Ground beetles in Romanian oilseed rape fields and adjacent grasslands (Coleoptera: Carabidae)

Abstract This study aimed at clarifying species composition and ecological structure of the ground beetles associated with oilseed rape fields during flowering, ripening and post-harvest, as well as pastures adjacent to them. Field work was carried out in 2017. Pitfall traps (5 in each site) were set in 20 sampling sites in the Transylvania region, Cluj County. A total of 8,151 individuals were collected (7,576 in rapeseed fields and 575 in pastures) belonging to 82 species from 29 genera. The richest tribes were Harpalini (25 species), Zabrini (12 species), Pterostichini (10 species), and Carabini (9 species). The most species-rich were the genera Harpalus (13 species), Amara (11 species), Carabus and Ophonus (8 species each). The most abundant species in the rape fields were Poecilus cupreus (1,760 ind.), Brachinus explodens (1,500 ind.), Brachinus elegans (1206 ind.), and Anchomenus dorsalis (875 ind.). The most abundant in the grasslands were Pterostichus hungaricus (101 ind.), Calathus fuscipes (74 ind.), Harpalus caspius (67 ind.), and Cylindera germanica (64 ind.). The species found only in rape fields were 36 while 13 species were exclusive to pastures; 34 species were discovered in both types of habitats. The investigation acquired some new data on carabid diversity in Romania, including two new country records.