Structural organization of the copulation site in the medfly Ceratitis capitata (Diptera : Tephritidae) and observations on sperm transfer and storage

The copulation site of the medfly Ceratitis capitata was investigated at an atomical and ultrastructural levels. It consists of the anterior vagina, wi th a ventral fertilization chamber and a dorsal insemination pocket into wh ich the two spermathecal ducts open. The fertilization chamber is an organ comprised of a number of alveoli that in virgin females are filled with a f ilamentous secretion, whereas in mated females contain sperm bundles. Throu gh study of the internal morphology of the aedeagus, its position in the an terior vagina, and the direct observation of sperm transfer and storage, we confirmed that sperm are ejaculated through two gonopores at the top of th e distiphallus and another at the base of the genital rod. The sperm flow d orsally into the insemination pocket and ventrally into the fertilization c hamber. During copulation, the two spermathecae and the fertilization chamb er are progressively filled with spermatozoa. (C) 2001 Elsevier Science Ltd . All rights reserved.