Identification and behavioral assays of sex pheromone components in Smerinthus tokyonis (Lepidoptera: Sphingidae)

Hawk moths are classified into the subfamilies Sphinginae, Macroglossinae and Smerinthinae. The sex pheromones of hawk moths have been intensively investigated recently. However, these reports were mainly on Sphinginae and Macroglossinae and there are only a few reports on Smerinthinae. Here, we identified sex pheromone components from the Smerinthinae, Smerinthus tokyonis Matsumura (Lepidoptera: Sphingidae). Observation of female calling behavior showed that the behavior started immediately after the photo-phase started. Gas chromatography (GC) coupled with electroantennography detection analysis indicated that male antenna responded to three components in the pheromone gland extract. GC–MS and GC analyses demonstrated that the three components were (10Z,12E)–, (10E,12Z)–, and (10Z,12Z)–hexadecadienyl acetates in a 6:7:87 ratio. We subsequently performed behavioral assays in cages. We observed the orientation and contact behavior of males in response to different odor sources, including a solvent control, calling female, pheromone gland extract, and synthetic blend. Males did not respond to the solvent control, but did respond to the other sources. Since males responded more to the calling female than to the synthetic blend, additional cues seem to be required for complete mating behavior. Nevertheless, the pheromone components determined in this first study of a Smerinthinae species are important chemicals in mating communication.