What does the silkworm do. The silkworm (lat. Bombyx mori) is the only domesticated insect. Pictured is a silk thread farm

The silkworm (lat. Bombyx mori) is a nondescript little butterfly with off-white wings that can't fly at all. But it is thanks to her efforts that women of fashion all over the world for more than 5,000 years have been able to enjoy outfits made of beautiful soft fabric, the brilliance and colorful transfusion of which fascinate at first sight.

flickr/c o l o r e s s

Silk has always been a valuable commodity. The ancient Chinese - the first manufacturers of silk fabric - kept their secret securely. For its disclosure, an immediate and terrible death penalty was due. They domesticated silkworms as early as the 3rd millennium BC, and to this day, these small insects work to satisfy the vagaries of modern fashion.

flickr/Gustavor..

There are monovoltine, bivoltine and polyvoltine silkworm breeds in the world. The former give only one generation per year, the latter two, and the third several generations per year. An adult butterfly has a wingspan of 40-60 mm, it has an underdeveloped mouth apparatus, so it does not feed throughout its short life. The wings of the silkworm are off-white in color, brownish bandages are clearly visible on them.

flickr/janofonsagrada

Immediately after mating, the female lays eggs, the number of which varies from 500 to 700 pieces. The laying of a silkworm (like all other representatives of the peacock-eye family) is called grena. It has an elliptical shape, flattened on the sides, with one side slightly larger than the other. On a thin pole there is a recess with a tubercle and a hole in the center, which is necessary for the passage of the seed thread. The size of the grena depends on the breed - in general, Chinese and Japanese silkworms have less grena than European and Persian ones.

flickr/basajauntxo

Silkworms (caterpillars) emerge from the egg, to which all the views of silk producers are riveted. They grow in size very quickly, shedding four times in their lifetime. The entire cycle of growth and development lasts from 26 to 32 days, depending on the conditions of detention: temperature, humidity, food quality, etc.

flickr/Rerlins

Silkworms feed on the leaves of the mulberry tree (mulberry), so silk production is possible only in places where it grows. When the time of pupation comes, the caterpillar wraps itself in a cocoon, consisting of a continuous silk thread with a length of three hundred to one and a half thousand meters. Inside the cocoon, the caterpillar transforms into a chrysalis. In this case, the color of the cocoon can be very different: yellowish, greenish, pinkish or some other. True, only silkworms with white cocoons are bred for industrial needs.

flickr/JoseDelgar

Ideally, the butterfly should leave the cocoon on the 15th-18th day, however, unfortunately, it is not destined to live up to this time: the cocoon is placed in a special oven and kept for about two to two and a half hours at a temperature of 100 degrees Celsius. Of course, the pupa dies, and the process of unwinding the cocoon is greatly simplified. In China and Korea, fried pupae are eaten, in all other countries they are considered just “production waste”.

flickr/Roger Wasley

Sericulture has long been an important industry in China, Korea, Russia, France, Japan, Brazil, India and Italy. Moreover, about 60% of all silk production falls on India and China.

The history of silkworm breeding

The history of breeding this butterfly, which belongs to the family of real silkworms (Bombycidae), is connected with ancient China, a country that for many years kept the secret of making an amazing fabric - silk. In ancient Chinese manuscripts, the silkworm was first mentioned in 2600 BC, and during archaeological excavations in the southwest of Shanxi province, silkworm cocoons dating back to 2000 BC were found. The Chinese knew how to keep their secrets - any attempt to take out butterflies, caterpillars or silkworm eggs was punishable by death.

But all secrets will eventually be revealed. This is what happened with silk production. First, some selfless Chinese princess in the 4th century. AD, having married the king of small Bukhara, she brought him a gift of silkworm eggs, hiding them in her hair. About 200 years later, in 552, two monks came to the emperor of Byzantium, Justinian, who offered to deliver silkworm eggs from distant China for a good reward. Justinian agreed. The monks set out on a perilous journey and returned the same year with silkworm eggs in their hollow staffs. Justinian was fully aware of the importance of his purchase and by a special decree he ordered silkworms to be bred in the eastern regions of the empire. However, sericulture soon fell into decline and only after the Arab conquests flourished again in Asia Minor, and later throughout North Africa, in Spain.

