Aggregation of ground beetles (Carabidae, Coleoptera) on winter rape seeds dispersed on the ground

The preference of adult polyphagous ground beetles (Carabidae, Coleoptera) for winter rape seeds was investigated using an indirect method. Rape seeds were scattered around pitfall traps. The catches of carabid beetles in these traps and control traps without seeds were compared. The traps were exposed in two stands of winter wheat. In the wheat stand where overall carabid activity density was high, the presence of rape seeds significantly increased the catches of total seed-eating carabids, and of the two species Pseudoophonus rufipes and Calathus fuscipes. The effect was not significant in the other wheat stand where activity density was low. The aggregation of carabids at places with winter rape seeds indicated the importance of carabid predation on seeds scattered on the ground.