The accessory glands of the female reproductive system of Ceratitis capitata Wied. (Diptera): an updated review

In general, females of insects have two ectodermic organs connected with the genital chamber. One is the spermatheca, typically opening at the anterior of such a chamber and serving as storage for spermatozoa to be used for fertilizing eggs. The other organs are the accessory glands opening more posteriorly and serving for several functions in the different insect orders (DAVEY, 1985; GILLOT, 1996). In the medfly the accessory glands, which have been ultrastructurally studied in recent years (DALLAI et al., 1985; 1988), flow their secretions on the anterior dorsal region of the bursa copulatrix at the same site of the spermathecal duct openings. We summarize the results obtained on the fine structure of the accessory glands and on the biochemical and molecular characterization of the secretions produced by these organs. Particularly, ceratotoxins are antibacterial peptides identified in the Ceratitis accessory gland secretions (MARCHINI et al., 1993; 1995; ROSETTO et al., 1996; ROSETTO et al., 1997). As the maximum expression of such peptides overlaps the female sexual maturity, it was hypotesized that their presence in the female genital ducts might ensure the realization of the proper environmental conditions for fertilization avoiding bacterial infections which could interfere with the sperm-egg interaction. Moreover, the finding of this antimicrobial material on the chorion of laid eggs raises the possibility that these substances play some specific role in the oviposition site, possibly protecting the eggs and the young larvae from environmental injuries (MARCHINI et al., 1997).