Can a pond snail live without water? Garden snail (Cepaea hortensis)

After starting a new aquarium, novice aquarists are often faced with the problem of contamination and the appearance of unwanted algae. There are many ways to clean an aquarium tank, the best of which, perhaps, is biological, that is, adding natural cleaners to the 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 pulmonate mollusks. As the name implies, it lives in fresh water bodies with stagnant water or water with a very slow flow.

Did you know? Snails belong to 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, torso and leg. The pond snail has a finely spiraled shell with five to six whorls, mostly twisted to the right. Left-handed ones are found among the inhabitants of New Zealand and the Sandwich Islands. The shell opening is large, rounded at the front. The shape of the shell depends on the current of the body of water 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-shaped tentacles with eyes on their inner edge. The hole through which the pond snail breathes is protected in the form of a prominent 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 brownish.
In nature, the pond snail is represented by many species living in the Northern Hemisphere, Eurasia, North Africa, and North America. Some of its representatives can be found in geysers, sulfurous, slightly salty and salty waters. They can be found even at an altitude of 5.5 thousand meters in Tibet and at a depth of 250 m.

Did you know?The snail's tiny 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 simple algorithms in robotics.

Each species is distinguished by the characteristic color of the shell, body, leg, as well as the shape and thickness of the shell walls, the shape of the helix and the mouth.

We invite you to take a closer look at the most famous species:

The common prudovik is a big one. 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 bodies.
This species has an elongated, pointed at the top and durable shell. The curls twist to the right and have six to seven turns. The shell is thin, almost transparent, pale yellow color. Its dimensions are small: length - 1-1.2 cm, width - 0.3-0.5 cm. The body and mantle of this pond snail are light gray. There are dark spots on the mantle. The species is distributed throughout Russia, living in ponds, swamps, and puddles. Can live along the banks of drying up reservoirs.
Ushkovy. It is named so because the mouth of the shell is very similar in appearance to a human ear. Its shell is small - 2.5-3.5 cm in height and 2.5 cm in width. Has thin walls. Painted in a gray-yellow tint. 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 plain - light gray, or spotted. The eared pond snail lives in various reservoirs, lives on plants, snags, and stones.
Ovoid or oval. Like the eared pond snail, the egg-shaped shell curl makes up a third of the mouth. The sink has thin walls and is therefore 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 is light gray or light olive in color. The mantle is also light gray. The natural habitat of the egg-shaped pond snail is lakes and quiet rivers. It can live both in the coastal zone and in the depths.
The marsh pond snail has a shell height of 3.2 cm and a width of 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 usual: the height of the shell is 2-3 cm, the width is 1 cm. There are six to seven whorls on the shell. Its walls are thick. The body is greenish-gray in color. The mantle is light. Lives in small bodies of water - swamps, puddles, streams, ponds.
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 and smooth. It can be colorless, yellowish or yellowish-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 shape of the shell resembles a ball. The mouth is oval and large. The body is colored olive with gray color with numerous inclusions. The mantle is yellow-brown or yellow-green with large light spots. Lives in lakes, quiet rivers, and shallow waters.

Habitat in nature

In nature, common pond snails eat mainly plants. However, their diet may also include animal food (flies, fish eggs, etc.) and bacteria. They breathe as they crawl out of the water to the surface. They need to carry out six to nine such lifts per day. Those snails that live at great depths are able to subsist on air dissolved in water. They draw water into the pulmonary cavity. Pond snails can swim - they turn their soles up and give it a slightly concave shape.

Did you know? Snails have no hearing or 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. Receptors are located on their horns.

Under natural conditions, these snails can rarely be found idle; usually they are “in a hurry” somewhere, busy with something - for example, scraping algae from stones. Maximum speed which they can develop is 20 cm per minute.
It is interesting that these mollusks are able to survive when the reservoir dries out, sealing the shell with a thick film, as well as when the pond is covered with ice - after it thaws, they come to life and continue their life activities. The average lifespan of an aquarium pond snail is two years, in the wild it is nine months.

The pond fish is an unpretentious aquarium inhabitant. The main conditions for its maintenance are the water temperature not lower than 22°C, its moderate hardness and weak light - preferably fluorescent with minimal power.
With warmer water, snails will reproduce more often and actively, and this is not desirable for home aquariums. The size of the aquarium is not important. Rocky soil is suitable. It can be pebbles or coarse sand.

No special cleaning is required for shellfish. All you need is standard procedures that every aquarist should follow:

weekly water change by 30%;
aeration;
filtration.

