Question

Once silkworms produce cocoons, they are immediately transferred to boiling water. Why?

Answer 1

Hint: The silk is produced from the silkworm. Silk is the natural fibre that is obtained during the cocoon stage. The larva forms the cocoon during its life cycle which is the transition phase before the development of an adult moth.

Complete answer:
The rearing of silkworms is known as sericulture. During sericulture, several steps are followed so as to obtain silk from silkworms.

Let us discuss the life cycle of the silkworm.

The silkworm undergoes four stages- egg, larva, pupa and moth. The eggs are laid on the mulberry leaves. The larvae or caterpillars are hatched from the eggs of the silkworm. The caterpillar forms a protective covering around itself and forms a cocoon. This covering is made up of silk. After the metamorphosis is over, the moth breaks the cocoon and the adult moth comes out of it.

The cocoon is made up of a single long fibre of silk. In sericulture, once the cocoon stage is attained, the cocoons are put in hot boiling water. This is done so that the worms inside get killed and do not break the cocoon in order to come out. This helps in obtaining a single long thread of silk.

Note: The cocoons can also be sun-dried in order to kill the worms. After the worms are killed, the reeling of the thread takes place. Then the breaching and dying of the yarn take place. The silk fibres are strong, lustrous fibre which is used for making fabrics.