Revelations on the Regulatory Mechanisms in Moth Sex-Pheromone Signals

The understanding of chemical communication in Lepidoptera, particularly in moths, has advanced greatly over the last half-century including sex-pheromone identification and synthesis, but the application of this knowledge in pest management has had only marginal success, possibly due to the complexity of the biosynthetic cascades that result in the production of the pheromone components. Sexual encounters in moths are initiated by the release of a unique blend of volatile organic compounds, the sex pheromones, by one sex, to attract conspecifics and signal receptivity for mating. After mating, pheromone biosynthetic activity in females is reduced, calling behavior ceases and oviposition is enhanced. Both post-mating responses i.e. reduced receptivity and increased oviposition, can be theoretically visualized as systems that could be manipulated to the advantage for pest management. This review examines the research trend concerning mating behavior in moths by appraising the available information revealed by molecular, genomic, phylogenetic and transcriptomic studies on the mechanisms that up-regulate sex-pheromone production in receptive females and down-regulate after mating. The review concludes by examining future research directions needed to enhance our present-day knowledge concerning these regulatory mechanisms so as to reach a level of understanding that will facilitate its utilization for pest management.