How Drosophila males make eggs: it is elemental

Oogenesis in Drosophila requires a significant amount of phosphorus. Oocyte s mature in follicles, each of which contains 15 highly polyploid, transcri ptionally active chromosomes. We show that the demand for phosphorus is met in part from the male's ejaculate following mating Females incorporate pho sphorus-32 from radiolabelled males into their ovaries, specifically into t heir nucleic acids. Male-derived phosphorus is also present in significant amounts in mature oocytes. The mechanism by which phosphorus uptake from th e female reproductive tract occurs must differ front that previously report ed for radiolabelled carbon and hydrogen derived from ejaculatory proteins, as phosphorus uptake is observed in species not showing female incorporati on of radiolabel derived from ejaculate proteins.