In this article we suggest you to talk about what kind of creature is a dragonfly. Structure, nutrition, reproduction, benefit and harm - all these are our main questions, to which you will find the answer by reading this short article.
To begin with, let's make a reservation: the dragonfly has six articulated limbs. This is an insect belonging to the winged insect subclass. These numerous creatures even have their own squad - dragonflies.
Have you ever wondered how you got such a name for dragonflies? In Russian, it is a combination of two obsolete words: Egoza and chant. The first word is translated as fidget, and the second - to jump. This name fully describes the flight style of these fast creatures called dragonfly. The structure is the first question that we will consider right now.
Dragonfly, the structure of which we consider in this material, has a long and very thin body. It, in turn, is connected to the head. On the body of a dragonfly, we can see three pairs of legs and two pairs of wings. It is important to note that the wings are transparent, they can be both the same size and shape, and different. We will discuss this in more detail when we consider the species. Dragonfly, the structure of which can vary from species, can belong to one of two main groups:
As it is not difficult to guess, the first group contains individuals that have wings of equal length and shape, while others - vice versa (one pair can be very different from the other). On the head of a dragonfly, we can clearly distinguish between large eyes and antennae. A little more about the senses. The eyes of these insects are complex. You can divide them into two sections:
- top, responsible for object recognition,
- bottom, responsible for color recognition.
You have probably noticed that the transparent wings of dragonflies have streaks along their entire length, and on their tips are specks darker than the color of the wings themselves. This fixture helps to avoid wing fractures, reducing vibration during flight.
Remember how other flying creatures fly. This is a beautiful and synchronous movement of the wings. Dragonflies and then distinguished themselves, the movement of the wings can be asynchronous, when they balance, and synchronous to increase the speed. It is also important to know that these nimble creatures can reach flight speeds of up to 50 kilometers per hour.
We considered some of the features of the structure of dragonflies, but it is important to clarify the fact that they can live up to ten years. These are real centenarians in the world of insects. Let's talk about this in more detail.
In total, there are over 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 life span of dragonflies directly depends on the species, at least it is two months, and the longest-livers can last about ten years. This period includes the full cycle of insect development, and the development of the larva in some species may take more than one year.
The external structure of dragonfly depends on the species. There are only three suborders of insect data:
How are they different? The first type has two pairs of wings, they are narrow and almost the same shape. If the dragonfly is at rest, then both the front and rear wings are raised up and interconnected. In the second case, the wings have a different shape, at rest spread to the sides. The third sub-order is a single genus, these insects are common in Japan and India. The peculiarity of the latter is also in the fact that they combine the signs of the first and second sub-order.
The most common representatives of horned dragonflies:
- Pretty women.
- Megaloprepus caerulatus.
It is very important to know that the last of these are the largest dragonflies in the world. The length of their body reaches ten centimeters, and the wingspan of nineteen.
Bright representatives of the suborder raznokrylyh:
- The Seer-Emperor.
- Kordulegaster ringed.
- Grandma metal.
- Dedkov ordinary.
- Dragonfly ordinary.
Features of the external structure of the dragonfly and the method of reproduction directly depends on the habitat. These insects prefer to be and conduct their livelihoods near the water. How can we explain this to the water element? It's very simple: dragonflies lay their eggs in the water.
They choose places at the swift mountain streams, at ponds, lakes, rivers and canals. There are also those types of dragonflies who prefer swamps. Dragonflies are sun-loving insects, they often bask under the sun in the meadows and meadows. However, they do not fly away from the water. On cloudy and rainy days, the dragonflies do not fly out; they prefer to be in “shelter”.
Our next question is the internal structure of the dragonfly and food. As mentioned earlier, the dragonfly is a type of arthropod. We know that in representatives of the type the circulatory system is open, the heart looks like a multi-chamber vessel. The brain and abdominal nervous chain represent the nervous system of insects.
What can a developed gnawing mouth apparatus, a well-developed vision, an elongated body and large, rather powerful wings say? Of course, dragonflies are predators. They prefer to eat their prey right on the fly. They feed on insects, as a rule, harmful. They catch large ones with their paws, and small ones (midges, mosquitoes) are caught right by the jaws. In order to taste large prey, dragonfly has to go down to the ground. Hunting is a spectacle. Even such good and brisk flyers, like flies, do not escape from the legs of dragonflies. It is important to know that the representatives of dragonflies are very voracious. During the day, they eat prey several times their weight (for example, flies can kill more than forty per day).
