River pond snails. Small prudovik

Common pondweed– lat. Limnaea stagnalis, a member of the phylum Mollusca, belongs to the class Gastropods. A feature of the common pond snail, like all representatives of the pond snail family, is its peculiar swimming in water. A special organ (leg) is directed upward during movement, protruding slightly on the surface of the water. To prevent the common pond snail from drowning while moving, the middle of the leg bends down, thus acquiring the shape of a boat, while the animal’s shell is directed down to the bottom. Scientists do not yet understand this peculiar movement.

Structure

The snail's eyes are located at the base of the second pair of tentacles. The common pond snail breathes through one lung, which is a modified mantle cavity. The air in the lungs, in a calm state of the mollusk, prevents it from falling to the bottom. But if at this time you touch an ordinary pond snail, it instantly releases air from the respiratory tract and instantly falls down. It also has one kidney and one atrium. The shell of the common pond snail has the shape of a twisted spiral.

Animal characteristics:

Dimensions: clam length 5 – 7 cm.

Color: The common pond snail has variable colors, from dark blue to yellow flowers. The shell has a thin translucent structure.

Food and habitat

Common pond snails are omnivores; they can feed on both plant and animal foods, mainly algae, aquatic plants, uruti leaves, etc. Common pond snails are widely distributed throughout to the globe, mainly on ponds, rivers, lakes, etc. They live at shallow depths.

The common pondweed is the most common member of the family in Europe. It feeds on waste and carrion that other animals do not consume.

   Class - Gastropods
   Row - Basommatophara
   Genus/Species - Lymnaea stagnalis

Basic data:
DIMENSIONS
Shell length: 45-70 mm.
Shell width: 20-30 mm.

REPRODUCTION
Mating season: spring or summer when the water warms up.
Type of reproduction: pond snails are hermaphrodites.
Number of eggs: 200-300 eggs in cords attached to underwater objects. The eggs hatch into miniature versions of the adults.

LIFESTYLE
Habits: stay solitary in standing reservoirs and rivers with slow flow.
Food: organic waste and algae, sometimes carrion.
Lifespan: 3-4 years.

RELATED SPECIES
The pond snail family includes about 100 species, for example, long-eared, marsh and small pond snails.

The common pond snail lives in water, but breathes atmospheric air. That is why it can inhabit reservoirs with stagnant water, which contains minimum quantity oxygen. In such swamps and lakes there is a lot of rotten plant and animal remains - the main food of the common pond snail.

REPRODUCTION

Pond fish are hermaphrodites. Each individual has both male and female reproductive organs. Despite this, during mating, both partners mutually fertilize each other. Later, pond snails lay eggs in long dragnet cords. The cords are attached to underwater parts of plants and rocks. Sometimes they even stick to the shells of other individuals. Pond snails do not have a free-swimming larval stage. Each egg develops into an embryo, which, after emerging from the shell, looks like a smaller copy of the adult.

LIFESTYLE

Many snails that live under water breathe using thread-like gills. The gills of these cephalopods contain many blood vessels. Animals get oxygen directly from water. However, in the common pond snail, the respiratory organs have the form of pulmonary sacs. The mantle cavity of these cephalopods, which connects to external environment only through a small breathing hole by a pneumostome, penetrated by a dense network of small blood vessels. It acts like the human lungs. The disadvantage of this type of breathing is the need to surface approximately every 15 minutes in order to replenish air reserves. However, thanks to this respiratory organ, the pond snail can live in water bodies with low oxygen content.
The pond fish can move freely from the underside of the surface film of water. This is possible due to the fact that with the help of the lungs the mollusk scoops up large number air, which lifts it to the very surface.

