Silkworm Moth
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| Silkworm | ||||||||||||||
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| Missing image Silkworm.png Prometheus silkworm | ||||||||||||||
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| Bombyx mori Linnaeus, 1758 |
The silkworm (Bombyx mori, Latin: "silkworm of the mulberry tree") is the larva of a moth that is very important economically as the producer of silk. A silkworm's diet consists solely of mulberry leaves. It is native to northern China.
The silkworm is so called because it spins its cocoon from raw silk. The cocoon is made of a single continuous thread of raw silk from 300 to 900 meters (1000 to 3000 feet) long. The fibers are very fine and lustrous, about 1/2500th of an inch in diameter. About 2,000 to 3,000 cocoons are required to make a pound of silk. Based on 2/3 of mile (1 km) per cocoon, ten unraveled cocoons could theoretically extend vertically to the height of Mt Everest. It is estimated that at least 70 million pounds of raw silk are produced each year, requiring nearly 10 billion pounds of mulberry leaves. According to E. L. Palmer (Fieldbook Of Natural History, 1949), one pound of silk represents about 1,000 miles of filament. The annual world production represents 70 billion miles of silk filament, a distance well over 300 round trips to the sun!
Silkworms have a good appetite. They eat mulberry leaves day and night continuously. Thus, they grow very fast. When the color of their heads turn darker, it means that it is time for them to moult. After they moult about four times, their bodies turn slightly yellow and their skin becomes tighter, which means they are going to cover themselves with a silky cocoon. If the caterpillar is left to eat its way out of the cocoon naturally, the threads will be cut short and the silk will be useless, so silkworm cocoons are thrown into boiling water, which kills the silkworms and also makes the cocoons easier to unravel. The silkworm itself is often eaten.
The adult moth has been bred for silk production and cannot fly. It is also called the silkworm-moth or mulberry silkworm.They have a wingspan of 2 inches and a white hairy body. Because of its long history and economic importance, the silkworm genome has been the object of considerable modern study.
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History
In China, there is a legend that the discovery of the silkworm's silk was by an ancient empress called Xi Ling-Shi (Template:Zh-cp). She was walking around when she noticed the worms. She used her finger to touch it, and wonder of wonders, a strand of silk came out! As more came out and wrapped around her finger, she slowly felt a warm sensation. When the silk ran out, she saw a small cocoon. In an instant, she realized that this cocoon was the source of the silk. She taught this to the people and it became widespread. There are many more legends about the silkworm.
The Chinese jealously guarded their knowledge of silk. It is said that a Chinese princess smuggled eggs to Japan, hidden in her hair. The Japanese thus began their love affair with silk. It takes 2100 silk worms to make a single kimono.
Medical uses
Silkworm is the source of the traditional Chinese medicine "bombyx batryticatus" or "stiff silkworm" (Template:Zh-stp). It is the dried body of the 4–5th stage larva which has died of the white muscadine disease caused by the infection of the fungus Beauveria bassiana. Its uses are to dispel wind, dissolve phlegm and relieve spasm.
Cuisine
In Korea silkworm pupae, boiled and seasoned, are a popular snack food.
Genetic material
In September 1998, a scandal broke out in New Zealand, when the Green Party of Aotearoa New Zealand announced Crop and Food Research’s intention to try to make potatoes resistant to soft rot bacteria by introducing DNA from toads via an existing soil bacterium (RSNZ News, 12 Nov. 1998, [1] (http://www.rsnz.org/news)). Approval for trials was given by ERMA (Environmental Risk Management Authority) in late December, 1998, and included an application for the use of DNA from silkworm to prevent damage to potatoes by tuber moths.
In March 1999, the research trial was destroyed by a group calling itself the Wild Greens, a wing of the Green Party.