The large pond snail is a typical representative of freshwater. In our article, we will consider the living conditions and typical structural features of this animal.

Mollusks: organization features

Translated from Latin, the name of this type of animal means "soft-bodied". Some of them have shells. But in any case, the body of these invertebrates is soft and unsegmented. You can meet them in fresh and salt water. So, toothless and barley live in ponds and lakes, and mussels and octopuses live in the seas. Snails and slugs can be found in wet areas of land.

In the body of mollusks, three parts can be distinguished: the head, trunk and leg. Most of them move quite slowly, since the muscles are represented by separate bundles. In all mollusks, the body is surrounded by a fold skin which is called the mantle.

Basics of classification

Depending on the structural features, three classes of molluscs are distinguished. characteristic feature cephalopod is a modification of the legs into tentacles. They are located around the mouth. On the tentacles are suction cups, with the help of which animals catch and hold prey. Cephalopods are capable of jet propulsion due to a special tubular formation - a funnel. Representatives of this class are squids, cuttlefish and octopuses.

There are barley, mussels, mussels and oysters. All of them have a body consisting of a trunk and legs, as well as a shell of two valves. The large pond snail is a representative of gastropod molluscs. Let us dwell on its structure in more detail.

Large pond snail - a representative of gastropod mollusks

Large, or found in fresh waters rich in vegetation. His body, like all gastropods, consists of a head, torso and legs. The middle part is completely located inside a spirally twisted shell, consisting of lime covered with a layer of a horn-like substance. This is a kind of dwelling and shelter. The shell of a large pond snail is spirally twisted. The maximum is 4-5 turns. It has a hole called a mouth. Through it, the head and leg are drawn inward. The shell of a large pond snail and a horn coil is closed with a special lid in case of danger. This structure is an additional defense against enemies.

The structure of a large pond

Why are the mollusks represented by the pond snail called gastropods? It's all about the structure of their body. There are no clear boundaries between its parts. The leg is a flat and muscular protrusion that completely occupies the abdominal part of the body. Its surface exudes mucus, which provides easy sliding on various substrates and water film.

The pond snail has a pair of tentacles. This If you touch them, the mollusk will pull its head inside the shell. The eyes are located at the base of the tentacles. The pond snails also have organs of balance. They are represented by small bubbles, inside of which special bodies are located. Changing the position of these structures keeps the mollusc in balance.

Circulatory and respiratory systems

The large pond snail has a type. It consists of a two-chambered heart and vascular system. The blood mixes with the abdominal fluid, washing all tissues and organs. From the heart, it enters the arteries, and in the opposite direction moves through the veins. Despite the fact that a large pond snail lives in the water, it breathes exclusively atmospheric oxygen. To do this, the animal moves to the surface of the water and opens a breathing hole located at the edge of the shell to the outside. It leads to the lung, where the blood is enriched with oxygen.

Digestive and excretory systems

The big pond snail moves slowly but surely. Why does he constantly "travel"? The mollusk moves in search of food, scraping it from underwater objects with the help of its jaw and grater. The latter consists of several rows of horn teeth. splitting process nutrients accelerate the enzymes of the digestive glands - salivary and liver.

An anus opens above the head of the pond snail. And next to it, the duct of the urinary system opens. The latter is represented by a single kidney and an ureter with a hole.

Reproduction and development

According to the type of reproductive system, a large pond snail is a hermaphrodite. This means that both female and male sex cells are formed in his body. Fertilization in these mollusks is internal. As a result, sperm exchange occurs. Mollusks place zygotes in gelatinous cords, which are attached to underwater objects. As a result, young individuals with a thin shell develop.

So, to summarize: a large pond snail is a representative of gastropod mollusks. These are typical inhabitants of fresh water bodies. Pond snails have three body parts: the head, trunk and leg, as well as a spirally twisted shell.

The small pond snail is similar to the common pond snail, only the shell size is smaller (see appendix fig. 25). The small pond snail lives in temporary reservoirs - puddles, ditches, swampy meadows, sometimes even on moist soil near the water's edge. In a word, there are many places where a temporary resident is found.

It feeds, like its relative, on algae and microorganisms.

The small pond snail is distributed throughout Europe and North Asia, as well as common pond snail.

gastropods;

coil family;

horn coil.

