Where do leeches live. What does a medical leech look like and what does it eat? benefit. Acne treatment with leeches

The long-awaited report from the leech farm. You will learn how leeches live in captivity, what they eat, how they reproduce. For the first time, we were able to capture unique footage of the birth of a leech in natural conditions and in captivity.

Five pairs of eyes were intensely watching the water column, all the senses were aimed at finding the victim. For more than three weeks, in search of food, one has to move from one corner of the reservoir to another. Even repeated attacks on land did not bring the desired result. Sad thoughts overcame the vampire. Blood and only blood... “Well, you can hold out for another three months, but if happiness does not smile, you will have to emigrate to a nearby reservoir; they say that cattle come there to drink...” A splash was heard somewhere, another, a third - the steel muscles tensed. The vampire determined the source of the vibrations and directed his body towards the victim with smooth wave-like movements. Here she is! Light, warm body, and how little wool, if only not to miss. The vampire spread his huge mouth, bared three terrible jaws with the sharpest teeth, and dug into the victim... A heartbreaking cry resounded the water surface of the reservoir.

01.

02. Today we will tell you about International Center medicinal leech, created on the basis of the association "Medpiyavka", formed in 1937, which was engaged in keeping leeches in artificial ponds of the holiday village Udelnaya (Moscow region).

03. At 2500 sq. m. there are production facilities for growing more than 3,500,000 medicinal leeches and the production of cosmetic products.

04. In total, 400 species of leeches are known to science, which look approximately the same and differ mainly in color. Leeches are black, greenish or brownish. Russian name These nimble worms indicate their ability to "dig into" the victim's body and suck out blood.

05. Leeches live in three-liter jars. Nothing better as a house for them came up with. The leech breeder must ensure that the vessel with leeches is constantly closed with a thick white cloth, which is tightly tied.

06. Leeches are unusually mobile and often tend to crawl out of the water. Therefore, they are able to easily leave the container in which they are stored. Escapes occasionally happen.

07. A leech has 10 eyes, but the leech does not perceive a complete image. Despite the seeming primitiveness of the sensory perception of leeches, they perfectly orient themselves in space. Their sense of smell, taste and touch are extraordinarily developed, which contributes to their success in finding prey. First of all, leeches respond well to odors emanating from objects immersed in water. Leeches do not tolerate foul-smelling water.

08. Unhurried, devoid of sharp movements allow you to see the entire body of a leech. On the back, against a dark background, bright orange blotches form a fancy pattern in the form of two stripes. On the sides - black piping. The abdomen is delicate, light olive in color with black edging. The body of an ordinary medical leech consists of 102 rings. On the dorsal side, the rings are covered with many small papillae. On the ventral side, the papillae are much smaller and less visible.

09. But behind the harmless external beauty of a leech lies its secret weapon - the front sucker, outwardly invisible. A large, intimidating rear sucker does not cause any physical damage, but in the depths of the front, jaws lurk, geometrically located according to the sign of the prestigious company in the automotive world - Mercedes. In each jaw, there are up to 90 teeth, a total of 270. Here it is - deceit.

10. Record maximum size leeches grown in this center - 35 centimeters in length. The leech in the photo still has everything ahead.

11. Bitten by a leech - like a nettle stung. The bite of the same horsefly or ant is much more painful. Leech saliva contains painkillers (analgesics). The leech feeds exclusively on blood. Hematophagus, that is, a vampire.

12. The epidermal layer of the leech is covered with a special film - the cuticle. The cuticle is transparent, it performs a protective function and continuously grows, being periodically updated in the process of molting. Normally, molting occurs in leeches every 2-3 days.

13. Dropped films look like white flakes or small white cases. They clog the bottom of the vessels for storing used leeches, and therefore must be removed regularly, and the water is also periodically stained from digestion products. Water is changed twice a week.

14. Water is specially prepared: it settles for at least a day, it is purified from harmful impurities and heavy metals. After cleaning and passing control, the water is heated to desired temperature and enters the common network for leeches.

15.

16. Leeches poop up to several times a day, so the water in the vessel where the used leeches are stored is periodically stained. The clogging of water that occurs from time to time does not cause any harm to leeches if the water is systematically changed.

17. The most important condition for the rapid cultivation of full-fledged medicinal leeches is their regular feeding with fresh blood, which is purchased from slaughterhouses.

18. Large clots are used, formed during the coagulation of the blood mass. For the full feeding of leeches, only the blood of healthy animals, mainly large and small, is taken. cattle. Clots are placed at the bottom of special vessels, where leeches are then released.

19. To make it pleasant for leeches to eat, a film is laid on them, which they bite through and suck blood out of habit.

20. During growth, the leech feeds every one and a half to two months.

21. After the leeches have grown and starved for at least three months, they are collected in a batch and sent for certification, and then they go on sale or are used in the production of cosmetics. The Center has an accredited laboratory of the quality control department. But more on that tomorrow.

