Sex Peptide may regulate vitellogenesis in Drosophila melanogaster.

Michael Pfeiffer *, Michelle Patrick and David S. Richard, Department of Biology, Susquehanna University, Selinsgrove, PA 17870-1164.

Juvenile hormones (JHs) stimulate early yolk protein (YP) synthesis and trafficking by ovarian follicle cells in Drosophila melanogaster and ecdysteroids stimulate late YP synthesis by fat body and uptake by the oocyte. Sex peptide (SP), a 36-amino acid hormone produced by males and transferred during mating, was injected into diapausing females since YPs are known to be present in diapausing hemolymph and SP is proposed to be responsible for stimulating ovarian YP uptake directly. Preliminary data suggest that the effect of injection of 5pmol SP/female may be quite subtle; no significant changes in the development of ovaries following injection were noted. Nevertheless, some accumulation of YPs may be seen by immunofluorescence in the diapausing egg chambers. Similar experiments with the non-vitellogenic mutant apterous4 stock may provide further evidence as to the roles of SP, JHs and ecdysteroids in the regulation of egg development. (Supported in part by NIH GM/OD54905, to DSR).