A contribution to the ground beetle fauna (Coleoptera: Carabidae) from the Belasitsa Mts. in Bulgaria

The Belasitsa Mountain is unique for Bulgaria, given its geographical location and climate, favouring the presence of transitional Mediterranean mesophilous biota. One of the animals unique to Belasitsa is the ground beetle Carabus menetriesi, which discovering in 1976 still represents a true zoogeographical enigma. In the period 21.V.2024–27.V.2025, trying to clarify its distribution (presence) and assess the status of its potential habitats, we surveyed specific habitats – riparian, with many heavily moss-covered boulders and decaying trunks fallen into the river. We used pitfall traps operating a whole year, live traps (set twice for a day) and handpicking. We had no success in finding Carabus menetriesi, but we collected 2145 other carabids from 45 species and 24 genera. Of them, 17 species were new for the mountain, along with the genera Agonum, Masoreus, Paranchus, Sinechostictus and Tachys. Carabus intricatus was a constant species, found in all sampling sites. It was also eudominant species (13%), along with the superdominant Platynus scrobiculatus charleswerneri (67%). There were 21 rare species, found in only one locality or only collected by hand; 18 of them were represented by single individuals. Beetles belonged to 19 categories from the five faunal types of Bulgarian carabids, which had relatively even share with slight predominance of the European-Asiatic (11 species; 25%) and Northern (10; 23%) complex. The analysis of the life forms classes showed strong and unusual for Bulgaria prevalence of the Zoophagous beetles (36; 82%) over Mixophytophagous (8, 18%). We found a low number of winged beetles (48%), which is typical for montane habitats. In relation to their humidity preferences, mesophilous (37%) and mesohygrophilous (27%) carabids predominated. Spatial distribution analysis demonstrated that the anthropogenic factor impacts the grouping of carabid coenoses. We concluded that carabid fauna of Belasitsa is of specific composition and deserves more profound and wider research.