Coils (Planorbis) belong to the class of gastropods (Gastropoda), to the order of pulmonary (Pulmonata), to the family of coils (Planorbidae).


The coil can be distinguished at a glance due to its extremely characteristic
shell, curled in one plane in the form of a spiral cord.
The horn coil (P. corneus L.) attracts the most attention, the largest among the others (shell diameter 30 mm, height 12 mm), reddish-brown. This coil is found everywhere in both pond and lake waters.
The movements of the coils resemble the movements of pond snails. Crawling, snails expose their dark soft body far from the shell and move along underwater objects with the help of their wide flat legs. On the head there is a pair of thin tentacles, at the base of which the eyes are placed. Coils, just like pond snails, can wander along the surface of water bodies, being suspended from a film of surface tension of a liquid.
Coils breathe atmospheric air, taking it into the lung cavity formed by the walls of the mantle. The respiratory opening leading to the indicated cavity opens on the side of the body, near the edge of the shell. It opens when the coil rises to the surface of the water for a supply of air. With a lack of air, the coil uses a special leathery outgrowth, which is placed on the body near the pulmonary opening and plays the role of a primitive gill. In addition, the coil, in all likelihood, breathes directly through the skin.
Nutrition. Coils feed on plant foods, eating parts of plants that are scraped off with a grater. Especially willingly, these snails eat green plaque from small algae, which forms on the walls of the aquarium. Outside, through the glass, it is not difficult to observe how the animal works with its grater, raking up plaque like a spatula. It is very possible that coils can also eat animal food. At least in captivity, they willingly pounce on raw meat.
Reproduction. Coils reproduce by laying eggs on the leaves of aquatic plants and other underwater objects. The masonry of the horn coil is constantly found on excursions and is so characteristic that it can be easily distinguished: it has the appearance of a flat gelatinous plate of oval yellowish or light brown color and contains several dozen round pinkish transparent eggs. After two weeks or more (depending on the temperature of the water), tiny snails hatch from the eggs, which grow quite quickly. The caviar of coils, like other snails, is readily eaten by fish and exterminated by them in large numbers. Like the pond snail, coils are hermaphrodites.
The behavior of the coils during the drying of the reservoirs in which they occur is interesting. They burrow into moist silt, like the large horn coil (P. corneus). Sometimes this coil remains on the surface of the soil, sticking to the silt with its mouth, if moisture remains in it, or it releases a dense, water-insoluble film, which closes the shell opening. In the latter case, the body of the mollusk gradually shrinks, eventually occupying a third of the shell, and the weight of the soft parts drops by 40-50%. In this state, the mollusk can survive out of water for up to three months (marginal coil P. marginatus P. planorbis).

The body of the coil, like that of pond snails, is divided into three parts: head, torso and leg (see appendix fig. 26). The leg is a muscular abdominal part of the body, leaning on which the mollusk slowly glides. At the coils, the turns of the shell are located in the same plane. Coils are not as mobile as pond snails, and cannot be suspended from the surface film.

Coils live on plants in stagnant and slow-flowing reservoirs, in the same place as an ordinary pond snail, but rises to the surface of the water much less frequently.

beauty family;

larva of a beauty girl.

On a sunny day, blue lights flash up and then go out over the river (see appendix fig. 27). It is flitted by graceful dragonflies. At some point, they resemble helicopters.

The body is bronze-green, the wings of females are light smoky, those of males are almost entirely blue.

All dragonflies, wherever they are, wherever they fly, need water. They lay their eggs in the water. And only in water their larvae can live. The larvae do not look like adult dragonflies. They just have the same eyes.

Special mention must be made of the eyes of dragonflies. Each eye is made up of thousands of small eyes. Both eyes are large and protruding. Thanks to this, dragonflies can look in all directions at the same time. This is very handy for hunting. After all, dragonflies are predators. And their larvae, living in the water, too.

Dragonflies hunt in the air - they grab insects on the fly. The larvae live in the water, and here they also get food for themselves. But they do not chase prey, but lie in wait for it. The larva sits motionless or crawls slowly along the bottom. And some tadpoles or some insects swim by. The larva does not seem to care about them, but how this tadpole or insect turns out to be close. Once! She instantly throws out her long arm and grabs the prey, quickly pulling it to her.

