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Insect silkworm. Butterfly - silkworm. Life cycle of the silkworm

The history of breeding such an insect as the silkworm is extremely interesting. The technology was developed a long time ago, in ancient China. The first mention of this production in Chinese chronicles dates back to 2600 BC, and silkworm cocoons found by archaeologists date back to 2000 BC. e. The Chinese elevated the production of silk to the status of a state secret, and for many centuries this was the country's obvious priority.

Much later, in the 13th century, Italy, Spain, the countries of North Africa, and in the 16th century, Russia began to breed and produce such worms. What kind of insect is the silkworm?

Silkworm butterfly and its offspring

The domesticated silkworm butterfly is not found in the wild today and is bred in special factories to obtain a natural thread. An adult is a fairly large light-colored insect, reaching 6 cm in length with a wingspan of up to 5-6 cm. Breeders from many countries are engaged in breeding various breeds of this interesting butterfly. After all, optimal adaptation to the characteristics of various localities is the basis for profitable production and maximum income. Many breeds of silkworm have been bred. Some give one generation a year, others two, and there are species that give several broods a year.

Despite its size, the silkworm butterfly has long lost this ability. She lives only 12 days and during this time she does not even eat, having an undeveloped oral cavity. With the onset of the mating season, silkworm breeders deposit pairs in separate bags. After mating, the female for 3-4 days is engaged in laying eggs in the amount of 300-800 pieces per grain, which has an oval shape with significantly varying sizes, which are directly dependent on the breed of the insect. The period of removal of the worm also depends on the species - it can be in the same year, or maybe in the next.

Caterpillar - the next stage of development

The silkworm caterpillar hatches from eggs at a temperature of 23-25 ​​°C. In the factory, this happens in incubators at a certain humidity and temperature. Eggs develop within 8-10 days, then a brown small up to 3 mm long silkworm larva, pubescent with hairs, appears from the grena. Small caterpillars are placed in special trays and transferred to a well-ventilated warm room. These containers are a structure like a bookcase, consisting of several shelves, covered with a net and having a specific purpose - here the caterpillars constantly eat. They feed exclusively on fresh mulberry leaves, and the proverb “appetite comes with eating” is absolutely accurate for determining the voracity of caterpillars. The need for food grows in them and already on the second day they eat twice as much food as on the first.

Moult

By the fifth day of life, the larva stops, freezes and begins to wait for its first molt. She sleeps for about a day, clasping her legs around a leaf, then, with a sharp straightening, the skin bursts, releasing the caterpillar and giving it the opportunity to rest and again take up satisfying hunger. For the next four days, she absorbs the leaves with an enviable appetite, until the next molt comes.

caterpillar transformations

For the entire period of development (about a month), the caterpillar molts four times. The last molt turns it into a rather large individual of a magnificent light pearl shade: the body length reaches 8 cm, the width is up to 1 cm, and the weight is 3-5 g. It stands out on the body with two pairs of well-developed jaws, especially the upper ones, called "mandibles ". But the most important quality that is important for the production of silk is the presence in an adult caterpillar of a tubercle under the lip, from which a special substance oozes, which hardens on contact with air and turns into a silk thread.

The formation of a silk thread

This tubercle ends with two silk glands, which are long tubes with a middle part turned into a kind of reservoir in the body of the caterpillar, accumulating a sticky substance, which subsequently forms a silk thread. If necessary, the caterpillar releases a trickle of liquid through the hole under the lower lip, which solidifies and turns into a thin, but strong enough thread. The latter plays a big role in the life of an insect and is used, as a rule, as a safety rope, since at the slightest danger it hangs on it like a spider, not being afraid to fall. In an adult caterpillar, silk glands occupy 2/5 of the entire body weight.

Stages of building a cocoon

Having reached adulthood after the 4th molt, the caterpillar begins to lose its appetite and gradually stops eating. By this time, the silk secreting glands are filled with liquid so that a long thread constantly stretches behind the larva. This means that the caterpillar is ready to pupate. She begins to look for a suitable place and finds it on cocoon rods, promptly placed by silkworm breeders along the side walls of the stern "shelves".

