Changes in Number and Size of Corpus Allatum Cells of Blattella germanica during Oocyte Maturation

Abstract

The corpus allatum (CA) of the female German cockroach shows cyclic changes in both size and juvenile hormone III (JH III) biosynthesis during the gonotrophic cycle (Gadot et al., 1989). The increase in CA volume during oocyte maturation has been considered mainly due to increases in both cell number and cell size (Cassier, 1979; Tobe and Stay, 1985). To date, the number of nuclei in the CA has been estimated from sections of fixed thickness in fixed organs (Scharrer and von Harnack, 1958; Szibbo and Tobe, 1981; Tobe et al., 1984). Since nuclear size and shape vary with different developmental stages of the CA during the gonotrophic cycle in Diploptera punctata (Johnson et al., 1985) and other insects (Cassier, 1979), nuclear counts from sections may under- or over-estimate the total number of cells. The size of CA cells is usually presented as the nucleocytoplasmic ratio in fixed glands (Engelmann, 1957). We report on changes in number and size of CA cells of Blattella germanica during oocyte maturation by direct measurements of enzymatically dissociated cells.