Farnesoic Acid-stimulated Rates of Juvenile Hormone Biosynthesis during the Gonotrophic Cycle in Blattella Germanica

Juvenile hormone III biosynthesis in vitro by the corpora allata of adult female Bluttellu germanica is precisely correlated with the gonotrophic cycle. Farnesoic acid-stimulated rates of juvenile hormone synthesis are always higher than the corresponding basal rates, and follow the same pattern of cyclic changes during oijcyte maturation. Both basal and farnesoic acid-stimulated rates decline to undetectable levels while the female carries an o6theca and oticyte development is inhibited (‘pregnancy’). This suggests that, in this species, the main control mechanism of the corpora allata operates through structural/developmental processes, affecting the maxima1 biochemical capacity of the glands. Morphometric data re:lating gland volume and the main events during oocyte development and ‘pregnancy’ support this conclusion. We speculate that the type of corpora allata control which is predominant in different insects might be functionally related to their ovipositional behavior. Key Word Index: Juvenile hormone; in Gtro assay; Farnesoic acid; Corpora allata regulation; Ovarian cycle; Pregnancy; Blattella germanica