Ultrastructural observation of the sex pheromone communication system in Holcocerus vicarius(Walker)(Lepidoptera:Cossidae)

The aim of the study was to understand the location,surface conformation and ultrastructure of the sex pheromone glands(the release system of sex pheromone) of female moth,and type,configuration,distribution and function of male antennae sensilla(sex pheromone receiving system) of Holcocerus vicarius(Walker) adult.Sex pheromone glands of the females and the antennae of the males were observed by using scanning electron microscope(SEM) and transmission electron microscope(TEM).The results showed that the pheromone glands were formed at the mid-dorsal region of the intersegmental membrane between the 8th and 9th abdominal segments.Many plump cones were distributed on the surface of the gland.There was evident conjugation between glandular cells and there were many basal involutions in the basal membrane of cells.Microvilli were distributed on the cytoplasmic membrane and linked with endocuticle on which there were many layers of chitin.In the glandular cytoplast of 2-day-old virgin female moths,the cells contained lipid granules,a lot of empty bubbles,smooth and rough endoplasmic reticulum,and mitochondria.There were five types of sensilla on male antenna flagellum,including sensillum trichodea,sensillum chaetica,sensillum basiconica,sensillum coeloconica and sensillum trichodea curvata,among which sensillum trichodea is the most abundant and sensillum trichodea curvata is the least abundant.The sensilla were not observed on the antenna scape and pedicel for they were covered by a large number of scales.The study provides the basis for understanding the biosynthesis of sex pheromone,extraction and identification of sex pheromone,and reproductive and mating behavior of H.vicarius.