Ground beetles in Swiss oilseed rape fields and adjacent mowed meadows (Coleoptera: Carabidae)

This study aimed at clarifying species composition and ecological structure of carabids associated with the oilseed rape during its flowering, ripening and after the harvest. The research also encompassed the adjacent mowed dry grasslands. Field work was carried out in spring and summer 2017. Pitfall traps (5 in each site) were set in 8 sampling sites located in the Swiss Jura (cantons of Argovia and Solothurn). We collected 11549 specimens (11033 in rapeseed fields, 516 in grasslands). Collected beetles belonged to 60 species from 29 genera. The richest tribes were Harpalini (17 species), Pterostichini (8 species), Amarini (7 species), Bembidiini and Carabini (6 species each). The highest species richness was among genera Harpalus (11 species), Amara (7 species), and Carabus (6 species). The most abundant species in the rapeseed fields were Poecilus cupreus (7126 ex.), Anchomenus dorsalis (842 ex.), Pterostichus melanarius (663 ex.), and Amara ovata (583 ex.). The most abundant in grasslands were Carabus auratus (176 ex.), and Harpalus dimidiatus (102 ex.). In rapeseed fields we found 45 species, and in grasslands – 31 species. Specific to the rapeseed fields were 29 species, and to grasslands – 15 species; 16 species were common for both types of habitats.