Ecdysteroid release by the prothoracic gland of Gryllus bimaculatus (Ensifera: Gryllidae) during larval-adult development

The in vitro secretion of ecdysteroids from the prothoracic glands of larvae of Gryllus bimaculatus was analysed by HPLC-RIA. The primary product was identified as 3-dehydroecdysone (65-93%), with lesser amounts of ecdysone (7-35%). Production and release of ecdysteroids from the prothoracic glands are calcium-dependent. The rate of ecdysteroid release was low during the beginning and the end of the last two larval stages and high in between. Prothoracic glands from young adult females produced only minor amounts of ecdysteroids and ceased hormone production around day 4 after the moult.