Blastoderm Formation

In most insects, the early syncytial cleavages proceed rapidly to form a syncytium with up 6000 nuclei. Syncytial nuclei are surrounded by islands of cytoplasm that separate the nuclei from one another. In general, these early cleavages are synchronized and, as the nuclei divide, they separate, such that there is regular spacing between them. Nuclei and associated cytoplasm are referred to as energids. Upon reaching a critical density, the energids migrate to the periphery of the egg. The arrival of the energids at the surface is sometimes visually apparent as bumps along the surface. At the periphery, the energids continue to undergo several rounds of division. In most insects, some of the nuclei remain in the yolk mass. These nuclei subsequently cellularize and become vitellophages, which serve to break down yolk to be used for embryo nutrition. Following the arrival of energids at the egg periphery, the egg membrane invaginates from the egg surface to surround each of the individual syncytial nuclei, marking the end of the syncytial stage of development. The single sheet of cells thus formed at the periphery of the egg is the cellular blastoderm (Fig. 1).

Bee Keeping

Bee Keeping

Make money with honey How to be a Beekeeper. Beekeeping can be a fascinating hobby or you can turn it into a lucrative business. The choice is yours. You need to know some basics to help you get started. The equipment needed to be a beekeeper. Where can you find the equipment you need? The best location for the hives. You can't just put bees in any spot. What needs to be considered when picking the location for your bees?

Get My Free Ebook

Post a comment