Distributional record of oak gall wasp (Hymenoptera: Cynipidae) species’ diversity in different regions of West-Azerbaijan, Iran

Abstract

Among gall–inducing insects, the majority of species are gall wasps (Hymenoptera: Cynipidae) that occur on oak trees (Quercus spp.) and produce galls on a certain part of the host. In this survey, oak gall wasp species were collected from the oak forests of Pardanan, Mirabad, Nalas, Sardasht, Hamran and Dar-ghabr in West-Azerbaijan province. The galls occurring on 50 cm sampled branches from four cardinal directions on each tree were counted multiple times throughout the season. Species richness of oak gall wasps was estimated for each region and also species diversity indices such as Simpson’s index, Shannon’s H', and Sorensen similarity quotient were calculated. In this survey, 40 oak gall wasps species were identified. Most galls were found on Quercus infectoria. All of the collected oak gall wasps belonged to seven genera: Andricus, Cynips, Neuroterus, Chilaspis, Pseudoneuroterus, Biorhiza and Aphelonyx. Among these species, 28 were related to the Andricus genus. The highest Simpson and Shannon indices were recorded in the Dar-ghabr and Pardanan regions in the fall, respectively. The highest Sorensen similarity was recorded in the spring's galls (sexual generation of oak gall wasps) and fall' galls (asexual generation) between Pardanan and Mirabad, and between Pardanan and Dar-ghabr regions, respectively. Differences in the local distribution of oak species, especially their subspecies, and the climate of the locations should be considered as main factors in oak gall wasp species diversity and the distribution of oak gall wasp species.

Key words: Diversity, Similarity index, oak, gall wasps, forest.