External structure of a dragonfly. Dragonflies

These weightless fragile creatures that decorate our planet have a long and, undoubtedly, amazing story, because dragonflies are the oldest of all existing insects.

Their ancestors appeared on Earth about 350 million years ago and were gigantic in size. Their wingspan reached 90 cm, which is comparable to the characteristics of the largest birds living on the planet today.

But over time the world around us has changed a lot. The creatures inhabiting it have also lost their primitive appearance. Now the wingspan of the largest dragonfly barely reaches 20 cm.

These insects are primarily attracted to their eyes. At first glance they seem disproportionately large. But since everything in nature is purposeful, natural and harmonious, there are no accidents here either. The eyes of dragonflies are facet-shaped and consist of many tiny eyes, the number of which can reach 30 thousand. Each of them functions independently and is separated from the others by pigment cells. Thanks to this structure, the dragonfly can simultaneously see everything that is happening around it to the left, right, front and back.

Sometimes it seems that these weightless creatures live outside the laws gravity and air resistance: they either freeze in flight, then sharply rush upward, then rush somewhere at a speed reaching 90 km/h. Their continuous movement can last for several hours. Four wings provide amazing endurance and high speed to dragonflies. Each of the two pairs acts independently, but at the same time incredibly harmoniously, producing up to 150 strokes per second. As a result, insects can withstand long flights, and when tired in the evening, they sit on plant stems and rest until the morning.

It’s hard to believe, but it was the specificity of dragonflies fluttering in the air that became a clue when creating a jet aircraft. When the finished experimental engine was installed on the winged vehicle, it literally crumbled into separate fragments due to high speed and strong vibration. Entomologists helped improve the model of the aircraft, explaining to the designers the principle of operation of dragonfly wings, which have a special thickening at the front. This is precisely what dampens vibration during flight.

Despite the development modern science, entomologists have still not been able to explain this mysterious phenomenon, like the flight duration of dragonflies, which can travel thousands of kilometers. According to sailors, they often see these insects very far from the shore. Dragonflies decide to undertake such risky journeys infrequently - once every six to seven years, gathering in huge flocks.

They move in a continuous mass, the height and width of which reaches several meters. Where and why they fly is unknown. Unsolved mystery has given rise to many signs: some interpreters of unknown phenomena are confident that meeting a flock of dragonflies will bring a lot of trouble, others, on the contrary, see this as a favorable sign. In turn, scientists suggest that long-term unusual flights are most likely associated with an attempt to find new habitats.

The dragonfly is a fast and agile predator, as evidenced by its elongated oblong body, gnawing mouthparts, wide chest, and sweeping wings. With serrated jaws, it grabs small insects simply on the fly, and in order to feast on larger prey, it descends to the ground, sits on the stems of plants and catches the prey with its nimble paws. These insects are unsurpassed hunters. Seeing a small insect during its flight, a dragonfly instantly freezes in the air and, abruptly changing course, pounces on its prey. She still has the same appetite: she can swallow more than 40 flies in a day. They are also not averse to eating mosquitoes and midges.

Dragonflies are insects “free” from the laws of gravity.

Dragonflies look for a place to lay eggs in the area of ​​quiet, shallow reservoirs with low flow or standing water. Only males engage in a thorough search, choosing plant stems or moist coastal soil. They also protect the maturing offspring from the attacks of numerous competitors. The larvae of winged beauties (they are called naiads) begin to develop and live in the water. The ripening period, depending on the type, lasts from three months to five years. It is quite easy to distinguish them on the sandy bottom of reservoirs, although they have a similar color.

Dragonflies are the oldest insect predators: the remains of their distant ancestors discovered by archaeologists date back to the Carboniferous period (350-300 million years ago). However, many years of evolution have had virtually no effect on the appearance of dragonflies, so these creatures are classified as primitive. To date, scientists have discovered and classified more than 5,000 species of these insects. But the species of dragonflies that can be observed in the European part of Russia are very few in number: there are no more than a hundred of them. These insects prefer tropical climates, so the vast majority of them inhabit humid forests South America And Southeast Asia. Dragonflies are not found in regions with arid climates.

