silkworm

The silkworm is a general name given to the silk-producing caterpillar belonging to several species of butterflies. The adult silkworm butterfly is usually yellow or yellowish in color

The silkworm is an insect belonging to the family Lepidoptera of the order Lepidoptera. Its color is white to yellowish, its antennae are double metatarsal in both sexes. It does not feed during its life of only a week or so. It has two flaps of scaly wings, and its front wings are decorated in the form of semi-gray broad stripes

The female insect begins laying eggs on mulberry leaves approximately twenty-four hours after mating, and the number of eggs laid is about 500 eggs. The length of one egg is about one millimeter, and when laid, it appears in a yellow color that soon turns gray with blue or red according to the breed. The eggs are attached to a sticky substance that quickly dries up when exposed to air

The eggs hatch about a week after being laid; To give larvae start feeding raspberry leaves. The caterpillar is about 3 mm long, with a black head equipped with rodent mouth parts. It is grayish in color, cylindrical in shape, and has bristles on both the back and sides. The larva sheds four moults, replacing each time a new skin with its old one. It increases in length with each moult, until it eventually turns into a larva about 3-6 cm long, translucent white in color, and begins searching for something; To climb on it, and to sip after it had satiated its thirst for nourishment with mulberry leaves

The larvae secrete silk threads from mutated silk glands from the salivary glands of cocoon spinning. So it works day and night non-stop for a few days. The larva has two glands for secreting silk that extend on both sides of the alimentary canal. Their excretory ducts unite in a collecting duct at the front of the head to drain into the front of the lower lip. The length of one gland is approximately four times the length of the larva. From each gland comes a thin thread that fuses with its counterpart with a substance called silk gum. The two sutures, when they come out of the gland opening, wrap around each other; to form a single, double strand. When the cocoon spinning is complete, the larva inside it turns into a cuffed, oval-shaped pupa with a grayish color

The virgin remains in the cocoon for two or three weeks, until the formation of the butterfly. Then the butterfly punctures one end of the cocoon with the effect of a few drops of an alkaline liquid secreted by its special glands, which leads to the relaxation of the silk threads and cutting them, which facilitates the butterfly's exit

The butterfly appears when it comes out in a white to yellowish color with a wet, soggy body

Butterflies are nocturnal, but they do not have the ability to fly. The female is slightly larger than the male, and it is used in the silk industry after being raised according to certain principles. China is the first country to pay attention to this industry, which dates back to the year 2900 BC, when it flourished at that time with the encouragement of emperors and court men. The Chinese kept the secret of this industry for three thousand years until its secret became known, and the silk industry spread after that in many countries of the world