Organs of the circulatory system of the earthworm. Earthworm. Description of the animal and its role in nature. The structure and description of worms

26.01.2018

Dear colleagues! Today we will continue the topic "earthworms", in which we will consider the structure of an earthworm. Who knows, maybe among those reading these lines there are those who consider earthworms to be harmful, such as: "they gnaw at roots in pots, eat seedlings, sprouts, seeds ..." of which - soil freezing. And they tell all sorts of nonsense about earthworms. I myself communicated with such people, convincing them of the opposite, namely, what invaluable help and benefit these tireless workers bring.

So, let's start studying the earthworm in order to understand how its vital activity is maintained.

To absorb food, worms have an organ called pharynx... It works on the principle of a rubber bulb: when squeezed and then unclenched, a vacuum is created, due to which food is drawn in. It is clear that there are no teeth in the mouth, therefore, the worm is not able to gnaw or bite something.

In order to pass through a rather small mouth opening, the food must be sufficiently soggy or softened. Therefore, plant food (shoots, leaves) should not be freshly picked (or freshly eaten), but already dried, with softened fibers. Therefore, earthworms love to live and feed so much in semi-rotten humus, under last year's fallen leaves, in mown or cut vegetation that has lain on the soil surface for a long time.

Goiter- This is a large thin-walled cavity in which swallowed food accumulates. What happens next? How to be without teeth? It turns out that the worm has them, only they are located ... in the stomach!

Stomach Is a muscular thick-walled chamber, the inner surface of which consists of hard tooth-like protrusions. When the walls of the stomach contract, they crush (grind) food into small particles. And already in this state, food enters the intestines, where it is digested under the action of digestive enzymes, and the nutrients released during this are absorbed. By the way, the stomach is arranged in a similar way in crocodiles and most birds.

The features of digestion make earthworms detritivorous, that is, they feed on detritus- decaying plant organic matter located on the surface of the earth or in their underground burrows, as well as in the soil itself, biting into the soil itself. Therefore, the coprolites that the earthworm leaves behind are lumps of soil enriched with nitrogen, microelements, and having low acidity due to the alkaline environment of its intestines.

Upon closer examination of the picture, you will see that the worm has a brain, nerves, and a heart (of which there is not even one, but as many as five!). That is, the earthworm feels and understands everything, but it cannot say. Here is another tragic secret, still not understood by biologists and not disclosed by criminologists: why do they crawl out onto the sidewalks after the rain, and there they die en masse?

The earthworm has its own "Achilles heel", its weak point. the thing is that worms need energy for normal life. And they get it through respiration (and oxygen oxidation), and it requires gas exchange between the body and the environment.

The structure of the earthworm is such that the worm does not have a special organ for gas exchange (such as lungs or gills), so it breathes skin... To do this, it must be thin and constantly moisturized. Since worms lack any protective shell, the most common reason for their death is drying out.

The body of earthworms consists of many annular segments (80 to 300) that can be easily seen. The worm can be both slippery and rough at the same time. He rests bristles- they are on each ring and can be seen with an ordinary magnifying glass.

The bristles are the main support in the life of the worm, they are very convenient to grab onto tiny irregularities in the soil, which is why it is so difficult to pull the worm out of the burrow - it will rather let itself be torn in half. Thanks to the bristles, it is inactive on the surface, it deftly escapes danger.

If necessary, the body of the worm is covered with abundant mucus, which serves as an excellent lubricant for squeezing through the ground. The same mucus prevents the body from wasting water in vain, which is in the worm as much as 80% of the total weight.

Under certain conditions, the missing body parts of the worms can regenerate. For example, the back will grow back if it is torn off in an accident. But this does not always happen. So let's take care of our underground architects, "earth angels", and create favorable conditions for them. And they, in turn, will thank us with a healthy soil on the plots and a generous harvest.

A strong muscular pharynx is located behind the mouth opening, passing into a thin esophagus, and then into an extensive goiter. In the goiter, food accumulates and is moistened. After that, it enters the muscular chewing stomach, which looks like a bag with thick, hard walls. Here the food is rubbed, after which, by contraction of the muscular walls of the stomach, it moves into a thin tube - the intestine. Here, under the influence of digestive juices, food is digested, through the intestinal wall nutrients are absorbed into the body cavity and enter the bloodstream. With the blood, nutrients are carried throughout the body of the worm. Undigested food debris is thrown out through the anus.