We considered the features of the structure of dragonflies, the way of feeding and the habitat. Now briefly about the method of reproduction. Fertilization takes place in the air. The larvae are deposited by the female mainly in stagnant water, their number reaches five hundred. This amount is necessary due to poor survival of the larvae. Larvae are deposited in different ways:
- dropping into the water
- partial immersion
- full immersion in the air bubble.
In this form, the larvae can be from twenty days to nine months, it all depends on the type of dragonfly, the environment and other factors. After it appears pronymph (life cycle of a few seconds), then naiad. Further, the larva develops from several days to several years.
Benefit and harm
The benefit is that adult dragonflies eat annoying and harmful insects (mosquitoes, flies and others), their larvae exterminate mosquito larvae. However, dragonflies spread a dangerous disease of birds - protogonimosis. The larvae of some representatives are able to eat fry in the fish industry.
Small scales called dragonflies in antiquity for their flight and the type of wings that are horizontally spread in the air. Today, the dragonfly population is rapidly declining, and this is due to poor ecology and climate change. Dragonflies are heat-loving: they need a high temperature of water and air for their vital activity and reproduction. They are demanding to the flora of the area, prefer swampy and flood meadows, where there is a lot of food.
Not likely, but true: a dragonfly can hunt an object many times larger than itself. Large individuals even attack small frogs or fry.
Dragonfly is a predator. It eats a flying midge that abounds in swamps and coastal areas of rivers and lakes. Thanks to the huge eyes and wide-angle capture of the image, the insect can see the victim at a distance of up to 12 meters. In this case, the location of the latter does not actually matter, because the dragonfly can fly backwards and see all that is happening in her area of the tail.
The dragonfly's jaw is relatively powerful, and its teeth resemble nail files, so mosquitoes and flies that have been captured by dragonflies die almost instantly, having been cut in half. On the fly, the dragonfly catches the victim with its paws, which, thanks to the moving bristles, seem to lock it in the grip of its own body. There is no insect in flight. Therefore, it lands with prey on the nearest large grass or leaf.
The main diet of dragonflies consists of:
- may day
However, a large proportion of the food is still dipteran insects.
Dragonfly breeds by laying eggs from which nymphs hatch. They lead exclusively underwater life for one and a half years, feeding exclusively on water fleas, tadpoles, larvae of other underwater inhabitants. The “child” of dragonfly is extremely voracious in view of the fact that it consumes a large amount of energy, quickly, rapidly moving. In addition, the larvae and nymphs change skin 10-15 times during life, and this is a huge waste of energy.
Unique nymphs live longer dragonflies. The life cycle of dragonfly - 6 weeks, the nymph - 5 years.
Not paws or the ability to swim in spurts due to the ejection of water from the calf, as many people think, help the nymphs to hunt, but the unique organ - the lip, which is located under the “chin”. The lip nymph literally captures a small insect and sends it into the mouth.
Biological features of dragonflies
Insects live near freshwater bodies, although they can be found at a considerable distance from the water.
Dragonflies have a variety of abilities that a person could only envy. First of all, it concerns the structure of the eyes and the exceptional vision of the insect. Dragonfly sees simultaneously in all directions, which helps her to provide herself with food that requires a very large amount.
Due to the unique vision, it rarely becomes prey of other predators. And a man to catch her, too, is not easy.
The movement of dragonfly wings is interesting in that they can flap alternately and in any sequence. Only her own such perfect aircraft. It is he who allows to move in different directions during the flight, to hover, to make sharp throws.
What eat dragonflies
The insect hunts for its prey on the fly. To do this, the dragonfly has to be worn over the pond or along the coast at a tremendous speed. An interesting fact is that she does not track down and does not chase the insects, but intercepts them, “counting” on the trajectory of the victim. Butterflies, mosquitoes, flies become prey. These are what dragonflies eat daily.
The captured insect is first neutralized. For this dragonfly wraps its front paws to make it impossible to move. Then the victim's wings come off. A helpless insect enters the mouth apparatus of a predator, where with the help of powerful gnawing organs, food is ground to a state of gruel, and then its further digestion occurs.
After swallowing the prey, the dragonfly again begins the hunt for insects. Predator rarely rests. Most of the time she spends in motion, it is connected with it feeding the dragonfly. Unusual gluttony does not allow her to "idle".
Scientists, observing the life of an insect, made an amazing discovery and established how dragonflies feed at home and how they do it. In one such experiment, it was recorded that the dragonfly ate 30 flies one after the other without stopping. It is possible that the number of eaten insects could be more.
