Ultrastructural organization of the genital tracts in amphigonic females of Euceraphis betulae Koch (Aphididae: Calaphidinae)

The ultrastructure of the genital tracts in amphigonic females of Aphidoidea is described for the first time, using Euceraphis betulae Koch (Aphididae: Calaphidinae) as a representative. The female reproductive apparatus consists of two ovaries, each one with three/four meroistic telotrophic ovarioles; two sac-like accessory glands lie laterally to a sac-like seminal receptacle, opening into the dorso-medial part of the common oviduct by means of a spermathecal duct. A marked secretory activity takes place in the epithelial cells of all the investigated tracts as shown by ultrastructural observation of many organelles involved in this process. No evident golgian area was observed in the cytoplasm of these cells. Extensive smooth endoplasmic reticulum, whose probable role is here discussed, was observed in epithelial cells of the wall of the accessory gland. Spermathecal duct and seminal receptacle had peculiar features that could be related to different secretory activities carried out by these two parts of the spermatheca.