The Life Cycle of Silk Worms
The silkworm is just one part of the life cycle of the silkworm moth. The life cycle of the moth is dependent upon the changing seasons. In areas where summer, fall, spring and winter are clearly discernible, the silkworm moth will reproduce only once annually. In warm climates where the seasons are not discernible, silkworm moths reproduce continuously.
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Eggs
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The female silkworm moth will lay many tiny eggs on mulberry leaves and from these leaves hatches the silkworm or caterpillar. In areas where the seasons change, the moth will generally lay the eggs in late summer or early fall, and the eggs will not hatch until spring.
Larva
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The caterpillar or silkworm that emerges from the egg is only about an eighth of an inch long and covered in hair. The caterpillar feeds on the mulberry leaves, going through four separate molts as it matures toward the pupal stage. As it molts, the old skin is shed and a new, larger one is grown.
After the first molt, the silkworm loses its hairy exterior and remains smooth and soft throughout this stage of its life.
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Pupa
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After the fourth molt in the larval stage, the caterpillar will spin a cocoon of silk thread around itself. The cocoon is about the size of a cotton ball. Inside the cocoon, the caterpillar becomes a pupa.
Silk
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It is at this stage that the silk worm's life cycle ends if the cocoon is taken to make silk thread. The process involves plunging the cocoon into boiling water to kill the pupa and dissolve the glue that holds the cocoon together. The cocoon will be unwound, and the threads used to weave cloth.
If the pupa is allowed to continue its development, it will change from pupa to moth within the cocoon and emerge as an adult about two to three weeks after going inside the cocoon.
Adult
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The silkworm moth has creamy white wings with brown patterns across the front. Today, there are no silkworm moths living naturally. In the four millennia since the silk industry began the species has become so domesticated that it can barely fly, find it own food or defend itself from predators.
Copulation between adult silkworm moths may last for several hours. Adult silkworm moths do not eat or drink, but mate and die after the female has laid her eggs.
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References
- Photo Credit University of Nebraska Department of Entomology
Comments
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Life Cycle of a Silkworm. The silkworm life cycle goes through several stages. Egg Egg is the first stage of a silkworm's life cycle. The female moth lays an egg about the size of an ink dot during summer or the early fall. The egg remains in dormant stage until spring arrives. The warmth of the spring stimulates the egg to hatch. Larvae The silk worm, upon hatching, is about 1/8th of an inch and extremely hairy. Young silkworms can only feed on tender mulberry leaves. However, during the growth phase they can eat tougher mulberry leaves as well. The larval stage lasts for about 27 days and the silkworm goes through five growth stages called instars, during this time. During the first molting, the silkworm sheds all its hair and gains a smooth skin. Cocoon Cocoon is the stage in which the larva spins silk threads around it, to protect itself from its predators. The larva traps itself inside the cocoon in order to pupate. The color of the cocoon varies, depending upon what the silkworm eats. It can range from white to golden yellow. The second molting occurs inside the cocoon, when the larva turns into a brown pupa. It takes about 2-3 weeks for the pupa to metamorphose into an adult moth. Adult Moth Once the adult moth comes out of its cocoon, it's only purpose is to find a member of the opposite sex, and mate. Males are larger than females and more active. They flap their wings rapidly to attract the females. Within 24 hours of mating, the male moth dies, while the female lays abundant eggs, after which it dies as well. There on, a new silkworm life cycle begins. Normally, there is only one season in a year when silkworms reproduce to give one generation. However, in countries like India and China silkworms reproduce continuously, round the year. Also, when silkworms are bred for commercial purposes, they are made to reproduce round the year. Commercially, these insects have to be bred very systematically. They cannot eat or drink on their own. Thus, everything from their food to their habitat has to be organized artificially. Although, silkworms feed on mulberry leaves, it is not always possible to find them, especially during fall and winter. Commercial silkworm breeders feed larvae a substance called silkworm chow, which is a good alternative to mulberry leaves.
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I can undestand now.
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thnks nw I can understand it.