Having settled on a twig, the caterpillar begins to work intensively: it alternately turns its head, applying a tubercle with a hole for the silk gland to different places on the cocoon, thereby forming a very strong network of silk thread. It turns out a kind of frame for future construction. Then the caterpillar crawls to the center of its frame, holding itself in the air by means of threads, and begins to twist the actual cocoon.

Cocoon and pupation

When building a cocoon, the caterpillar turns its head very quickly, releasing up to 3 cm of thread on each turn. Its length to create the entire cocoon is from 0.8 to 1.5 km, and the time spent on it takes four or more days. Having finished work, the caterpillar falls asleep in a cocoon, turning into a chrysalis.

The weight of the cocoon together with the chrysalis does not exceed 3-4 g. Silkworm cocoons are very diverse in size (from 1 to 6 cm), shape (round, oval, with bridges) and color (from snow-white to golden and purple). Experts have noticed that male silkworms are more diligent in terms of cocoon weaving. Their pupal dwellings are distinguished by the density of the winding of the thread and its length.

And again a butterfly

After three weeks, a butterfly emerges from the chrysalis, which needs to get out of the cocoon. This is difficult, since it is completely devoid of jaws that adorn the caterpillar. But wise nature solved this problem: the butterfly is equipped with a special gland that produces alkaline saliva, the use of which softens the wall of the cocoon and helps to release the newly formed butterfly. So the silkworm completes the circle of its own transformations.

However, industrial breeding of the silkworm interrupts the reproduction of butterflies. The bulk of the cocoons is used to produce raw silk. After all, this is a finished product, it remains only to unwind the cocoons on special machines, after killing the pupae and treating the cocoons with steam and water.

So, the silkworm, the cultivation of which on an industrial scale will probably never lose its relevance, is a magnificent example of a domesticated insect that brings a very considerable income.

People know a lot about the merits of silk, but few people are familiar with the “creator” who gave this miracle to the world. 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 sheer 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- well known insect. The wild species of this species was first seen in the Himalayas. The silkworm has been domesticated for a very long time - from the third millennium BC.

He gained great fame in connection with the unique ability to create such cocoons, which are the raw material for obtaining real silk itself. Systematics of the silkworm- belongs to the genus Silkworms of the real family of the same name. Silkworm is a representative detachment butterflies.

The main habitat of the insect is the regions of Southeast Asia with a subtropical climate. It is also found in the Far East. Silkworms are bred in many regions, but the only requirement is that mulberry must grow in those places, since silkworm larvae feed exclusively on it.

An adult is able to live only 12 days, during which it does not eat, since it does not even have a mouth. Surprisingly, silkworm butterfly can't even fly.

Pictured is a silkworm butterfly

As can be seen on photo, silkworm looks rather unattractive and looks like the most common moth. Its wingspan is only 2 centimeters, and their color varies from whitish to light gray. It has a pair of antennae, which are abundantly covered with bristles.

Lifestyle of the silkworm

The silkworm is a well-known garden pest, as its larvae are very voracious and can greatly harm garden plants. Getting rid of it is not so easy, and for gardeners the appearance of this insect is a real disaster.

Silkworm life cycle includes 4 stages and is about two months. sedentary and live only to lay eggs. The female lays up to 700 eggs, which are oval in shape. The laying process can take up to three days.

Types of silkworm

Nun silkworm living in the forest. Wings black and white, antennae with long serrations. Reproduction occurs once a year, in summer. Caterpillars are very harmful to coniferous trees, beech, oak and birch.

Butterfly silkworm nun

Ringed - bears this name because of the characteristic shape of the masonry - in the form of an egg. The clutch itself contains up to three hundred eggs. It is the main enemy of apple trees. The body of the butterfly is covered with a light brown fluff. ringed silkworm- it is his cocoons that are the main raw material for the production of silk.

Butterfly ringed silkworm

Pine silkworm- Pine pest. The color of the wings is brownish, close to the color of pine bark. Quite large butterflies - females reach a wingspan of up to 9 centimeters, males are smaller.

Pine silkworm butterfly

gypsy moth- the most dangerous pest, as it can affect up to 300 plant species. The name is due to the large difference between the female and male in appearance.

Gypsy moth butterfly

Nutrition of the silkworm

It feeds mainly on mulberry leaves. The larvae are very voracious and grow very quickly. They can eat figs, breadfruit and dairy trees, ficuses and other trees of this species.

