When this happens, the cocoon will be noticeably larger, however, if the two are members of the opposite sex, sometimes the cocoon does not hatch — and you will open it to find two dead Silk-Moths and a bunch of eggs inside the cocoon! Some males may be able to almost fly if you drop the from a small height, however it is uncontrolled, and they will hit the ground after a few moments. It is quite easy to separate the male and female Silk-Moths, with the females having larger abdomens and males possessing smaller abdomens.
Males also tend to be more active, as they are constantly searching for a mate. The moth lives a very brief life of days, with males generally living longer than Females. Silk-Moths will begin to search for a mate almost immediately after emerging from their cocoon, with some seen mating with a moth of the opposite sex inside their cocoon should two moths share one! After mating, the Female Moth will lay between eggs, and die, whereas the male Silk-Moth will search for another mate, should it not be too old.
Remember me Log in. Lost your password? Record your observations in a notebook or on the silk cocoon dissection sheet. Use your fingers to gently tug at the loose silk around the outside of the cocoon. You may find you are able to remove the exterior silk in one single sheet. Rub this silk between your fingers, describing the texture in your notes, then pin it to your pinboard and label it so that you can compare it to silk collected in later steps.
Now, use a pin to snag some of the second layer of silk from the outside of the cocoon. Pull enough that you can feel it between your fingers and observe its texture, and record your observations. Pin this silk next to the silk you pulled off in the previous step, and label it. Why do you think that it might be advantageous for a silkworm to use such thick, stiff silk during the initial stage of cocoon construction? How does the outer-most layer of silk differ in color, texture, and flexibility from the silk layer just beneath it?
Using sharp scissors, nick the center of the cocoon, creating a hole just big enough to get the tip of your scissors into. Carefully, cut around the outside of the cocoon along the long axis. Stop periodically to peek into the cocoon and make sure that you are not cutting into anything that might be hidden inside. Cut until you have two halves. If you have a scale, measure the mass of the empty cocoon and compare it to its original mass.
Pin one half of the cocoon to your pin board. Look closely at the pupa inside your cocoon. Can you find any structures on it that resemble the body parts of an adult moth?
If you can, label them in your sketch. Were you able to find the discarded caterpillar exuvia? Make sure to label that in your sketch as well as on your pinboard if you pinned it.
The pupa inside of your cocoon has likely been dead for some time. How do you think its body has changed since it was alive? Take your finger and touch the inside of the unpinned half of your cocoon. Record your observations in your notebook or on your dissection sheet. Use a needle to scrape gently at the inside wall of the cocoon half until you are able to pull a layer of silk away.
Feel the silk between your fingers and, in your notes, compare its color, texture, and flexibility to the silk from the exterior of the cocoon. How is the silk from the exterior of the cocoon different from the interior silk? How does a change in the thickness of the silk fiber affect its texture? Inside this shell, the pupa turns into a moth.
This process takes three weeks, and then the moth emerges from the cocoon. They usually emerge at dawn. The adult moth has a special spit which is used to dissolve the silk so it can push its way out of the cocoon.
Silkworm farmers kill the moths before they emerge and make holes in the silk thread. When they emerge, the wings are crumpled, but they get pumped full of fluid and harden it about an hour. Moths cannot fly, and neither eat nor drink. They mate, lay eggs, and then die within five days. After the moths emerge from the cocoon, they look for an opposite-sex moth to mate with. Females are significantly larger than males. Females periodically extrude a scent gland through the hole in their abdomen.
Males have a flap of skin at the end of their abdomen and flutter their wings a lot. Each moth will "urinate" a reddish-brown fluid shortly after emerging from the cocoon. It dries to look like blood. Explain to the kids that this is the moth's "pee" that it saved up since it couldn't "go" while it was in the cocoon.
The moths stay mated for about a day. After separation, the female lays eggs and the male looks for another female. Sometimes another male grabs the female before she can lay eggs. Each female will lay between - eggs! Put paper on the bottom of the container and remove empty cocoons as the moths emerge. The moths will lay eggs on the paper. It is interesting to note that one ounce of silkworm eggs contains 40, eggs 1, eggs per gram. These worms will eat 3, pounds kilograms of mulberry leaves, and will spin cocoons which will produce 18 pounds 8 kilograms of silk thread.
It takes to cocoons to make one silk dress! When first laid, all eggs are lemon-yellow. After three days, they will turn white if they are infertile, or turn black if they are fertile. Fertile eggs might hatch a week or two after being laid in the middle of the summer, but they usually won't hatch unless subjected to "winter" in your refrigerator for at least several weeks.
Wait until the eggs turn black before putting them in the Ziplock bag in the refrigerator. Once you take eggs out of the fridge, they will hatch in days, or maybe not at all. Direct sunlight in the morning for a few hours hastens hatching.
Eggs will remain viable in the refrigerator for about five years. If the moths were allowed to emerge from the cocoons, they would make holes in the silk thread.