Excretory organs

The excretory organs of the worm consist of the finest whitish convoluted tubes. They lie in pairs in almost every segment of the body of the worm. Each tube at one end opens with a funnel-shaped expansion into the body cavity. The other end opens outward on the ventral side of the animal with a very small opening. It is through these tubes that unnecessary substances accumulate there are excreted from the body cavity.

Nervous system

The nervous system of an earthworm is more complex than that of a hydra. It is located on the ventral side of the body and looks like a long chain - this is the so-called abdominal nerve cord. Each segment of the body has one double nerve ganglion. All nodes are interconnected by jumpers. At the front end of the body, in the pharynx region, two bridges extend from the nerve chain. They cover the pharynx on the right and left, forming the periopharyngeal nerve ring. Above, there is a thickening in the periopharyngeal ring. This is the supraopharyngeal ganglion. Many of the finest nerves depart from it in the front, part of the body of the worm. This explains the great sensitivity of this part of the body. This feature of the structure of the earthworm has a protective value. Branching out along the tissues and organs of the body, the nervous system of the earthworm and other animals regulates and unites the activities of all organs, uniting them into one whole - the animal's organism.

Body symmetry

In contrast to hydra and many other coelenterates, a clearly expressed bilateral symmetry of the body is observed in the body of the earthworm. In animals with such a structure, the body is divided into two identical halves, right and left, by the only plane of symmetry that can be drawn along the main axis of the body from the mouth to the anus. Bilateral symmetry is common in worms and many other animals.

The transition of worms from the radial radial symmetry of the body, characteristic of their ancestors - coelenterates, to bilateral symmetry is explained by their transition from a swimming or sedentary lifestyle to crawling, to a terrestrial lifestyle. Consequently, the development of different forms of symmetry in multicellular animals is associated with a change in the conditions of their existence.

Everyone knows earthworms, they make up a large group of different species belonging to the oligochaete family.

The common earthworm belongs to the most famous family Lumbricidae, consisting of about 200 species, and about 100 of them are found on the territory of our country. The body length of an ordinary earthworm reaches 30 centimeters.

Types of earthworms

Depending on the biology of earthworms, they are divided into 2 types: worms that feed in the soil and worms that feed on the surface of the soil.

Worms that feed in the soil include litter worms that live in the litter layer and do not sink to a depth of 10 centimeters, even when the soil freezes or dries out.

This type also includes soil-litter worms, which under unfavorable conditions can penetrate to a depth of 20 centimeters. This also includes burrowing worms that constantly live at a depth of 1 meter or more. These worms rarely leave their burrows, and when mating and feeding, they stick out only the front part of the body to the surface. In addition, burrowing worms belong to this type; they spend their lives in the deep layers of the soil.

Burrowing and litter worms live in areas with waterlogged soils: on the banks of water bodies, in marshy areas, in humid subtropical zones. Litter and soil-litter worms live in the taiga and tundra. And soil worms live in the steppes. The most favorite habitat for all types of earthworms is coniferous-deciduous forests.

Worms lifestyle

Earthworms are nocturnal. At night, they can be found swarming in large numbers in various places.

At the same time, they leave their tails in burrows, and the body stretches out and scouts the surrounding space, grabbing the fallen leaves with their mouths and dragging them into the burrows. During feeding, the pharynx of the earthworm turns out a little, and then retracts back.

Eating earthworms

Worms are omnivores. They swallow large amounts of soil and assimilate organic matter from it. In the same way, they eat half-rotten leaves, except for hard leaves or leaves that have an unpleasant odor for worms. If the worms live in pots of soil, then you can see how they eat the fresh leaves of the plants.

Darwin researched worms, he did a lot of scientific work and in the course of it made interesting observations. In 1881, Darwin's book "The Formation of the Vegetation Layer by the Activity of Earthworms" was published. The scientist kept the worms in pots of soil and studied how they conduct their daily life and feed. For example, to find out what other worms eat besides earth and leaves, he pinned pieces of boiled and raw meat with pins and watched as the worms fiddled with the meat every night, while eating some of the pieces. In addition, pieces of dead worms were used, so Darwin concluded that they were cannibals.

Worms drag semi-rotten leaves into burrows to a depth of about 6-10 centimeters and eat them there. The scientist observed how earthworms grab food. If a leaf is pinned to the ground with a pin, the worm will try to drag it underground. Most often, they grab small pieces of the leaf and tear them off. At this moment, the thick pharynx protrudes outward and creates a fulcrum for the upper lip.

