Male contributions to egg production: The role of accessory gland products and sperm in Drosophila melanogaster

Drosophila melanogaster seminal fluid components, accessory gland proteins (Acps) and sperm, induce females to deposit high numbers of fertilized eggs for about 11 days. This high and sustained level of egg deposition requires that oogenesis be stimulated to provide the necessary mature oocytes. To investigate the relative timing and contributions of Acps and sperm in the egg-production process, we examined the rates of oogenic progression and egg deposition in females mated to genetically altered males that have seminal fluid deficient in Acps and/or sperm, and subjected these data to path analysis. We found that Acps and sperm are complementary stimuli necessary for inducing high rates of oogenic progression and rapid egg deposition. While egg deposition and oogenic progression can be induced by Acps alone, both Acps and sperm arc required for maximum stimulation of oogenic progression and egg deposition immediately after mating.