Silkworm Life Cycle

Known for the silk thread they produce to form their cocoons, the silkworm is the larvae stage for the Bombyx mori moth. As an insect that undergoes complete metamorphosis, it has 4 stages of development.


The eggs are very tiny and are usually laid near the end of summer or early fall. They remain dormant until spring or when warmth stimulates a spring season environment. It takes the eggs about two weeks to hatch after they are activated.

If you want to store Silkworm eggs, be sure to put them in a fridge right away (don’t freeze them). Keep them near the warmer part of the refrigerator.

Larvae (Silkworm)

silkwormsNewly hatched silkworms are small (1/8 inch), hairy, and eat tender mulberry leaves. The hair gets shed when they go through their first of five growth stages called instars.

You can tell an silkworm is about cross an instar stage because it will hold its head up in the air. Its important to not touch or disturb the silk worm as its transitioning between instar stages. It will then shed its outer layer of skin. After each instar the silkworm is able to eat tougher mulberry leaves and will be bigger.

After 5 instar stages, the Silkworm will encase itself with a silk cocoon.

Pupa (Cocoon)

Silkworm cocoonSilkworm cocoons will be shades of white, cream, and yellow. They will have a glistening shine because of the silk they are made from.

After 2 weeks, the silkworm releases an enzyme from its head that dissolves the silk. It then emerges as an adult moth.

Adult (Moth)

Adult: Bombyx Mori mothSilkworm moths (Bombyx mori) do not eat or drink. They crawl around but do not fly. Females have a larger abdomen and are not very active. Males have much larger antennae and will vibrate its wings rapidly as it seeks a female.

After reproduction, the male moth dies. The female will lay eggs within 24 hours and die shortly thereafter.

Interesting Silkworm facts

Due to hundreds of years of domestication (providing abundant food and pampering them), Bombyx mori (silkworms) do not crawl away in the pupa stage and can’t fly in the adult stage.

Silk is harvested by killing the pupa (by heating or pricking with a needle) and then unwinding the thread of silk, which can be half a mile long.

The entire life cycle only takes a couple months.

The Bombyx mori silkworms were originally domesticated in China where the secret to producing silk was closely guarded for centuries but was leaked around 200 BC and eventually was also produced in India and Europe.

Silkworm pupae are a delicacy eaten in China.

Where you can buy Silkworm Supplies

Silkworm food

25 live silk worms

25 silk worm eggs

Silkworm life cycle model

Where you can learn more about Silkworms

Detailed life cycle

History and general information

Another step-by-step life cycle

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