Electron Microscopic Studies on the Oogenesis of Dragonfly and Cricket With Special Reference to the Panoistic Ovaries

Abstract

The successive ultrastructural changes during oogenesis in Sympetrum frequens (Odonata, Libellulidae) and Gryllus yemma (Orthoptera, Gryllidae) were studied.The structures of the terminal filament and boundary between the terminal filament and the germarium differed from each other in these 2 species; in Sympetrum the boundary between the terminal filament and the germarium was a special acellular transverse septum, whereas that in Gryllus was composed of several flattened cells which seemed to be similar to the prefollicular cells in the germarium.During the previtellogenesis, the nucleolar extrusions and emissions of the outer nuclear envelope were observed frequently in young oocytes. In Sympetrum, electron dense masses were observed in the oocyte cytoplasm, which seemed to be "yolk nuclei" or "Balbiani bodies" and were composed of aggregated small particles (about 200 A in diameter). They were gradually dispersed in the cytoplasm until the onset of vitellogenesis.In both Sympetrum and Gryllus, yolk precursors seemed to be incorporated into oocytes by micropinocytosis as observed in various animals.The egg membranes, viz., the vitelline membrane and the chorion, seemed to be formed by secretion products from follicle cells which developed rough-surfaced endoplasmic reticulum and Golgi bodies. Thus, both of these egg membranes were assumed to be the secondary egg membranes.The ovaries of Thysanura, Ephemeroptera, Odonata, Orthoptera, Isoptera and Plccoptera are composed of panoistic ovarioles having no specialized nurse cells. Therefore, these ovaries may be more suited than ovaries with nurse cells for studying the process of oogenesis.Since MCGILL'S histological study on the ovaries of Odonata in 1906,a considerable amount of works has been undertaken on the oogenesis of various insects. In the past decade electron microscopic and autoradiographic studies were carried out on insect oogenesis by KING ( 1 9 6 4 ) , KING and AGGARWAL (1965), KING and DEVINE ( 1 958), KING and KOCH (1 963), K I N G , AGGARWAL and AGGARWAL ( I 968), OKADA and WADDINGTOI~ (1 9 5 9 ) , BIER (1 963), RAMAMURTY (1964) and others, and many important findings have been obtained. 379

Oogenesis inKalotermes flavicollis(Fabr.) (Isoptera: Kalotermitidae). II‐prefollicular and follicular cell ultrastructure during oogenesis in female supplementary reproductives

“…The ultrastructural observations reported here on prefollicular and follicular cells are in agreement with those described for other insect species with the same kind of ovary (Anderson, 1964(Anderson, , 1969Beams & Kessel, 1969;de Loof & Lagasse, 1970;Matsuzaki, 1971;Kessel & Ganion, 1979;Matsuzaki et al, 1979;Wüest, • 1979;Mazzini & Giorgi, 1984;Matsuzaki et al, 1985).…”

Oogenesis inKalotermes flavicollis(Fabr.) (Isoptera: Kalotermitidae). I. Differentiation and maturation of oocytes in female supplementary reproductives

“…Moreover, annulate lamellae and oocyte Balbiani bodies are present (Fig. 18), as found in Libellula pulchella , Sympetrum frequens (Matsuzaki, 1971) and Protobermes grandis (Matsuzaki, 1985). This process of synthesis and storage of ribosomes is the first functional differentiation related to the building-up of the egg.…”

Electron microscopic studies on the follicle epithelial cell—oocyte cortex interface inArrhenothrips ramakrishnae Hood (Insecta: Thysanoptera)

“…Such a stratification is very typical of A. ramakrishnae oocyte and follows the appearance in the cortical cytoplasm of the oocyte of small pinocytic vesicles filled with electron dense material immediately below the oocyte. As discussed by Matsuzaki (1971) for panoistic ovaries of dragonfly and cricket, these tiny vesicles or spheres in the peripheral cytoplasm of the oocyte tend to coalesce with each other resulting in larger spheres of protein yolk, which make their way or migrate to the central region of the oocyte.…”