22. For one feeding, a leech sucks out five times its weight, after which it may not eat for three to four months, a maximum of a year. After eating, the leech looks like a solid muscle bag filled with blood. In her digestive tract there are special substances that protect the blood from putrefaction, which preserve it in such a way that the blood always remains complete and stored for a long time.

23. A leech usually eats up in 15-20 minutes. A sign that the leech is full, foam appears.

24. Well-fed leeches are trying to escape from the "dining room".

25. Yum-yum!

26. After feeding, the leeches are washed.

27. And they put it back in the jar.

28.

29. And they wash the dishes.

30.

31. Leeches communicate with each other extremely rarely, only during the mating period. And then, most likely, out of necessity, so as not to die out. Leeches that are suitable for reproduction, that is, carefully fed and have reached a given size, are called queens.

32. They are placed in pairs in jars filled with water and stored in special rooms where optimum temperature an environment that supports the activity of leeches and their reproductive abilities. Copulation and laying of cocoons with eggs occur in leeches at an environmental temperature of 25 to 27 °C. And although each individual carries both the male and female principles (hermaphrodites), she cannot satisfy herself in this intimate matter and is looking for a partner.

33. mating season, during which mating takes place, takes about 1 month, after which the leeches are seated in queen cells - three-liter jars. Moist peat soil is placed at the bottom of the mother liquor, which is a favorable environment for medical leeches and their cocoons. Soft moss sods are lined over the peat, which regulate soil moisture. The queens move freely on the moss, in which they feel comfortable, and gradually dig into the peat.

34. Leeches practice different positions in which copulation is carried out. There are 2 main positions that make biological sense. First position: the front ends of the bodies of copulating leeches are directed in one direction. The second main position: the ends of the bodies are opposite, that is, they look in different directions.

35. The peat is thoroughly washed so that the leeches are damp and comfortable.

36.

37. By light rings, you can identify a pregnant leech and plant it in a jar of peat.

38. Breaking through a shallow passage in the soil, the leech lays a cocoon in it, from which the threads are subsequently removed - this is the name of the leech growers of small young leeches. Their mass reaches a force of 0.03 g, and the body length is 7-8 mm. Filaments are fed in the same way as adults.

39. Each mother leech lays on average 3-5 cocoons, each of which contains 10-15 fry.

40. After a while, the cocoons become like soft foam balls.

41. It can be seen through the light that fry are sitting inside the cocoon.

42. And here are unique birth shots. The leech leaves the cocoon through a hole in the end.

43.

44. The first minutes of the life of a small leech.

45. And this is how they are born in the conditions of the center. The cocoons just burst.

47. As shown by laboratory studies, the average life expectancy of a leech is 6 years. How long wild individuals live, scientists do not know for certain, although it is possible that there are long-livers among leeches.

Tomorrow at the same time there will be a story about how leeches are killed to help people. What happens to a leech after it has sucked blood from a person? How are these cute worms tortured? How to make leech powder and much more!

Text:
The book of D.G. Zharov "Secrets of hirudotherapy"
The Kiss of the Vampire book. Authors: Nikonov G.I. and Titova E.A.

But for treatment, only a medical leech is used. Among medical leeches, there are two subspecies:

Medicinal leech (Hirudina medicinalic)

Apothecary leech (Hirudina officinalic)

Color. May vary from black to reddish-brown. Abdomen motley. The sides are green with an olive tint.

Size. About 3 - 15 cm - length, about 1 cm - width.

Lifespan. Up to 20 years.

Habitat. They are found mainly in Africa, Central and Southern Europe, as well as Asia Minor. In Russia, they are not so numerous, they mainly spread to the south of the European part of the country. Although there is evidence that individual individuals of the species were found in the southern and eastern parts of Siberia.

They love fresh clean water- lakes, ponds, quiet rivers, as well as damp places near the water - clay shores, wet moss. Leeches live in stagnant water - running water is unfavorable for them.

Lifestyle and behavior. Most part of time medicinal leech spends hiding in thickets of algae, hiding under snags or stones. This is both a cover and an ambush.

Leeches love warm sunny weather and even tolerate heat quite well, it is in these conditions that they are most active. They are also not afraid of drought - they either crawl away from a drying up reservoir, or dig deeper into the coastal silt. Leeches are able to stay on land for a long time in hot and humid weather.

With the deterioration of conditions (lower air temperature, windy weather), medical leeches become lethargic and passive. Leeches overwinter by burrowing into coastal silt or bottom soil. Frosts are detrimental to them.

The body of the leech is greatly flattened and elongated when swimming, and the posterior sucker acts as a fin. With wave-like movements, the leech moves in the water.

For medical leeches, an instant reaction to external stimuli is quite characteristic: smell, temperature, splash.