Nutrition, mineral supplements

Every aquarium owner planning to place a pond snail in it will be interested in the question of what it eats and where to get food for it. There will be no problems with this, since he can eat what the fish haven’t eaten, their excrement, and rotten plants. A person can prepare a salad for him from finely chopped greens, cabbage, zucchini, pumpkin, tomatoes, and other vegetables and fruits.
You should be careful when introducing pond snails into an aquarium, since upon reaching adulthood they can be very voracious and eat most underwater vegetation. Occasionally, snails will need to be fed with mineral supplements. The main thing for them is calcium, so you can add crushed eggshells, chalk, and sepia to them.

Important! You should not plant pond snails in a tank where soft and succulent underwater plants grow. This threatens the death of the latter. These snails cannot handle only algae with hard, dense leaves.

Compatibility with other aquarium inhabitants

Diseases

Snails rarely get sick. But they themselves serve as a source of infectious diseases for other aquarium inhabitants. Moreover, the danger lies in the fact that usually the presence of infection in the body of a mollusk does not affect its appearance, so it is not always possible to immediately determine whether it is dangerous for fish or not. The most common disease in the small pond snail is fungal infection - its shell becomes covered with a white coating.
Treatment will consist of baths with the addition of solutions of salt or potassium permanganate. Also, if a clam does not consume the required amount of vitamins and minerals, the walls of its shell may become thin and damaged. If you observe this problem, it is worth feeding the snail with substances containing calcium. Small cracks will disappear on their own after some time after starting treatment. But the deep ones will need to be “glued together” 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 snail family reproduce by laying eggs, usually from 20 to 130 per clutch. This process can occur in them several times a year, and over the course of its entire life, one individual is capable of producing offspring about five hundred times. Mollusks lay eggs on the leaves of plants. Incubation occurs within 14-20 days. The eggs hatch into babies with a thin shell. Thus, pond snails, in addition to being very voracious, are also fertile. Therefore, aquarists do not have a question about breeding them. 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 the reproduction process can be stimulated by raising the water temperature by a couple of degrees.

Did you know? The largest sea snail is considered to be the giant Australian whelk, 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 a body weight of about 1 kg.

It is not necessary to add snails to the aquarium yourself. They can appear unexpectedly - their eggs are carried 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 capabilities of the aquarium tank. If it is possible to control their reproduction, then the presence of pond snails will definitely benefit the fish’s home - they can help get rid of unfriendly algae settling on the decor, walls and plants, and keep their place of residence clean. Mollusks are indispensable cleaners for spawning aquariums. An overpopulation of snails threatens oxygen deficiency, which is why, first of all, the fish will suffer. Thus, it is possible, but not advisable, to keep pond snails in an aquarium. On the one hand, they are able to clean the tank and get into places where they cannot reach 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, to the beauty of the aquarium. They are often added to an aquarium without live algae by beginners. Experienced aquarists prefer to deal with snails of other species.

Every beginner in the aquarium business after a while is faced with the fact that the water becomes cloudy and aquatic plants begin to grow uncontrollably. Cleaning an aquarium and putting it in order takes a considerable amount of time. But you can have assistants - one of them is a pond snail. She is a natural cleaner of walls and aquarium accessories. In addition, snails are no less interesting to watch than fish.

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, with inside there are eyes.

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

Habitats

The water snail pond 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.

Common pond snail (or large pond snail) is the most common species in the family 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 warmer water, the mollusk will begin to actively reproduce, which is undesirable in a small volume of water.
Hardness of water – 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 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 favorable conditions contribute to this, 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 of a white coating 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 owners, and not to catch them yourself in water bodies. The average cost of one adult is about 50 rubles.

Contact Hazard

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

Like its relative, it feeds on algae and microorganisms.

The small pond snail is widespread throughout Europe and Northern Asia, as well as common pond snail.

Gastropods;

coil family;

horn coil.

