Analysis of the ways of formation of the entomofaunistic complexes in the Northwest Caucasus based on the material on coleopterous insects (Coleoptera)

Abstract

By the example of 14 coleopterous insect families, namely Gyrinidae, Haliplidae, Noteridae, Dytiscidae, Carabidae, Hydrophilidae, Staphylinidae, Lucanidae, Trogidae, Scarabaeidae, Elateridae, Alleculidae, Tenebrionidae, and Chrysomelidae, regularities and the basic sources of formation of the most typical landscapecoenotic complexes in the Northwest Caucasus are discussed. The total number of the species included in the material analyzed amounts to about 2000. The maximal species diversity (854 species) is registered for the deciduous forests and dry open woodlands. In total, 11 types of the chorological complexes and distributional ranges (chorotypes) of the regional beetle fauna are distinguished. Significant concordance of the chorologic patterns in some groups of beetles is established. In this respect, Carabidae and Tenebrionoidea seem to be the closest on the one hand, and also Elateridae and Scarabaeoidea, on the other. The zonal fauna of the Northwest Caucasus is formed basically by species possessing Boreal ranges, while the azonal fauna, predominantly by species with the Ancient Mediterranean ranges. Allocation of coleopterous insects within regional zoochorones is investigated as well. It is established, that in different zoochorones of the upland part of the region the majority of coenofaunas show significant similarity of the arealogical pattern, even though being composed frequently by different taxa. The fauna of agrarian landscapes of the Northwest Caucasus is also examined. It includes 382 beetle species. The overwhelming majority of them belongs to the ground beetles (229 species), leaf beetles (78), and Scarabaeoidea (30). This fauna reveals the maximal similarity with the coenofaunas of the lowland steppe and meadows. It is established that the major role in formation of the agrocenoses beetle fauna belongs to the natural plain and upland steppe and treeless fields, foothill broad-leaf forests and open woodlands, and also to the floodplain and lowland forests. The bulk of the species occurring in the agrocenoses possesses wide ranges, predominantly of the Boreal type. Some peculiarities of the regional endemism are discussed as well.