Andricus hystrix Kieffer, 1897

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 : 464

Andricus hystrix Kieffer, 1897

Host plants. Israel: Q. boissieri (asexual generation). Elsewhere: Q. petraea , Q. pubescens , Q. robur and Q. infectoria (asexual generation); Q. cerris (sexual generation).

Life history. The sexual generation of this species has been described recently ( Folliot & Pujade-Villar 2006) from adult males, but in Israel the species is known only from the bud galls of its asexual generation. These are composed of multiple elongate, flexible projections that form a sphere of up to 6 mm in diameter ( Fig. 10 ). They are green to purple and sticky when young, turning light brown, woody, and not sticky when mature. The sexual generation develops in single-chambered, solitary bud galls, 8 mm long and 1.3 mm in diameter, with longitudinal ribs and blunt tip. The gall is almost entirely concealed within the bud scales, smooth, medium to light brown or orange-brown ( Folliot & Pujade-Villar 2006).

Phenology. In Israel, galls of the asexual generation begin to develop in June on branches close to the ground on young trees, and adults emerge from them in October. In Europe and Asia Minor adults emerge in September. Galls of the sexual generation develop in early spring and adults emerge from them in April-May.

Distribution. Israel: Rare, found only on Mt. Meron and Pa’ar cave. Elsewhere: Southern and Central Europe and Turkey.

Comments. Galls of the asexual generation are somewhat similar to those of A. grossulariae ( Fig. 9 ) but differ from them in their smaller size, more delicate lobes, and the lack of longitudinal ridges along the lobes. Furthermore, in Israel A. grossulariae galls develop on high branches whereas A. hystrix galls are usually found on lower branches of young trees. The rare, single-chambered, spiny gall of Andricus serotinus (Giraud) (unknown from Israel) develops in similar regions on similar hosts, but can be distinguished form galls of A. hystrix by the fact that it is covered in many fine, almost feathery spines.

Figures

FIGURES 5–10. Galls on Quercus boissieri. 5. Andricus lucidus, asexual generation (arrow) and Andricus moreae, asexual generation (bottom); 6. Andricus cecconii, asexual generation; 7. Andricus caputmedusae, asexual generation, young gall; 8. Andricus caputmedusae, asexual generation, mature gall; 9. Andricus grossulariae, asexual generation; 10. Andricus hystrix, asexual generation.