Effect of plumbagin on gonadotrophic cycle of the housefly, Musca domestica L.

Topical treatment of the phytochemical plumbagin in doses ranging 0.005-5 micrograms prevented oocyte development and affected fecundity and fertility in M. domestica. The treatment to wandering larvae was less effective as the compound could only effect the fertility to a significant level whereas the fecundity was not significantly reduced. The effect of the compound was more pronounced in adult treatments where both fecundity and fertility reduced drastically. The compound also effected the oocyte maturation as it arrested the development of vitellogenic oocyte at stage six. As the juvenile hormone analogue methoprene and moulting hormone 20-hydroxyecdysone or the mixture of these hormones could not restore the development of the oocyte in ovaries of plumbagin treated flies, it is concluded that the compound does not effect the female houseflies through hormonal pathways, instead in all probability it acts like a cytotoxic compound.

Ultrastructural spermatid and sperm morphology in Poecilocerus pictus (Fab.) with a reference to spermeiophagic cells in the testis and sperm duct.

Electron microscopical studies were carried out on spermatid and sperm structure in P. pictus. The spermatid nuclear envelope possesses pores and is surrounded by microtubules which disappear on metamorphosis to sperm though centriolar adjunct, and its corresponding centriole comprising the basal body for flagellum. remains persistent in both. The mitochondria are arranged as two fused bodies with prominent cristae flanking the central axoneme and also contain curved end feet. In axoneme the microtubular complex is comprised of 9 + 9 (doublet) + 2 tubules + nine coarse fibres and also reveals nine radial links with electron-dense link heads. In P. pictus an alteration in temperature range, ambient for its rearing and generation of fertile spermatozoa, induces the production of sterile sperms which are characterized by multiple axonemes and mitochondrial bodies engirdled by a common plasma membrane. Presence of phagocytic cells is also an essential feature of its testis and vas deferens. These spermeiophagic cells engulf the neighbouring spermatozoa as evidenced by the fragments of axoneme, nuclei, and acrosomes in their cytoplasm.