Maturation and Responsiveness to Extracts of Corpora Allata from Male Locusta migratoria containing Allatotropic Factors

Corpora allata (CA) from male Locusta migratoria were tested for their ability to synthesize juvenile hormone (JH) and to respond to stimulating brain/corpora cardiaca (CC) extracts under in vitro conditions. We found that a preincubation of the CA of both sexes at 4 °C for 24 h lowers their basal rate of synthesis and retains their responsiveness to allatotropic factors. Male CA can be stimulated by brain/CC extracts as well as female CA. JH biosynthesis stimulating factors are also present in male brain/CC extracts. Thus such extracts from male locusts can be used for the isolation of locust allatotropin. Furthermore male locust CA are appropriate for bioassaying such allatotropic factors.