PESI, 2018) France, Italy and the Iberian Peninsula; as the photo above demonstrates also Britain, where the species is expanding (Maria Fremlin, in litt., 2018).

synonyms

Plagiotrochus fusifex Mayr, 1882; P. f. var. ilicina Tavares, 1900; P. ilicis Lichtenstein, 1877; P. emeryi Mayr, 1882; P. lichtensteni, ilicis var. lichtensteini von Dallla Torre & Kieffer, 1910; Plagiotrochus ilicis var. abdominalis Kieffer, 1897-1901; Plagiotrochus ilicis var. nigra Kieffer, 1897-1901; Plagiotrochus ilicis var. Kiefferi Kieffer, 1897-1901.

inquilines

Saphonecrus lusitanicus.

references

Béguinot (2003a), Bellido, Ros-Farré & Pujade-Villar (2003a), Bellmann (2012a), Cerasa (2015a), Cogolludo (1921a), Dauphin & Aniotsbehere (1997a), Hellrigl (2009a), Hellrigl & Bodur (2015a), Houard (1908a), Katılmış & Kıyak (2008a), Kemal & Koçak (2010a), Nieves-Aldrey (2001a), Nieves-Aldrey, Gómez, Hernández Nieves & Lobo (2006a), Pellizzari (2010a), Pujade, Villemant & Andreï-Ruiz (2000a), Redfern & Shirley (2011a), Salas-Remón, Llimona, Lozano ao (2015a), Tomasi (2014a).

mod 12.vi.2018