If the worm encounters a large flat surface of a leaf, then its strategy is different. He slightly presses the front rings into the subsequent ones, as a result of which the front end becomes wider, it acquires a blunt shape, and a small fossa appears on it. The pharynx extends forward, attaches to the surface of the sheet, and then is pulled back and slightly expanded. As a result of such actions, a vacuum is obtained in the fossa in the front of the body, which is attached to the sheet. That is, the pharynx acts as a piston, and the worm is firmly attached to the surface of the leaf. If the worm is given a thin cabbage leaf, then on its back side it will be possible to notice a depression located above the worm's head.

Earthworms do not eat leaf veins, they only suck out delicate tissues. They use the leaves not only for food, but also close the entrances to their holes with their help. Withering flowers, pieces of stems, wool, feathers, paper are also suitable for this. Often, bunches of leaf petioles and feathers can be seen from the holes of earthworms. To drag the leaf into the hole, the worm crushes it. The worm tightly folds the leaves together and squeezes. Sometimes the worms widen the holes of the holes or make an extra move to collect new leaves. The space between the leaves is filled with damp earth from the worm's intestines. This completely clogs the minks. Such closed minks are most often encountered in the autumn before the worm leaves for the winter.

Earthworms spread their leaves on the top of the mink, Darwin believed that they do so that their bodies do not touch the cold ground. In addition, Darwin learned about various methods of digging minks. The worms do this either by swallowing the earth or pushing it apart in different directions. If the worm pushes the soil apart, then it pushes the narrow end of the body between the soil particles, then inflates, and then contracts it, due to which the earth particles move apart. That is, it uses the front of the body as a wedge.

If the soil is too dense, then it is difficult for the earthworm to push the particles apart, so it changes its tactics. He swallows the earth, then passes it through himself, thus sinking gradually into the ground, and behind it a heap of excrement grows. Earthworms can absorb chalk, sand and other non-organic substrates. This feature helps the worms to sink into the soil when it is dry or freezing.

Burrows of earthworms are located vertically or slightly deeper. On the inside, they are almost always covered with a thin layer of black recycled soil. The worm throws out the earth from the intestines and compresses it along the walls of the hole, making vertical movements. As a result, the lining is smooth and very durable. The bristles on the body of the worm adhere to the lining, they create a fulcrum, as a result of which the worm moves quickly in its hole. The lining not only makes the walls of the burrow more durable, but also protects the body of the worm from getting scratched.

The minks that lead downward usually end with an extended chamber. Earthworms hibernate in these chambers. Some individuals spend winter alone, while others are woven together in a ball. Mink worms are lined with seeds or small stones, resulting in a layer of air and the worm can breathe.

After the earthworm swallows the earth, feeding on it or digging it, it rises to the surface and throws it out. These lumps of earth are saturated with intestinal secretions and are therefore viscous. When the lumps dry out, they harden. The worms do not throw out the earth randomly, but in turn in different directions from the entrance to the burrow. The worm uses its tail during this work as a shovel. Thus, a tower of excrement is formed around the entrance to the burrow. All turrets of different types of worms differ in height and shape.

Earthworm exit

To stick out of the hole and throw out the excrement, the worm pulls its tail forward, and if the worm needs to collect leaves, it sticks its head out of the ground. That is, in burrows, earthworms can turn over.

Earthworms do not always throw out soil near the surface, if they find a cavity, for example, in the plowed ground or near the roots of trees, then they throw excrement into this cavity. There are small lumps of earthworm excrement between many rocks and under fallen tree trunks. Sometimes worms fill their old burrows with excrement.

Life of earthworms

These small animals have played a significant role in the history of the formation of the earth's crust. They live in large numbers in humid places. As worms dig the ground, it is constantly in motion. As a result of the burrowing activity, soil particles are rubbed against each other, new soil layers fall on the surface, are exposed to humic acids and carbon dioxide, and most of the mineral substances are dissolved. Musk acids are formed when semi-decomposed leaves are digested by worms. Earthworms increase the amount of potassium and phosphorus in the soil. In addition, the earth that has passed through the intestines of the worm is glued together with calcite, which is a derivative of calcium carbonate.

The excrement of the worms is tightly compressed and gets out in the form of strong particles, which do not erode as quickly than ordinary soil lumps of the same size. These excrements are elements of the granular structure of the soil. Earthworms produce huge amounts of excrement every year. Each earthworm produces about 4-5 grams of earth per day, that is, this amount is equal to the body weight of the worm itself. Every year, earthworms throw a layer of excrement on the surface of the soil, the thickness of which is 0.5 centimeters. Darwin calculated that 1 hectare of pasture in England accounts for up to 4 tons of dry matter. Near Moscow, in the fields of perennial grasses, worms form 53 tons of excrement per hectare of land every year.

