Regulation of competence for milk production inDiploptera punctata: interaction between mating, ovaries and the corpus allatum

Abstract

Summary The brood sac of the viviparous cockroach Diploptera punctata produces a protein-rich milk to nourish its young during gestation. Competence for milk production begins 7 days postoviposition and 5 days prior to the onset of milk synthesis. Brood sacs that have become competent and have not begun to produce milk can be identified by their ability to generate milk when implanted into the hemocoel of females that are actively synthesizing milk. Factors responsible for the development of competence were examined by various experimental treatments. Topical application of the juvenile hormone analog, 7S-hydroprene, to postoviposition females in doses sufficient to support a second vitellogenesis prevented competence; lesser doses permitted competence. Thus, elevated juvenile hormone titer during vitellogenesis (days 34) is sufficient to prevent competence at this time but the low titers that follow the onset of oviposition are not. Allatectomy of mated animals demonstrated dependence on the corpora alla...