Silkworms, Not Spiders, Are The Source of Silk Fabric

By Chris Williams on December 10, 2015.

My sister says that silk fabric is woven from spider silk, mostly in China. She says that they raise spiders just for their silk which they then harvest by hand. That doesn’t sound right.

T. M., Boston, MA

Your sister is right about everything but the spider part. Silk is harvested from arthropods that produce silken threads, but it comes from silkworm caterpillars, not spiders. It is largely harvested by hand in China as part of a very labor-intensive process, called sericulture.

The Mulberry Silkworm Spins Tirelessly

Although there is production of synthetic silk these days, most silk fabric originates with the large larvae of the silkworm moth, Bombyx mori, that are reared by silk farmers and fed on mulberry leaves. After about 35 days of feeding, the silkworm caterpillar is fully grown and uses its silk glands to spin a cocoon in which to pupate. After 2-3 days of work, the silkworm has spun about a mile of silk thread to enclose its single pupal case!

The completed cocoon is boiled to dissolve the pupal case inside and silk workers painstakingly unwind the caterpillar’s work, twisting several thin strands together into threads of raw silk that are later used to produce silk fabric. China, India, and Thailand produce most of the world’s silk fabric which is still woven on hand looms.

Wikipedia says that it takes 5,000 silkworms to make one pure silk kimono. The extremely involved process of silk production has always seemed hard to believe. If I didn’t know for a fact that it was true, I would think someone was pulling my leg. After centuries of harvesting silk from caterpillars, the process is still done primarily by hand, no new technology. Next time you enjoy that silk blouse or the feel of silk sheets, think about what went into producing that fabric…and thank the silkworms!

Photo Credit : By P.gibellini (Own work) [CC0], via Wikimedia Commons



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