|Paired male (above) and female (below)|
|Fifth instar silkworm larvae|
The silkworm (Bombyx mori) is the larva or caterpillar of a moth. Silk has been made for at least 5000 years in China. The moth is important because it makes the silk, and no longer lives in the wild. It is entirely dependent on humans. Silkworms eat mulberry leaves, and were native to northern China.
The domesticated B. mori and the wild Bombyx mandarina can still breed and sometimes produce hybrids.:342
Growth[change | change source]
Silkworms eat mulberry leaves day and night. Silkworm eggs take about ten days to hatch. When the colour of their heads turns darker, it means that it is time for them to shed their skins (moulting). After they shed moult times, their bodies turn slightly yellow and their skin becomes tighter, which means they are going to become a pupa. While they are a pupa, they turn into moths. Before becoming a pupa, the silkworm wraps itself in a cocoon, to help protect itself. The silkworm is called a silkworm because it spins its cocoon from raw silk that it makes in its mouth. Many other larva produce cocoons, but only a few silkworms are used to make silk.
Silk[change | change source]
The cocoon is made of one thread of raw silk from 300 to 900 meters (1000 to 3000 feet) long. The fibers are very thin. About 2,000 to 5,000 cocoons are needed to make a pound of silk.
If the animal is allowed to survive after spinning its cocoon, it will make a hole in the cocoon when it exits as a moth. This would cut the threads and ruin the silk. Instead, silkworm cocoons are thrown into boiling water, which kills the silkworms and also makes the cocoons easier to unravel. Often, the silkworm itself is eaten.
The adult silkworms (moths) cannot fly. The silkworm-moths have wings about 2 inches wide and a white hairy body. Females are about two to three times bigger than the males, but similarly colored. Adult silkworms have small mouths and do not eat.
Silkworm legends[change | change source]
In China, there is a legend that the discovery of the silkworm's silk was by an ancient queen called Leizu. She was drinking tea under a tree when a cocoon fell into her tea. She picked it out and as it started to wrap around her finger, she slowly felt something warm. 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 common. There are many more legends about the silkworm.
The Chinese guarded their knowledge of silk. It is said that a Chinese princess smuggled eggs to Japan, hidden in her hair. The Japanese also love silk. It takes 5000 silkworms to make a single kimono.
Food[change | change source]
In Korea, silkworm pupae are boiled and seasoned, then eaten as a popular snack food known as beondegi.
In China, street vendors sell roasted silkworm pupae. The pupae are a delicacy in the Northern Area of China. They are baked with Satay sauces and rice to add extra flavour. In Japan, Silkworm Pupae is used in many dishes, including some types of sushi and even salads.
References[change | change source]
- Brian K. Hall (2010). Evolution: principles and processes. Topics in biology. Jones & Bartlett Learning. p. 400. . http://books.google.com/books?id=V24EHUgEl5EC&lpg=PA342.
- Wisseman, Sarah Underhill & Williams, Wendell S. 1994. Ancient technologies and archaeological materials . Routledge, p131. ISBN 2-88124-632-X
- Scoble, MJ, 1995. The Lepidoptera: Form, function and diversity. Princeton Univ. Press.
- Goldsmith, M, Toru Shimada, and Hiroaki Abe. 2004. The genetics and genomics of the silkworm, Bombyx mori. Annual Review of Entomology 50:71-100.
- Grimaldi and Engel, 2005. Evolution of the Insects. Cambridge University Press.
Other websites[change | change source]
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