"But insects don't have arms," ​​you say. And you will be right. Yes, of course they don't have hands. But there is a very long lower lip with hooks at the end. The lip folds like a hand at the elbow when you press the brush to your shoulder. And while the larva watches for prey, the lip is not visible. And when the prey is close, the larva instantly throws out its lip to its full length - as if shooting it - and grabs a tadpole or an insect.

But there are moments when the larva needs to save itself. And here saves her speed. More precisely, the ability to move with lightning speed from place to place.

Some predator rushed at the larva. Another second - and the larva was gone. But where is she? Just been here, and now in a completely different place. How did she get there? Very simple. Activated her "jet engine".

It turns out that dragonfly larvae have a very interesting adaptation: a large muscular sac inside the body. The larva sucks water into it, and then throws it out with force. It turns out a water "shot". The water jet flies in one direction, and the larva itself in the opposite direction. Just like a rocket. This is how it turns out that the larva makes a lightning-fast jerk and slips out from under the very "nose" of the enemy.

After flying a few meters, the larva slows down, sinks to the bottom or clings to some plant. And again it sits almost motionless, waiting for the time when it will be possible to throw out the "hand" and grab the prey. And it will be necessary - it will re-launch its " rocket launcher True, not everyone has a "jet engine", but only the larvae of large dragonflies.

A year later, the larvae of some dragonflies, after three years, the larvae of others climb out of some plant sticking out of the water to the surface. And this is where it happens small miracle: the skin of the larva bursts and a dragonfly appears from it. The most real and not at all like a larva.

The dragonfly will shed its skin like a suit, and even pull out its legs, like out of stockings. He will sit for several hours, rest, spread his wings and go on his first flight.

Some dragonflies fly far from their birthplace. But the time will come, and they will definitely return. Because they cannot live without a river or a lake, a pond or a swamp - without water, in a word. And the river, the pond, the lake also cannot live without these friends of theirs.

Dragonfly eggs are laid in water or in the tissues of aquatic plants. The eggs hatch into larvae of an extremely characteristic shape, interesting in their biological features. These larvae are playing important role among other things live stuff freshwater excursions.
Dragonfly larvae are found everywhere in stagnant and slowly flowing water. Most often they are on aquatic plants or at the bottom, where they sit motionless, sometimes move slowly. There are species that burrow into the silt.

The larvae move either by swimming or crawling. Larvae from the group of buttercups swim differently than others. An important role in the movement is played by the expanded gill plates located at the posterior end of the abdomen, which serve as an excellent fin. Bending its long body, the larva beats the water with this fin and rapidly pushes forward, moving like a small fish.

Dragonfly larvae feed exclusively on live prey, which they watch motionless for hours, sitting on aquatic plants or at the bottom. Their main food is daphnia, which they eat in huge quantities especially by younger larvae. In addition to daphnia, dragonfly larvae willingly eat water donkeys. They are less willing to consume cyclops, perhaps due to the small size of the latter.
The favorite food of dragonfly larvae are also mayfly larvae and mosquito larvae from the families of culicids and chironomids.
They also eat the larvae of aquatic beetles, if only they are able to master them. However, they do not touch large larvae of swimmers, well-armed and no less predatory, even if they are planted in a common vessel with them.
Dragonfly larvae do not chase their prey, but sit motionless on aquatic plants or on the bottom and guard the prey. When a daphnia or other animal suitable for food approaches, the larva, without moving from its place, throws out its mask with lightning speed and grabs its prey.

For grasping prey, the larvae have a wonderful oral apparatus, which is aptly called "masks". This is nothing more than a modified lower lip, which looks like grasping tongs, sitting on a long lever - a handle. The lever is equipped with a hinge joint, thanks to which the whole device can be folded and, in a calm state, covers the underside of the head like a mask (hence the name). Noticing the prey with its large bulging eyes, the larva, without moving, aims at it and with a lightning movement throws its mask far forward, grabbing the prey with remarkable speed and accuracy. Captured prey is immediately devoured with strong gnawing jaws while the mask brings the prey to the mouth and holds it like a hand while eating.


Breath. Dragonfly larvae breathe with tracheal gills. In lute-type larvae, the gill apparatus is located at the posterior end of the abdomen in the form of three thin, expanded plates pierced by a mass of tracheal tubes. Shortly before the adult dragonfly hatches, the larvae also begin to breathe atmospheric air with the help of spiracles that open on their upper side of the chest. This explains why adult larvae often sit on aquatic plants, exposing the front end of their body out of the water.

