Silk Production

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  • Topic: Silk, History of silk, Bombyx mori
  • Pages : 23 (8378 words )
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  • Published : December 11, 2012
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SILK

Silk is undisputedly the most beautiful of all natural fibers, with its unearthly sheen. It is also uncommonly strong, even at its finest, when it is almost invisible. It is unlike any other fiber used to make fabrics, for it is neither grown in a field or on an animal. It is not manufactured in a factory. A humble caterpillar about the size of a woman’s smallest finger produces the silk fiber, spinning it out of its mouth, using tiny fore-legs to place the silk where it should go. It is known scientifically as Bombyx mori, although other species of silkworm produce less famous types of silk

The process of making silk has not changed very much in the thousands of years since the silkworm’s thread was first used, in ancient China. Wooden trays may be exchanged for the more sanitary plastic ones. Powdered silkworm chow is available for those without access to fresh mulberry leaves, making it possible for more people to grow silkworms, and at times of year when the mulberry leaves are not around. Over the centuries, the silkworm moth has lost its ability to fly, but that has little bearing on its care or cultivation. It is still a hands-on process involving live creatures, and takes a lot of time. But the result is certainly worth all the work and will certainly give one a truer understanding of why silk has been so desirable and so expensive throughout history. The silkworm isn’t really a worm, it’s a caterpillar! The silkworm has been used by people for over 4,000 years to make silk. The practice first began in China in about 2600 BC. The Chinese kept the secret of producing silk for thousands of years, trading silk to Europe and the Middle East. But eventually the secret of how to get silk from the silkworm was learned by other countries. More recently we have learned how to make silk-like material from synthetic materials, but the demand for real silk is still high, and silkworms are still raised for the silk threads they produce.

SERICULTURE

The practice of raising silkworms is called sericulture.

The silkworm, when fully grown, reaches a length of about 5 to 7 centimetres, and it’s an amazing worker. In only a few days, a single silkworm spins a cocoon from which can be removed a silk thread up to 600 meters in length. But it still takes about 25,000 cocoons to make half a kilogram of raw silk. Most of the silk today is produced by China and India, and a few other countries. 60,000 tonnes of raw silk are made each year, and are turned into dresses, shirts, bed sheets, curtains, and other products. It’s a big industry, especially in China, where ten million Chinese farmers grow silkworms, and another half million make silk fabrics. There are 600 silk weaving mills in China. 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. A silkworm moth is yellowish-white, with a thick, hairy body, and a wingspread of about 4 cm. The adults live only a short time… long enough for the female to lay her eggs. The larvae, which hatch in about ten days, are about half a centimetre long. Larvae in captivity are fed their favourite food, the leaves of the white mulberry plant, so they will produce the finest quality silk. Full-grown larvae are up to 7 cm long, and yellowish-gravy in color.

After about six weeks of continuous eating, the larvae climb to the top of a branch and spin their cocoon. It takes about six days, and to do it they produce one continuous long silk thread. They will emerge from their cocoon after several weeks of pupating, as adult moths. But on silkworm farms, only enough adult moths are allowed to emerge to...
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