Born predator

Without exception, all types of dragonflies (both nymphs and adults) feed on insects, often blood-sucking (horseflies, mosquitoes, midges). The dragonfly's body shape is ideal for hunting on the fly. These insects are “lean”, with a pronounced chest and elongated abdomen. The head of a dragonfly is very mobile. There are two complex compound eyes on it, allowing the insect to see everything that happens around and behind, and between these two there are ordinary ones, which serve for orientation in space. The organs of vision are designed in such a way that a dragonfly sees best against the sky. Therefore, she attacks the victim from below. The insect has a powerful mouth (“gnawing,” as scientists say), short antennae and stiff legs covered with hairs that help capture prey. Each representative of the order has two pairs of wings, which are equally well developed. This means that she is a bimotor insect. Dragonflies can fly at speeds of over 55 km/h.

Homoptera

There are three suborders of dragonflies. The first of them is Homoptera. It includes graceful, light and, as a rule, small insects with a very elongated abdomen. Both pairs of wings are identical in size and shape; when at rest, the dragonfly folds them at the back so that they form an acute angle with the surface of the back. Homoptera fly slowly and smoothly. Among them are such species of dragonflies as the graceful arrow, the beauty-girl and the dim lute. Homoptera nymphs living in water have a special respiratory organ located at the end of the abdomen - caudal gills.

Variopterans and Anisozygoptera

The second suborder is heteroptera. They have a powerful body, and the base of the hind wings is widened. The eyes often touch. The flight speed of heteroptera is high. At rest, the wings of these dragonflies are spread apart. The larvae of dragonflies live in mud and breathe using rectal gills. It is worth mentioning some species of dragonflies belonging to heteroptera. This is an ordinary grandfather, a large rocker, a bronze headstock, and a blood dragonfly.

Representatives of the third suborder (Anisozygoptera) combine the characteristics of the first two, although in appearance they are closer to heteroptera. These dragonflies do not live in Russia.

Beauties

In general, the order of dragonflies stands out among other orders of insects for its aesthetic merits. And it’s basically impossible not to admire the representatives of the family of beauties. For example, beautiful girls are small (up to 5 cm long), thin even-winged dragonflies with a wingspan of no more than 7 cm. The body and wings of males are painted in blue, green, purple shades and have a metallic sheen.

In females, the body is colored, but the wings are not. Beauties prefer the overgrown banks of quiet rivers and small streams. They lay eggs in the leaves of coastal plants; The larvae also try to stay close to the stems and roots. The flight of a beautiful girl resembles the flight of a butterfly.

Arrows

Arrows are not as spectacular as beauties, but just as graceful dragonflies. The photo of the graceful arrow, posted below, confirms this fact.

Shooters lead the same lifestyle as beauties, except that their prey is more modest. And it is not surprising, because the body length of the graceful arrow is only 3.5 cm, while the wingspan is 4.5 cm. The male has an elongated blue chest with a longitudinal black stripe and a black abdomen, as if intercepted by thin blue rings. The wings are narrow and transparent. Some females have a similar coloration, others are rather inexpressively colored and have neither stripes nor rings. Arrows fly slowly and rarely leave their homes. Their larvae live and hunt in the stems and roots of aquatic plants. Distinguishing one species from another within this family is not an easy task. But it is impossible to confuse them with another family of arrows.

Real dragonflies

This family of the heteroptera suborder includes numerous species of dragonflies. Their names speak for themselves: swamp, flat, blood. These insects are distinguished by a massive, wide and relatively short body, wings slightly shifted towards the head and the presence of dark spots at their base. The female true dragonfly lays eggs directly into the water of a pond or quiet river, and sometimes into coastal sand. Large nymphs of true dragonflies live in the mud. The flat dragonfly is a medium-sized insect. The wingspan is 8 cm, the body length is 4.5 cm. Both females and males have a brownish-yellowish breast, but the male's abdomen is covered with bright blue pollen, while the female's abdomen is brown, with dark stripes on the sides. At the base of both pairs of wings there are dark triangles. The eyes are greenish.

Other representatives of the family are very noteworthy - blood dragonflies (photo below). They are easily recognized by their bright body color - reddish-yellow, orange or brown-red.