A hungry leech can be recognized by the characteristic position of the body - it sticks to a plant or stone with its back suction cup, while the front one makes circular movements.

Enemies: Desman, water rat, shrews, bugs, dragonfly larvae.

Nutrition. As food, medicinal leeches use the blood of worms, molluscs and vertebrates, and in their absence they can eat insect larvae, ciliates, and mucus of aquatic plants. The leech bites through the skin of the victim and sucks out a small amount of blood, about 10-15 ml. Having satiated, the leech can remain without food for quite a long time - an average of six months, since the blood in its body is digested slowly. However, a record fasting period was observed, which amounted to 1.5 years.

Reproduction. The medicinal leech is a hermaphrodite. Leeches begin to lay eggs during the warm period, approximately two weeks before the end of August or in mid-September. With unfavorable weather conditions this period comes earlier or is delayed.

In the process of reproduction, the leech crawls out onto land, digs a small depression in the silt, then a special department of medical leeches, buy medical leeches, buy leeches in Perm, buy leeches in Perm, the cover of a leech - a girdle - secretes a foamy cocoon in which eggs are laid. This cocoon contains albumin, a protein that serves as food for embryos. The egg incubation period is about two months.

Newborn medicinal leeches are transparent and resemble adults, they still spend some time in a cocoon, feeding on albumin, but soon crawl out. Small leeches that have not reached puberty attack tadpoles, snails, frogs.

If a leech does not drink the blood of a mammal within three years from the moment it emerges from the cocoon, it will never reach puberty.

leeches(lat. Hirudinea) - a subclass of annelids from the class of belt worms (Clitellata). Most representatives live in fresh water. Some species have mastered terrestrial and marine biotopes. About 500 species of leeches are known, 62 species are found in Russia. The Russian word "leech" goes back to the Proto-Slavic *pjavka (cf. Czech. pijavka, Polish. pijawka), formed from the verb *pjati, a multiple form verb from *piti "drink".

general information

Leeches can move both in water and on land using the contraction of the muscles of the body. In water, it swims, making wave-like movements, on land it moves with the help of suction cups and crawling, like other worms. Both suction cups are used to move along the substrate and attach to it. Due to the strong muscular body, active leeches can, freely held by the posterior sucker, lift the body and make prowl searching movements with the anterior end of the body. During the rest, it prefers to climb under stones, snags and lie, partially leaning out of the water.

Leeches are able to respond to light, as well as to temperature, humidity and water fluctuations. They have a reflex reaction to the shadow, which may indicate the approach of potential food. The sensitivity of leeches decreases sharply during sucking and mating, to the point that when the posterior end of the body is cut off, the leech does not show a reaction and continues its behavior.

Nutrition

On average, a hungry leech weighing 1.5–2 g is capable of sucking up to 15 ml of blood at a time, while increasing by 7–9 times in mass.

IN natural conditions hungry leeches wait for their prey, attaching to plants or other substrate with both suckers. When signs of an approaching victim appear (ripples, shadows, water vibrations), they unhook and swim in a straight line towards the source of vibrations. Having found an object, the leech fixes on it with its back sucker, while the front one makes prowl movements in search of a suitable bite site. This is usually the place with the most thin skin and superficial vessels.

The duration of bloodsucking varies depending on the activity of the leech, the properties of the blood of the animal and other conditions. On average, a leech that has been starving for 6 months is saturated in 40 minutes - 1.5 hours.

Reproduction and development

Wild leeches reach puberty in 3–4 years, feeding up to this age only 5–6 times. In captivity, maturation occurs faster, in 1-2 years.

Reproduction occurs once a year summer period from June to August. Copulation takes place on land, two leeches wrap around each other and stick together. Despite the fact that leeches are hermaphrodites, and cross-fertilization is possible, each individual, as a rule, acts in only one capacity. Fertilization is internal, immediately after it, leeches look for a place on the shore near coastline for laying a cocoon.

Leech cocoon

One leech can lay up to 4-5 cocoons, they are oval in shape and covered with a spongy shell on the outside. Inside the cocoon there is a protein mass for feeding embryos, the number of which can be up to 20-30, their development to hatching takes 2-4 weeks. The hatched little leeches are miniature copies of adults and are ready to feed on blood. They feed mainly on frogs, as they cannot yet bite through the skin of mammals.

The history of the use of leeches in medicine

Hirudotherapy(lat. hirūdō - "leech", other Greek. θεραπεία - "treatment") - a method of alternative medicine, one of the areas of naturopathy, treatment various diseases person using a medical leech. Leech therapy was previously used in conventional medicine, but fell into disuse in the 20th century due to the advent of synthetic anticoagulants, including hirudin.