Luke-type larvae have the ability to discard gill plates if they are infringed. This is easy to verify by experience: put the larva in the water and squeeze the gill plate with the tip of tweezers. This phenomenon is called self-mutilation (autotomy) and is well known in many animals (spiders, lizards, etc.). For this reason, it is necessary to catch larvae from the water that lack 1 - 2, and sometimes all 3 tail plates. In the latter case, breathing takes place, in all likelihood, through a thin skin that covers the body. The torn off plate is restored again after some time, due to which it is possible to observe larvae with gill plates of unequal length. It should be noted that in Calopteryx one of the plates is always shorter than the other two, which is not an accidental circumstance, but a generic feature.

Dragonflies reproduce using eggs that the females lay in the water. The clutches of different species are very diverse. Dragonflies such as yoke and buttercups drill their eggs into the tissues of aquatic plants. In this regard, their eggs also have a characteristic oblong shape, and the stuck end is pointed. In the place where the egg is stuck, a trace remains on the surface of the plant, which then takes the form of a dark spot or scar.
Since the eggs different types dragonflies are placed on the plant in a certain order, then peculiar, sometimes very characteristic patterns are formed.

The suborder of dragonflies is homoptera;

Lutka family; sunflower-bride.

A very slender, elegant, graceful dragonfly (see appendix fig. 28). The body is green, metallic-shiny. In females, the sides, breasts are yellow, and in males with a bluish-gray bloom.

There are no significant differences between dragonflies, and all descriptions of dragonflies and their larvae are the same, so in the previous chapter you can find all descriptions of both larvae and adults.

Mayfly Squad;

Mayfly ordinary.

Quiet summer evenings when the sun's rays are no longer burning, some insects that look like butterflies, but with two or three long threads on their tails, swarm in the air near the banks of rivers, lakes and ponds (see appendix fig. 29). They either soar up, then freeze, stabilizing the fall with long tail threads, then, spreading their wide wings, slowly sink down. So they swirl over the shore, like a dense fog or cloud about ten meters high and about a hundred meters long. These swarms rush over the water like a storm. You will not see such an exceptional phenomenon every day, only in July-August it is repeated several times.

This is dancing, carrying out the mating flight, mayflies. Their wings and they themselves are so tender that it is simply amazing how they do not break during the flight. You involuntarily think that they will not live long. And this opinion is true: many mayflies live only one day. Therefore, they are called mayflies, and their scientific name comes from the Greek word "ephemeron" - fleeting.

After the mating flight, the females lay their eggs in the water and die. With such short life they don't eat anything.

Mayfly larvae develop in water. The larvae live longer, two to three years. And unlike an adult, they eat very well. And they feed on algae, decaying organic matter, small invertebrates and molt up to twenty-five times during development. Many fish feed on the larvae of mayflies, and various birds eat adult mayflies.

On examination, the quick, sharp movements of the larvae are primarily striking. When disturbed, it takes off headlong and swims very briskly, with three feathery caudal filaments, richly pubescent with hairs (Cloon, Siphlurus), serving as fins. The legs serve mainly for attachment to aquatic plants. The quick movements of the mayflies probably serve as a defense against their many enemies, who actively hunt for these tender larvae. The color of the larvae, in general, greenish, matching the color of the aquatic plants among which they huddle, probably also plays a protective role.

The respiration of larvae is easy to observe during excursions. It is of great interest as good example tracheal-gill breathing. The gills look like thin delicate plates that are placed in rows on both sides of the abdomen (Cloeon, Siphlurus). These delicate tracheal leaves are constantly moving, which can be perfectly seen in a larva sitting in water even without the help of a magnifying glass. Most often, these movements are uneven, jerky: like a wave runs through the leaves, which then remain motionless for some time until a new wave. Physiological significance This movement is completely understandable: in this way, the flow of water washing the gill plates increases, and the exchange of gases accelerates. The larvae's need for oxygen is generally very high, therefore, in aquariums, the larvae die at the slightest damage to the water.
The food of the larvae is very diverse. The free-swimming, stagnant water forms most commonly encountered on excursions are peaceful herbivores, feeding on microscopic green algae (Cloeon, Siphlurus). Other species lead a predatory lifestyle and actively hunt for small aquatic animals. The food of many species of mayflies is still not well understood.

