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The Silk Larvae Growth Process (Silkworm) and Life Cycle
By Galit Zamler

The silk larvae growth process

The "Kids initiate" page describes a venture of a boy who raised silk larvae and sold them near kindergartens to parents who were interested in showing their children the larva wheel of life.

In light of this great interest in raising silkworms, especially in the spring, we described here the development process stages of the silkworm.

It should be noted that the term silk caterpillar was done here because it was the most common form of Google search, but the name is silkworm, and the larval form is only one stage of their life cycle.

Larval Silk Eggs

Usually, the children are familiar with the silkworms when they are already at the larvae stage, but before that, silkworm eggs were actually gray, like in this photo.

We kept the larvae eggs in the refrigerator for a whole year and took them out in the spring. This is the season when the mulberry trees are blooming.

Eggs of silkworms

Eggs of silkworms.

Mulberry Tree

You can also get to the stage where you will have silk caterpillar eggs as long as you implement all the steps with us.

Immediately after the Passover, in the spring season, we will look for a mulberry tree, from which we will pick leaves. These leaves are the only food of the silkworms.

Why after Passover? Because in Israel, Passover is celebrated in the spring, and just before Passover, mulberry trees begin to bloom and to feed the larvae, we need many leaves to meet the larva's feeding needs.

In this picture, we see the beginning of the flourishing of mulberry trees. The photo was taken before Passover.

Mulberry tree

This is a mulberry tree. You can see the strawberries.


Sometimes you can see the strawberries fell from the tree on the ground, and then you can know that a mulberry tree is growing there.

But do not bother looking for silkworms on mulberry trees, because they do not survive in the wild.

Berries on the ground

Once we see the strawberries, we'll pick leaves from the mulberry tree.

Pick leaves from the mulberry tree

We will put a mulberry leaf in a shoebox, and on top of the leaf, we will put the larvae eggs.

A mulberry leaf in a shoe box

Larvae eggs inside a shoebox.

The Larvae Hatch

After about ten days, larvae of two-millimeters length will hatch from the eggs. Please note that the worms are so small that you may not notice them. That is why we recommend that you place fresh leaves around the eggs so that if we fail to see the hatching larvae, they still would have food.

As they hatch from the eggs, the larvae will begin to eat and grow quickly. So we have to keep replacing the leaves and make sure to supply fresh food.

To avoid harm to the larvae mounted with fresh leaves, every time we add new leaves to the existing ones, we will not remove the dry leaves. The larvae will notice the fresh leaves and will move to eat them, and only after they moved, we can take out the dry leaves.

Over time, as the larvae grow, we can lift them by hand and put them on the fresh leaves and then remove the dry ones.

For the larvae to reproduce, they are divided into two genders: male and female. But during their time of being larvae, it isn't very easy for us to distinguish between them. Therefore, those interested in seeing the entire life cycle of silkworms should have more than two caterpillars to increase the probability of the existence of both genders.

mature larvae silk

Mature larvae silk.

The Larvae Become a Cocoon

Be prepared that silkworms eat a lot, so make sure so be sure to stock up on strawberry leaves. To keep the leaves fresh, you can store them in a bag in the refrigerator.

When the caterpillars grow enough, you will notice that they are looking for a place to build their cocoon, which will serve as a convenient place to turn from a caterpillar into a chrysalis.

Most of the larva's body weight is liquid silk, which it secretes with two glands that are on both sides of his body. Once the caterpillar secretes liquid silk, it creates a long continuous fiber around itself.

Once the caterpillar begins building its cocoon, it is recommended that you don't touch the yarns so as not to interfere with this natural process.

In the following photo, a caterpillar that has begun to spin the expropriation process, and a single cocoon is ready.

The larvae spins a cocoon

The larva spins a cocoon

Cocoon Becomes a Butterfly

Until the last of the larvae spin the cocoon, we will continue to provide mulberry leaves.

We cannot see the process that is going on within the cocoon, but for two or three weeks, the larva's body undergoes changes during which it becomes a pupa, and in the end, it becomes a white butterfly.

Even though the cocoon is made from a powerful silk thread, the butterfly secretes a yellowish liquid. It melts the silk threads and creates a hole in the cocoon, from which the butterfly emerges into the world.

Now we can just look and enjoy - no need to worry about food for butterflies. The silkworm butterflies are unable to eat; they live thanks to the pool of food they had accumulated when they were caterpillars.

Butterfly hatched loom

Butterfly hatched chrysalis

The Butterflies Mate

The female silkworm butterfly knows how to attract the male. She actually tells him she is ready to mate by the emission of a substance called Bombykol, which the males "smell."

The olfactory organs of the butterfly are located in their antennae.

This stage is accompanied by a lot of waving wings, even though silkworm butterflies are unable to fly.

butterflies mating

Butterflies are mating

For the next step, we should take another shoebox and put white pages inside it. At this stage, the females would lay eggs on the white pages.

One female butterfly lays between 300 to 500 eggs.

Initially, the eggs will be white, but after a few days, they will turn to gray. The gray color indicates that the egg is fertilized, and a larva can hatch from it: meaning, another cycle of egg - caterpillar - cocoon - butterfly.

They lay eggs with a sticky substance, so they remain attached to the paper. Then we can get the pages, cut out the areas where there is a concentration of eggs, and keep them in a small plastic box in the fridge for next year.

Keeping larval silk eggs

Placing the pieces of paper with the eggs in a small plastic box

Does that Interest You?

Those interested, can learn more about silkworms on Wikipedia, and watch this video showing the life cycle of the silk larvae.

Read About the Project Growing and Selling Silk Larvae

Children interested in turning silk caterpillars into a venture are invited to learn from a child who operated such a project of growing and selling silkworms.

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