The Courtship Behavior and the Ultrastructure of Sex Pheromone Glands in the Hind Tibiae of Male Ghost Moth Endoclita davidi (Lepidoptera: Hepialidae)

The courtship behavior of moths is closely related to the biosynthesis and release of sex pheromones. To understand the mechanisms of the reproductive behavior of the ghost moth <i>Endoclita davidi</i>, a host insect of <i>Cordyceps xuefeng</i> (<i>Ophiocordyceps xuefengensis</i>), this study examined the courtship behavior and the ultrastructure of the sex pheromone gland of <i>E. davidi</i>. Infrared photography was used to analyze the courtship behavior, while SEM, paraffin tissue sectioning, and TEM were employed to examine the sex pheromone glands on the hind tibia. The courtship behavior of <i>E. davidi</i> occurs during the scotophase, during which males vibrate their wings and unfold the hairpencils located on the hind tibiae to lure the female moths. The hairpencil's surface features regular longitudinal ridges interspersed with multiple circular pits. Multiple small holes were evident on the slightly enlarged areas close to the ends of the hairpencils. These small holes, formed at the base of the circular pits, connect to the internal glandular duct within the hairpencil, which links to the tibia glandular canal. The epidermal layer of the hind tibiae contains numerous glandular canals and dense microvilli. The glandular cells, specialized from dermal cells, contain numerous mitochondria, rough endoplasmic reticulum, clear vesicles of varying sizes, and round lipid droplets. The sex pheromone glands of male <i>E. davidi</i> release pheromones through the hairpencils in the hind tibia. The courtship behavior and ultrastructure of the sex pheromone gland of the male <i>E. davidi</i> provide a basis for further understanding pheromone release and communication mechanisms.