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 behaviour 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 feeding when added to agar. The amount of feeding that occurred was affected by the type and concentration of glucosinolate and sugar and also by combinations of components. Although glucosinolates were potent feeding stimulants for P. chrysocephala, they were not a prerequisite for feeding, nor does it seem likely that glucosinolate profiles are used by this species to discriminate amongst cruciferous plants at the gustatory level.