Genetic Basis Underlying Structural Shift of Monoterpenoid Pheromones in Mealybugs

Insect sex pheromones are examples of semiochemicals that trigger the most conspicuous biological activities, and they have attracted the interest of chemical ecologists since the dawn of this multidisciplinary field. For a deeper understanding of the ecological and evolutionary scenario of pheromones, as well as other targets of chemical ecology, it is essential to analyze the chemicals produced by individual organisms along with sound chemical identifications using reference compounds. Prof. Kenji Mori and his colleagues have developed various synthetic routes and have provided their products as authentic standards to many researchers. Using such a legacy, the tiny amounts of pheromones emitted by individual mealybug females were successfully analyzed and quantified by selected-ion-monitoring mode of gas chromatography-mass spectrometry. The results of the analyses of the monoterpene pheromones from Planococcus citri, P. minor, and their hybrids suggested that shift of the cyclobutane structure in P. citri and its acyclic form in P. minor is largely attributable to a single genetic locus.