Distribution and Trophic Associations of Herbivorous Bark Beetles of the Genus Thamnurgus Eichhoff (Coleoptera, Curculionidae: Scolytinae) in the Volga Region and in the Urals

Abstract

Based on the author’s and literature data, three species of the scolytid genus Thamnurgus Eichhoff, 1864 associated with herbaceous plants are reported from the Volga Region and the Urals: Th. petzi Reitter, 1901 (= Th. rossicus Alexeev, 1957), Th. caucasicus Reitter, 1887, and Th. pegani Eggers, 1933. Two former species are widely but spottedly distributed in the native steppe and steppificated landscapes of the Volga Region and the South Urals. Thamnurgus pegani was found in 2019 in the semi-desert and desert zones of the Lower Volga area (Astrakhan Province) and is recorded from Russia for the first time. These species have different host plants: Th. petzi is associated in the region with perennial species of the genus Delphinium L. (D. aggr. cuneatum Stev. ex DC. and D. aggr. dictyocarpum DC.), Th. caucasicus appears to be mostly associated with spurges Euphorbia spp. and thistles Carduus spp., while Th. pegani is monophagous on Peganum harmala L.