New data on the changes in the abundance and distribution of several species of beetles (Coleoptera) in European Russia and the Caucasus

Аннотация

Changes in the abundance and distribution of selected species of beetles in European Russia and in the Caucasus are reported. Most of these species have been recorded from the Northwestern Caucasus in the last 10–15 years. The abundance and distribution during the last two years have changed most sharply in the introduced species, the Harlequin lady beetle Harmonia axyridis and two East Asian bruchids, Megabruchidius dorsalis and M. tonkineus. In 2016, the latter has been found in Georgia for the first time, and Harmonia axyridis was found in St. Petersburg. Abundance of the weevil Alcidodes karelinii with the range situated mostly east of the Caucasus and Volga River remains in Northwestern Caucasus at about the previous level. The flea-weevil species, a leaf miner on Ulmus pumila, misidentified previously as Orchestes mutabilis, is described in this paper as Orchestes steppensis sp. n. based on the material from Russia, Kazakhstan, Mongolia and Northern China; no its further distribution westward in 2015–2016 has been found. This species, rapidly widening its range in North America in the recent decade, is misidentified there as Orchestes alni. A key for differentiation of Orchestes alni, O. mutabilis and O. steppensis sp. n. is provided with photographs of adults of all three species. Magdalis armigera has increased abundance in Northwestern Caucasus in 2016 and was for the first time found in Northwestern Russia (Pskov Province) in 2015. Regular faunistic surveys during several decades provide a possibility of recording considerable changes in the abundance of some common species of Coleoptera, often associated with changes in their distribution.