The phenomena of reproduction in mayflies are of great interest and have long attracted the attention of observers. Unfortunately, these phenomena on excursions have to be seen only by accident. As mentioned above, females drop their eggs into the water. The eggs hatch into larvae, which grow and molt many times (the Cloeon has more than 20 molts), and the rudiments of wings gradually form in them. When the larva completes its development, a winged insect hatches. At the same time, the larva floats to the surface of the reservoir, the covers on its back burst, and in a few seconds an adult mayfly emerges from the skin, which flies into the air. Since the process of hatching in larvae is often carried out simultaneously, the surface of those reservoirs where larvae are found in large numbers presents a wonderful sight during hatching, which has been described more than once in the literature: the surface of the water seems to boil from a multitude of hatching insects, and clouds of mayflies, like snow flakes hovering in the air. However, the winged insects that hatch from the larvae do not represent the final stage of development. They are called subimago and after a short period of time (from several hours to 1-2 days) they molt again, thus turning into imago (the only case among winged moulting insects). Sometimes on an excursion you can watch how a winged mayfly sits on some plant or even on a person and immediately sheds its skin.

Detachment ticks;

hydrachnida family;

The vast majority of ticks are very small animals, no more than one millimeter, only a few are larger, for example, our tick.

The habitat of Lymnaea stagnalis is very extensive - water bodies of North Africa and North America, Asia, Europe.

The snail Prudovik Ordinary is able to live both in fast streams and in swamps, but it feels best in the coastal part of lakes. The pond snail actively crawls along the bottom of the reservoir and coastal vegetation, and sometimes goes out onto wet meadows.

The main difference between this one is that her eyes are at the base of the antennae.

The shell of the Prudovik has a brown color, which sometimes reaches dark. The base of the shell is rather fragile, the number of whorls varies within 4-5, the shell dimensions are up to 55 mm in height and up to 30 mm in width. Lymnaea stagnalis are able to move vertically (by secreting a path of mucus, they crawl along it in all directions).

Snails breathe atmospheric air with the help of a lung (a special section of the mantle cavity). To renew the air in the lung cavity, the mollusks rise to the surface of the water and breathe with the help of the edge of the mantle rolled into a tube.

In oxygen-rich water, pond snails are able to live at depth without rising to the surface. In this case, the lung is filled with water, through which gas exchange takes place.

The snail Prudovik feeds on both plant food and small insects and microorganisms. Quite often you can see snails eating the foliage of aquatic and coastal plants. If the number of molluscs in the reservoir increases greatly, then this is very harmful to the surrounding plants.

In an aquarium, Prudovik Ordinary can be fed with cabbage stalk, lettuce or raw potatoes.

Many freshwater inhabitants do not mind eating this snail, as well as its caviar.

reproduction

By nature, Lymnaea stagnalis are hermaphrodites, so the eggs are fertilized both by their sexual products and other snails.

at one time the snail lays a large number of eggs enclosed in transparent mucous masonry.

In an aquarium, reproduction of the pond snail is difficult, since most of the eggs laid are eaten.

The Prudovik snail reaches puberty when its shell grows up to 20mm in length.

After starting a new aquarium, novice aquarists often face the problem of pollution, the appearance of unwanted algae. There are many ways to clean the aquarium tank, the best of which, perhaps, is biological, that is, adding natural cleaners to fish. Often, fish owners resort to the help of pond snails. They not only help fight pollution, but are also interesting in terms of observing their behavior.

Description, types

The pond snail (lat. Lymnaeidae) is a snail belonging to the genus of pulmonary molluscs. As the name implies, it lives in fresh water bodies with stagnant water or water with a very slow current.

Did you know? Snails are among the most ancient animals on earth. According to scientists, they appeared over 500 million years ago..

