How Does The Silkworm Make Silk?

The silkworm is the caterpillar or larva form of the silk moth. The larva develops from eggs and then it feeds voraciously on mulberry leaves. When it is full grown, the larva stops feeding and starts spinning a cocoon. The silk fluid is produced from special silk glands which are modified salivary glands. While spinning a cocoon, the worm swings its head from side to side in a series of movements resembling the Arabic numeral eight. The silk fluid on coming into contact with air hardens to form the silk thread. At the same time, a gum like substance, this is known as sericin is produced from it, which cements the threads of silk together.

There is no particular name given to this process but the job of rearing silkworms to obtain silk is called sericulture.

The silkworm spins a cocoon after about 1 year. The cocoons are picked and boiled in which the silkworm dies. Then the strand is unraveled and it can be up to 1600m long. It is then reeled and woven. The woven piece of silk is then sold.

The silk worm which hatches from eggs is known as caterpillar. It is a tiny creature, about 6mm long and move about in a looping manner.

The caterpillar stops feeding and returns to corner among the leaves. It now begin to secrete the sticky fluid of its salivary glands through a narrow pore, called spinneret, situated on the hypophyarynx.The sticky substance turns into a fine , long and solid thread of silk into the air. The silk thread is made of 5 filaments stuck together by gummy substance, the secin, which is secreted by two other glands. The thread becomes wrapped around the body of the caterpillar forming a pupal covering or known as cocoon. This process goes on for about 3-4 days at the end of yellow silken cocoon.

Stiffing:
For obtaining the commercial silk, the cocoons are treated with hot water or placed in a hot oven to kill the pupae inside; for, if allowed to hatch, they would cut the silk threads while emerging. This process of killing cocoons is called stiffing.

Reeling:
The removal of silk thread from cocoons is termed reeling. The silk unwound or reeled off from the cocoons is twisted into thread of commercial silk on a large wheel and transfer to spools. This is called raw silk or reeled silk. The damaged cocoons and waste threads are also teased and spun into threads called spun silk.

Silkworms, offspring of moths, produce their highly-desirable, pricey silk, by spewing out thread from tiny holes in their jaws, which they use to spin into their egg-bearing cocoons. This entire production takes a mere 72 hours, during which time they produce between 500-1200 silken threads. These miniature, mulberry leaf-munching marvels lay, at minimum, 500 eggs each spring, thereby increasing the number of workers for the production line.

The ancient Chinese unearthed the silkworm's secret, and were the first to spin the silkworm's threads into cloth. They kept this covert, top-secret operation, from the rest of the world by imposing the death sentence upon those who smuggled the worm and/or its eggs out of China. Eventually, however, the secret was out, and silkworms are now farmed for their silk, in China, of course, in Japan, in India, in France, in Spain, and in Italy. These countries harness the power of the silkworm through a tedious, labour-intensive, time-consuming process, a process which prominently figures into the price of silk.

Farm workers painstakingly place the 500 plus eggs the prized greyish-white moth lays, upon strips of paper or cloth (not made of silk!), until the following spring, when the incubated eggs hatch, and the tiny, black worms emerge. Once hatched, workers transport the worms to trays brimming with the worm's favorite fodder of finely chopped, white mulberry leaves. After approximately 6 weeks, the satiated worms begin slowly to sway their heads back and forth to signal that show time is at hand.

Once the silkworm completes its cocoon, the farmer snatches his cocoon from him, to prevent the shrunken chrysalis, carefully encased inside, from hatching into a moth in 12 days. The silk farmers ensure that this event does not transpire, and does not kill his moneymaking venture, by exposing the cocoons to heat, thereby executing the chrysalis. Now, the silkworm's labour of love is prepared for the silk production process.

The process begins by bathing the now-empty cocoons in troughs of warm water, which serves to soften the gum binding the silken filaments together. He now proceeds with the arduous task of unravelling several cocoons, and winding the filaments onto a reel that twists 10-12 filaments together into a "single" thread of silk. The end product is a skein of raw silk, which the farmer profits from by selling to the highest bidder.

Cloth and clothing manufacturers, use the trade terminology, in labelling their product, as being either 2 or 3 threaded, depending upon the number of threads woven into the cloth.