Some brain peptides regulating the secretion of digestive enzymes in the Indian meal moth, Plodia interpunctella (Lepidoptera: Pyralidae)

Abstract

The Indian meal moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae) is a destructive polyphagous pest of many stored products. To interfere with the physiological processes, especially digestion, of the larval pest, more information on the regulatory mechanisms is needed. The brain extract from 1-day-old last instar larvae of P. interpunctella was examined. In the bioassays, the midguts were treated with the brain extract, and the carbohydrase and protease activities were measured. The brain extract showed increasing dose-dependent effects on α-amylase, α-glucosidase, β-glucosidase, α-galactosidase, β-galactosidase, and trypsin secretion in the larval midgut. The extract was further characterised and partially purified using high performance liquid chromatography (HPLC). Several peptides were determined in the brain extract regulating hydrolase activities in the larval midgut of the pest.