Patterns of formation of the flea (Siphonaptera) fauna in the Caucasus

Fleas of the Caucasus belong to 155 species of 40 genera, constituting 17% and 43% of the species and generic composition of the Palaearctic fauna, respectively. The Caucasian fauna includes 23 endemic species but no endemic genera or subgenera. In the number of species, the Caucasian fauna is similar to that of the Mediterranean Subregion and is significantly poorer than the faunas of the Euro-Siberian (by 2.2 times) and Irano-Turanian (by 1.7 times) Subregions. Based on taxonomic diversity, we can propose a hypothesis on the West and East Palaearctic sources of the Caucasian fauna. The West Palaearctic source has determined the distribution of pulicomorph fleas of the families Pulicidae and Coptopsyllidae from Africa, on the one hand, and of fleas of the genera Ctenopthalmus and Palaeopsylla from Europe, on the other hand. Fleas of the Holarctic genera, such as Ceratophyllus and Megabothris, entered the Caucasus by the north Asian route; fleas of the genera Neopsylla, Rhadinopsylla, and Hystrichopsylla migrated to the Caucasus from east and central Asia by the south Asian route, through Middle and Western Asia.