These dragonflies are one of the latest. They are active from mid-summer until November. The transformation of blood dragonfly larvae into adults occurs in just a couple of months.

Grandfathers

Among the features of these dragonflies are the variegated coloration, widely spaced eyes and the presence of a notch at the base of the hind wings in males. Grandfathers are capable of long flights and prefer flowing reservoirs with clean water, where females lay eggs directly in flight.

Common dedka, tailed dedka and horned dedka are the most common species of dragonflies in Central Russia. These names sound funny (as well as “metal grandmother” or “bronze grandmother”), but you need to keep in mind that grandfathers are also called rivermen, and grandmothers - patrolmen. Dedka common is a black and yellow dragonfly with transparent wings. The coloring is vaguely reminiscent of wasp.

Dedok larvae are voracious, strong and can burrow into soft mud. And adult grandfathers, oddly enough, are short-lived. They live no longer than a month.

Rocker arms

These are large, bright and expressively colored dragonflies. Representatives of the order of dragonflies rarely have such endurance: rockers can fly many kilometers from their native body of water (it happened that they were seen over the ocean). The size of these insects also inspires respect: the wingspan of the watchman-overlord (or emperor) reaches 8 cm.

The patrolmen's chest is greenish, their abdomen is blue, with a yellow ring. The wings of males are completely colorless, while those of females are barely yellowish. The organs of vision are bluish-green. Watchmen live near stagnant, often drying up bodies of water. They lay their eggs in rotting plant tissues immersed in water. Their large larvae are able to cope even with fish fry.

In addition to those mentioned above, in the European part of Russia there are representatives of such families as: grandmothers, lyutki, cordulegasteridae. All dragonflies are considered beneficial. They eat blood-sucking insects and pests and, in turn, are food for birds and fish.

Dragonflies (Odonata), an order of predatory, good-flying insects. Large, with a movable head, large eyes, short bristle-like antennae, 4 transparent wings with a dense network of veins and an elongated slender abdomen. Dragonflies are divided into 3 suborders - Homoptera.

The life of dragonflies is inextricably linked with water. Their eggs and larvae develop in water. Adult insects and their predator larvae. Therefore, in the evening, in calm weather, you can see many dragonflies that flutter restlessly in the air. They eat dinner, catching mosquitoes, midges, etc. on the fly. In pursuit of insects, they fly at a speed of 50 km/h. Dragonflies live only in bodies of water with clean water, and therefore they are good bioindicators.

State of knowledge of dragonflies and their species composition

Dragonflies (Odonata), an order of predatory, good-flying insects. Large, with a movable head, large eyes, short bristle-like antennae, 4 transparent wings with a dense network of veins and an elongated slender abdomen. Dragonflies are divided into 3 suborders - homoptera (Zygoptera), heteroptera (Anisoptera) and Anisozygoptera with unique gender, common in Japan and India, whose representatives combine the characteristics of the first two suborders. In homoptera dragonflies, the fore and hind wings are narrow, almost identical in shape, and at rest they are raised up and pressed against each other; in heteroptera dragonflies, the wings are different in shape, at rest they are spread out to the sides, the rear pair has widened bases. Wing length 10-94 mm, abdomen 14-120 mm. Dragonflies feed on insects, snatching prey in flight. They exterminate mosquitoes, midges and other harmful insects, which is beneficial. They can also cause harm by spreading protogonimosis, a dangerous disease of poultry. Dragonflies mate on the fly. The secondary copulatory apparatus of males is highly specialized and has no analogues among insects. Eggs are laid in water or tissue of aquatic plants, less often in wet soil. The larvae develop in water and breathe through gills. The larvae of homoptera dragonflies have tracheal gills on the caudal appendages, and the larvae of heteroptera have rectal gills on the walls of the rectum, which is periodically filled with water. The transformation is incomplete. The larvae have a greatly elongated lower lip, which forms a grasping organ - a mask. When capturing prey, it is thrown forward and covers its head from below when at rest. Dragonfly larvae are also predators, they feed on the larvae of aquatic insects, and sometimes attack tadpoles and fish fry; in turn, serve as food for fish. Once development is complete, the larvae emerge from the water and attach themselves to plants or uneven soil. The last moult occurs on land near a body of water. Some types of dragonflies can fly long distances from bodies of water. During mass migrations, the spotted dragonfly Libellula quadrimaculata forms a continuous strip tens of kilometers long. Over 4,500 species, most of which live in the tropics and humid subtropics.