Hiruda, a medicinal leech native to Europe, has been used for bloodletting for hundreds of years. Hippocrates, Galen, Avicenna wrote about the treatment with leeches. On the walls of Egyptian tombs, drawings of the use of leeches were found. Medicinal properties Medicinal leeches have been known to people for thousands of years. A description of the methods of treating various diseases with the help of a leech can be found in the medical collections of most ancient civilizations: ancient egypt, India, Greece. The use of leeches was described by Hippocrates (4th-5th centuries BC) and Avicenna (Ibn Sina, 980-1037).

Medicinal leeches were most widely used in the 17th-18th centuries in Europe for bloodletting in connection with the concept of "bad blood", which then dominated medicine. In order to release bad blood, doctors sometimes put up to 40 leeches at the same time to one patient. Preference over vein bloodletting was given to them in case of need for bloodletting from hard-to-reach or tender places (for example, gums). In the period from 1829 to 1836, 33 million leeches per year were used in France for the treatment, in London - up to 7 million with a population of 2.3 million inhabitants. Russia supplied Europe with about 70 million leeches a year. After a paradigm shift in the middle of the 19th century, bloodletting was abandoned, and the use of leeches in Europe practically ceased.

Scientific studies of the mechanisms of action of leeches on humans began in the late 19th and early 20th centuries with the work of John Haycraft, who discovered the anticoagulant effect of leech extract. In 1884, he discovered an enzyme from the saliva of a leech - hirudin, and in 1902 preparations were obtained from hirudin. These studies marked the beginning of the scientific use of leeches in medicine. In our time, treatment with the help of medicinal leeches is experiencing a rebirth.

Features of the therapeutic effect

Live leeches are attached directly to the human body according to specially designed schemes. The choice of the place of attachment is determined by many factors: the disease, the severity of the process, the condition of the patient. The sucking process lasts from 10–15 minutes to an hour, after which the leeches are removed with alcohol, iodine, or, if fed to the full, they are released on their own. Well-fed leeches must be destroyed by placing them in a solution of chloramine, their reuse is not allowed. The therapeutic effect of exposure to live leeches is due to several factors:

• Dosed bloodletting (from 5 to 15 ml of blood for each leech, depending on the mass of the leech and the duration of the attachment). It is used to treat arterial hypertension, glaucoma, congestion in the liver, general intoxication of the body.
• The action of biologically active substances in leech saliva, the main of which is the anticoagulant hirudin, which reduces blood clotting. Used to treat angina and myocardial infarction, thrombophlebitis, vein thrombosis, hemorrhoids.
• A complex of body responses to a bite, biologically active substances of leech saliva and subsequent blood loss.

A reliable guarantee of protection against the transfer of infectious agents by a leech is the use of animals grown under artificial conditions and starving for a sufficient time, in the intestines of which there is no pathogenic flora. The use of leeches in therapy was revived in the 1970s: in microsurgery, they are used to stimulate blood circulation in order to save grafted skin and other tissues from postoperative venous stasis.

Other clinical uses for medicinal leeches include the treatment of varicose veins, muscle spasms, thrombophlebitis, and arthrosis. The therapeutic effect comes not only from the flow of blood through the tissues while feeding on leeches, but from further and steady bleeding from the wound left after the detachment of the leeches. The saliva of leeches has analgesic, anti-inflammatory and vasodilating properties.

What leeches can treat?

Of several dozen types of medicinal, there are only three:

• pharmacy;
• medical;
• eastern.

We hasten to upset lovers of self-treatment with leeches. Caught in a local reservoir, at best they will be useless, at worst they will bring irreparable harm, rewarding a person with a number of unpleasant diseases that they can carry. Leeches intended for hirudotherapy are grown in the complete sterility of special laboratories and are used only once.

Indications for use

There are a number of diseases in which treatment with leeches significantly improves the patient's condition:

• Problems with blood vessels, blood formation, tendency to form blood clots, blood stasis.
• Diseases of connective tissues and joints.
• Violation of the functions of the genitourinary system.
• Diseases of a neurological nature.
• Violations menstrual cycle, inflammation of the genital organs, ovarian dysfunction, endometriosis.
• Neurosis, epilepsy, migraine, sleep disorders.
• diseases associated with disorders of the thyroid gland.

The benefits of leeches in the treatment of blood vessels and blood

At varicose veins vein treatment with leeches stimulates blood formation, helps to strengthen the walls of blood vessels. Hirudin, secreted by a leech with saliva, is a natural biologically active substance that improves metabolism and prevents the formation of blood clots. On early stages diseases can be completely cured or stopped its development with the help of hirudotherapy.

Treatment for arthrosis and osteochondrosis

Non-inflammatory lesions of the joints and cartilaginous tissues, caused by circulatory or metabolic disorders, large or improperly distributed loads, injuries, are successfully treated with leeches. Treatment is aimed at reducing pain, increasing the motor work of the joints and stopping the progression. The secret secreted by leeches when bitten contains a natural analgesic enzyme that improves the patient's condition. No wonder a couple of centuries ago, military doctors put soldiers of these bloodsuckers in the wound area to prevent pain shock.