FOOD

In stagnant water, they settle on submerged tree trunks or stems of aquatic plants. organic matter and microorganisms that contribute to their decomposition. Pond snails eat this layer of organic debris, waste, bacteria, protozoa, blue-green algae and mud. These mollusks are omnivores. The snail also feeds on the eggs and larvae of other aquatic animals, and also attacks wounded fish, tadpoles or newts.
With the help of the radula, pond snails eat the leaves of water lilies and scrape algae from the lower surface of the leaves of water lilies. The radula of gastropods resembles a sharp file, which is constantly renewed, since it wears off quite quickly. The anterior worn teeth on the radula are periodically replaced by new sharp teeth. The basis of the radula is chitin - chemical compound, which is contained in the strong shells of insects. The pond snail's radula acts like a grater. Carnivorous snails use the radula to make a hole in the shell of other mollusks and get inside. At unfavorable conditions the growth of pond snails stops.

OBSERVING THE PONDER

Common pond fish are found in ponds, lakes or rivers. They can only live in hard water. From hard water, pond snails obtain lime, which they need to build their “house” and shells. In areas where the main rock is limestone or similar sedimentary rocks, pond snails can live almost anywhere: in small lakes, ponds, water-filled ditches, irrigation canals and rivers. Ordinary pond snails can be placed in aquariums, where they slowly travel along the glass and scrape off a layer of algae from it with their radula. These gastropods can swim near the surface on the underside of the water film. The disturbed pond snail “falls” to the bottom.

DID YOU KNOW THAT...

The shape of the common pond snail shell depends on the location of the particular individual. These mollusks are extremely variable; not only their size, color, shape, but also the thickness of the shell varies.
The small pond snail is one of the smallest representatives of the family. It lives not only in reservoirs, but also in flooded meadows and pastures. The small pond snail is intermediate host liver fluke, which causes fascioliasis in sheep and cattle.
Shells of all European species pond snails twisted to the right. Only as an exception are there individuals with left-handed (leotropic) shells.

FEATURES OF THE COMMON PONDOWER

   Horn Coil: a close relative of the pond snail lives in the same habitat. However, it is much smaller than the pond snail, and in addition, it has a shell of a different shape. Sometimes you can see a horn-like coil that is attached to the shell of a common pond snail.
   Tentacles: grow on the sides of the head, they are flattened and triangular, which markedly distinguishes them from the thread-like tentacles of other types of snails. The tentacles perform only the function of an organ of touch. The eyes are located at their base.
   Sink: ends with a long tip. It consists of lime and is covered with a yellowish stratum corneum. It is quite thin and easily damaged.
   Eggs: The pond snail deposits in long drag-like cords, which are glued to various underwater objects. The number of eggs in a clutch varies between 200-300 pieces. The eggs are surrounded by a mucous mass, which is dressed like a special capsule, or cocoon. Hatched from eggs to look like miniature versions of their parents.

PLACES OF ACCOMMODATION
The pond fish lives in ponds with stagnant water and in rivers with a slow flow. It is found in Central, Western and Southern Europe, V South West Africa and Asia Minor, and from there the range of the pond snail reaches Southwestern India.
SAVE
The prudovik is not in danger of extinction, but they are currently being polluted by the natural environment.

Pond snails are gastropods.

The largest of domestic representatives pond snail family (Limnaeidae) - common pond snail (Limnaea stagnalis), having an elongated conical shell up to 55 mm high. U eared pond snail (L. auricularia) shell with a short curl, resembling an ear (height 26 mm). Marsh pond snail (L. palustris) similar to the common one, but its shell has the shape of a sharp cone with a small hole (shell height 32 mm). Sink egg-shaped pond snail(L. ovata) with a short whorl, and its last whorl with a wide ovoid opening (shell height 18 mm).

Pond fish live in freshwater bodies of water. The common pond snail is especially widespread. It stays near the surface of the water and is easy to catch. In the jar, it slowly crawls along the walls of the vessel. SlipperThis occurs due to the fact that the muscles of the sole of the wide leg contract in a wave-like manner.

Ponds: 1— ordinary; 2 - ear; 3 - swamp; 4 - ovoid

Pond snail structure: 1— oral lobes; 2— tentacles; 3— eyes; 4 - leg; 5— breathing hole

Pond snails can wander along the underside of the surface film of water, holding onto it with the help of their soles. At the same time, a ribbon of mucus remains behind them. It is believed that this movement is due to the surface tension of water.

