Genetic divergence in the kinetics of ovarian activity and brain control in virgin Drosophila melanogaster females

Abstract

In D. melanogaster genetic differences in egg retention of virgin females are associated with differences in egg-laying determined both by a divergence in ovulation pattern and a difference in egg production. In the short-retention phenotype, the rapid and substantial daily fecundity is supported by constant ovarian activity only slightly reduced in comparison to the mated flies' productivity. In contrast, in the long-retention phenotype, ovarian activity is characterized by a drastic arrest occurring 24 h after emergence. Vitellogenesis drops, massive egg retention and oöcyte resorptions occur and the emission of follicles by the germarium ceases for several days. Since the regulation of oögenesis depends on the brain and corpus cardiacum-corpus allatum, and since the onset of ovulation depends on a myotropic brain hormone, it is hypothesized that the genetic determinants of retention capacity exert control over the kinetics of brain activity.