The silkworm farmers kill the pupas inside the cocoons by baking them in a hot oven. Then they soak the cocoons in boiling water to loosen the threads. A person finds the end of the thread and places it on a winding bobbin. Then a machine unrolls the cocoon, winding the silk from five cocoons together to make one silk thread. Then the thread is woven into cloth. Silkworm math. Have the kids measure the length of the silkworms and graph them as they grow.
Rainfall: When the silkworms are large, take the lid off the container and have the children be extremely quiet. They will be able to hear the sound of the silkworms moving around! It sounds like a gentle rainfall. The sound is not chewing, but their little suction-cup feet lifting off the leaves and plopping back down again. Silkworm pet. Give each kid a silkworm in a cut-down milk carton on their desk. Have them put in a fresh leaf twice a day, and empty the poop out. Put in a stick and they can see it crawl around.
Wait until the caterpillars are two weeks old since there is a high mortality rate for the first few weeks. With a full-grown caterpillar, you can easily see the heart pumping blood through the translucent skin. The heart is located at the rear end of the caterpillar on the top. You can see it pulse. The main artery carrying the blood is where the backbone would be if it had one.
Egg laying. If a female moth happens to be laying eggs, have the children watch. You can actually see the yellow eggs emerge one at a time from her rear end! She feels around with her ovipositor "egg-layer" in Latin until she feels an empty place to put the egg. Coarse thread. You can make silk thread without killing any of the pupas.
When the cocoons are spun, there is a fair amount of loose silk on them. Have the children gently pull it off the cocoon, making sure not to crush it. They can then roll it between their fingers to make a coarse silk thread.
Fine thread. In order to unwind the cocoon, you must kill the pupa inside. Place the cocoons on a cookie sheet in degree oven for 30 minutes. Then drop the cocoons in boiling water. After five minutes, you can reach in wearing rubber dishwashing gloves , and begin to unwind the cocoon. Unwinding five at a time will make a fine, strong, thread.
Silk bookmarks. You can cut out shapes from cardboard and stick it on a bottle. Then place the spinning worm on the top. The worm, not having a corner to spin it's cocoon, will criss cross over the top of the card, and around the edges.
Once the worm became a pupa, take it off the card, take the silk off the card and have a silk woven shape like a heart or cross or star. Of course the worms don't care much for corners on shapes, so there will be rounded corners instead of sharp ones. You can put more than one worm on a shape to make it thicker.
These silk shapes made great bookmarks! The history of the silkworm, which is also the story of silk, goes back to ancient times in China. Some of the stories have been handed down through the generations and are probably based party on fact and partly on legend and myth. The tale which persists is that about 2, B. She unwound one of the threads on a cocoon and found that it was one, very long strand of shiny material. Fascinated, she pulled strands from several cocoons through her ring to form a thicker thread.
Eventually, with the help of her ladies of the court, she spun the threads into a beautiful piece of cloth to make a robe for the emperor, Huang-Ti. This magnificent material, silk, became known at the "cloth of kings". For thousand of years on the royal family of China had silk. The Chinese kept the secret of how silk was made for years. The material was sold to the rulers of the West, but the source of the shiny thread that made the material was not revealed. The penalty in China for telling that the silk came from the cocoons of the little silkworms was death!
Some very strange ideas were formulated as to the origin of silk. Here are a few: Silk came from the colored petals of flowers in the Chinese desert, silk was made of wondrously soft soil, silk came from a spider-like animal that ate until it burst open and the silk threads were found inside its body, and silk came from the silky fuzz on special leaves.
These ideas seem far-fetched today -- but in ancient times they were serious theories. Legend has it that the Japanese carries off four Chinese maidens, who knew the secret of silk, along with mulberry shoots and silk moth eggs. Today Japan is the leading producer of silk! Another story is that a Chinese princess married an Indian prince.
She carries silkworm eggs and mulberry shoots in her elaborate headdress and the secret of raising silkworms in her head. Now silk was grown and produced in India. Finally, two poor monks told Emperor Justinian of Constantinople that they had learned the secret of silk.
Justinian send them back to China to get some eggs and mulberry shoots for him. They returned many years later with the eggs and shoots hidden inside their hollowed-out walking sticks. Since Justinian was the emperor of Constantinople, a crossroads city, the secret soon spread throughout Europe. There are many more interesting stories about the history of silk. Have older children do some research in the library and report to the class.
Today silk can be worn by anyone -- not just emperors and noblemen and their families. Silk is made into many lovely fabrics, such as satin, velvet, chiffon, crepe, brocade, taffeta, faille, and shantung.
A good class project would be to see how many different kinds of silk cloth could be collected and put them on a chart for the kids to see and feel. The beautiful colors of silk would also make a nice chart.
Modern silkworm moths have been bred to have white silk instead of the amber-colored silk of their wild ancestors.
They also have large, fat bodies and tiny wings, so they cannot fly.
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