Control of the Corpora Allata During a Reproductive Cycle in a Viviparous Cockroach

Abstract

SYNOPSIS. This paper describes factors which regulate the corpora allata (CA) during the reproductive cycle in the viviparous cockroach Diploptera punctata . Experiments, designed to alter the rate of juvenile hormone (JH) synthesis by the CA, are performed on whole animals and their effects are demonstrated by an in vitro radiochemical assay for JH synthesis by the CA. The CA is both inhibited and stimulated. Axonal pathways from the brain to the CA are required for inhibition of the CA in virgin females but not in young pregnant females. Humorally transmitted inhibition of the CA is caused in vivo by JH (in high titers) and ecdysteroid hormone. JH in low titers also stimulates the CA. Since these hormones do not affect the CA in vitro we suggest that they exert their effect via the central nervous system. The ovary, a possible source of ecdysteroids in the hemolymph, is necessary both for maintenance of JH synthesis and for inhibition in the rate of JH synthesis at the end of egg growth.