Ground beetles in Bulgarian oilseed rape fields and adjacent actively grazed pastures (Coleoptera: Carabidae)

This is the first study of the carabid fauna in oilseed rape fields in Bulgaria. It aimed at clarifying the species composition and ecological structure of the carabids associated with the oilseed rape during its flowering, ripening and after the harvest. The research was also encompassing the adjacent pastures. Field work was carried out in 2018, and partly in 2017. Pitfall traps (5 in each site) were set in 10 sampling sites in Thracian Lowland and Sarnena Sredna Gora Mts. A total of 6914 specimens were collected (463 in 2017 and 6451 in 2018). Collected beetles belonged to 138 species from 45 genera, representing 18.5% of all Bulgarian carabid species and 36% of the genera. The richest tribes were Harpalini (57 species), Amarini (15 species), and Lebiini (13 species). The most species-rich were the genera Harpalus (26 species) and Amara (14 species). The most abundant species in the rape fields were Harpalus distinguendus (714 ex.) and Calosoma auropunctatum (692 ex.). The most abundant in the pastures were Harpalus flavicornis (168 ex.) and Microlestes fissuralis (110 ex.). Thirty-eight species were ascertained to be new for the fauna of the Thracian Lowland and 51 species were new for the Sarnena Gora Mts.