The pond snail has air inside its respiratory cavity, which, like the swim bladder of a fish, supports it. If you give a slight push to a crawling snail, it will submerge in the water and float up again, like a cork. The cochlea can voluntarily compress the respiratory cavity and, due to a decrease in specific gravity sink to the bottom; when the cavity expands, it floats to the surface.

Pond fish are capable of staying underwater for very long for a long time. This is explained by the fact that the closed lungIn this cavity, air is used very rationally during breathing, and oxygen is gradually replaced by carbon dioxide. In addition, it is likely that respiration also occurs through the skin, using oxygen dissolved in water.

Pond snails feed on the leaves and stems of aquatic plants. Therefore, individuals of large species cannot be planted in decorative aquarium. In addition to plants, they eat small organisms (hydra, protozoa), fish eggs, meat and even the remains of dead fish and snails. So it is better to keep pond snails in a separate container.

When breeding, these snails lay eggs on aquatic plants and other objects. The masonry has the appearance of a transparent gelatinous sausage. In twenty daysThe eggs hatch into tiny snails, which, feeding on plant foods, grow quite quickly. This whole process can be observed in the aquarium.

All pond snails, like most gastropods, hermaphrodites.

Appearance and structure of the pond snail

Lymnaeidae is the Latin name for the pond snail. They live in fresh, stagnant water or in bodies of water with slow currents.

The common pond snail has a fine-spiral shell with 5-6 curls, usually twisted to the right. Species with left-handed shells are found only in New Zealand and the Sandwich Islands. The degree of its elongation depends on the current in a given body of water - the width can be 0.3-3.5 cm, the height is from 1 to 6 cm. There is a large hole in the shell on the front side.

The color of the pond snail depends on natural features habitats. Most often, sinks are in a brown palette. And the head and body are from yellowish-brown to bluish-black.

The body of a mollusk consists of three sections - head, trunk and legs. All these parts are tightly attached to the inner surface of the shell. The snail's head is large, there are flat triangular tentacles on the head, and there are eyes on the inner edges of them.

The mollusk breathes through an opening protected by a noticeably protruding blade.

Habitats

The pond water snail is found in Europe, Asia, North America and North Africa. In addition to fresh standing waters and slow-flowing reservoirs, they are found in slightly salty and salty waters, as well as in geysers. In Tibet they live at an altitude of 5.5 thousand meters and a depth of 250 meters.

Varieties of pond snail

The species differ in the shell color characteristic of each locality, the thickness of its walls, the shape of the rings and mouth, the color of the legs and body.

The common pond snail (or large pond snail) is the most common species in the family of gastropods. The length of the shell, which has a conical shape, is 4.5-6 cm, its width is 2-3.5 cm. The spiral of the shell has 4-5 rings, which expand significantly with each revolution, ending with an impressive size hole. The color of the semi-translucent walls is brown. The body has a greenish-brown tint. This type Ubiquitously inhabits freshwater bodies of the countries of the Northern Hemisphere.

The small pond snail (also called the truncated pond snail) has an elongated, pointed shell with 6-7 whorls. The turns of the rings are twisted to the right. The walls of the shell are thin but strong, whitish-yellow, almost transparent. It is 1-1.2 cm long, 0.3-0.5 cm wide. The body color is white-gray, uniform, but dark spots are possible on the mantle. This species is widespread in the nature of Russia, inhabiting swampy reservoirs and ponds. Sometimes found at low water levels in drying up reservoirs.

In the auricular species, the opening of the shell resembles a human ear - hence the name of this species. The shell is from 2.5 to 3.5 cm in height, 2.5 cm in width. Its walls are thin, the color is gray-yellow. This mollusk has no more than 4 shell rings. The shell has an almost round appearance, since the last whorl is quite large in diameter compared to others. The body is yellowish-green and grayish-green with many specks. The mantle is gray or spotted. Found in bodies of water with different water compositions. Lives on rocks, sunken tree trunks, stems and leaves of aquatic plants.

Other known species pond snail:

frilled (cloaked);
oval (ovoid);
swampy

Habits in the wild and life expectancy

IN natural environment Pond snails feed mainly on plants. But sometimes they eat flies, fish eggs and other similar small aquatic life.

