The Ovarian Structure and Vitellogenesis, Spermatheca, and Egg in the Alfalfa Weevil, Hypera postica (Gyllenhal,...

The female reproductive system, spermatheca, and eggs of the alfalfa weevil, Hypera postica, were analyzed using stereo, light, and scanning electron microscopy (SEM). The system consists of paired ovaries, lateral and common oviducts, a spermatheca, and a genital chamber. Each ovary contains two long, telotrophic-meroistic ovarioles, divided into the terminal filament, germarium, vitellarium, and pedicel. The germarium houses trophocytes and young oocytes, while the vitellarium contains oocytes at various developmental stages. Previtellogenic oocytes feature a cylindrical follicular epithelium without yolk. In contrast, vitellogenic oocytes possess a cuboidal epithelium and yolk-filled ooplasm; during the choriogenic stage, the follicular epithelium becomes squamous, and the ooplasm becomes densely packed with yolk. Histological differences in epithelium and muscle layers distinguish the lateral and common oviducts. Eggs, measuring approximately 0.2 mm by 0.3 mm, are laid on alfalfa stems. Initially whitish, they darken to black during embryonic development. SEM analysis revealed a porous endochorion and an exochorion characterized by transverse and longitudinal lamellar air spaces, likely facilitating gas exchange. These morphological and histological findings offer critical insights into the reproductive biology of H. postica, providing a structural basis for improving pest management and biological control interventions.