Ultrastructure of Ejaculatory Ducts of Cerapanorpa nanwutaina and Furcatopanorpa longihypovalva (Mecoptera: Panorpidae)

SIMPLE SUMMARY: Panorpidae are the most speciose family in Mecoptera and are commonly called scorpionflies, because the genital bulb of their males is enlarged and recurved upward, superficially resembling the stinger of a scorpion. The ejaculatory ducts of Panorpidae are studied for the first time via light and transmission electron microscopy. The ejaculatory duct consists of a median duct and an accessory sac. The epithelium of the median duct has conspicuous secretory activities, which are likely considered a supplement to the male accessory glands. The median duct of F. longihypovalva has one thin muscular layer, which is missing in that of C. nanwutaina. The thin or absent muscular layer may be associated with the sperm pump. ABSTRACT: The ultrastructure of the ejaculatory duct was investigated in the scorpionflies Cerapanorpa nanwutaina (Chou 1981) and Furcatopanorpa longihypovalva (Hua & Cai, 2009) (Mecoptera: Panorpidae) using light and transmission electron microscopy. The ejaculatory ducts of both species comprise a median duct and an accessory sac. The median duct consists of a basal lamina, a mono-layered epithelium, a subcuticular cavity, and an inner cuticle. The accessory sac contains a single layer of epithelium and a basal lamina. A muscular layer is present in the accessory sac of C. nanwutaina and in the median duct of F. longihypovalva. The epithelia in the median duct and the accessory sac are well developed, their cells containing numerous cisterns of rough endoplasmic reticulum, mitochondria, and microvilli. The secretions of the median duct are first extruded into the subcuticular cavity and then into the lumen through an inner cuticle, while the secretions of the accessory sac are discharged directly into the lumen. The ejaculatory duct of F. longihypovalva is longer and has thicker epithelium with more cell organelles and secretions than that of C. nanwutaina.