Main trends of invasion processes in beetles (Coleoptera) of European Russia.
The analysis of my own and published data has made it possible to reveal the main trends of invasions in coleopterans of European Russia. On the whole, 168 alien species of beetles from 30 families have been recorded in the region; 102 of them are pests. The following biotopes are typical for alien beetles of European Russia: houses, agrocenoses, biocenoses of human settlements, and ruderal biotopes. However, more than 50% of species occur in their native biotopes: forests, animal shelters, etc. No species has drastically changed native communities, but species of tree pests, which penetrated recently from East Asia, can potentially inflict serious damage to the forests of European Russia: Agrilus planipennis (Buprestidae), Trichoferus campestris (Cerambycidae), Anisandrus maiche (Curculionidae, Scolytinae), Xyleborinus attenuatus (Curculionidae, Scolytinae), and Xylosandrus germanus (Curculionidae, Scolytinae). About half of these species were accidentally introduced with products of either animal or plant origin, about 25% of them were transported with plant substrates (straw, compost), about 10% came with wood, about came 14% with living plants, and less than 5% of species were introduced intentionally. The native ranges of alien beetles of European Russia are situated in the Mediterranean region, East and Southeast Asia, Central Asia, Africa, South and North America, Western Europe, and Australia. The highest number of species (about 20%) originate from East Asia. Most alien beetles were introduced to European Russia not directly, but rather from Western Europe (invasion in stages). In the last 20 years, the number of new alien species originating from East Asia has increased. The regions in which the majority of new beetle species alien to European Russia have been found over the last 20 years are Krasnodar krai and Adygea (14 species) and Moscow oblast (8 species). The process of invasion of beetles into European Russia is accelerating. More alien beetles have penetrated into European Russia during the last 20 years than in the same periods in the past: 42 new alien species, including 23 pest species. The percentage of new alien species associated with living plants has been constantly increasing since the middle of the 20th century and has reached more than 50% in the last 20 years. Alien beetles typically have wide ranges. About 80% of alien beetle species of European Russia have adapted not only in Europe but also in other parts of the world; more than 50% of them have become cosmopolitan. The distribution of an alien species is usually fast: such a species spreads thousands of kilometers in several decades.