Despite the archaic nature of the organization (both pairs of wings are developed almost equally), they achieved perfection in flight. Thanks to their well-developed mouthparts and tenacious limbs, they can catch insects in flight (many dragonflies even mate in the air). The larvae develop in bodies of water, have three tracheal gills (or rectal gills in the abdomen) and a mask - a grasping organ, which is a modification of the lower lip. The larvae live from one to five years. There are about 5 thousand dragonflies in the world.

Dragonflies are aerial predators. They often eat prey on the fly. Large wings with reticulate venation in large dragonflies are always spread out to the sides, in small ones (arrows, lute) they can fold along the body at rest. Some dragonflies have wings of the same shape, narrowed towards the base (suborder Homoptera), while others have hind wings wider than the front ones, especially at the base (suborder Hemoptera). The mentioned suborders also differ in the structure of the larvae and biological features.

When examining a dragonfly, attention is drawn to its huge eyes, which occupy most of the head. The eye consists of 28 thousand facets (ommatids), each of which is served by 6 light-sensitive cells. A dragonfly can spot a mosquito at a distance of up to 10 meters. By eating mosquitoes, horseflies and other bloodsuckers, dragonflies bring great benefits.

The mouthparts of dragonflies are gnawing, the lower lip is spoon-shaped, supporting prey when eating in the air. The long legs are directed forward and lined with strong bristles, with the hind legs being longer than the front ones. This helps the dragonfly catch prey by flying up to it from below.

The thin rod-shaped abdomen acts as a balancer during flight. Males have “tongs” at the top of their abdomen, with which they hold the female by the neck during mating. Such “tandems” of dragonflies can often be observed near water bodies. Female dragonflies drop their eggs into the water or place them in the tissues of aquatic plants using a piercing ovipositor.

The color of dragonflies is dominated by blue, green, and yellow tones; a bright metallic sheen is less common. Some have spotted or darkened wings. In dried specimens, the color fades greatly and changes.

The development of all dragonflies necessarily passes through the aquatic stage - the nymph (this is the name given to insect larvae that have the rudiments of wings). All dragonfly nymphs are voracious predators, seizing prey with a modified lower lip - a mask, which rapidly opens and is thrown forward, while the claws at its front end, like stilettos, penetrate deeply into the victim. When the mask is folded, the prey is pulled to the mouth and quietly chewed. For breathing, nymphs use the hindgut, which, like a pump, constantly pumps oxygen-rich water through the anus. Based on size, structural features and habits, dragonfly nymphs are divided into a number of groups.

Dragonflies are medium or large-sized (up to 13 cm long) predatory insects characterized by gradual metamorphosis. In its development, an insect goes through three stages - egg, larva (nymph), imago. An incomplete type of transformation is characteristic. The adult has a slender or stocky body, with two pairs of similarly constructed wings with reticulate venation. The head has large compound (compound) eyes and three simple ocelli. The antennae are short, bristle-like, consisting of 4–7 segments. The mouthparts are of a gnawing type with strong mandibles. The first pair of wings has a pterostigma. The wings can be transparent or colored. The legs are running, the first pair is designed for holding prey. The hearing organs are located in the antennae, the sound organs are located at the base of the wings.

Larvae of the naiad type (have tracheal gills) live from one to three years. They molt up to 25 times during development. The larvae have gnawing-type mouthparts with a strongly elongated and knee-bending lower lip, transformed into a powerful grasping organ capable of holding prey; legs are strong; Representatives of the suborder Zygoptara have three lithic tail gills. The egg size, depending on the species, ranges from 0.5 mm to 2 mm. Adult dragonflies feed on insects caught in flight. Dragonflies are typical active predators. Each individual has its own territory on which it feeds, which it protects from its relatives and, if necessary, fights for it. Based on their behavior, they can be called predators - sentinels. Dragonflies eat mosquitoes, horseflies and many other representatives of arthropods, almost all insects that they can catch and defeat. Nymphs lead an aquatic lifestyle, living mainly in stagnant bodies of water: lakes, ponds and oxbow lakes. They cannot swim, but they walk along the bottom among decaying debris or vegetation. Nymphs are also predators: they catch aquatic insects and crustaceans, grabbing them with their retractable lip (mask), equipped with pincers. They also feed on mosquito and fly larvae.

