CROP TYPE EFFECTS ON THE ACTIVITY AND DISTRIBUTION OF GROUND BEETLES (COLEOPTERA, CARABIDAE)

The activity of carabid beetles and predation pressure of ground-dwelling predators were investigated in four crop types, barley (Hordeum vulgare L.), faba bean (Vicia faba L.), barley-pea (Pisum sativum L.) intercrop and fescue (Festuca rubra L.). Pitfall captures of carabids and disappearance rate of experimentally placed fly pupae were similar across the intercrop of peas and barley and monocultures of faba bean and barley, but pupal disappearance was lower in plots of fescue grass than in the crops. In habitat choice experiments, the intercrop attracted significantly more individuals of Pterostichus melanarius Illiger than did the three monocultures. Our results show that carabids can be affected by vegetation structure associated with differences in agronomic practice and that such effects have potential implication for rates of predation in agricultural systems.