More slug-predator Carabid beetles in the edge of forest fragments than in their interior

Slugsare an increasingly serious problem for many crops in Europe. Thus, there is a growing interest concerning the service of regulation of these populations which can be provided by Carabids. As these species are known to be present in forest, the question arises of knowing if there is a flow of these carabids from the forest fragmentstowards the crops, where they could help to control slugpopulations. This flow was evaluated thanks to directed pitfall trapswhich separated individuals according to their direction of movement. These traps were installed in the interior and the edge of 220 woodlots, old and recent, distributed among 2 types of landscape (bocage and open field) in 8 regions of Europe (from the south of France to central Sweden). The results showed higher abundances in the edges than in the interior of woodlots. These differences were more marked in the open fieldlandscapes, where abundances were higher, than in bocage landscapes. They were also higher in old than recent woodlots. The distribution of abundances of Carabid species let us suppose the possibility of a flow from the interior towards the edge. Monitoring of individual movements would be necessary to validate this hypothesis.