Treatment of diseases of the spine

Hirudotherapy plays important role in the complex treatment of diseases of the spine. It contributes to the restoration of normal physiological processes occurring in the deep tissues surrounding the spinal column. As effective remedy, supplementing the main one, is the treatment with leeches for a hernia of the spine. In the absence of the desired result from conservative treatment, one has to resort to surgical intervention. During the period of postoperative rehabilitation, leeches can bring a lot of benefits to the patient. Their use helps to prevent postoperative complications. Thanks to hirudotherapy sessions, cicatricial adhesions in ligaments and tendons are reduced, the likelihood of new hernias is reduced due to the redistribution of loads, congestion in the vertebral veins disappears.

Treatment with leeches is also effective in osteochondrosis. The cause of this pathology is degeneration of the intervertebral discs, ligaments that lose water, become thinner, covered with microcracks. As a result, the distance between the vertebrae decreases, there is pressure on the nerve roots, causing them to be pinched, spasms and inflammation in the paravertebral muscles.

The benefits of leeches for weight loss

Medical leeches are actively used in aesthetic medicine for weight loss and cellulite treatment. This effect occurs due to the influence of substances in the saliva of annelids on metabolism and blood circulation. Biologically active substances of leeches have a lipolytic effect - they burn fat. In addition, the process of microcirculation is being established and the provision of cells with oxygen is enhanced, the stagnation of lymphatic fluid in adipose tissue is eliminated. All this contributes to the reverse development of pathological changes in cellulite and a decrease in body volume.

The effect after using leeches for weight loss will be even more noticeable if you combine hirudotherapy with a balanced diet and regular exercise.

Acne treatment with leeches

Acne treatment with medicinal leeches is very effective. Already after several sessions of putting leeches on the face, the rash is significantly reduced, and after the entire course it completely disappears. The result of such treatment lies in the amazing and varied properties of these animals on the skin.

Firstly, saliva of leeches has a powerful bacteriological and antiseptic effect. It destroys all pathological pyogenic microorganisms, which cause the formation of acne. Secondly, substances that leeches transmit with a bite have a pronounced anti-inflammatory effect, due to which the inflamed areas heal quickly. Thirdly, thanks to the mechanical and biological action animals, the blood supply to the skin increases, which plays an important role in establishing the normal functioning of the sebaceous glands.

As you can see, hirudotherapy in cosmetology has a wide range of applications. Do not refuse such treatment just because you are disgusted with leeches. You just have to be patient a little and, perhaps, you will get rid of the cosmetic problem that has tormented you for many years forever.

Contraindications

Contraindications are:

• diseases accompanied by bleeding due to reduced blood clotting;
• hemolysis;
• anemia (anemia);
• weakening or exhaustion of the body;
• intolerance to the body of leech enzymes (allergic reactions);
• tuberculosis of various localizations;
• oncological diseases.

Harm of leeches

Due to its specific structure and diet, the use of leeches for medicinal purposes may be associated with the following risks:

• The digestive tract of the medical leech constantly contains the bacterium Aeromonas hydrophila, which protects it from infections when feeding on the blood of sick animals and promotes proper absorption nutrients. In humans, it can cause gastrointestinal disorders, poisoning, and even diseases of the mucous membranes. Although hirudotherapists deny the possibility of bacteria getting into the jaws of leeches, this hypothesis has not been definitively refuted.
• With the blood of infected animals, pathogens of various dangerous diseases enter the body of a leech. Settling on the jaws, they can be transmitted by bite to other people and animals. The use of leeches grown in artificial conditions made it possible to get rid of this problem.
• Leech saliva contains substances that thin the blood, and after removing it, the wound can bleed for a long time. Besides, in individual cases these substances can severely irritate the skin.

The process of breeding leeches is simple and accessible to anyone. In order to organize a leech farm, you need to find a room with several rooms, since leeches at various stages of their growth: cocoon, fry, adult, should be kept separately. Alternatively, one room can be adapted by dividing it into sectors. The main condition for breeding leeches is to maintain a favorable microclimate for them: the air temperature is from 25 to 27º C.

Although wild leeches in natural environment live in colder waters, the reproduction and development of their medical relatives in the heat is much better. The temperature of the water in which the leeches are located should be at room temperature, that is, the same 25-27º C. The air humidity in the room should be at least 80%.

Containers for leeches are the usual 3 liter cans filled with purified water through special filters. Aquariums can also work, but it will be much more expensive. It is necessary to carefully monitor all stages of the growth of leeches and “transfer” animals to other premises (sectors) in time when they reach the next “age”.

