give reason ...pupa is killed after 8 days of cocoon formation..
Answers
Stage 1: Egg
An egg is the first stage of the life cycle of the silkworm. The egg is laid by a female moth which is mostly the size of small dots. A female moth lays more than 350 eggs at a time. In the springtime, the eggs hatch due to the warmth in the air. This procedure happens once in every year.
Stage 2: Silkworm
A hairy silkworm arises after the eggs crack. In this stage of silkworms, the growth happens. they feed on mulberry leaves and consume a large amount of these leaves for around 30 days before going to the next stage.
Stage 3: Cocoon
In this stage, silkworms spin a protective cocoon around itself. It is the size of a small cotton ball and is made of a single thread of silk.
Stage 4: Pupa
The pupa stage is a motionless stage. In this stage, people kill the pupa by plunging the cocoon into boiling water and unwind the silk thread.
Stage 5: Moth
In this stage, the pupa changes into an adult moth. The female moth lays eggs after mating and thus the life cycle of silkworm begins again.
Processing of silk
Extracting silk from the cocoon is known as the processing of silk. Silk is separated from the cocoon by exposing it to sunlight. After the reeling of silk is done, the process of unwinding silk from a cocoon takes place. Silk thread is then bleached. The silk fibre is then spun into silk threads.