Isolation of sex pheromone mimic of the American cockroach by monitoring with male/female ratio in electroantennogram

The electroantennogram (EAG) technique was applied as a monitoring tool to isolate germacrene-D, a sex pheromone mimic of the American cockroach. Large values of the male/female ratio, and its index derived from EAG responses of adult males and females to a standard, indicated significant amounts of germacrene-D in plant fractions. Monitoring with behavioural assays and gas chromatographic analysis during the isolation confirmed that the EAG technique using the male/female index was a good indicator in the isolation of sexually active components.