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Life Cycle of a Silk Worm

life cycleLife cycle of the silk worm. Image copyright Ozgur Babacan 2015


Silk is a natural fibre which comes from the cocoons of silkworms, which are the larvae of the mulberry silk moth Bombyx mori.

bombyx mori charcoalBombyx Mori silk moth, drawn in charcoal by Ozgur Babacan. Copyright Ozgur Babacan 2015 Life Cycle of a Silkworm

- A female moth lays 300-500 tiny eggs and after around 10 days, the larvae (silkworms) hatch.

- The silkworms feed solely on large amounts of leaves from the mulberry tree for around 30-40 days.

- The silkworms shed their skin up to four times, or molt, as they continue to eat and grow.

- After their final molt, the silkworm builds a cocoon around itself. The cocoon is a protective casing spun from silk.

- Inside the cocoon, the silkworm changes into a pupa, the stage between larvae and adult moths.

- After around two weeks, the pupa emerges from the cocoon as an adult moth.

- The adult moth looks for a mate so that the female can lay more eggs and begin the cycle again.

- The thread from a mulberry cocoon when unwound can be 900 metres long
-  Over 50,000 cocoons are needed to make 1 kg of silk
- To feed 25 silkworms from egg to the cocoon stage you need a 10 foot mulberry tree or 2 small bushes to provide enough leaves.
-  A silkworm increases its size 10,000 times before it is ready to spin its cocoon. A small branch will most probably last a week and it takes 4 weeks for the silkworm to grow before it spins a cocoon. 

Activity: Draw a diagram showing the life cycle of the silkworm.