In captivity, lettuce leaves are sometimes eaten, but this has a bad effect on the health of the caterpillar, and therefore on the quality of the cocoon. At the moment, scientists are trying to create a special feed for the silkworm.

Reproduction and life span of the silkworm

Reproduction in this insect takes place in the same way as most others. Between the time the female lays her eggs and the first appearance of the caterpillars, about ten days pass.

With artificial breeding, a temperature of 23-25 ​​degrees is set for this. Silkworm caterpillar each subsequent day eats more and more food.

Pictured are silkworm caterpillars

On the fifth day, the larva stops feeding, freezes, and the next day, when it emerges from the old skin, it starts feeding again. Thus, four molts occur. At the end of development, the larva is one month old. Under her lower jaw is the same papilla from which a silk thread stands out.

silkworm thread, despite its very small thickness, can withstand up to 15 grams of cargo. It can be isolated even by newly born larvae. Very often it is used as a saving tool - in case of danger, the caterpillar can hang on it.

In the photo, a silkworm thread

At the end of the life cycle, the caterpillar feeds little, and by the beginning of the cocoon construction, feeding stops completely. At this time, the gland that secretes the silk thread is so full that it always reaches for the caterpillar.

At the same time, the caterpillar exhibits restless behavior, trying to find a place to build a cocoon - a small branch. The cocoon is built within three to four days, and it takes up to a kilometer of silk thread.

There are cases when several caterpillars twist one cocoon for two, three or four individuals, but this rarely happens. Myself silkworm cocoon weighs about three grams, has a length of up to two centimeters, but some specimens reach a length of up to six centimeters.

Pictured is a silkworm cocoon

They vary slightly in shape - it can be round, oval, ovoid or slightly flattened. The color of the cocoon is often white, but there are specimens whose color is close to golden, and even greenish.

The silkworm hatches in about three weeks. It does not have a jaw, so it makes a hole with saliva, which eats away at the cocoon. With artificial breeding, the pupae are killed, otherwise the cocoon damaged after the butterfly is not suitable for obtaining silk thread. In some countries, the slaughtered chrysalis is considered a delicacy.

Silkworm breeding is widespread. To do this, mechanized farms are created for the production of yarn, from which a real yarn is subsequently obtained. silkworm silk.

Pictured is a silk thread farm

The clutch of eggs laid by the female is kept in an incubator until the larvae appear. As food, the larvae receive the usual food - mulberry leaves. In the premises, all air parameters are controlled for the successful development of the larvae.

Pupation occurs on special branches. When creating a cocoon, males secrete more silk thread, so silkworm breeders try to increase the number of males.

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.

From a small tubercle under the lower lip of the caterpillar, a sticky substance is released, which, upon contact with air, immediately solidifies and turns into a silk thread. The thread is very thin, but can withstand weight up to 15 grams.

All modern domestic animals and cultivated plants are descended from wild species. Not without an insect on the farm - silkworm butterflies. Over four and a half millennia of breeding work, it was possible to breed breeds that give silk of different colors, and the length of a continuous thread from one cocoon can reach a kilometer! The butterfly has changed so much that it is now difficult to say who was its wild ancestor. In nature, the silkworm is not found - without human care, it dies.

Recall that many other caterpillars weave a cocoon of silky threads, but only in the silkworm they have the properties we need. Silk threads are used to produce fabrics that are very durable and beautiful; they are used in medicine - for sewing up wounds and cleaning teeth; in cosmetology - for the manufacture of decorative cosmetics, such as shadows. Despite the advent of artificial materials, natural silk threads are still widely used.

Who first came up with the idea of ​​weaving silk fabric? According to legend, four thousand years ago, a silkworm cocoon fell into a cup of hot tea, which the Chinese empress drank in her garden. Trying to pull it out, the woman pulled on a protruding silk thread. The cocoon began to unwind, but the thread did not end. It was then that the quick-witted empress realized that yarn could be made from such fibers. The Chinese emperor approved the idea of ​​his wife and ordered his subjects to grow mulberry (white mulberry) and breed silkworm caterpillars on it. And to this day, silk in China is called the name of this ruler, and her grateful descendants elevated her to the rank of a deity.

