Abstract: Pterostichus melanarius is a generalist predator that may be a significant predator ofslugs in arable ecosystems and therefore potentially part of an integrated pest managementprogramme against this pest taxon. A suite of field and laboratory experiments were conducted toinvestigate feeding behaviour in this beetle, and its ability to reduce slug population size.Experimental results suggest: (1) at the semi-field scale, P. melanarius did not reduce slugdensity despite beetles being in a state of hunger. (2) The feeding activity of P. melanariuschanged according to the vital status of prey. (3) Conditioning of P. melanarius to specific foodtypes had little effect on subsequent feeding behaviour. Dietary conditioning only affected theirsubsequent propensity to feed on seeds.