THE INFLUENCE OF GLUCOSINOLATES AND SUGARS ON FEEDING BY THE CABBAGE STEM FLEA BEETLE, PSYLLIODES CHRYSOCEPHALA

Agar was used as an artificial substrate to investigate the feeding be haviour of the cabbage stem flea beetle, Psylliodes chrysocephala L. ( Coleoptera: Chrysomelidae), an important pest of winter oilseed rape ( Brassica napus) in Europe. Both glucosinolates and sugars stimulated f eeding when added to agar. The amount of feeding that occurred was aff ected by the type and concentration of glucosinolate and sugar and als o by combinations of components. Although glucosinolates were potent f eeding stimulants for P. chrysocephala, they were not a prerequisite f or feeding, nor does it seem likely that glucosinolate profiles are us ed by this species to discriminate amongst cruciferous plants at the g ustatory level.