The silkworm. It is a species of lepidopteran insect in the family Bombycidae native to North Asia . Today it is bred in many regions of the world to take advantage of the cocoon that protects its chrysalis, made up of a long filament of silk , produced by the caterpillar when it retracts for metamorphosis . Although there are other mushroom species, B. mori is the most widespread, and the one commonly known by this name.
Summary
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- 1 History
- 2 Identification Characteristics
- 1 Morphology
- 3 Egg development
- 4 Growth
- 5 Origin of silk
- 6 Death of worms for silk
- 7 Culinary use
- 8 home use
- 9Fuente
History
In China there is a legend that the discovery of the silkworm was made by an ancient empress named Xi Ling-Shi. It is said that while she was having tea under a mulberry tree in her garden at the royal palace when something fell into her teacup, when she wanted to remove it, it frayed and she, as she was a weaver par excellence, took it and began to weave with it. This secret of silk was not spread to a country other than China since it was something exceptional, that secret was kept very well until approximately 1500 years after its discovery. Given its long history and economic importance, the silkworm genome has been the subject of considerable study. Its antiquity has been dated by analyzing the genome of the worms, which have up to 354 genes linked to their productive utility, in 5000 years.
Beneficial uses for man, Silkworm caterpillars.
Man has raised silkworms for several centuries to obtain the precious silk, today they are also used as “pets”. Both uses have prevented them from appearing naturally, so today it can be said that they have almost disappeared in the wild.
Identification Characteristics
Morphology
The larvae are worm-like with a short anal horn. Three distinct body parts: head, thorax, and abdomen. The adult has four wings covered with scales Adult Males and Females.
Adult moths have cream-colored wings with brown patterns on the forewings. The body is very hairy and the wingspan measures about 50 mm. Adult females are larger and less active than males. Males expend a lot of energy and are very active looking for females. Copulation lasts a few hours.
Lepidoptera are holometabolous, so it has three distinct morphological stages; larvae, nymphs and adults. After hatching, the larvae molt four times during their growth. During each molt, the old shell is shed and a new, larger shell is produced. The life of silkworm larvae is divided into four stages, separated by the four times they molt. They have three pairs of short, jointed legs with a claw at the tip. These legs are found on all three body parts immediately behind the head. They also have five pairs of fleshy protuberances (abdominal ducks) that are located ventrally and posteriorly on the abdomen and are used by the larvae to grasp and hang from plants. These bumps have a garnchor sene at the tips.
development of the eggs
The development of the germs that give rise to the silkworm only requires a lot of care, they feed on mulberry leaves, which is their best food. This tree was imported from the Far East , it is cultivated in other countries in order to provide food for silkworms. The caterpillars of the silkworm need help to shed a shell that is attached to them when they come out of the egg, they do this by rubbing against something that detaches it. This eliminates the danger that they perish because they have not been able to get rid of it.
Silkworms are capable of eating the leaves of the entire forest. The amount of mulberry leaves that the worms get to eat is truly amazing. During the eight weeks during which they live in a caterpillar state, speaking only of forty thousand worms, they will need six hundred kilos of mulberry leaves to feed themselves, and it is very amazing how quickly these caterpillars grow.
Increase
When they are six days old, the worms stop feeding; the skin splits down the back and the caterpillar crawls out wrapped in its new covering. Then he recovers his appetite, starting to eat with great avidity again. It grows rapidly while its skin is still soft; but after a few days, it has to undergo another moult, and so on until it reaches the fourth.
Each time of moulting is a painful ordeal for the caterpillar, and many perish in the course of the operation, but as soon as the last moult is over, the worm feeds voraciously, as if it knew that its supply would soon run out. nutrition period. At this point, it weighs about ten grams and its length reaches seven centimeters, which represents extremely rapid growth in a couple of months.
Then comes the most important moment in the life of the caterpillar. It is necessary that it transforms into a chrysalis and precisely to pass in an adequate way through that state of chrysalis, the insect spins the famous silk .
During the entire period of its growth, two large vessels or sacs have been formed and filled with fluids, placed along each side of the caterpillar’s body. The sticky fluid contained in these two sacs does not offer anything in particular: and if we saw it in its natural state, that is, inside the body of the worm, we would not suspect the use to which it is destined.
origin of silk
This sticky substance that encloses the body of the silkworm is what becomes the precious threads that have given the insect so much fame. As soon as it is ready, let’s put it that way, to spin, the caterpillar stops feeding. If we observe it carefully we will see that two tiny filaments of a kind of slime come out of the lower side, coming from the aforementioned sacs.
It is worth knowing about these sacs that are scientifically known as siriciparous glands and also that the silkworm is called bombyx mori. The worm begins, because the spinning of its cocoon by making two silky filaments come out through the tiny holes, in which the aforementioned glands end near the mouth. the worm brings them together, forming a single thread with the two.
To carry out his work, it takes two, three, four and even five days. The worm little by little builds his mansion, spinning with such art, that finally it is entirely enclosed.
As he continues his work, he continually moves his head with absolute regularity without resting for a moment and without ever running out of material.
At the beginning of its work, the worm weighs more than nine grams, when it is finished, it only weighs five, including the weight of the cocoon. This can be white or pale yellow.
If we don’t touch them, a beautiful butterfly will come out of each cocoon after two or three weeks, its length is usually two or three centimeters, they eat very little and sometimes absolutely nothing. The females die after laying about 500 eggs and the males do not usually survive for long. Their butterfly life lasts but a few days and during this time they never attempt to take flight. The females cannot fly and the males have only the strength to keep their balance when descending through the air , making it impossible for them to fly upwards.
death of worms for silk
This seems horrible to us, but in reality, it is not. The life of the silkworm, as a worm, ends from the moment the insect becomes a chrysalis, then it enters a state of lethargy and does not perceive any sensation.
All the cocoons are immersed in boiling water, which kills the chrysalis . This operation is essential because if the chrysalis remains alive it would become a butterfly .
Then comes the operation of winding the silk, for which it is necessary to soften the cocoons in hot water at a temperature of eighty-eighty degrees. Then an operator using a brush spins the cocoons, collecting the ends and causing the silk to gradually develop.
When the ends of the silk are uncovered, four or five of them are joined, passed through the very fine metal hook and the cocoons are allowed to remain in the water and all the silk is wound, then all the rubber that is removed is removed. has remained in it, it is washed by passing it through boiling water until it dries. The silk is clean, but tangled, with a machine the knots are combed until the soft threads remain.
culinary use
In Korean cuisine, the silkworm is used to make cheap and nutritious (high protein) biscuits for school children, called ( beon dae gi ). It is consumed boiled, fried or as an ingredient in sauces. When eating the fried worm the most important aspect is the juice.
In traditional Chinese medicine, Bombyx mori is used as a tonic to dissolve phlegm and relieve spasms.
Domestic use
Silkworms are used in the domestic sphere as pets and as “teaching guides” to learn the life cycle and metamorphosis of caterpillars . This is due to their ease of feeding (because you only have to give them mulberry leaves), their little attention, their easy cleaning, their profitability since they are totally peaceful since they can be picked up and touched without danger.