After the IV Crusade (1203–1204), silkworm eggs came from Constantinople to Venice, and since then silkworms have been successfully bred in the Po Valley. In the XIV century. sericulture began in the south of France. And in 1596, silkworms were first bred in Russia - first near Moscow, in the village of Izmailovo, and over time - in the more suitable southern provinces of the empire.

However, even after the Europeans learned to breed silkworms and unwind cocoons, most of the silk continued to be delivered from China. For a long time, this material was worth its weight in gold and was available only to the rich. Only in the 20th century, artificial silk somewhat pressed natural silk on the market, and even then, I think, not for long - after all, the properties of natural silk are truly unique.
Silk fabrics are incredibly durable and last a very long time. Silk is lightweight and retains heat well. Finally, natural silk is very beautiful and lends itself to uniform dyeing.

Used sources.

Niramin - Feb 23rd, 2017

The silkworm lives almost nowhere in the wild. The ancient Chinese domesticated this useful insect 4.5 thousand years ago. Despite the fact that the Chinese have long kept the process of producing natural silk in the strictest confidence, it has also become known in other countries where there are optimal conditions for growing silkworm larvae.

An ancient legend says that a Chinese princess, having married an Indian rajah, stealthily took grena - a clutch of silkworm eggs - when she left China. It is worth noting that such an act was considered a state crime, and the princess was threatened with the death penalty in her homeland. Nowadays, silkworm breeding is carried out on special farms in Asian countries: China, Japan, India, Pakistan, North and South Korea, Uzbekistan and Turkey. In addition, similar farms exist in Italy and France.

Like most insects, the silkworm looks different in the course of its life, as it goes through several stages of development:

Grena stage - laying eggs.

Photo: Silkworm laying eggs.

Caterpillar stage (larva).

Photo: Silkworm caterpillars.

Pupation (cocoon formation).

Photo: Silkworm cocoons.

The adult stage is the butterfly.

Photo: Silkworm - butterfly.

The white butterfly is quite large in size with a wingspan of about 6 cm. In the process of natural selection, the silkworm butterfly has lost the ability to fly. During its short existence, about 20 days, the butterfly does not feed. Its main function is mating and laying up to 1000 eggs in one clutch, after which the butterfly dies.

Depending on a certain temperature, black, hairy larvae emerge from the eggs. In the process of its development, the larva molts several times and becomes a smooth white caterpillar.

It is the caterpillar that feeds exclusively on the leaves of the mulberry (mulberry tree).

Photo: Mulberry tree with fruits.

Any other plant food is not suitable for her. Hence the name of the insect. After 5 weeks of intensive caloric intake, the caterpillar attaches itself to a suitable twig and forms a cocoon of silk thread, which it produces thanks to the presence of a special gland. In the cocoon, the caterpillar turns into a butterfly. To obtain silk thread, farmers do not allow the butterfly to come out of the cocoon. But a certain number of cocoons are still left for butterflies as successors to the next generation of silkworms.

Video: MULBERRY SILKMOTH Grade 6

Video: What is it made of? (S7). Silk.

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Video: Silkworm cocoon Uzbekistan

People know a lot about the merits of silk, but few people are familiar with the "creator" who gave the world this miracle. Meet the silk caterpillar. For 5,000 years, this small, humble insect has been spinning silk thread.

Silkworms eat the leaves of mulberry (mulberry) trees. Hence the name silkworm.

These are very voracious creatures, they can eat for days without a break. That is why hectares of mulberry trees are specially planted for them.

Like any butterfly, the silkworm goes through four life stages.

• Larva.
• Caterpillar.
• A chrysalis in a silk cocoon.
• Butterfly.

