Have you ever raised a silkworm in your life? I have. Here is my story.
When I was a second grader, like most other kids in the class, in the spring semester I kept several silkworms as pets. Hey, they are cute little animals, really! Cool, shy, and unbelievably silky, they constantly engage themselves in munching mulberry leaves.
In early spring, we put a few silk seeds (aka eggs) in a padded matchbox, and tucked it under our sweaters to hatch the babies. We checked our matchboxes so frequently that our teachers had to stop us. In a couple of days, tiny black silkworm babies appeared, and they were immediately provided with freshly picked mulberry leaves, sweet and juicy. Their diapers got frequently changed, too--seriously. (No unpleasant smells, I assure you.) Each week they got moved into a new house, for they were growing FAST!
In four or five weeks they were already fully grown, ready to wrap themselves with fine silk. The silk gland had always been there--when they accidentally fell out of the box, like spiders they hang on a lifeline. But now, they have finished their last meal ever, become semi-transparent, angrily running around to pick a nice corner. Sometimes two would fight for one ideal corner, then you have to move one to a new box! Once settled, a silkworm would start a few trial runs and carefully attach its silk thread to the three surfaces. If satisfied, it would start the real work.
[Traditionally, the silkworms are provided with bundled rice stalks. That's easier for them to use than corners of a paper box, and the aeration is superb.]
They were diligent workers, busy wrapping themselves without rest. Within a few hours I bid them goodbye. Then the beautiful cocoons stopped moving and all of us waited patiently.
[In that year, every cocoon I had were in bright lemon yellow color. They turned out to be all girls, so I ended up borrowing a guy from a friend. Lucky guy...]
Silkworms are different from other moths, there is no mouth so they can not eat--reproduction is the only mission. After completing their job, My silky girls only lived for a day. I buried them under my mulberry tree, and their babies were kept for the next spring.
Years later when I was in university, we had a professor in cell biology class who studied fluorescent proteins. He had a box of beautiful neon-colored cocoons, produced by silkworms carrying different types of fluorescent protein gene tags. They were so stunning that the whole class turned green with envy. Such beautiful things can never be forgotten, and I hope one day I can see the naturally colored silk again--in my local yarn shops.