The number of generations per year or season depends on the voltinism of the silkworm strain and variables including temperature. Voltinism is when some members of a species enter a hibernation-like period of diapause, while others do not. Under natural conditions, silkworm strains producing one generation per year are univoltine.

After removal from cold storage, ova in diapause begin final development until hatching, about two weeks later. About six to eight weeks after the start of ova incubation, one generation of Bombyx mori is complete.

The egg of Bombyx mori is a very small and hard structure; about the size of a pin head and resembling a poppy seed. The egg shell provides a protective covering for embryonic development. When first laid, an egg is light yellow. Fertile ova darkens to a blue-gray within a few days.

The larva is the vegetative stage where growth takes place. The larva of Bombyx mori, commonly called a silkworm, is host specific to mulberry. During growth, the larva will molt 4 times. The period between successive molts is called an instar.

The silk cocoon serves as protection for the pupa. Cocoons are shades of white, cream and yellow depending on silkworm genetics. After a final molt inside the cocoon, the larva develops into the brown, chitin covered structure called the pupa. Metamorphic changes of the pupa result in an emerging moth.

The adult stage completes the life cycle of Bombyx mori. It is the reproductive stage where adults mate and females lay eggs. Moths are flightless and lack functional mouth parts, so are unable to consume nutrition.