Histology of the ovarioles and the role of nurse cells in corpus luteum formation in Philosamia cynthia ricini (Boisd.) (Saturniidae: Lepidoptera)

Summary

There are two ovaries, each comprising four polytrophic ovarioles and containing many chorionated eggs, some unchorionated eggs without nurse cells and few unchorionated eggs with nurse cells. Each ovariole has an anterior germarium and a posterior vitellarium. The vitellarium is connected to the lateral oviducts through a long pedicel. The pedicel and the basal plug are observed in the pupal ovary only. Histology of all these regions is described. The nurse cells in each follicle are exhausted before the onset of chorionation of the egg. The role of nurse cells in the corpus luteum formation is discussed.