A lot of effort on the part of the silkworm goes into making a very small amount of silk. We examine what it takes to create just 1 kg of raw silk. The stats may astound you.
Producing silk isn’t as easy as it sounds. We’re going to examine some of what’s involved including a look at what typical mass production is in some of the more productive countries such as Japan, China and Thailand.
Silk production is done in stages. The first stage is hatching the silkworm egg in a controlled environment. This is usually done in an aluminium box. The boxes first have to be examined to make sure they are free of disease. The female silkworm usually lays about 300 to 400 eggs at a time. In an area about the size of a piece of typing paper about 50 moths can lay over 20,000 eggs at one time. Each of these eggs is about the size of a pinhead and virtually undetectable to the human eye. After laying the eggs the female dies almost immediately. The male lives only for a short while after this.
The eggs are then tested for disease. If they are disease free they are then raised in a controlled environment. The eggs are fastened to a flat surface by a substance that is secreted by the female. The larvae hatch out of the eggs in about 10 days and are about a half a centimeter long. After the larvae hatch they are placed under a layer of gauze. Afterwards, they are fed a large amount of cut up mulberry leaves. During this time they are left to shed their skin, which they do about four times during the process. Sometimes they’ll feed the larvae orange juice or lettuce. The larvae that are fed the mulberry leaves are the ones that produce the finest silk. Each larvae can eat over 50,000 times its size in food.
After the larvae has reached its maximum length, which is about 7.5 centimeters, it stops eating. This takes about four to six weeks. After this happens it changes color and attaches itself to some kind of object like a frame, tree branch, twig or shrub. Once attached, they start spinning their silk. This goes on for about three to eight days.
This is where the hard work by the silkworms comes in. Over the next few days, the silkworm produces a thread by making a figure eight motion over 300,000 times, during which time it is actually constructing a cocoon. This is a non stop process. The cocoon is made because this is where the silkworm plans to live during what is called its chrysalis stage. During this stage it sleeps and sheds its skin. During this stage, which lasts about sixteen days, the silkworm begins the next process of turning into a moth. The problem, for the silk manufacturer, is if the pupae remains alive it will secrete a substance that will destroy the cocoon, thus ruining the silk threads. To prevent this from happening the pupae are killed. This is why activists have such a problem with the process.
The truth is, the percentage of silk that is actually saved in this process is very small. Thousands of pupae die. It takes about 80 kg of cocoons to produce just 1 kg of raw silk.