The body of the mollusk is divided into three parts: head, body and leg. The pond snail has a fine-spiral shell, on which there are five or six whorls, mostly twisted to the right. Left-handed are found in the inhabitants of New Zealand and the Sandwich Islands. The shell opening is large, rounded in front. The shape of the shell depends on what current is characteristic of the reservoir where the snail lives. Its dimensions range from 1 to 6 cm in height and from 0.3 to 3.5 cm in width. The body is tightly attached to the shell. The head of this mollusk is large. It has flat triangular tentacles with eyes on their inner edge. The hole through which the pond snail breathes is protected in the form of an outstanding blade. The color of the snail depends on the living conditions. The shell is usually brown. The head and body can be colored from black with a blue tint to yellow with a brownish tint.
In nature, the pond snail is represented by many species that live in the Northern Hemisphere, in Eurasia, North Africa, and North America. Some of its representatives can be found in geysers, sulphurous, slightly saline and salty waters. You can find them even at an altitude of 5.5 thousand meters in Tibet and at a depth of 250 m.

Did you know?The tiny snail brain is divided into four sections and is quite efficient. Scientists claim that these mollusks have the ability to make independent decisions. After conducting more detailed studies of two neurons that are responsible for the feeling of hunger and the decision to go for food, they decided to use this data to work with the simplest algorithms in robotics.

Each species is distinguished by the characteristic coloration of the shell, body, legs, as well as the shape and thickness of the shell walls, the shape of the whorl and mouth.

Let's take a closer look at the most famous species:

  1. Prudovik ordinary, he is big. The largest in our area and the most famous representative families. The shell is elongated, conical, 4.5-6 cm long and 2-3.5 cm wide. It is twisted in a spiral with 4-5 turns, which quickly expand, forming a large hole. Its color is brown, the walls are thin and translucent; the body of the mollusk is greenish-gray. The species is widespread, found throughout the Northern Hemisphere in various freshwater reservoirs.
  2. This species has an elongated, pointed to the top and strong shell. Curls twist to the right, have six to seven turns. The shell is thin, almost transparent, pale yellow. Its dimensions are small: length - 1-1.2 cm, width - 0.3-0.5 cm. The body and mantle of this pond snail are of light gray shades. There are dark spots on the mantle. The species is distributed on the territory of Russia, lives in ponds, swamps, puddles. It can live along the banks of drying water bodies.
  3. Ear. So named because the mouth of the shell in appearance is very similar to the human ear. Its shell is small - 2.5-3.5 cm in height and 2.5 cm in width. Has thin walls. Painted in greyish yellow. Has up to four turns. The last turn is very large. The body is colored green-gray or yellow-green with numerous inclusions. The mantle can be monophonic - light gray, or spotted. The ear pond snail lives in various reservoirs, lives on plants, snags, stones.
  4. Oval or oval. Like the auricular pond snail, the ovoid shell curl makes up a third of the mouth. The shell has thin walls, so it is very fragile. In an adult, it is 2-2.7 cm in height and 1.4-1.5 cm in width. The shape of the mouth is ovoid. The shell is painted light pink, shiny and almost transparent. The body color is light gray or light olive. The mantle is also light grey. Habitat habitats of the egg-shaped pond snail - lakes, quiet rivers. It can live both in the coastal zone and at depth.
  5. In a swamp pond snail, the height of the shell reaches 3.2 cm, the width is 1 cm. In appearance, this species is similar to the common pond snail, but differs from it in that its shell has the shape of a sharp cone with a small hole. It is dark brown in color. In addition, the marsh one is smaller than the ordinary one: the height of the shell is 2-3 cm, the width is 1 cm. There are six to seven whorls on the shell. Her walls are thick. The body is greenish gray in color. The mantle is light. It lives in shallow water bodies - swamps, puddles, streams, ponds.
  6. Frilled or frilled. It got its name due to the fact that its shell is completely or partially covered by a mantle. The shell of the raincoat is shiny, smooth. May be colorless, yellowish or yellow-horny. It is small in size, its height is 1.9 cm, width is 1.2 cm. It has 2.5-4.5 curls. The last one is very big. The shell is shaped like a ball. Mouth - oval, large. The body is painted olive with gray color with numerous inclusions. The mantle is yellow-brown or yellow-green with large light spots. Lives in lakes, quiet rivers, in shallow water.

Habitat in nature

In nature, common pond snails eat mainly plants. However, their diet can also include animal food (flies, fish eggs, etc.) and bacteria. They breathe, crawling out of the water to the surface. On the day they need to carry out from six to nine such lifts. Those snails that live at great depths are able to exist due to the air dissolved in water. They draw water into the lung cavity. Pond snails can swim - they turn the sole upside down and give it a slightly concave shape.