As soon as the head of the caterpillar darkens, the lenok process will begin. Usually the insect sheds its skin four times, the body becomes yellow, the skin acquires density. So the caterpillar moves to a new stage, becomes a chrysalis, which is in a silk cocoon. Under natural conditions, the butterfly gnaws a hole in the cocoon and shaves itself out of it. But in sericulture, the process proceeds according to a different scenario. Manufacturers do not allow silkworm cocoons to "ripen" to the last stage. Within two hours under the influence of high temperature ( 100 degrees), the caterpillar then dies.

Appearance of a wild silkworm

Butterfly with big wings. Domesticated silkworms are not very attractive (the color is white with dirty spots). It is radically different from the "home relatives" is a very beautiful butterfly with bright large wings. Until now, scientists cannot classify this species, where and when it appeared.

In modern sericulture, hybrid individuals are used.

1. Monovoltine, produces offspring once a year.
2. Polyvoltine, gives offspring several times a year.

The silkworm cannot live without human care, it is not able to survive in the wild. The silkworm caterpillar is not able to get food on its own, even if it is very hungry, it is the only Butterfly that cannot fly, which means that it is not capable of finishing food on its own.

Useful properties of silk thread

The productive ability of the silkworm is simply unique, in just a month it is able to increase its weight ten thousand times. At the same time, the caterpillar manages to lose “extra pounds” four times within a month.

It would take a ton of mulberry leaves to feed thirty thousand caterpillars, enough for the insects to weave five kilograms of silk thread. The usual production rate of five thousand caterpillars yields one kilogram of silk thread.

One silk cocoon gives 90 grams natural fabric. The length of one of the threads of a silk cocoon can exceed 1 km. Now imagine how much work a silkworm needs to work on, if on average 1,500 cocoons are spent on one silk dress.

Silkworm saliva contains sericin, a substance that protects silk from pests such as moths and mites. The caterpillar secretes a viscous substance of sloping origin (silk glue) from which it spins a silk thread. Despite the fact that most of this substance is lost during the manufacture of silk fabric, even the little that remains in the silk fibers can save the fabric from the appearance of dust mites.


Thanks to serecin, silk has hypoallergenic properties. Due to its elasticity and incredible strength, silk thread is used in surgery for suturing. Silk is used in aviation; parachutes and balloon shells are sewn from silk fabric.

Silkworms and cosmetics

Interesting fact. Few people know that a silk cocoon is an invaluable product; it is not destroyed even after all silk threads are removed. Empty cocoons are used in cosmetology. Masks and lotions are prepared from them not only in professional circles, but also at home.

silkworm gourmet food

Few people know about the nutritional properties of the silk caterpillar. This is ideal protein product, it is widely used in Asian cuisine. In China, the larvae are steamed and grilled, seasoned, usually with a huge amount of spices you don’t even understand what “is on the plate”.


In Korea, they eat half-cooked silkworms, for which they are lightly fried. This is a good source of protein.

Dried caterpillars are commonly used in traditional Chinese and Tibetan medicine. The most interesting thing is that mold fungi are added to the “medicine”. Here is a useful silkworm.

What do good intentions lead to?

Few people know that the gypsy moth, which is the main pest of the US forestry industry, spread as a result of an unsuccessful experiment. As they say, I wanted the best, but the following came out.

Silkworm or Silkworm

A silkworm is called a silkworm caterpillar. He is from the family of true silkworms, which has about a hundred species. Their caterpillars weave a cocoon of silk: in it, the transformation of a chrysalis into a butterfly takes place. Some have so much silk in their cocoons that by skillfully unwinding it, one can obtain threads suitable for making fabrics. Coarse varieties of silk are obtained from the cocoons of the Chinese oak peacock eye and some other silkworms (philosamia, telea). The best silk, however, comes from the silkworm. This butterfly is a real pet, it is completely dependent on the person. Not like bees, which can live perfectly well without people in the wild.