The worms prepare the soil for plant growth: the soil is loosened to form small lumps, which improves air and water ingress. In addition, earthworms drag the leaves into their burrows, partially digesting them and mixing them with excrement. Thanks to the activity of worms, the soil is evenly mixed with plant residues, thus a fertile mixture is obtained.

It is easier for plant roots to spread in the passages of worms, moreover, they contain nutritious humus. It is difficult not to be surprised by the fact that the entire fertile layer has been treated with earthworms, and after a few years, they will process it again. Darwin believed that there are no more animals that have had the same importance in the history of the formation of the earth's crust, although worms are low-organized creatures.

The activity of earthworms leads to the fact that stones and large objects go deep into the earth over time, and small fragments of the earth are gradually digested and turn into sand. Darwin emphasized that archaeologists should be indebted to the worms for their contribution to the preservation of ancient objects. Items such as gold jewelry, tools, coins and other archaeological values ​​are gradually buried under the excrement of earthworms, thanks to which they are reliably preserved for future generations, who will remove the layer of earth that covers them.

Damage to earthworms, like many other animals, is caused by the developing economic activity of man. The use of pesticides and fertilizers leads to a decrease in the number of worms. To date, there are 11 species of earthworms in the Red Book. More than once, people have moved various types of earthworms to areas where they are scarce. The worms underwent acclimatization, and these attempts ended in success. These measures, called zoological reclamation, help preserve the number of earthworms.

If you find an error, please select a piece of text and press Ctrl + Enter.

The internal structure can be clearly seen when opening the worm.

Before opening, the worm is killed by immersing it in diluted alcohol (10%) for several minutes. Then the worm is placed in the dissecting bath with its back upward (a red blood vessel is clearly visible along its back), with two pairs of pins, it is pinned by the anterior and posterior ends of the body to the bottom of the dissecting tray, and then, starting from the posterior end, it is done either with thin scissors or with a blade razor longitudinal section of the skin-muscle sac, keeping slightly to the right of the midline (so as not to damage the translucent blood vessel).

Then the cut walls of the body are deployed on both sides, secured with several pairs of pins and water is poured in so that it covers the opened worm (then its internal structure will be more clearly visible).

On the opened worm, first of all, the body cavity is visible, in which various internal organs lie. Thin transverse partitions divide the body cavity into separate chambers, corresponding to the external division of the body into segments (Fig. 89).

Of the internal organs, the most clearly visible is a straight and voluminous intestine, which runs along the entire length of the body. It consists of several sections: from a small oral cavity, followed by a muscular pharynx, which then passes into a narrow esophagus, leading first to the goiter, then to the gizzard, in which food is rubbed, and finally to the long intestine, which stretches to the posterior end of the body and ends in the anal, or anal, opening.

The vessels of the circulatory system are visible above the intestines; they are clearly visible in the earthworm, because its blood is red (remember that in lower worms, and even more so in two-layer animals, we do not find a circulatory system). A large dorsal vessel runs along the entire intestine.

In the front part of the body, clearly visible paired branches extend from the dorsal vessel, which, like hoops, encircle the esophagus and connect the dorsal vessel with the abdominal vessel, which runs along the body already under the intestines. These several pairs of vessels are called "hearts" because their muscle walls, by their contractions, force blood to move through the vascular system.

Through the dorsal vessel, blood flows from the posterior end of the body to the front, then through the "hearts" it passes into the abdominal vessel and here it flows in the opposite direction, that is, to the posterior end of the body.

In addition to these main vessels, the worm has even thinner vessels; some of them, like "hearts", encircle the intestines, others go to various organs of the body.

The circulatory system brings to the tissues of the body the substances they need - nutrient material that enters the blood from the intestines, and oxygen - and carries away decay products from them - carbon dioxide and nitrogenous substances.

The excretory system of the earthworm has the form of small white convoluted tubes adjacent to those partitions that divide the body cavity into separate segments. One end of each such tube opens in the form of a small funnel into the body cavity, the other end opens outward. Since these excretory tubes (nephridia) are in pairs distributed over separate segments, or segments, of the body, they are also called segmental organs.

