Silkworms spin cocoons that are made out of silk. The most common silkworm used for silk is the Bombyx mori. Over the years, silkworms have been bred to increase silk production. Selective breeding has made silkworms far different from their ancestors. Today, Bombyx mori silkworms cannot emerge from their thick cocoons. Some species of domesticated silkworms, such as peace silkworms, can still emerge from their cocoons as moths, but they emerge blind, unable to fly and unable to eat. Domesticated silkworm eggs are available for purchase from some educational and insect supply stores.
- Skill level:
Things you need
- Blooming mulberry tree
- Artificial silkworm food
- Silkworm eggs
- Three or more open-topped boxes or plastic trays
- Cling film
- Empty toilet paper rolls (1 for every 2 worms)
- Empty egg cartons (1 egg space for every 1 worm)
Locate a mulberry tree where you can obtain plenty of fresh leaves. If you do not have access to a mulberry tree, you can order artificial silkworm food (See Resources). Note: Not all species of silkworms will eat artificial food. Check with the silkworm egg supplier before ordering.
Order silkworm eggs (See Resources).
Keep the silkworm eggs in the refrigerator until you are ready for them to hatch. If you will be feeding them fresh mulberry leaves, wait until spring when the mulberry trees are in bloom.
Take the silkworm eggs out of the refrigerator and put them in a box or a plastic tray. Leave them out at room temperature while you wait for them to hatch. Hatching takes about a week.
Transfer the silkworm eggs into an open-topped box or plastic tray that is lined with fresh mulberry leaves or artificial food when the eggs are close to hatching. The eggs are close to hatching when you can see dark rings in the eggs.
Place a piece of cling film with air holes poked through it on top of the box or tray to keep the mulberry leaves or artificial food from drying out.
Put new leaves or artificial food in the box or tray three times a day. Make sure leaves do not have drops of water on them so that the tiny worms do not drown. For the first week after hatching, the silkworms cannot crawl very well. If you choose to remove the old food, carefully transfer the worms onto the new food.
Check the silkworms several times a day to make sure they do not run out of food. As the worms grow older, they will eat larger amounts of food. Add new food at least three times a day, but more often if necessary. The silkworms need fresh food, so if you notice the leaves have dried out, replace them with new fresh ones.
Clean the silkworm environment every two days. The easiest way to clean the box or tray is to prepare a second one with fresh leaves or artificial food. Put the silkworms in the second home and empty out the first one. Save the first box or tray for the next cleaning.
Set up an environment for the silkworms to spin their cocoons when the worms are ready to pupate. Silkworms start spinning their cocoons at about one month old. You can tell the worms are ready to spin when they stop eating and turn yellow in color.To set up the environment, place empty toilet paper rolls or the bottom half of an egg carton in the silkworms' box or tray. Put enough toilet paper rolls or egg cartons to provide spinning space for each worm. Figure two worms can use one toilet paper roll and one worm can use one space in an egg carton.
Leave the silkworms alone while they spin their cocoons so that you do not disturb the complex spinning process. They no longer need to be fed or have their environment cleaned at this point. It takes about three days for the worms to finish spinning their cocoons.
Wait for the silkworms to emerge from their cocoons as moths. The moths emerge after approximately three weeks.
Place the newly emerged moths in a new container that is lined with paper towels.
Allow the moths to mate and lay their eggs. The moths do not need to be fed, because domesticated silkworm moths cannot eat. They also do not need a covered cage because domesticated silkworm moths cannot fly. The females lay their eggs in the first one to three days after emerging from their cocoons. Each female silkworm moth lays an average of 200 to 500 eggs. Soon after mating, the moths starve to death and die.
Collect the eggs off the paper towels and put them in a plastic container with a lid. Refrigerate the eggs until you are ready to hatch the next generation.
Remove the cocoons from the container that the silkworms discarded after emerging as moths.
Soak the cocoons in warm water for 24 hours to remove the gummy substance that holds the silk strands together.
Unwind the silk threads in the cocoons and save the silk for craft projects. Each cocoon is one long piece of silk. To unwind the silk, first find the end of the thread. Then pull the thread and wrap it around a stick to keep it from tangling.
Tips and warnings
- Silkworms get their moisture from eating mulberry leaves or artificial silkworm food.
- To increase silk production, some domesticated silkworms have been bred to spin such thick cocoons that the moths are unable to emerge, which results in the moths dying in their cocoons. Peace silkworm moths can emerge from their cocoons. If you want your moths to be able to emerge, purchase peace silkworms.
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