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

The reel can be distinguished at first glance due to its extremely characteristic
shell, curled in one plane in the form of a spiral cord.
The most eye-catching is the horny coil (P. corneus L.), the largest among the others (shell diameter 30 mm, height 12 mm), reddish-brown in color. This reel is found everywhere in both pond and lake waters.
The movements of the coils resemble the movements of pond snails. When crawling, snails expose their dark, soft body far from the shell and move along underwater objects using their wide, flat legs. The head has a pair of thin tentacles, at the base of which are eyes. Coils, just like pond snails, can wander along the surface of reservoirs, suspended from a film of surface tension of the liquid.
The coils breathe atmospheric air, drawing it into the pulmonary cavity formed by the walls of the mantle. The breathing hole leading into 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. When there is 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 matter by eating plant parts that are scraped off using a grater. These snails are especially willing to eat the green coating of small algae that forms on the walls of the aquarium. From the outside, through the glass, it is not difficult to observe how the animal uses its grater, raking up plaque like a spatula. It is very possible that the coils can also feed on animal food. At least in captivity, they willingly pounce on raw meat.
Reproduction. Coils reproduce using eggs that are laid on the leaves of aquatic plants and other underwater objects. The clutch of the horny coil is constantly encountered on excursions and is so characteristic that it can be distinguished without difficulty: it looks like a flat gelatinous oval plate of yellowish or light brown color and contains several dozen round pinkish transparent eggs. After two weeks or more (depending on the water temperature), the eggs hatch into tiny snails that grow quite quickly. The caviar of reels, like other snails, is readily eaten by fish and is consumed by them in large quantities. Like the pond snail, spoolies are hermaphrodites.
The behavior of the coils when the reservoirs in which they are found dry out is interesting. They burrow into moist mud, like the large horn spool (P. corneus). Sometimes this coil remains on the surface of the soil, sticking its mouth to the silt if there are residual moisture in it, or it releases a dense film insoluble in water, which closes the hole of the shell. In the latter case, the body of the mollusk gradually contracts, 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, body and leg (see Appendix, Fig. 26). The leg is the muscular abdominal part of the body, on which the mollusk slowly glides. In coils, the shell turns are located in the same plane. The 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 the common pond snail, but they rise to the surface of the water much less often.

beauty's family;

larva of a beauty girl.

On a sunny day, blue lights flash and then go out over the river (see appendix, Fig. 27). Graceful dragonflies flutter about. At some point they resemble helicopters.

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

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

Special mention must be made about the eyes of dragonflies. Each eye consists of thousands of small ocelli. Both eyes are large and protruding. Thanks to this, dragonflies can look in all directions at the same time. This is very convenient when hunting. After all, dragonflies are predators. And their larvae that live in water, too.

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

“But insects don’t have hands,” you say. And you'll 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 hand to the 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 insect.

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

Some predator rushed at the larva. Another second and the larva disappeared. But where is she? I was just here, and now I’m in a completely different place. How did she end up there? Very simple. She 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 to be a water “shot”. The water jet flies in one direction, and the larva itself flies in the opposite direction. Just like a rocket. This is how it turns out that the larva makes a lightning-fast dash and slips away 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 he sits almost motionless, waiting for the moment when he can throw out his “hand” and grab the prey. If he needs it, he will launch his “reactive installation” again. True, not everyone has a “jet engine”, but only the larvae of large dragonflies.

After a year, the larvae of some dragonflies, and after three years, the larvae of others climb out to the surface along some plant sticking out of the water. And then a small miracle happens: the skin of the larva bursts and a dragonfly emerges 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 as if from stockings. He will sit for a few hours, rest, spread his wings and take off 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 lake, pond or swamp - without water, in a word. And the river, pond, lake also cannot live without these friends.

Dragonfly eggs are laid in water or in the tissue of aquatic plants. Larvae hatch from eggs extremely characteristic shape, interesting in their own way biological features. These larvae are playing important role among other living material from freshwater excursions.
Dragonfly larvae are found everywhere in standing and slowly flowing water. Most often they are found on aquatic plants or on the bottom, where they sit motionless, sometimes moving slowly. There are species that burrow into silt.

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

Dragonfly larvae feed exclusively on live prey, which they stand motionless for hours on end, sitting on aquatic plants or on the bottom. Their main food is daphnia, which they eat in huge quantities, especially by younger larvae. In addition to daphnia, dragonfly larvae readily eat water donkeys. They consume cyclops less willingly, perhaps due to the latter’s small size.
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 take possession of them. However, they do not touch large larvae of swimming beetles, well armed and no less predatory, even if they are placed 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 their prey. When a daphnia or other animal suitable for food approaches, the larva, without moving from its place, quickly throws out its mask and grabs its victim.

To grasp prey, the larvae have a remarkable oral apparatus, aptly called “masks.” This is nothing more than a modified lower lip, which looks like grasping forceps sitting on a long lever - a handle. The lever is equipped with a hinge joint, thanks to which this entire device can be folded and, when at rest, covers the underside of the head like a mask (hence the name). Noticing prey with its large bulging eyes, the larva, without moving from its place, targets it and, with a lightning-fast movement, throws its mask far forward, grabbing the victim with remarkable speed and accuracy. The caught prey is immediately devoured using strong gnawing jaws, while the mask brings the victim to its mouth and holds it like a hand while eating.