The worm does not have a special respiratory system, and gas exchange takes place through the entire surface of the body, dressed with a thin and always moist cuticle. Respiratory gas exchange takes place in moist soil, where atmospheric air also penetrates. In rainy weather, when the soil is saturated with water with a high content of carbon dioxide (released during the decomposition of humus), earthworms feel a lack of oxygen, and this forces them to come to the surface.

The nervous system of the earthworm forms a periopharyngeal ring in the front of the body, consisting of the supraopharyngeal ganglion, or "brain", of a pair of nerve cords covering the pharynx on both sides, and from the subpharyngeal ganglion, located already under the intestine.

The subopharyngeal ganglion begins the abdominal nerve chain, which stretches along the lower wall of the body (to see it, you need to remove the intestines). The abdominal chain consists of nerve nodes - one node for each segment of the body - and of the nerve cords that connect them together. All these nodes are double, that is, each was formed from a pair of nodes merged with each other, and nerves extend from each node to neighboring organs.

Thus, each nerve node is a special nerve center for its segment, but they all act in concert depending on the activity of the epopharyngeal ganglion, which is therefore called the "brain" of the worm.

Reproductive organs are located closer to the front end of the worm at the bottom of the body cavity. Earthworms are bisexual animals, or hermaphrodites, that is, each of them has both male and female reproductive organs - both testes and ovaries. Both the testes and ovaries open with separate paired holes on the ventral side of the body.

In the structure of the body of the earthworm, one feature clearly stands out: in it, the whole body is subdivided into segments that follow one another, which, in their structure, seem to repeat each other.

Outside, the segments are separated by interceptions and look like rings with eight bristles on each ring, and inside each interception there corresponds a transverse septum and each segment has its own paired nerve node, its own pair of transverse blood vessels encircling the intestines, its own pair of excretory tubes, its own annular and longitudinal muscles. Such a structure, when in the body there are repeating, almost identical parts one after the other, is called metameric (Fig. 89, 91).

Many people underestimate the importance of the work of earthworms. These representatives of the invertebrate kingdom are known primarily for the fact that in large quantities they crawl out of the earth after a heavy rain. They are often used as bait by numerous fishing enthusiasts. Even Darwin noted the fact that worms perform an important function in nature, acting as a kind of agricultural technicians. In the process of creating an extensive system of tunnels, which the earthworm breaks through, excellent aeration is formed by the flow of air to the inner layers of the soil.

Thanks to the excellent aeration, the respiratory activity of many plants is facilitated. Feeding on organic matter and waste, the worms provide crushing of soil components, enriching them with their secretions. The amazing ability of representatives of this species is the ability to disinfect huge areas of soil, sterilizing it from harmful bacteria. Thanks to the countless holes that form a kind of capillary system, ideal drainage and ventilation of the soil is ensured.

The body of an earthworm can be up to three meters long. However, on the territory of Russia there are mainly individuals whose body length does not exceed 30 centimeters. In order to move, the worm uses small bristles, which are located on different parts of the body. Depending on the variety, there can be from 100 to 300 segments. The circulatory system is closed and well developed. It consists of one artery and one central vein.

The structure of the earthworm is very unusual. Breathing is realized with the help of special hypersensitive cells. The skin produces protective mucus with a sufficient amount of natural antiseptics. The structure of the brain is rather primitive and includes only two nerve nodes. Earthworms in laboratory experiments have confirmed their outstanding ability to regenerate. The severed tail grows back after a short period of time.

The genitals of the earthworm are also arranged in a very unusual way. Each individual is a hermaphrodite. She also possesses male organs. According to biological factors, all such worms can be divided into several subgroups. Representatives of one of them are looking for food on the surface of the soil layer. Others use the soil itself for food and rarely show up from the ground.

The earthworm is of the annelid type. Under the skin layer there is a developed muscle system, consisting of muscles of various shapes. The mouth opening, from which food enters the esophagus through the pharynx, is located on the front of the torso. From there it is transported to the area of ​​the enlarged goiter and the small size of the gizzard.

Burrowing and litter earthworms live in areas with loose and moist soil. Preference is given to moist soils of the subtropics, swampy lands and the shores of various reservoirs. In the steppe territories, soil worms are usually found. Litter species live in taiga and forest-tundra. The coniferous broadleaf strip boasts the highest concentration of individuals.

What kind of soil do worms like?

Why do earthworms love sandy loam and loam soils? Such a soil is characterized by low acidity, which is best suited for their life. An acidity level above pH 5.5 is detrimental to organisms of these annelids. Wet soils are one of the prerequisites for expanding the population. During dry and hot weather, the worms go deep underground and lose the ability to reproduce.

