Andricus quercustozae

Andricus quercustozae (Bosc, 1792)

Host plants. Israel: Q. boissieri. Elsewhere: several oak species from section Quercus.

Life history. Known only from the bud galls of the asexual generation, although population genetic evidence strongly supports the existence of an unknown sexual generation (Rokas et al. 2003). The galls constitute some of the most conspicuous cynipid galls in Israel. They are big and spherical (up to 40 mm in diameter), with a whorl of small, tapered spines around their widest circumference (Figs 13–14). Young developing galls are green, soft, fleshy and very sticky (Fig. 13), and turn purple and woody as they mature. Mature galls are deep purple, resembling the color of a plum, sticky, woody on the outside but spongy on the inside, with a single central larval chamber. Old galls may remain on the tree for several years.

Phenology. Galls begin to develop in July and adults emerge the following spring. Adults may diapause for up to 3 years.

Distribution. Israel: Mt. Hermon 1500 and 1780 m.a.s.l., Odem Forest, En Zivan, Allone HaBashan, Tel Hazeqa, Mt. Meron (very rare). Certain trees in Odem Forest and Allone HaBashan regularly bear hundreds of galls. Elsewhere: a widespread and common Western Palaearctic species, from North Africa across Southern Europe to Asia Minor.

Comments. Galls of this species are somewhat similar to those of A. hungaricus Hartig from Hungary, Austria and the Balkan, but A. hungaricus galls do not have the typical whorl of small spines and are not sticky.