The histology and histochemistry of development and resorption in the terminal oocytes of the desert locust, Schistocerca gregaria

Abstract

During vitellogenesis the follicular cells play an active part in the synthesis of yolk. The term ‘corpus luteum’ as applied to the ovary of the locust is invalid and two terms ‘white’ and ‘yellow’ follicle have been introduced to describe the separate identities of the normal and pathological postovulatory follicle. The protein yolk is a proteincarbohydrate compound, presumably a glycoprotein. Three kinds of lipid bodies are present; the first is a phospholipid, the second a combined phospholipid and triglyceride, and the third triglyceride. Lipids are coloured by dissolved β-carotene. Concentration or absorption of the lipids causes the crystallization of carotene and the formation of the pigment body. During resorption the follicular cells act as lecitholytic cells, first breaking down the protein and then the lipid yolk, and finally degenerating themselves. It is suggested that the oocytes have an inherent potential for resorption, the realization of which depends on various factors within the body.