To breathe, they climb out from the water column to the very surface. A snail needs to rise at least 6-9 times a day. But for species that live at considerable depths, oxygen dissolved in water is sufficient. The mollusk takes water into the lung cavity, turns over in the water with its sole up and slightly pulls it into the shell.

In nature, a pond snail can rarely be found sitting motionless on some snag. The mollusk is almost constantly busy - scraping algae from stones and eating aquatic vegetation. pond snail is about 20 cm/min.

Despite the fact that pond snails spend most of their lives in the water column, they survive well in dry reservoirs and in water covered with a crust of ice. The mollusk simply seals the shell with a film, and when moisture appears or thaws, it comes to life.

On average, under conditions wildlife The lifespan of a pond snail is only about 9 months. But with proper maintenance, a pond snail in an aquarium can live up to 2 years.

Aquarium content

The pond snail is a voracious mollusk. Therefore, it is better not to place them in carefully grown luxurious home “herbal gardens” - you may lose all aquatic plants. Snails especially like soft plants with succulent stems and leaves. But the pond snail is unpretentious in its maintenance.

Basic conditions:

Water temperature in the aquarium should be maintained at 20-26°C. In more warm water the mollusk will begin to actively reproduce, which is undesirable in a small volume of water.
Water hardness – moderate, lighting – dim (optimally – low-power fluorescent lamp).
Aquarium volume Any will do, the main thing is to control the population, not allowing pond snails to multiply endlessly. If there are too many individuals, diseases may develop.
you need a rocky one - pebbles are best, but a coarse sandy bottom is also acceptable.
Clean the aquarium with pond snails as usual, replacing a third of the water every 7 days. Filter You will need a powerful one, the direction of the jet is preferably horizontal.

Before introducing new pond snails, they must be kept in quarantine for several days. It is recommended to buy shellfish from pet stores. Since in the markets, snails can be freshly caught in a pond, and infect the entire aquarium with infections.

Who can you put in the same aquarium with?

Feeding at home

Pond fish prefer plant foods. They do not require frequent additional feeding - algae, rotten parts of plants and fish waste are sufficient for nutrition. The mollusks, like a grater, scrape off all these remains from the walls and soil with long, powerful tongues. You can also give them:

fresh pumpkin,
apples,
zucchini,
white cabbage,
broccoli,
tomatoes,
carrot,
greens grown at the dacha (all cut into small pieces).

From time to time, pond snails need mineral feeding - calcium is needed for their shells. It is found in chalk, egg shells, sepia - all this must be given in crushed form.

Breeding

Pond fish are hermaphrodites. They reproduce either singly or in flocks. Eggs are laid several times throughout the year. That is, during a lifetime they hatch offspring from about 500 clutches. Clutches of eggs are attached to plant leaves.

The clutch consists of small transparent eggs fastened together with mucus, forming an oval-shaped sac. If this is facilitated favorable conditions maintenance, one individual makes up to 25 clutches of 80 eggs within 4 months.

The incubation period is 14-20 days. Newly hatched babies already have thin shells.

Sexual maturity in pond snails occurs at approximately 7 months.

Diseases

These snails are resistant to disease, but they themselves are often carriers of infection (which is practically undetectable by eye). They themselves suffer from fungus - visually this manifests itself in the form white plaque on the sink. Therapy - regular baths with manganese and saline solutions, long-term quarantine.

How much does a pond snail cost?

To avoid infections, it is better to purchase pond snails from specialized pet stores, rather than from private traders, and not to catch them yourself in water bodies. The average cost of one adult is about 50 rubles.

Contact Hazard

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

The Common Prudovik snail 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 comes out onto wet meadows.

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

The Prudovik shell has brown, which sometimes goes dark. The base of the shell is quite fragile, the number of curls varies between 4-5, the dimensions of the shell are up to 55mm in height and up to 30mm 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 using the lung (a special part of the mantle cavity). To renew the air in the pulmonary cavity, the mollusks rise to the surface of the water and breathe using the edge of the mantle rolled into a tube.

In water rich in oxygen, 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 occurs.

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