An Insight in the Reproductive Biology of Therophilus javanus (Hymenoptera, Braconidae, and Agathidinae), a Potential Biological Control Agent against the Legume Pod Borer (Lepidoptera, Crambidae)

Figure 4

Oogenesis and ovarioles organization in Therophilus javanus. (a) View of the anterior region of T. javanus ovariole (germarium), indicating cell nuclei that increase in size along the germarium. Bar 20 µm. (b) Individual follicle taken out from a T. javanus ovariole. The picture shows the disposition of the nurse cells (Nc) at the top of the oocyte (Oo). The nuclei of follicular cells (Fc) from the sheath surrounding the follicle can also be observed. Bar 50 µm. (c) Basal part of the ovariole of T. javanus. Follicles are in increasing development stages along the vitellarium (from A to B). On the left of the picture, follicles display small oocytes and trophocytes with a large nucleus. On the right, oocytes have increased in size thanks to progression of vitellogenesis. Note the network of actin fibers (in green) surrounding the egg chamber. Nurse cells (Nc); oocyte (Oo). Bar 50 µm. (d) Organization of the ovarioles and follicles within T. javanus ovaries: cross-sections of an ovary containing 15 ovarioles. The ovary is enveloped by the ovarian epithelial sheath (Ov sht) and each ovariole is surrounded by an epithelial sheath (Ovl sht). In the section, oocytes are in different stages within and between ovarioles. Some eggs with a chorion can be observed (shown by arrows). Semithin section stained with methylene blue. Bar 50 µm. (e) The mature egg of T. javanus. The egg has an ovoid shape and a slender tapering stalk at its posterior end. Bar 50 µm.

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