By the way, all work on feeding leeches, purifying water in containers, transplanting leeches, etc., is carried out only manually. Even on large leech farms. Leeches feed on blood, which can be obtained from livestock farms, from private farmers, at a slaughterhouse, having concluded appropriate agreements with them.

Breeding leeches in industrial scale engaged in special biofactories. Currently, there are only four such factories in Russia: two in the Moscow region, one in St. Petersburg and one in Balakovo, Saratov region. In total, they grow 5-5.5 million leeches per year, which makes Russia the world leader in the production of leeches in the world: only 0.5 million per year are grown in France and the United States.

A leech is a worm that has a kind of "brain". The Nietzschean Zarathustra tried to assert that he was familiar with the mental, or rather the mental activity of these leeches. interesting worms. The researchers, of course, have not yet found the “brain” of leeches, but it can be argued that the leech has a fairly branched nervous system, consisting of a peripheral section and a sympathetic autonomic system.

There is an opinion that a leech "loves" a person. Researchers of this "crawling world" have long wondered if any senses are possible in leeches or any other worms. Well, animals, of course, cannot love like people. But some species of mammals are characterized by certain emotional experiences associated with devotion, friendliness, affection.

Sources

https://ru.wikipedia.org/wiki/Leechs http://www.pijavki.com/o_pijavkah.html http://polzovred.ru/zdorovie/piyavki.html#i-2 http://pomogispine.com/lechenie/girudoterapiya.html http://www.aif.ru/health/life/1188201

But for treatment, only a medical leech is used. Among medical leeches, there are two subspecies:

Medicinal leech (Hirudina medicinalic)

Apothecary leech (Hirudina officinalic)

Color. May vary from black to reddish-brown. Abdomen motley. The sides are green with an olive tint.

Size. About 3 - 15 cm - length, about 1 cm - width.

Lifespan. Up to 20 years.

Habitat. They are found mainly in Africa, Central and Southern Europe, as well as Asia Minor. In Russia, they are not so numerous, they mainly spread to the south of the European part of the country. Although there is evidence that individual individuals of the species were found in the southern and eastern parts of Siberia.

They love fresh clean water - lakes, ponds, quiet rivers, as well as damp places near water - clay shores, wet moss. Leeches live in stagnant water - running water is unfavorable for them.

Lifestyle and behavior. Most of the time, the medicinal leech spends hiding in thickets of algae, hiding under snags or stones. This is both a cover and an ambush.

Leeches love warm sunny weather and even tolerate heat quite well, it is in these conditions that they are most active. They are also not afraid of drought - they either crawl away from a drying up reservoir, or dig deeper into the coastal silt. Leeches are able to stay on land for a long time in hot and humid weather.

With the deterioration of conditions (lower air temperature, windy weather), medical leeches become lethargic and passive. Leeches overwinter by burrowing into coastal silt or bottom soil. Frosts are detrimental to them.

The body of the leech is greatly flattened and elongated when swimming, and the posterior sucker acts as a fin. With wave-like movements, the leech moves in the water.

For medical leeches, an instant reaction to external stimuli is quite characteristic: smell, temperature, splash.

A hungry leech can be recognized by the characteristic position of the body - it sticks to a plant or stone with its back suction cup, while the front one makes circular movements.

Enemies: Desman, water rat, shrews, bugs, dragonfly larvae.

Nutrition. As food, medicinal leeches use the blood of worms, molluscs and vertebrates, and in their absence they can eat insect larvae, ciliates, and mucus of aquatic plants. The leech bites through the skin of the victim and sucks out a small amount of blood, about 10-15 ml. Having satiated, the leech can remain without food for quite a long time - an average of six months, since the blood in its body is digested slowly. However, a record fasting period was observed, which amounted to 1.5 years.

Reproduction. The medicinal leech is a hermaphrodite. Leeches begin to lay eggs during the warm period, approximately two weeks before the end of August or in mid-September. Under adverse weather conditions, this period comes earlier or is postponed.

In the process of reproduction, the leech crawls out onto land, digs a small depression in the silt, then a special department of medical leeches, buy medical leeches, buy leeches in Perm, buy leeches in Perm, the cover of a leech - a girdle - secretes a foamy cocoon in which eggs are laid. This cocoon contains albumin, a protein that serves as food for embryos. The egg incubation period is about two months.

Newborn medicinal leeches are transparent and resemble adults, they still spend some time in a cocoon, feeding on albumin, but soon crawl out. Small leeches that have not reached puberty attack tadpoles, snails, frogs.

If a leech does not drink the blood of a mammal within three years from the moment it emerges from the cocoon, it will never reach puberty.

External structure

The body of leeches is noticeably flattened in the dosoventral direction. At the anterior end there is a muscular anterior sucker, in the center, which is placed mouth opening. At the posterior end there is a second, very strongly developed posterior sucker, above which the anus opens on the dorsal side.

