Morphometric analysis of corpus allatum cells in adult females of three cockroach species.

The number of cells and their sizes in the corpus allatum (CA) of adult female Blattella germanica, Supella longipalpa and Diploptera punctata were determined during oocyte maturation. Cell number and size were directly measured in cell suspensions following enzymatic dissociation of freshly excised CA. Cell numbers were verified by total cell counts in whole-mount CA monolayers and by hemocytometric sampling. In all three species, cell number did not change during the period of CA activation, averaging ca. 2000 cells per gland in B. germanica, 3500 cells per gland in S. longipalpa and 11,000 cells per gland in D. punctata. Cell diameter increased significantly in all three species during this period from a mean value of 8.9 microns to 11.7 microns in B. germanica, from 9.2 microns to 14.6 microns in S. longipalpa and from 10.0 microns to 15.6 microns in D. punctata. During a 4 h incubation period, dissociated CA cells incorporated L-[methyl-3H]-methionine into juvenile hormone-III at rates comparable to intact glands. These data suggest that CA activation in the first ovarian cycle of these species is associated mainly with an increase in cell size with minor changes in cell number.