Where does the silkworm come from and who is its wild ancestor?

Many researchers believe that his homeland is the Western Himalayas, some areas of Persia and China. The mandarin theophila butterfly lives there, darker in color than the silkworm, but generally similar to it, and most importantly, can interbreed with it, giving hybrid offspring. It is possible that the Chinese began to breed this butterfly in ancient times, and after thousands of years of skillful selection, a silkworm was obtained - in the human economy, the most useful insect after the bee. Artificial silk successfully competes with natural silk today, and yet the annual world production of silk obtained from the silkworm amounts to hundreds of millions of kilograms.

When, how long ago did they start breeding silkworms? The legend tells: 3400 years ago, a certain Fu Gi made musical instruments with strings from silk threads. But the real cultivation of the silkworm and the constant use of its silk for the production of fabrics began later: about four and a half thousand years ago. As if Empress Xi Ling Chi was the initiator of this useful work (for which she was elevated to the rank of deity, and this significant event was celebrated annually with ritual holidays).

At first, only empresses and women of high rank were engaged in the production of silk. They kept the secrets of this business in secret. “For more than 20 centuries, the Chinese jealously guarded the monopoly of silk and protected it with laws that punished by death or torture anyone who sought to take abroad the egg of a wonderful silkworm or divulge the secret of breeding and unwinding cocoons” (J. Rostand).

Twenty centuries is a very long time, hardly any other secrets have been kept for so long. But sooner or later, the secret ceases to be a secret. This is what happened with sericulture. Be it true or genda, but ancient texts say that in the 4th century AD, a Chinese princess brought her husband, the ruler of Bukhara, an invaluable marriage gift - silkworm eggs. She hid them in her intricate hairstyle.

In the same century, sericulture began to develop in some parts of India. From here, apparently (this story is probably known to many), Christian monks carried silkworm eggs and seeds of a mulberry tree in hollow staffs, the leaves of which feed the caterpillars that produce precious silk. The eggs brought by the monks to Byzantium did not die, caterpillars hatched from them and cocoons were obtained. But later, the sericulture started here withered and only in the 8th century flourished again in the vast territory occupied by the Arabs, from Central Asia to Spain.

“The main centers of sericulture are located in Central Asia and Transcaucasia. Their position is determined by the distribution of the host plant, which is the mulberry tree (mulberry). The lack of cold-resistant mulberry varieties hinders the advancement of sericulture further north” (Professor F.N. Pravdin).

The leaves of this tree are eaten by silkworms with a loud crunch, which Pasteur compared to "the sound of rain falling on the trees during a thunderstorm." This is when there are a lot of worms and they all eat. And by the end of their larval life they eat continuously - day and night! And in any position: squeezed by neighbors, lying on their backs, on their sides, and everyone eats and eats - they eat as much greenery in a day as they themselves weigh.

They eat and grow. A tiny caterpillar emerges from the egg, about three millimeters long. And after 30-80 days, the silkworm that has completed its development is already 8 centimeters long and a centimeter thick. It is whitish, pearl or ivory. On his head he has six pairs of simple eyes, tactile antennae and, most importantly, what made him so valuable in the human economy - a small tubercle under the lower lip. A sticky substance oozes from the hole at its end, which, when it comes into contact with air, immediately turns into a silk thread. Later, when he spins a cocoon, we will see how this natural silk spinning works.

The silkworm, strictly speaking, eats only the leaves of the mulberry tree. We tried to feed him with other plants: blackberry leaves, for example, or lettuce. He ate them, but grew worse, and the cocoons were not the first grade.

So, eating at first the soft parts of the leaves, and then, when it matures, the veins, even the petioles, the silkworm grows rapidly. In the first days, it doubles its weight every day, and during its entire larval life it increases 6-10 thousand times: before pupation, it weighs 3-5 grams - more than the smallest mammals, some shrews and bats.

