Shiny silk dresses have always been a favorite of everyone. We often remember weavers weaving clothes. But there is a species that we kill to make beautiful silk. Few people know about such a group. Get acquainted with present-day techniques that came from silkworms and the yarn they produce.

Sericulture is the name given to the process by which silkworms are raised to produce the raw material needed for silk. The history of silk starts from the agricultural sector. Behind a silk cloth are various processes such as mulberry cultivation, silkworm seed production, silkworm rearing, separation, spinning, and weaving. India is the only country that produces silk from the four varieties of mulberry, tusser, eri and muga, which are of commercial importance to natural silk.

The history of silk dates back to China. History shows that silk was produced in China from 4,000 BC. However, the popularity of silk in various parts of the world increased during the Christian era. The use of silk in Japan began in the 3rd century AD. It dates back to the 4th century in India. During this period sericulture also became industrialized in the Arab world. Later, the growth of silk was very rapid and European countries also turned to it. In the 16th century, France gained a clear dominance in the silk market. But many countries have not been able to thrive in this area. It is safe to say that silk was able to pave the way for an industrial boom. During this period, the popularity of silk declined with the introduction of cotton instead of silk. The decline in the popularity of silk was due to the fact that it was possible to make cotton garments at low cost and with minimal labor. In addition, the death of silkworms in France due to a deadly disease seriously affected its silk production. Later, France was unable to recapture the old charm. Today, China is the world's largest silk producer.

Apart from silk, the worms give some byproducts too. Although worms are mainly raised for silk, they are also used for other purposes. Silk is used in electrical materials as insulators, tire linings, artificial blood vessels, and surgical threads. Amino acids and vitamin B2 (riboflavin) are extracted from silkworm pupae. Food waste and manure from these can be used to make vermicompost and biogas. Disposable cocoons are also used to make handicrafts.

Silk is a thread-like protein that silkworms release to make cocoons during their burial season. The purpose of this thread is to provide a safe shield for the extremely soft body during pupal stage. The special fluid released by the worm turns into a long firm thread on contact with air.

Silk contains two proteins, fibroin and sericin. Fibroin is an important protein that strengthens silk. Sericin is a protein that coats the fibrous part of the body like glue. The yarn obtained from a cocoon can be 350 to 1800 meters long. Yarn made from cocoon is used for industrial silk. The yarn is separated from the cocoon after the pupa is killed.

The different species of silkworm include Mulberry Silkworm, Eri Silkworm, Tasar Silkworm, and Muga Silkworm. The scientific name of Mulberry Silkworm is Bombix Mori. The cocoon thread is unbroken along its length. Therefore, 95% of the silk produced worldwide comes from the Bombix Mori variety. Univoltine includes mulberry silkworm varieties grown in cold countries. This breed is produced only one generation per year. Bivoltine includes mulberry silkworm varieties that produce two generations a year. Silkworm species of this genus are mainly cultivated in Japan, China and India. Multivoltine category includes mulberry silkworm varieties that produce more than three generations in a year. They are mostly grown in the southern states. It is also a highly immune species. The most popular silk in the world market is bivoltine. This category is the second largest breeding ground for mulberry silkworm in India. Eri Silkworm is a silkworm cultivar grown on a castor plant. Also known as castor silkworm. The yarn they produce is white or reddish brown. The yarns in the cocoon are made up of many strands of yarn. They can also be difficult to distinguish. Therefore, Erysipelas silk is extracted only after the cocoon has burst open. Assam is the main hub of Eri Silk in India.

The scientific name of Tasar Silkworm is Antarctica mileta. It is a bivolatine species. The leaves of the Thanni tree are fed to the Tusser worms in India. The cocoon is more resilient.

Muga Silkworm’s scientific name is Antarctica assamensis. They produce beautiful and firm gold colored yarns. Found only in Assam. Muga silk is the silk used by the noble family of Assam.

Life cycle of the silkworm (based on Bombix Mori) has four life stages.

Egg – Each female butterfly lays an average of 400 eggs. The eggs laid on the leaves of mulberry are oval in shape.

Larva – The larvae hatch in 9-12 days and turn black or dark brown. They have large heads and small bodies. Larval life is 25-30 days. To this day it eats well and grows very fast.

Pupa – During this quarter of the life cycle, the larvae stop feeding and begin to form a shell using a special secretion released from the body. The secretion from the silk gland is made up of a small organ called the spinneret which forms the worm shell. This sticky sap combines with the air in the atmosphere to form a firm silk. The shield they are made of is called a cocoon. Each worm prepares its burial place in 48 to 72 hours. The pupa stage lasts from 8 to 14 days (cocoons are collected for silk five days after the cocoon is made). At the end of the pupa stage, the butterfly hatches by splitting the cocoon with alkaline saliva.

Moth (Butterfly) - Butterflies that hatch from cocoons do not have the ability to fly. The ability to fly has been lost as a result of being cultivated for over 4000 years. In the moth stage they do not eat. They lay their eggs as soon as they reach the pupa stage and die within two to three days.

Silk Reeling is the process of removing the silk filament from the cocoon. This is an important process in silk-making industry. A silk yarn is made by pulling filaments out of more than eight cocoons. Five days after the larvae begin to enter the pupal stage, the collected cocoons are buried in hot water. The process of killing the pupa by soaking it in hot water at 95-97 C for 10-15 minutes is known as cooking. This makes the sericin protein in the cocoon filament softer. The filament can then be easily removed from the cocoon.