Leeches do not have any appendages or parapodia. The bristles are preserved only in a primitive species - the bristle leech. It has four pairs of setae on five anterior segments.

leeches very mobile, crawling and floating animals . Attached by the posterior oral sucker, the leech pulls the body forward, then attaches with the oral sucker, while the posterior sucker is pulled away from the substrate and the body is pulled to the head end, bending into a loop. Then the leech is sucked again by the back sucker, etc. Thus, the leeches make "walking" movements. Leeches swim, producing wave-like movements with their whole body, in which their body bends in a dorsoventral direction.

The external ringing of leeches is false, secondary, it does not coincide with the true internal segmentation. Each real segment in different leeches corresponds to 3 to 5 outer rings. External ringing of leeches is an adaptive trait that provides body flexibility with powerful development. skin-muscular sac.

The body of leeches is formed by 33 segments (with the exception of the bristle leech, which has 30 segments), of which a weakly separated head lobe - the prostomium - and four head segments are part of the anterior sucker. The trunk section is represented by 22 segments. The posterior sucker is formed by the fusion of the last seven segments.

Skin-muscular sac

The skin-muscular sac of leeches is formed by a single-layer epithelium, which secretes a dense layered cuticle, and powerfully developed muscles. The skin of leeches is rich in glandular cells that secrete mucus and is permeated with a network of lacunar capillaries. Under the epithelium there are numerous pigment cells that cause a peculiar pattern of leeches.

Leeches are characterized by the presence of three continuous layers of musculature of the skin-muscle sac, as in flatworms: outer ring, diagonal, the most powerful longitudinal. The dorsoventral muscles, which are not part of the skin-muscular sac, are also strongly developed.

Body cavity and circulatory system

In almost all leeches, the entire space between the organs is filled with parenchyma, like in flatworms. Only in leeches does the parenchyma fill secondary cavity bodies, while in flatworms it is primary.

In another order - proboscis leeches (Rhynchobdellida) - a stronger growth of the parenchyma is observed. This leads to a partial reduction of the coelom. However, the coelomic cavity is preserved as a whole system of lacunae. Four main coelomic lacunae run along the entire body: two on the sides, one above the intestine, surrounding the dorsal blood vessel, and one below the intestine, it contains the ventral blood vessel and the ventral nerve cord. These gaps communicate with each other, forming a network of smaller gaps. Thus, proboscis leeches have both a circulatory system and a lacunar system, which is a modified coelom.

In the third order, the higher jawed leeches (Gnathobdellida), which include the medical leech and many other freshwater leeches, the development of the parenchyma goes as far as in the proboscis leeches. The blood vessels lying inside coelomic lacunae in proboscis leeches are reduced in jaw leeches. The function of the circulatory system is performed by the lacunar system, which originates from the coelom. Such a process of functional replacement of one organ by another, different in origin, is called substitution or replacement of organs.

excretory system

The excretory organs of leeches are represented by segmental organs of metanephridial origin. However, the number of pairs of pephrindia does not correspond to the number of segments. The medicinal leech has only 17 pairs. In connection with the transformation of the coelom into a system of lacunae, the structure of the metanephridia of leeches also changed. The funnels of the metanephridia open into the ventral lacuna (coelom), but not directly into the nephridial canal. They are separated from the nephridial canal by a septum, so the secreted substances penetrate diffusely from the funnel into the nephridium.

Such a structure of the metanephridia of leeches (separation of the infundibulum from the nephridial canal) is explained by the functional transformation of the lacunae into the main circulatory system, replacing the circulatory one. The metanephridia of leeches are characterized by the presence of a special expansion - the bladder.

Digestive system

The mouth is placed on the bottom of the front sucker. It leads to the front digestive system lined with ectoderm and composed of oral cavity and muscular throat. The structure of the oral cavity and pharynx in proboscis and jaw leeches is different.

In proboscis leeches, the oral cavity, growing back, surrounds the pharynx in the form of a vagina. A very muscular pharynx turns into a proboscis, protruding and retracting with the help of special muscles. The proboscis can penetrate into the thin covers of various animals (for example, mollusks), and in this way the leech sucks out blood.

In jawed leeches (medical leeches, etc.) in the oral cavity there are three longitudinal muscular ridges that form jaws directed with their crests towards each other. Muscular rollers are covered with chitin, serrated along the edge. With these jaws, leeches incise the skin of an animal or person. In the throat of blood-sucking jaw leeches, glands open that secrete a special substance - hirudin, which prevents blood clotting.

Next, food enters the endodermic midgut, which consists of the stomach and posterior midgut. The stomach forms paired lateral protrusions, of which the last pair is usually especially developed, extending to the posterior end of the body. The stomach serves as a reservoir for long-term storage of blood. The blood that fills his pockets does not clot for weeks and months.

The posterior part of the midgut is represented by a relatively short straight tube in which the final digestion and absorption of food takes place. It passes into a short, often enlarged posterior ectodermic gut, which opens with an anus above the posterior sucker.

