Control of juvenile hormone biosynthesis during the reproductive cycle of a viviparous cockroach II. Effects of unilateral allatectomy, implantation of supernumerary corpora allata, and ovariectomy

Abstract

Using a direct radiochemical assay, the effects of implantation of supernumerary corpora allata (CA), unilateral allatectomy, and ovariectomy on rates of juvenile hormone (JH) biosynthesis by the CA and on the duration of the gonotrophic cycle have been investigated during the first gonotrophic cycle of the viviparous cockroach Diploptera punctata. Implantation of supernumerary CA decreased the duration of the gonotrophic cycle and had no effect on JH biosynthesis by denervated host CA or by implanted glands. Thus, there appears to be no evidence for a compensatory response reducing JH synthesis under these conditions of high JH titers. Unilateral allatectomy, however, resulted in compensation by the remaining CA: a single CA synthesized the same quantity of JH during the gonotrophic cycle as a pair of CA although maximum rates of synthesis were delayed by 1 day. Accordingly, the gonotrophic cycle is slightly longer in duration in unilaterally allatectomized animals. Ovariectomy either as nymphs or young adults depressed the rate of JH synthesis by the CA. A model for the regulation of JH biosynthesis by the corpora allata in cockroaches is proposed.