Silk is made from the cocoon of moth known as Bombyx mori. It has the complete metamorphosis that is egg changes to larva and pupa and to adult. Our ancestries have harvested this moth long time before. Due to the excessive domestication of this moth by the human, it has lost the capacity to fly.
Silkworm is the moth native to Asia. Due to high economic significance people have been using them to produce silk from around five thousand year ago. The knowledge for manufacturing silk was kept secret in China. Anyone trying to leak the information about the manufacturing process of silkworm used to be terminated. Due to the high secrete nature knowledge on how to produce silk was not available in past. It was only in 550 AD the knowledge of the manufacture of the silk and silkworm spread around the globe by spy Christian monks.
Silkworms are feed on the mulberry trees leaves. The precise timing is required in order to get high quality of silk. Lack of precise timing can impact the quality of the silk.
Eggs are hatched after 14 days and larva emerges out. The larva feeds on the mulberry tree voraciously and molt rapidly. After molting for four times the time for pupa stage arises. It starts to manufacture raw silk from the salivary glands. Submerging in the hot water kills the pupa in the cocoon. It is essential to kill the pupa because if the adult emerges from the cocoon the Proteolytic enzyme used for manufacturing the hole makes the extraction of silk difficult.
A single cocoon has the thread with the length of 300 to 900meters. The Fine thread is manufactured manually to make the large thread in order to obtain fine silk.