Eggs are laid in various ways in or near water. Some species immerse them in plant tissue or rotten wood, others place them in the form of lumps on some objects directly below the surface of the water, others deposit them in the water in ribbons or rings, and sometimes place them in wet mud near the water's edge. Females of many species dive into the water and wash the eggs from the end of the abdomen. Others crawl underwater, laying eggs.

When laying eggs, some females fold their wings into a fan shape. A female can lay from 200 to 1600 eggs in her life. Some species reach several tens of thousands. Dragonflies can form migrations.

Nymphs of smaller species develop throughout the year. In large species, from two to four years. Wintering occurs at the nymph stage. Having reached full size, the nymph crawls out of the water and climbs onto a plant stem or some other object protruding from the water to molt for the last time. The covers of newly emerged adults harden and acquire color relatively slowly: many of them require one or two days to do this.

Females and males can be distinguished by the intensity of their color: males are brightly colored, while females are inconspicuous. At the top of the abdomen of males there are paired upper and unpaired lower outgrowths - appendages, while females have only paired upper ones. A remarkable feature of the order is its mating method. The credit for this goes to the male: unlike other male insects, male dragonflies have secondary reproductive organs, which are located on the second abdominal sternum - the bladder-shaped receptacle. The genital opening itself is located on the 9th sternum of the abdomen. Having such genitals, the male has to do the following before mating: the male bends the end of the abdomen forward and transfers the sperm to a bladder-shaped receiver. During mating, the male uses his caudal gonopods to clasp the female's neck; after this, the female bends her abdomen forward to the second sternite of the male and in this position the actual transfer of sperm takes place. Such an unusual procedure is unknown in any other order of insects.

The order Dragonfly (ODONATA) includes three types of insects; they differ sharply in their appearance and behavior, but the number of diagnostic signs by which they differ from each other is small. Modern forms of one of the suborders - Anisozygoptera - are very rare and distributed only in Southeast Asia. In modern taxonomy, the order includes two suborders - homoptera (Zygoptera) - heteroptera (Anisoptera).

The suborder ZYGOPTERA are slender and delicate insects with a fluttering flight, sharply contrasting with the fast and purposeful movements of heteroptera dragonflies. The imago of homoptera dragonflies is distinguished by a very uniquely constructed thorax: the mesothorax, together with the metathorax, has the appearance of an approximately rectangular prism located at approximately an angle of 70-80 degrees relative to the longitudinal axis of the body. The wings at rest are directed all together backwards and upwards at right angles to the upper edges of the mid- and posterior rear. Due to the fact that the latter are inclined to a certain extent, the wings folded in this way lie parallel to each other and are located directly above the abdomen. Most adults are dark-colored, however, some have red or black wing bands or metallic green or bronze body and wings. Nymphs also have a slender body and three large caudal tracheal gills. They prefer to live among the stems of aquatic plants, rather than directly at the bottom of reservoirs.

The suborder ANISOPTERA includes insects with a more robust physique, and are characterized by powerful, graceful and excellently controlled flight. The chest is not inclined as in representatives of homoptera dragonflies and the wings at rest are directed to the sides. Many species are brightly colored and have a striking pattern on their wings - mottled or spotted. Older individuals often develop a pale blue waxy coating on the body and wings, which masks the original color and pattern.

Nymphs are also densely built, many live in silt or mud at the bottom of stagnant bodies of water. They do not have external gills, but they have a rectal respiratory chamber in which gas exchange occurs. No such respiratory chamber has been found in any other order of insects.

The suborder includes two families - Aeschnidae, Libtllidae. Well-known representatives of this suborder are the species: flat dragonfly (Libellula depressa), reed dragonfly (Aeschna juncea). This suborder also includes the following species: emperor watcher (Anax imperator), Macromia magnifica; an extinct dragonfly found in Central France with wings spread up to 70 cm - Meganeura monyi.