Did you know? Snails have no hearing and voice, very poor eyesight, but their sense of smell is well developed - they are able to smell food at a distance of about two meters from themselves. The receptors are located on their horns.

IN vivo these snails are rarely seen idle, usually they are “in a hurry” somewhere, busy with something - for example, scraping algae from stones. Max Speed, which they can develop - 20 cm per minute.
It is interesting that these mollusks are able to survive when the reservoir dries up, sealing the shell with a dense film, as well as when the pond is covered with ice - after thawing it, they come to life and continue their vital activity. Average duration life aquarium pond snail- two years in wild nature- nine month.

Prudovik is an unpretentious aquarium inhabitant. The main conditions for its maintenance are water temperature not lower than 22 ° C, its moderate hardness and weak light - preferably fluorescent with a minimum power.
With more warm water snails will breed more often and actively, and this is not desirable for home aquariums. The size of the aquarium is not critical. The soil is rocky. It can be pebbles or coarse sand.

Special cleaning for shellfish is not required. All you need is the standard procedures that every aquarist must follow:

  • weekly water change by 30%;
  • aeration;
  • filtration.

Nutrition, mineral supplements

Every owner of an aquarium who is going to place a pond snail in it will be interested in the question of what he eats and where to get food for him. There will be no problems with this, since he can eat both what the fish did not eat, and their excrement, rotten plants. A person can prepare for him a salad of finely chopped greens, cabbage, zucchini, pumpkin, tomatoes, and other vegetables and fruits.
With the addition of pond snails to the aquarium, you should be careful, because when they reach adulthood, they can be very voracious and eat most of the underwater vegetation. Occasionally, snails will need to be fed with mineral supplements. The main thing for them is calcium, so you can sprinkle them with crushed eggshells, chalk, sepia.

Important! Do not plant pond snails in a tank where soft and succulent underwater plants grow. It threatens the death of the latter. These snails are too tough for only algae with hard, dense sheets.

Compatibility with other inhabitants of the aquarium

Diseases

Snails rarely get sick. But they themselves serve as a source of infectious ailments for other aquarium inhabitants. Moreover, the danger lies in the fact that usually the presence of an infection in the body of a mollusk does not affect its appearance Therefore, it is not always possible to immediately determine whether it is dangerous for fish or not. In a small pond snail, the most common disease is fungal infection - its shell is covered with a white coating.
Treatment will consist in baths with the addition of salt solutions or potassium permanganate. Also, if the mollusk does not consume required amount vitamins and minerals, its shell walls can become thin and damaged. When observing this problem, it is worth feeding the snail with substances containing calcium. Small cracks will disappear on their own some time after the start of treatment. But the deep ones will need to be “glued” with a special preparation sold in zoological stores.

Breeding

Pond snails reach sexual maturity at six to eight months. Since they have no sexual differences, representatives of the pond family reproduce by laying eggs, usually from 20 to 130 per clutch. This process can occur in them several times a year, and in a lifetime one individual is capable of producing offspring about five hundred times. Mollusks lay their eggs on the leaves of plants. Incubation occurs within 14-20 days. The eggs hatch into thin-shelled babies. Thus, pond snails, in addition to being very voracious, are also prolific. Therefore, the question of their breeding among aquarists is not worth it. More often another problem arises - how to prevent their frequent reproduction and overpopulation of the aquarium. If the task is to breed these mollusks, then you can stimulate the breeding process by raising the water temperature by a couple of degrees.

Did you know? The largest sea snail is considered to be the giant Australian trumpeter, whose shell reaches 91 cm and weighs 18 kg. The tiger Achatina is recognized as the largest land mollusk - with a shell 27.5 cm high and weighing about 1 kg.

Snails do not have to be planted in the aquarium themselves. They may appear unexpectedly - their eggs are brought along with underwater plants. In this case, the owner needs to organize their proper maintenance and ensure that the number of individuals does not exceed the capacity of the aquarium tank. If it is possible to control their reproduction, then the presence of pond snails will certainly benefit the fish dwelling - they can help get rid of unfriendly algae that settle on the decor, walls and plants, and keep their place of residence clean. Shellfish are indispensable cleaners for spawning aquariums. Overpopulation by snails threatens with oxygen deficiency, because of which, first of all, the fish will suffer. Thus, pond snails are possible, but not desirable, to be kept in an aquarium. On the one hand, they are able to clean the tank, get into places where they can’t get human hand, get rid of unnecessary algae. In addition, they do not require special care and nutrition. On the other hand, these snails can cause serious damage to underwater plants and, as a result, the beauty of the aquarium. They are often placed in an aquarium without live algae by beginners. Experienced aquarists prefer to deal with snails of other species.