Breath. Dragonfly larvae breathe through 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, penetrated by a mass of tracheal tubes. Shortly before the adult dragonfly hatches, the larvae also begin to breathe atmospheric air using spiracles that open on the upper side of their chest. This explains why adult larvae often sit on aquatic plants, sticking the front end of their body out of the water.

Lute-type larvae have the ability to discard gill plates if they are pinched. This is easy to verify experimentally: place the larva in 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 are missing 1 - 2, and sometimes all 3 tail plates. In the latter case, breathing occurs, in all likelihood, through the thin skin covering the body. The torn plate is restored again after some time, due to which larvae with gill plates of unequal length can be observed. 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 characteristic.

Dragonflies reproduce using eggs that females lay in water. The clutches of different species are very diverse. Dragonflies of the rocker and lute type drill their eggs into the tissue of aquatic plants. In this regard, their eggs have a characteristic oblong shape, and the inserted end is pointed. In the place where the egg is stuck, a mark remains on the surface of the plant, which then takes the form of a dark spot or scar.
Since eggs different types When dragonflies are placed on a plant in a certain order, unique, sometimes very characteristic patterns are formed.

The suborder of dragonflies is Homoptera;

Lutka family; Lutka-bride.

A very slender, elegant, graceful dragonfly (see appendix, Fig. 28). The body is green, metallic-shiny. Females have yellow sides and breasts, while males have a bluish-gray coating.

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 the descriptions of both larvae and adults.

Mayfly squad;

Common mayfly.

Quiet summer evenings when it no longer stings Sun rays, some insects similar to butterflies, but with two or three long threads on their tail, swarm in the air near the banks of rivers, lakes and ponds (see Appendix, Fig. 29). They either soar upward, then freeze, stabilizing the fall with long tail threads, then, spreading their wide wings, slowly fall down. So they swirl above the shore, like dense fog or a cloud about ten meters high and about a hundred meters long. These swarms rush over the water like a storm. You don’t see such an exceptional phenomenon every day, only in July-August it repeats several times.

This is what mayflies dance during their mating flight. Their wings and they themselves are so delicate that it is simply amazing how they do not break during flight. You can’t help but think that they won’t live long. And this opinion is correct: many mayflies live only one day. That's why they are called mayflies, and scientific name They come from the Greek word "ephemeron" - quickly passing.

After the nuptial flight, the females lay 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 adults, 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 mayfly larvae, and various birds eat adult mayflies.

Upon examination, the first thing that catches your eye is the fast, sharp movements of the larva. When disturbed, it rushes headlong and swims very briskly, with three feathery tail filaments, richly pubescent with hairs (C1oeon, Siphlurus), serving as fins. The legs serve mainly for attachment to aquatic plants. The fast movements of mayflies probably serve as protection from their many enemies, which actively hunt these delicate larvae. The color of the larvae, generally 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 considerable interest as a good example of tracheobranchial respiration. 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 clearly seen in a larva sitting in the water even without the help of a magnifying glass. Most often, these movements are uneven, jerky: as if a wave runs through the leaves, which then remain motionless for some time until a new wave occurs. The physiological significance of this movement is completely clear: in this way, the flow of water washing the gill plates is enhanced and the exchange of gases is accelerated. The larvae's need for oxygen is generally very high, so in aquariums the larvae die at the slightest spoilage of the water.
The diet of the larvae is very varied. Free-swimming forms living in stagnant waters, which are most often 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 mayfly species is not yet well understood.

Reproductive phenomena in mayflies are of great interest and have long attracted the attention of observers. Unfortunately, you only see these phenomena on excursions by chance. As mentioned above, females drop their eggs into the water. The eggs hatch into larvae that grow and molt repeatedly (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 its skin and flies into the air. Since the hatching process of the larvae often occurs simultaneously, the surface of those reservoirs where the larvae are found in large numbers presents a remarkable spectacle 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 flakes of snow fluttering in the air. However, winged insects that hatch from 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 insects of winged molting). Sometimes on an excursion you can observe how a winged mayfly lands on some plant or even on a person and immediately sheds its skin.

Squad pincers;

family hydrachnids;

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

The small pond snail is one of the most common species of snails in the reservoirs of our country. It has an elongated, pointed shell and a short, wide leg. It reproduces easily and quickly and is a hermaphrodite.

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