Frozen and hard as glass, the worm does not die. If you warm it up, it comes to life, eats calmly again and later weaves a cocoon. But in general, he is warm-hearted. The most favorable temperature for him is 20-25 degrees. Then it grows rapidly: its larval life, if there is enough food, is 30-35 days. When it is colder (15 degrees) - 50 days. It is possible in 14 days to make him complete all the processes necessary for the caterpillar to grow and prepare for transformation, if you feed it abundantly and keep it at 45 degrees Celsius.

10 days after the last, fourth molt, the appetite of the worm is no longer the same as before. Soon he stops eating altogether and starts crawling around uneasily...

These butterflies are used by humans to obtain silk; in general, the silkworm is a very old inhabitant of our planet. Some argue that people began to use it as early as five thousand years BC.

Today, the worms of this butterfly are bred to produce silk, interesting facts are that in China and Korea, silkworm cockles are used for food, they are fried and such a dish is considered exotic, and these larvae are also used in folk medicine.

In our world, the most important countries that produce silk (60 percent of the total market) are India and China, where silkworms live the most.

Today, people know much more about the production and types of silk than about the insect that gave us this magnificent silk thread. We will talk about this in this article. We will find out what the silkworm looks like, what it eats, how it is bred, as well as its breeding characteristics.

Appearance

Silkworms got their name from their diet. They recognize only one tree - this is mulberry, in scientific language this tree is called mulberry. Silkworm caterpillars eat day and night without stopping. Therefore, some farm owners get inconvenienced if the tree is occupied by caterpillars of this breed. In the silk industry, the mulberry tree is specially grown to provide food for silkworms.

This insect goes through a standard development process, which can be seen in the video. Like all insects, the wild silkworm goes through four life cycles, namely:

• the formation of an egg (larva);
• the appearance of a caterpillar;
• pupa formation (silkworm cocoons);
• butterfly.

The butterfly is quite large. The wingspan is about 60 millimeters. The main characteristics of the appearance include the following indicators:

• the color is white with dirty spots;
• brown clear dressings on the wings;
• the front part of the wing is notched;
• males have comb whiskers, while females have this effect weakly expressed;

Outwardly, the wild silkworm is very beautiful. In the photo and video you can see how this breed of butterflies looks in life.

To date, this species practically does not fly, due to the content in unnatural conditions. There are also interesting facts that state that these insects do not eat when they become butterflies. This breed has clear distinctive features from all other species. The fact is that for many centuries, a man kept a silkworm at home and therefore, today these butterflies cannot survive without his care and guardianship. For example, caterpillars will not look for food, even if they are very hungry, they will wait for a person to feed them. To date, scientists cannot give an exact answer about the origin of this species.

In modern sericulture, there are many varieties of silkworms. Most often, hybrid individuals are used. In general, this breed can be divided into two types:

• the first is monovoltine, such a species can give offspring no more than once a year;
• the second is polyvoltine, which produces larvae several times a year.

Hybrids also differ in external signs, which include:

• wing color;
• body shape;
• the dimensions that characterize the pupa;
• shapes and sizes of butterflies;
• the size and color of the caterpillars (there is a breed of silkworm with striped caterpillars or one-color ones).

How all possible types of silkworms look can be seen in the photo or video.

The indicators of silkworm productivity include the following characteristics:

• the amount of output of dry cocoons and their total yield;
• how much cocoon shells can unwind;
• silk output;
• technical properties and quality of the resulting silk.

What are the characteristics of silkworm eggs?

In the scientific field, silkworm eggs are called grena. Features are as follows:

• oval shape;
• slightly flattened sides;
• elastic and translucent shell.

The size of the egg is incredibly small, in one gram there can be up to two thousand eggs. As soon as the butterflies have laid grena, it has a light yellow or milky color, and over time the color of the eggs gradually changes, at first turning a little pink and finally becoming dark purple. And when the color of the eggs does not change, this indicates that their vitality has been completely lost.

