The ultrastructure of the spermatheca in Ceratitis capitata Wied and Dacus oleae Gmel (Diptera: Tephritidae)

The spermatheca of two economically important insects, Ceratitis capitata and Dacus oleae (Diptera, Tephritidae) was studied by scanning and transmission electron microscopy. The organization of this organ is very similar in both species: it consists of an apical receptacle where spermatozoa are stored and a long duct opening in the vagina. The apical receptacle is characterized by a secretory epithelium structured as in insect ectodermal glands, lined by a cuticular intima. The secretory cells have an asynchronous secretion cycle, more evident in Ceratitis capitata. Two types of secretions have been observed in Ceratitis: one has a microtubular appearance, the second is glycoprotein in nature. The spermathecal duct consists of two ultrastructurally distinct parts: the distal one shows cells with microtubular bundles anchored to the opposite sides of the cell membrane; this organization is able to resist to mechanical stress during the transport of spermatozoa. The proximal tract of the duct is characterized by cells involved in osmoregulatory functions.