It took a lot of work to get beautiful silk from butterfly cocoons. To begin with, the cocoons need to be collected, discarded and, most importantly, unwound, for which they were dipped into boiling water. Next, the thread was strengthened with sericin - silk glue, which was then removed with boiling water or hot soapy water.

Before dyeing, the thread was boiled and bleached. They painted it with vegetable pigments (gardenia fruits, moraine roots, oak acorns), or mineral pigments (cinnabar, ocher, malachite, white lead). And only then they wove yarn - by hand or on a loom.

As early as one and a half thousand years BC, clothes made of silk fabrics were common in China. In other Asian countries and among the ancient Romans, silk appeared only in the 3rd century BC - and then it was fabulously expensive. But the manufacturing technology of this amazing fabric remained a secret for the whole world for many centuries, because an attempt to take the silkworm out of the Chinese Empire was punishable by death. The nature of silk seemed mysterious and magical to Europeans. Some believed that silk was produced by giant beetles, others believed that in China the earth was soft, like wool, and therefore, after watering, it could be used to produce silk fabrics.

The secret of silk was discovered in the 4th century AD, when a Chinese princess presented a gift to her fiancé, the king of Lesser Bukhara. These were silkworm eggs, which the bride secretly took out of her homeland, hiding in her hair. Around the same time, the secret of silk became known to the Japanese emperor, but here sericulture for some time was the monopoly of the imperial palace alone. Then silk production was mastered in India. And from there, with two monks who placed silkworm eggs in the hollow handles of their staffs, they ended up in Byzantium. In the 12th-14th centuries, sericulture flourished in Asia Minor, Spain, Italy and France, and in the 16th century it appeared in the southern provinces of Russia.


Silkworm pupa

However, even after the Europeans learned to breed silkworms, most of the silk continued to be delivered from China. Along the Great Silk Road - a network of roads running from east to west - it was taken to all countries of the world. Silk outfits remained a luxury item, silk also served as an exchange currency.

How does a small white butterfly live - "silk queen"? Its wingspan is 40-60 millimeters, but as a result of many years of cultivation, butterflies have lost the ability to fly. The mouth apparatus is not developed because the adult does not feed. Only the larvae differ in an enviable appetite. They are fed with mulberry leaves. When feeding on other plants that the caterpillars "agree" to eat, the quality of the fiber deteriorates. On the territory of our country, representatives of the family of true silkworms, to which the silkworm belongs, are found in nature only in the Far East.

Silkworm caterpillars hatch from eggs, the laying of which is covered with a dense shell and is called grena. In sericulture farms, grena is placed in special incubators, where the necessary temperature and humidity are maintained. After a few days, small, three-millimeter dark brown larvae appear, covered with tufts of long hair.

Hatched caterpillars are transferred to a special aft shelf with fresh mulberry leaves. After several molts, the babies grow up to eight centimeters, and their bodies become white and almost naked.

The caterpillar, ready for pupation, ceases to feed, and then wood rods are placed next to it, to which it immediately passes. Holding on to one of the rods with its abdominal legs, the caterpillar throws its head to the right, then back, then to the left and applies its lower lip with a "silk" tubercle to various places on the rod.


Caterpillars are fed with mulberry leaves.

Soon a rather dense network of silk thread is formed around it. But this is only the basis of the future cocoon. Then the "craftswoman" crawls to the center of the frame and begins to curl the thread: releasing it, the caterpillar quickly turns its head. The tireless weaver works on the cocoon for about four days! And then it freezes in its silk cradle and turns into a chrysalis there. After about 20 days, a butterfly emerges from the chrysalis. She softens the cocoon with her alkaline saliva and, helping herself with her legs, hardly gets out to start looking for a partner for procreation. After mating, the female lays 300-600 eggs.

However, not every caterpillar is given the opportunity to turn into a butterfly. Most of the cocoons are sent to the factory for raw silk. One centner of such cocoons yields approximately nine kilograms of silk thread.

It is interesting that the caterpillars, from which males are later obtained, are more diligent workers, their cocoons are denser, which means that the thread in them is longer. Scientists have learned to regulate the sex of butterflies, increasing the yield of silk during its industrial production.

Such is the story of the small white butterfly that made ancient China famous and made the whole world worship its magnificent product.

Olga Timokhova, Candidate of Biological Sciences