Sexual differentiation of nymphal corpora allata and the effects of ovariectomy on adult gland morphometrics in Blattella germanica.

Changes in the number of corpus allatum (CA) cells were investigated in nymphs and in intact and ovariectomized adult female Blattella germanica. The CA of intact adult females exhibit cyclic changes in volume in relation to juvenile hormone (JH) synthesis, while the CA of ovariectomized females become significantly hypertrophied as a result of a gradual and continuous increase in volume that is independent of JH biosynthesis. In both intact and ovariectomized females changes in JH synthesis and CA volume are not related to total cell number which remains relatively constant. However, adult females have twice as many CA cells as do adult males as a result of a female-specific increase in total cell number late in the last nymphal instar.