Faunistic barriers and zoogeographical zoning of the Central part of Volga-Kama region based on the data on Orthopterous insects (Orthoptera) and Rhopalocera butterflies (Lepidoptera: Rhopalocera)
The Volga-Kama region covers a vast territory in the basin of the Middle Volga and its tributaries, being bounded in the east by the Ural Mountains. With regards to the territorial division, the central part of the region is the Republic of Tatarstan. We have performed complex studies of orthopterans and rhopalocerans in the recent decades. The results of the studies allowed us to compile full lists of species belonging to these insect groups and to obtain data on their spatial distribution within the territory under consideration. To date, we have registered 72 orthopteran species from 48 genera and 6 families and 161 rhopaloceran species from 66 genera and 6 families. Based on the data on the distribution of insects in the region and on the analysis of faunistic similarities between different physiographic provinces of RT, the following nine zoogeographical borders were identified: 1. Upper Volga border. Low-efficiency border, runs along the Volga River up to the estuary pf the Kama River. 2. Vyatka border. Medium-efficiency border, runs along the Vyatka River and divides the Cis-Kama area into the western and eastern parts. 3. Upper Volga-Kama border. Low-efficiency border. 4. Vyatka-Kama border. Medium-efficiency border, runs along the Vyatka and Kama Rivers. 5. Kama border. Medium-efficiency border, runs along the Kama River from the borders of Tatarstan to the estuary of the Kama River. 6. Upper Kama border. Medium-efficiency border. 7. Lower Volga border. Low-efficiency border, runs along the Volga River from the estuary of the Kama River up to the RT boundary. 8. Lower Volga-Kama border. Low-efficiency border, runs along the Kama River and the Volga River up to the estuary of the Kama River. 9. Bugulma-Belebey border. This border coincides with the boundary of the Bugulma-Belebey Upland. Medium-efficiency border. According to the above zoogeographic borders, we suggest a scheme of zoogeographical zoning of the studied territory, which includes the following five provinces: I. Western Cis-Kama forest province (with pine, pine-deciduous, deciduous, and mixed forests). II. Eastern Cis-Kama province of forests and bogs (with dark coniferous and nemoral forests). III. Cis-Volga province of forests and forest steppes (with deciduous and pine-deciduous forests and a forest steppe with steppificated areas). IV. Trans-Kama province of forests and forest steppes (with deciduous and pine-deciduous forests and a forest steppe with steppificated areas). V. Bugulma-Belebey forest-steppe province (with meadow steppes and deciduous steppe-grass forests). Therefore, we have for the first time introduced a zoogeographical zoning of the territory based on the specifics of its entomofauna.