OOCYTE GROWTH, FOLLICLE CELL-DIFFERENTIATION AND VITELLIN PROCESSING IN THE STICK INSECT, CARAUSIUS-MOROSUS BR (PHASMATODEA)

Ovarian growth in stick insects (Phasmatodea) was examined ultrastruct urally and cytochemically with a view to studying: (1) the kinetics of oocyte growth and the staging characteristics of ovarian follicles un dergoing vitellogenesis; (2) the endocytic capability of the growing o ocyte, including the post-endocytic fate of the vitellins sequestered by the oocyte during vitellogenesis; (3) the differentiation of the fo llicular epithelium in relation to the appearance of intercellular spa ces and the extracellular release of a follicle cell product. These st ructural observations were interpreted in relation to the nature and k inetics of the vitellin processing in follicles undergoing vitellogene sis.