The ripening period of grena is long. Butterfly larvae are laid in July and August. Then they hibernate until spring. During this period, all metabolic processes in the egg slow down significantly. This is necessary so that the grena can endure low temperatures, and the appearance of caterpillars is regulated. For example, if in winter the eggs were at a temperature not lower than +15 degrees, then future caterpillars develop very poorly. This is due to the fact that they hatch very early, even before mulberry leaves appear (this is the main food source for silkworms). Therefore, during this period, the eggs are placed in the refrigerator, where a constant temperature regime is observed from 0 to -2 degrees.

Life cycle of caterpillars

The appearance of caterpillars refers to the larval stages of development of silkworms. They used to be called silkworms, but based on scientific terms, this name is incorrect. The external characteristics of the tracks include the following indicators:

• the body has a slightly elongated shape;
• there is a head, abdomen and chest;
• there are horny appendages on the head;
• on the inside of the body there are three pairs of pectoral, and five abdominal legs;
• caterpillars have chitinous covers that perform a protective function and at the same time are their muscles.

You can see the external data of the caterpillars in the photo, as well as see their life cycle in the video.

Once a caterpillar hatches from an egg, it is very small, weighing only half a milligram. But with such a small size and weight, the body of the caterpillars has all the necessary biological processes for a full life, so they grow rapidly. The body of the caterpillar has very powerful jaws, esophagus, developed pharynx, intestines, circulatory and excretory system. Thanks to such a developed organism, all the food consumed is very well absorbed. Imagine that these babies have more than four thousand muscles, which is eight times more than humans. Acrobatic numbers that caterpillars can perform are associated with this.

The life cycle of a caterpillar lasts about forty days, during which time it increases in size by more than thirty times. Due to this intensity of growth, the shell with which the caterpillars are born becomes small, so they need to shed their old skin. This process is called molting. During this period, individuals stop feeding and find a place to molt. Tightly attaching their legs to the leaves, or holding on to a tree, they freeze. In the people, this period is called sleep. This spectacle can be seen in detail in the photo. Then the caterpillar, as it were, hatches again from the old skin. First, the head appears, which has increased several times in size, and then the rest of the body. During sleep, the caterpillars cannot be touched, otherwise they will not be able to throw off the old cover, as a result of which they die.

Caterpillars go through the process of molting four times during their entire life span. And each time they have a different color. In the photo and video you can see the colors of the caterpillars.

The main part of the caterpillar's body for humans is the silk gland. This organ is best developed, thanks to artificial content for many centuries. In this organ, the silk we need is formed.

Final stage of development: silkworm chrysalis

Silkworm cocoons are formed for a short time (you can see them in the photo) This is an intermediate stage of development. The caterpillar forms a chrysalis around itself and stays there until it turns into a butterfly. Such silkworm cocoons are the most valuable for humans. Many amazing processes take place inside the cocoon, the caterpillar goes through the stage of the last molt and turns into a chrysalis, and then it becomes a butterfly.

The appearance of a butterfly and its departure can be easily determined. The day before the emergence of cocoons begin to move. If you lean against the cocoon at this time, you can hear a small noise, like tapping. This butterfly sheds its pupa skin. Interestingly, butterflies appear strictly at the allotted time. This is the period from five to six in the morning.

In order to get out of the cocoon, the mucous membranes of the butterfly secrete a specialized glue that splits the cocoon and makes it possible to fly out (newborn butterflies can be seen in the photo).

Butterflies live very little, no more than 18-20 days, but there are also centenarians who can reach the age of 25-30 days. The jaws and mouth of butterflies are undeveloped, so they cannot eat. During this short life span, their main purpose is to mate and lay eggs. One female can lay more than one thousand eggs per clutch. The laying process does not stop, even if the female does not have a head, because there are several nervous systems in her body. In order to provide future offspring with good survival, females very strongly attach grena to the surface of a leaf or tree. That's all! This is where the life cycle of silkworms ends.

Then the process begins again, and goes through all the above stages again, supplying humanity with a silk thread.