In this article we invite you to talk about what kind of creature this dragonfly is. Structure, nutrition, reproduction, benefits and harm - all these are our main questions, to which you will find the answer by reading this short article.

First, let's make a reservation: the dragonfly has six jointed limbs. This is an insect belonging to the subclass of winged insects. These numerous creatures even have their own squad - dragonflies.

Have you ever wondered how dragonflies got their name? In Russian it is a combination of two outdated words: fidget and goad. The first word is translated as fidget, and the second - jump. This name fully characterizes the flight style of these fast creatures called dragonflies. Structure is the first issue we will look at right now.

Structure

The dragonfly, the structure of which we are considering in this material, has a long and very thin body. It, in turn, is connected to the cephalothorax. On the dragonfly's body we can see three pairs of legs and two pairs of wings. It is also important to note that the wings are transparent; they can have the same size and shape, or different. We will talk about this in more detail when we look at the species. The dragonfly, whose structure can vary depending on the species, can belong to one of two main groups:

• Homoptera.
• Varioptera.

As you might guess, the first group includes individuals that have wings equal length and shapes, while others do the opposite (one pair may be very different from the other). On the dragonfly's head we can clearly distinguish large eyes and antennae. A little more about the senses. The eyes of these insects are complex. They can be divided into two sections:

• the top one, responsible for object recognition;
• the lower one, responsible for color recognition.

You've probably noticed that the transparent wings of dragonflies have veins along their entire length, and at their tips there are spots darker than the color of the wings themselves. This device helps avoid wing fractures by reducing vibration during flights.

Remember how flight occurs in other flying creatures. This is a beautiful and synchronized movement of the wings. Dragonflies have distinguished themselves here too; the movements of their wings can be asynchronous when they are balancing, but synchronous to increase speed. It is also important to know that these nimble creatures can reach flight speeds of up to 50 kilometers per hour.

Lifespan

We have looked at some of the structural features of dragonflies, but it is also important to clarify that they can live up to ten years. These are real long-livers in the world of insects. Let's talk about this a little more.

In total, there are more than 6.5 thousand species of these unusual, graceful and beautiful creatures on our planet. On the territory of Russia you can find a small number of species, about 150. So, the lifespan of dragonflies directly depends on the species, the minimum is two months, and the longest-livers can last about ten years. This period includes the full development cycle of insects, and the development of the larvae in some species can take more than one year.

Species

The external structure of a dragonfly directly depends on the species. There are only three suborders of these insects:

• Homoptera;
• heteroptera;
• anisozygoptera.

How are they different? The first species has two pairs of wings, they are narrow and almost identical in shape. If the dragonfly is at rest, then both the front and rear wings are raised up and connected to each other. In the second case, the wings have different shapes, at rest, spread out to the sides. The third suborder includes a single genus; these insects are common in Japan and India. The peculiarity of the latter is also that they combine the characteristics of the first and second suborders.

The most common representatives of homoptera dragonflies:

• Beauties.
• Arrow.
• Lute Dryad.
• Megaloprepus caerulatus.

It is also very important to know that the last of those listed are the largest dragonflies in the world. Their body length reaches ten centimeters, and their wingspan reaches nineteen.

Prominent representatives of the heteroptera suborder:

• Watcher-emperor.
• Cordulegaster annulated.
• The headstock is metal.
• The grandfather is ordinary.
• Common dragonfly.

Habitats

Peculiarities external structure dragonflies and their method of reproduction directly depend on their habitat. These insects prefer to stay and conduct their life activities near water. How can one explain this attraction to the water element? It's very simple: dragonflies lay eggs in water.

They choose places near rapid mountain streams, ponds, lakes, rivers and canals. There are also species of dragonflies that prefer swamps. Dragonflies are sun-loving insects; they often bask in the sun in clearings and meadows. However, they do not fly far from the water. On cloudy and rainy days, dragonflies do not fly out; they prefer to be in the “shelter”.