Nervous system and sense organs

The nervous system of leeches consists of a paired supraesophageal ganglion connected by circumpharyngeal connections with the subpharyngeal ganglionic mass. The latter is formed by the fusion of the first four pairs of ganglia of the abdominal nerve chain. This is followed by 21 ganglia of the ventral nerve chain and a ganglionic mass (of eight pairs of ganglia) that innervates the posterior sucker.

The sensory organs of leeches are represented by sensitive kidneys, or goblet organs. Each such organ consists of a bundle of spindle-shaped cells located under the epithelium. The outer end of sensitive cells forms a sensitive hair. Nerves from the ventral nerve cord approach the inner ends of these cells.

Some of the goblet organs perform the functions of chemical sense organs, others - tactile. The eyes of leeches have a similar structure to the goblet organs described above. There may be several pairs. The eye consists of vesicle-shaped photosensitive cells with large vacuoles inside, to which the nerves that make up the axial part of the eye approach. The eye is surrounded by dark pigment.

Reproductive system, reproduction and development

According to the structure of the genital organs and the method of reproduction, leeches have much in common with oligochaetal rings. They are hermaphrodites, and their genitals are concentrated mainly in the region of the 10th and 12th body segments. Leeches have a girdle section, which, unlike oligochaetes, coincides in position with the penis. The girdle becomes noticeable only during the breeding season.

The male reproductive apparatus consists of several pairs (4-12 or more) of the testes. The medicinal leech has 9 pairs of testes located inside the seed sacs. Short vas deferens depart from them, opening into longitudinal paired vas deferens. The latter in the area of ​​the 10th segment form dense balls - appendages of the testes, in which sperm accumulates. Then they pass into the ejaculatory (paired) canals that open in the copulatory organ, which can protrude forward through the unpaired male genital opening on the 10th segment. Not everyone has a copulatory organ. In many leeches, spermatozoa are enclosed in spermatophores. Spermatophores are either introduced into the female genital opening or stuck into the skin, and the spermatozoa penetrate the body of the leech and make their way to the female reproductive tract.

The female reproductive apparatus consists of a pair of ovaries located in egg sacs. They pass into short and wide uterus, which are interconnected and form an unpaired oviduct, which flows into a wide vagina, which opens on the 11th segment with the female genital opening.

Fertilized eggs are laid in a cocoon secreted by a girdle. Cocoon or attached to aquatic plants, or located at the bottom of the reservoir. Some leeches lay single eggs.

The development of leeches is not direct, since larvae emerge from the eggs, remaining, however, in a cocoon. The larvae have cilia and protonephridia. In the cocoon, the transformation of larvae takes place, and already formed leeches emerge from the cocoon into the water. The laying of eggs in relatively strong cocoons, which protect eggs and larvae well, causes a small number of eggs. It is measured in various leeches in units, in extreme cases, in tens.

Classification

The class of leeches is divided into three orders: 1. Bristle-bearing (Acanthobdellida); 2. Proboscis (Rhynchobdellida); 3. Jaw (Gnathobdellida).

Order Bristle-bearing leeches (Acanthobdellida)

A very primitive relic form bearing four pairs of sharp, curved setae on five anterior segments. The anterior sucker is absent, only the posterior one is present. The parenchyma is poorly developed, there is a coelomic cavity and a circulatory system.

Squad Proboscis leeches (Rhynchobdellida)

Proboscis leeches are remarkable for breeding and caring for offspring. The leech lays eggs that remain attached to the ventral side of its body. At this time, the leech is not very mobile: it sits, attached with suckers, on some plant and makes oscillatory body movements. When the juveniles hatch from the eggs, the leech does not change its position and the young leeches remain attached to the ventral side of the mother with their suckers, usually for several days, and then spread and begin to lead an independent existence.

Squad Jawed leeches (Gnathobdellida)

Most jaw leeches in the oral cavity have the jaw apparatus described above.

In addition to the medicinal leech (Hirudo medicinalis), common in the southern part of Russia, this order includes the ubiquitous false horse leech (Haemopis sanguisuga). This is a large dark-colored leech, has weak jaws and is not able to bite through the skin of humans and mammals. It feeds on worms, mollusks and other invertebrates. The cocoons of the false-horse leech are buried in the coastal strip, above the water level.

Some jawed leeches (especially those found in southern latitudes) can be human parasites, for example, from the genus Limnatis. One of them, L. turkestanica, is found in Central Asia. When drinking raw water from a reservoir, it can enter the human nasopharynx, where it settles and sucks blood. In addition to severe irritation, it causes bleeding. In the jungles of Sri Lanka, India, Indonesia, land animals from the genus Haemadipsa live. They hide in damp places, in grass and under foliage, and attack animals and humans, causing very sensitive bites.