The scientific name for the silkworm moth is Bombyx Mori. The silkworm moth belongs to genus Lepidoptera of the order of Insecta.
Silkworms reproduce from eggs of the silkworm moth.
Some of the fertilized eggs will hatch into larvae. The body of the newborn larva is dark coloured with stiff little hairs. The Chinese call it an “ant silkworm” because of its appearance like a little ant.
During my third grade, we had a silkworm raising project. During the summer vacation, I brought the silkworms home to care for them because nobody else wanted to. I had to go hunting for mulberry leaves for the silkworms to eat. As the silkworms ate a garbage-bag-ful of mulberry leaves every 3 hours or so, you can imagine how hard that job was. Mulberry leaves do not keep reproducing. The leaves that emerge in the spring will be all that the tree has that year, so if you strip the mulberry plant bare, the tree will not survive without any leaves to make food for the plant. I climbed every hill and park I could in my neighbourhood until my hands were scratched and bleeding.
But it was fun raising silkworms – the sound of silkworms eating was like the sound of rain, and when I went to bed, I could hear the sound of their crunching, like rain, as I fell asleep.
Silkworms molt – they grow new skins and shed the old ones. The stage between two sloughing off-skin periods is called an instar. When they are in the instar period, they stop moving and sleep with their heads held stiffly up.
Silkworms have five instars, i.e. they shed their skin five times while growing up. See how fat the silkworms get (below)
After eating continuously for 26 days, except during the instars, they stop eating and begin to build their cocoons.
You don’t have to help the silkworm look for a home. We used toilet rolls though others recommend building a grid-like boxed house. The silkworms when they are ready and stop eating and start to crawl up and down looking for the cozy hole that they want to build their cocoon in. Some didn’t mind sharing.
Three cocoons, then four, then six…one by one, they built their cocoons.
After the silkworm spins its cocoon, it sheds its skin one last time and turns into a pupa. Our teacher boiled the cocoon, cut it open to show us the pupa. We also left one of the eggs to hatch into the silkworm moth which you see in the photo below.
The female’s abdomen is large and has a rounded end. The male’s abdomen is smaller and has a pointier end. Since silkworm moths have been bred for thousands of years and do not exist in the wild, they have long ago lost their ability to fly and so cannot survive without the care of humans. That’s why we didn’t breed more than one silkworm moth for our experiment. After boiling the cocoon (silkworms can be eaten), and drying it, we unravelled the threads, dyed them and used the silk threads for a craft project lesson.
The female silkworm moth produces about 300 eggs. The cocoon is made from the raw silk that produced in the silkworm’s salivary glands. One cocoon gives out a continuous reel of silk thread of around 900 meters long but it takes 1,500 silkworm eggs to make one gram of silk (40,000 eggs per ounce) or 3,000 cocoons to make one pound of silk! It takes 2,100 silkworms to make one kimono.
Originating from China, the tradition of silkworm-raising goes back a long way in Japan. I visited the Gassho-zukuri village in the Shirakawa-go valley with my family which is a World Heritage site with a village that has been active in sericulture for centuries.
Inside these distinctive houses called gassho-zukuri homes….
you can see that they carried on silkworm raising in the steep-sided attics (see photo below).
(All the photos belong to my family)
Many art pictures showing traditional silk-rearing activities (sericulture) here