[The proteins of the ejaculatory bulbs in different species of Drosophila]

A comparative electrophoretic study or ejaculatory bulb proteins in 29 different Drosophila species has been carried out. In all analyzed species, ejaculatory bulb contains a major component (designated as PEB). It has molecular mass of 61-65 kDa in the species of virilis group, 33-36 kDa in species of obscura group, and 34-56 kDa in species of melanogaster group. Using immunoblotting technique, we have demonstrated that PEB is introduced into organs of female sex tract during mating. The nature and significance of revealed interspecific differences in PEB proteins has been discussed.