The nature and lifestyle of the earthworm

The active and productive life of the earthworm falls in the dark. As soon as night falls, many individuals crawl to the surface of the ground in search of food. However, the tail usually remains in the ground. By morning, they return to their burrows with prey, dragging bits of food into them and mask the entrance to their shelter with grass and foliage.

The role of earthworms in nature is difficult to overestimate. The worm literally passes an incredible amount of soil mixture through itself, enriching it with useful enzymes and killing harmful substances and bacteria. The worm moves by crawling. Pulling in one end of the body and clinging to the roughness of the ground with its bristles, it pulls up the back, making its many passages in a similar way.

How do earthworms survive the winter?

In winter, the vast majority of individuals hibernate. A sharp drop in temperature can instantly destroy the worms, so they try to bury themselves in the soil in advance to a depth of often more than one meter. Earthworms in the soil perform the most important function of its natural renewal and enrichment with various substances and microelements.

Benefit

In the process of digesting semi-fermented leaves, the body of worms produces specific enzymes that contribute to the active generation of humic acid. The soil, which has been loosened by earthworms, is optimal for a wide variety of representatives of the plant kingdom. The entangled tunnel system provides excellent aeration and root ventilation. Thus, the movement of the earthworm is an important factor in the task of restoring the beneficial qualities of the soil.

The earthworm is in fact very useful for humans. It makes the soil layers fertile and enriches them with all kinds of nutrients. However, the total number of individuals in many regions of Russia is rapidly decreasing. This happens due to the uncontrolled introduction of pesticides, fertilizers and mineral mixtures into the soil. Also, earthworms are hunted by numerous birds, moles, and various rodents.

What do earthworms eat?

At night, the earthworm crawls to the surface and pulls the half-decayed remains of plants and leaves into its shelter. His diet also includes humus-rich soil. One representative of the species can process up to half a gram of soil per day. Considering that up to several million individuals can be simultaneously located on an area of ​​one hectare, they are able to act as irreplaceable soil transformers.

After rain, a large number of worms can be seen on the asphalt and soil surface, what makes them crawl out? Even the name "earthworms" indicates that they are very fond of moisture and are activated after rain. Let's consider several possible reasons why earthworms come out after rain to the surface of the earth.

Soil temperature

It is believed that worms crawl to the surface in search of warmth, since after rain the soil temperature drops by several degrees, which causes discomfort for them.

Change in acid-base balance

Another theory says that worms crawl to the surface due to changes in the acid-base balance of the soil after rain, it becomes more acidic, which negatively affects these diggers. According to the researchers, emergency evacuation to the soil surface saves them from death in an acidic environment.

Lack of air

The third theory explains that after rain in the upper layer of the soil there is more oxygen, so the worms massively crawl out to the top. Water enriches the upper layers of the earth with oxygen, and many species of worms love moisture and vitally need sufficient oxygen. And through the surface of the body, oxygen is absorbed best in a humid environment.

Trips

British scientist Chris Lowe suggested that worms crawl to the surface of the earth during rain in order to make a long journey into new territory. On the surface, worms are able to crawl much farther than underground, and dry soil causes discomfort when moving, strong friction is created, grains of sand adhere to the surface of the worm's body, wounding it. And after the rain, the surface of the earth is highly moistened, which allows them to freely travel to new areas of the ground.

Sounds of the rain

Another scientist, Professor Joseph Gorris from the United States, suggested that earthworms are afraid of the noise of rain, since the vibration it creates is similar to the sound of the approach of their main enemy - a mole. That is why some fishermen use a technique to lure the bait to the surface: insert a stick into the ground, fix a sheet of iron on its surface and pull it so as to create vibration, which will be transmitted to the ground through the stick. Frightened, the worms get out to the surface of the earth and become easy prey for experienced fishermen.

Reproduction and life expectancy of earthworms

The earthworm is hermaphrodite. He has both female and male genitals. However, he is not capable of self-fertilization. With the onset of the warm climatic conditions required for reproduction, the individuals slide down in pairs, touching each other with the abdominal region, and perform a kind of seed exchange. After that, the clutch is transformed into a cocoon, in which the eggs develop.

Some species are distinguished by asexual reproduction. The body of the worm is divided in two, with one of the parts regenerating the front end, and the other - the back. There are also species of worms that reproduce without spermatophores by depositing spermatophores. The life span of worms can exceed ten years.