Characterization of volatile compounds in males of the skipper butterfly Daimio tethys (Lepidoptera: Hesperiidae)

Butterflies in the family Hesperiidae are characterized by male-specific structures referred to as scent organs. The volatiles released from the male scent organs of certain hesperiid species have been revealed to serve as chemical signals for mating. However, the chemical structures of male volatiles of hesperiid butterflies have been largely unexplored. Here, we report that the males of Daimio tethys (Lepidoptera: Hesperiidae) release (Z)-8-heptadecene and an oxygenated sesquiterpenoid tentatively identified as farnesene epoxide. These compounds were detected at very low levels in males within 3 days after emergence. In contrast, the females of D. tethys lack the sesquiterpenoid and contain only very small amounts of (Z)-8-heptadecene. Notably, neither of these two compounds were detected in the males of four contemporaneously and sympatrically occurring hesperiid species. The fact that D. tethys males are characterized by possessing these volatiles suggests that these compounds might be utilized for mating, as shown in other butterfly species. Moreover, we revealed that the thorax (including the legs) of D. tethys males contains the highest abundance of these compounds and appears to be the site of scent organs.