Postembryonic growth of the antennal lobes and their identified glomeruli in the cockroach Blaberus craniifer burm. (Dictyoptera : Blaberidae): A morphometric study

Abstract

In the growing antenna and antennal lobe of the cockroach, Blaberus craniifer (Dictyoptera : Blaberidae), the sizes of the various components, when expressed as a function of developmental stage, follow biphasic exponential kinetics. From first to last nymphal stage, the growth rates are constant. They vary widely with components. In the preimaginal phase, between the last nymphal and adult stages, these rates are generally not maintained, with the exception of deutocerebral cell bodies and some glomeruli. The rate of growth of the antenna decreases, whereas it increases for most glomeruli and antennal lobe. The growth rate of each identified glomerulus is characterized by a specific constant. The growth rate of glomerulus 106, the adult male macroglomerulus, is the same in male and female nymphs. During the preimaginal phase, however, it slightly decreases in the female and greatly increases in the male, resulting in adult dimorphism. The distribution of growth rates in the glomerular population is Gaussian. The slowest and most rapidly growing glomeruli are gathered into 3 spatially separate groups. Only one of them (the group comprising the macroglomerulus), includes both rapid and slow growing glomeruli. Glomerular growth in volume paralles growth of the antenna, allowing estimates of the number of antennal neurons per glomerulus to be determined.