Plagiotrochus quercusilicis ( Fabricius, 1798 )

Shachar, Einat, Melika, George, Inbar, Moshe & Dorchin, Netta, 2018, The oak gall wasps of Israel (Hymenoptera, Cynipidae, Cynipini) - diversity, distribution and life history, Zootaxa 4521 (4), pp. 451-498 : 477

Plagiotrochus quercusilicis ( Fabricius, 1798)

Host plants. Israel: Q. calliprinos . Elsewhere: Q. ilex and Q. coccifera .

Life history. Known only from the leaf galls of the sexual generation, which are multi-chambered, fleshy, rigid, ovoid, up to 8 mm in diameter, occupying most of the leaf ( Fig. 74 ). The galls are green when young, red when mature, with smooth and shiny surface.

Phenology. Galls begin to develop in March and adults emerge from them in April-May.

Distribution. Israel: Odem Forest, Mt. Meron, Pa’ar cave, Kfar Hahoresh, Tiv’on, Mt. Carmel, Zur Hadassa. Elsewhere: This is the most common and widespread species in the genus Plagiotrochus , with a circummediterranean distribution.

Comments. When young, the galls resemble those of Plagiotrochus australis Mayr on Q. ilex in the Western Mediterranean Region but P. australis galls are single-chambered whereas those of P. quercusilicis are multichambered. Sternlicht (1968b) referred to galls of this species as belonging to the sexual generation of Plagiotrichus kiefferianus Tavares, a species that has been synonymized under P. gallaeramulorum Boyer de Fonscolombe ( Pujade-Villar 2005) . The possibility that P. quercusilicis and P. gallaeramulorum are synonymous was first suggested by Tavares (1926) and later by Nieves-Aldrey (2001) but without clear evidence.

Figures

FIGURES 71–74. Galls on various Quercus species. 71. Andricus miriami, sexual generation on Quercus libani; 72. Same, old gall; 73. Plagiotrochus razeti, asexual generation on Quercus calliprinos; 74. Plagiotrochus quercusilicis, sexual generation on Quercus calliprinos.