Autonomous termination of diapause by ovaries from Drosophila melanogaster as determined by immunofluorescent localization of adaptin and the yolk protein receptor.

Suzanne Schelble* and David S. Richard, Department of Biology, Susquehanna University, Selinsgrove, PA 17870-1164. To be presented to the Pennsylvania Academy of Science meeting in April, 1999.

Female Drosophila melanogaster undergo photoperiodic ovarian diapause (when exposed to L12:D12 at 12oC) characterized by pre-vitellogenic arrest apparently associated with an endocrine block. During this diapause, ovarian ecdysteroid levels and corpus allatum juvenile hormone (JH) production are below the limits of detection of the assays used. Diapause termination (following transfer to 25oC), is associated with an increase in ecdysteroid, but not JH production prior to the onset of vitellogenesis. The warming of isolated ovaries in vitro did not result in visible ovarian development, either by changes in the Ovarian Maturity Index or in the immunofluorescent localization of either adaptin or yolk protein receptor (YPR). However, preliminary data suggest that exogenous 20-hydroxyecdysone may initiate adaptin and YPR production in isolated ovaries. Since the follicle cells of ovaries are a source of ecdysteroids, this suggests that the termination of ovarian diapause may be partially autonomous. (Supported in part by NIH GM/OD54905, to DSR).