Nutrition

Our next question is the internal structure of the dragonfly and nutrition. As mentioned earlier, the dragonfly is a phylum of arthropods. We know that in representatives of the type, the heart looks like a multi-chambered vessel. The brain and ventral nerve cord represent nervous system insects

What can a developed gnawing mouthpart, well-developed vision, an elongated body and large, rather powerful wings indicate? Of course, dragonflies are predators. They prefer to eat their prey on the fly. They feed on insects, usually harmful ones. They catch large ones with their paws, and catch small ones (midges, mosquitoes) directly with their jaws. To taste large prey, the dragonfly has to descend to the ground. Hunting is a real spectacle. Even such good and nimble flyers as flies do not escape the clutches of dragonflies. It is important to know that representatives of dragonflies are very voracious. During the day, they eat prey several times their weight (for example, they can destroy more than forty flies in a day).

Reproduction

We examined the structural features of dragonflies, their feeding method and habitat. Now briefly about the method of reproduction. Fertilization occurs in the air. The larvae are laid by the female mainly in stagnant water; their number reaches five hundred. This amount is needed due to poor survival of the larvae. Larvae are laid in different ways:

• dumping into water;
• partial immersion;
• complete immersion in an air bubble.

The larvae can remain in this form from twenty days to nine months, it all depends on the type of dragonfly, environment and other factors. Afterwards the pronymph appears (life cycle is several seconds), then the naiad. The larva then develops from several days to several years.

Benefits and harms

The benefit is that adult dragonflies eat annoying and harmful insects (mosquitoes, flies and others), their larvae destroy mosquito larvae. However, dragonflies spread a dangerous disease of birds - protogonimiasis. The larvae of some representatives are capable of eating fry in fisheries.

Scientists identify about 5 thousand species of dragonflies. Dragonflies are the largest representatives of flying insects.

There are two types of dragonflies: heteroptera and homoptera. Homoptera dragonflies are smaller in size and do not fly as well as heteropterous dragonflies.

Appearance of a dragonfly

The dragonfly has a long abdomen with a pair of pincers, a chest and a head. The body length of dragonflies varies from 3 to 12 centimeters depending on the species. The color is also varied: white, red, green, orange, yellow. The wings are transparent and thin, they have large number longitudinal veins that strengthen their fragile structure. In addition, there is a dark spot on the wing, this is not just a decoration, it serves to ensure that the insect in flight is not influenced by vibration.

All dragonflies have 3 pairs of legs covered with bristles. They have a gnawing type of mouthparts, with the lower lip acting as a harpoon; it flies forward and grabs the prey. Dragonflies have huge eyes, which help them find prey: they are able to see prey at a distance of about 10 meters. The eyes are complex and have a facet structure.

Lifestyle of dragonflies

Dragonflies are very agile, they fly at enormous speeds, for example, some species are capable of flying at a speed of 100 kilometers per hour. But most often they fly at a speed of 5 kilometers per hour. Moreover, they can travel hundreds of kilometers without stopping. Dragonflies can hover in the air, stopping instantly.

Dragonflies are the fastest of insects.

When a dragonfly lands on the ground or other surface, it does not fold its wings; its wings are always spread out.

All dragonflies are predatory insects; they feed on flies, mosquitoes, moths and other small insects. Dragonflies pursue their victims at high speed. During flight, the dragonfly folds its legs into a basket to make it convenient to grab prey on the fly.

Dragonflies lead a solitary lifestyle. Their enemies are a variety of birds, as well as spiders.

Where do dragonflies live

Dragonflies are solitary in their lifestyle.

Dragonflies are found in Europe, Asia, Africa, Australia and America. They settle in forest edges, meadows and fields. They definitely need a body of water to live.

Reproduction of dragonflies

During the breeding season, males perform a mating dance, with the help of which they win the attention of the female and drive away other contenders from her. After mating, the female lays about 200 eggs. She is laying in fresh water or on various plants and wood.

The development of dragonflies includes 3 stages: egg, larva and adult. The larvae move very little; they develop in fresh water bodies. The larvae of some types of dragonflies can develop over 5 years. The larvae have huge eyes. These predators are very voracious, they even eat their relatives. The larva sits in a shelter for hours; as soon as the prey approaches, the predator attacks with lightning speed. They feed on fry and aquatic insects.