Electrophysiological and behavioural responses of groundnut seed beetle Caryedon serratus (Olivier) (Coleoptera: Chrysomelidae) to conspecific and groundnut seed chemical cues

The olfactory and behavioural responses of groundnut seed-beetle, Caryedon serratus Olivier to semiochemicals isolated from conspecific insects as well as from groundnut seed headspace volatiles were investigated by coupled Gas Chromatography-Electroantennogram (GC-EAD) and Y-tube olfactometer bioassays. Significant orientation responses of male bruchids to the headspace volatiles from females and orientation responses of both sexes of seed beetles to headspace volatiles from male extracts confirm the existence of both sex and aggregation pheromone systems in C. serratus. Coupled GC-EAD analyses of headspace volatiles of female extract revealed seven bioactive peaks with strongest antennal responses of males towards flame ionization (FID) peaks at retention times of 3 min and 26 min, respectively. GC-EAD profiles of male headspace volatile extract indicated the presence of three distinct bioactive peaks elicited by both male and female antennae. These findings provided necessary leads for the identification of compounds in order to develop environmentally safe semiochemical-based control method for C. serratus.