Pheromone Blend Analysis and Cross-Attraction among Populations of Maruca vitrata from Asia and West Africa.

The legume pod borer, Maruca vitrata, is a pantropical pest on leguminous crops. (E,E)-10,12-Hexadecadienal, (E,E)-10,12-hexadecadienol, and (E)-10-hexadecenal were described previously as sex pheromone components for this nocturnal moth. A blend of these components in a ratio of 100:5:5 attracted males in field trapping experiments in Benin, but not in Taiwan, Thailand, or Vietnam. This finding suggests geographic variation in the pheromone blend between Asian and West African populations of M. vitrata. We, therefore, determined the pheromone compositions of single pheromone glands of females from the three Asian regions and from Benin by gas chromatography-mass spectrometry. Additionally, we compared the responses of males from Taiwan and Benin to calling females and to gland extracts of females from both regions in laboratory no-choice and two-choice assays. Chemical analysis revealed the presence of (E,E)-10,12-hexadecadienal and (E,E)-10,12-hexadecadienol, as well as the absence of (E)-10-hexadecenal in all four populations. The relative amounts of the detected compounds did not vary significantly among the insect populations. The behavioral bioassays showed that Taiwanese and Beninese males were similarly attracted to females from both regions, as well as to their gland extracts. As a result, we did not find geographic variation in the sexual communication system of M. vitrata between West African and Asian insect populations.