Mollusks, or soft-bodied, live in the sea, in fresh waters and on dry land. The body of mollusks, as a rule, is covered with a shell, under which there is a skin fold - the mantle. The space between the organs is filled with parenchyma. About 100,000 species of molluscs are known. We will get acquainted with representatives of three classes: gastropods, bivalves and cephalopods.

lifestyle and external structure. In ponds, lakes and quiet backwaters of rivers on aquatic plants you can always find a large snail - a large pond snail. Outside, the body of the pond snail is dressed in a protective spirally twisted shell about 4 cm long. The shell consists of lime covered with a layer of greenish-brown horn-like organic matter. The shell has a sharp top, 4-5 whorls and a large opening - the mouth.

The body of a pond snail consists of three main parts: head, torso and legs. Only the leg and head of the animal can protrude from the shell through the mouth. The leg of the pond snail is muscular. When undulating muscle contractions run along its sole, the mollusk moves. The leg of the pond snail is located on the ventral side of the body, and therefore it is classified as a class of gastropods. In front, the body passes into the head. A mouth is placed on the underside of the head, and two tentacles are located on its sides. The tentacles of the pond snail are very sensitive: when touched, the mollusk quickly draws its head and leg into the shell. Near the base of the tentacles on the head is an eye.

The body repeats the shape of the shell, closely adhering to its inner surface. Outside, the body is covered with a mantle, under it there are muscles and parenchyma. A small cavity remains inside the body, in which the internal organs are located.

Nutrition. The pond snail feeds on aquatic plants. In his mouth is placed a muscular tongue, covered with hard teeth. From time to time, the pond snail sticks out its tongue and scrapes with it, like a grater, the soft parts of plants, which it swallows. Through the pharynx and esophagus, food enters the stomach and then into the intestine. The gut loops inside the body and ends on its right side, near the edge of the mantle, with an anus. Next to the stomach in the body cavity lies a grayish-brown organ - the liver. Liver cells produce digestive juice, which flows through a special duct into the stomach. Thus, digestive system the pond snail is even more complex than that of the earthworm.

Breath. Despite the fact that the pond snail lives in the water, it breathes oxygen from the atmospheric air. For breathing, it rises to the surface of the water and opens a round breathing hole on the right side of the body at the edge of the shell. It leads to a special pocket of the mantle - a lung. The walls of the lung are densely woven with blood vessels. This is where the blood is enriched with oxygen and carbon dioxide is released. Within an hour, the mollusk rises for breathing 7-9 times.

Circulation. Next to the lung is a muscular heart, consisting of two chambers - the atrium and the ventricle. Their walls alternately contract (20-30 times per minute), pushing blood into the vessels. Large vessels pass into the thinnest capillaries, from which blood exits into the space between the organs. Thus, the circulatory system of the mollusk is not closed. Then the blood is collected in a vessel suitable for the lung. Here it is enriched with oxygen and enters the atrium through the vessel, and from there into the ventricle. The blood of the pond snail is colorless.

Selection. The pond snail has only one excretory organ - the kidney. Its structure is rather complicated, but in in general terms resembles the structure of the excretory organs of an earthworm.

Nervous system. main part nervous system the pond snail is a near-pharyngeal accumulation of nerve nodes. Nerves depart from them to all organs of the mollusk.

Reproduction. Prudoviks are hermaphrodites. They lay masses of eggs enclosed in transparent, slimy cords that are attached to underwater plants. Eggs hatch into small mollusks with thin shells.

Other gastropods. Among a large number of species of gastropods, marine mollusks are especially famous, thanks to their beautiful shells. Slugs live on land, so called because of the abundant mucus they secrete. They don't have shells. Slugs live in wet places and eat plants. Many slugs eat mushrooms, some are found in fields and gardens, causing damage to cultivated plants.

The grape snail is widely known, which is eaten in some countries.