THE OVARY IS A SOURCE OF CIRCULATING ECDYSTEROIDS IN BLATTELLA-GERMANICA (DICTYOPTERA, BLATTELLIDAE)

The developmental fluctuations in immunoreactive ecdysteroids in the h aemolymph of adult female Blattella germanica (L.) are reported. There is a relatively low titre in freshly ecdysed females, an increase dur ing vitellogenesis to a peak at choriogenesis, and a decrease after ov ulation. These fluctuations parallel those of ecdysteroid content in t he ovary. In addition, haemolymph ecdysteroid levels are reduced follo wing ovariectomy, and single ovarioles incubated in vitro effectively release ecdysteroids into the medium. The data strongly suggest that t he ovaries are a major source of circulating ecdysteroids in adult fem ales of this species. Since the prothoracic gland degenerates shortly after the imaginal moult, the presence of ecdysteroids in the haemolym ph of ovariectomized females suggests that there are other tissues tha t also serve as a source of these circulating hormones during the repr oductive cycle of B. germanica.