Erucin modulates digestive enzyme release via crustacean cardioactive peptide in the elm leaf beetle Xanthogaleruca luteola (Coleoptera: Chrysomelidae)

[Display omitted] •Erucin decreases α-amylase, lipase, and protease release in the elm leaf beetle.•Erucin decreases CCAP content in the midgut, brain, and hemolymph of the elm leaf beetle.•Digestive enzyme release increased in dissected midgut incubated with CCAP.•Injection of CCAP into the hemocoel increased digestive enzyme release.•The erucin decreases CCAP content in the midgut which in turn reduces digestive enzyme release. Plant secondary metabolites influence the feeding in insects through several modes of action. In this study, the physiological effects of erucin isothiocyanate were investigated on the elm leaf beetleXanthogaleruca luteola(Müller) (Coleoptera: Chrysomelidae) via impact on crustacean cardioactive peptide (CCAP) and midgut digestive enzymes. Third instar larvae of elm leaf beetle were fed on leaves impregnated with erucin for three days. The results showed that erucin decreasedα-amylase, lipase, and protease release. Western blot analysis and competitive ELISA showed that erucin decreased CCAP content of the midgut, brain, and hemolymph. Moreover, incubation of dissected midgut with CCAP and also its injection into the hemocoel increased digestive enzyme release. It could be concluded that erucin isothiocyanate decreases CCAP content that itself led to a decrease in digestive enzyme release. Also, it suggests that CCAP could be one of the factors, regulating feeding activities in the elm leaf beetle. This report shows that CCAP is both a midgut factor and a neuropeptide that regulates digestive enzyme release in the elm leaf beetle and could be used to study erucin effects in insects.