Dragonfly larvae lifestyle
Stagnant or slow flowing water is the place where you can see a large number of dragonfly larvae. They are inactive, can only slowly crawl along the bottom of the reservoir or swim. But most often the larvae sit motionlessly, clinging to the claws of the underwater parts of the plants with the claws on the paws. There are species that burrow into the mud.
If a danger arises or during a hunt, the larvae can very quickly leave their place of residence. To do this, they use the method of swimming with the help of recoil, in which a jet of water is thrown from the back of the abdomen of the larva with great force. Due to this, there is a great speed of movement.
We know what dragonflies eat, but it becomes interesting what the food of their larvae is. It turns out that they are very voracious, like adults. In addition, like dragonflies, they are predators - they are content only with live prey. The younger the individual, the more feed it needs.
The difference from adult insects lies in the fact that the larvae, hiding, wait patiently for their prey, and when convenient, instantly attack it. Daphnia, mosquitoes and other insects are those inhabitants of the reservoir who are the main food of the small dragonflies.
Having learned what dragonflies and their larvae feed on, it is easy to conclude about the benefits of an insect in nature. But this mysterious individual has another mystery, which must be revealed at least in order to get more complete information about the insect.
We remember the way of life they lead, the dragonflies feed on, and where their larvae live. But it turns out that the life span of individuals under water is much longer than that which occurs on the surface. The larva is able to live under water for about five years, while the adult insect exists for only 6-7 months.
Dragonfly: description and photos. What does a dragonfly look like?
Dragonflies have a distinctive recognizable appearance. In their structure stand out:
- slender elongated streamlined body (abdomen), often having a bright shiny color,
- large head,
The structure of the male and female dragonflies
The abdomen of the insects is elongated and thin, rounded in shape, in some species of dragonfly it may be flat and wide. It consists of 11 segments consisting of two parts: the ternite (upper semiring) and sternite (lower semigenet).
The males on top of the abdomen have “forceps“With which they hold the female’s neck during mating.
The head of the dragonfly is movably connected to the breast, which makes it possible for it to rotate around its axis through 180 degrees.
The eyes of the dragonfly, which occupy most of her head, consist of more than 30,000 small eyes (facets). Moreover, each miniature eye is able to work independently of the others.
The upper part of the facets is designed to recognize the shape of the object, and the bottom - its color.
Eye structure of dragonfly
In addition to two complex eyes, dragonflies on the crown have 3 simple eyes, which are located in a triangle. With the ability to see the environment not only in front, but behind him, as well as on the sides, dragonflies are able to notice the victim at a distance of up to 8 meters.
Mouth dragonflies armed with serrated jaws, because they are voracious predators.
The chest has a characteristic structure for all insects and consists of a prothorax with a pair of extremities and accrete middle and metathoraxes on which the legs are located.
Coloring of a dragonfly happens transparent, and also green, yellow, blue or blue color. Some species have patterns in the form of spots or blackouts on the body or on the wings.
Dragonfly Palpopleura Portia
Dragonfly Brilliant beauty Calopteryx splendens
Dragonflies have 2 pairs of wings. The wings of a dragonfly, depending on the species, may be the same or vary in size. Their maximum range reaches 18 cm. The wings consist of two thin layers of chitin, they are penetrated by a complex system of veins. Each of them has a special thickening on the top, excluding the appearance of vibration during flight.
When flying dragonflies use 2 pairs of wings, each wing can move independently of each other, which gives them the opportunity to freely maneuver in the air. The maximum speed of the dragonfly is 57 km / h, and the average speed exceeds 30 km / h.
How long does a dragonfly live?
The life span of a dragonfly averages 10 months. Many species die after 6 weeks. Long-livers can wait out adverse conditions (cold or drought) in shelters.
Where do dragonflies live?
The habitat of dragonflies is very extensive. They can be found in any region of the world where there is warm weather, there is water and a large supply of food. These insects are widely distributed in Russia and Belarus, Germany and France, Italy and Spain, and the countries of the Balkan Peninsula. Many species of dragonflies live in the Asian region: India and Pakistan, Thailand and Azerbaijan, Armenia and Iran, Turkey and China. Dragonfly also lives in the vast African continent, Australia, and North and South America.
Dragonfly is an insect that prefers a solitary lifestyle. She shows activity in the daytime, preferring the sundial, and awaits unfavorable overcast weather in shelters.
The natural enemies of dragonflies are many species of birds, fish and spiders.
The structure of the head and eyes
The predator can turn its head by 180 due to a special mobile connection with the breast.
Food takes place through rather powerful insect jagged jaws located below the front of the head.
Huge eyes, filling ¾ of the head, consist of 30,000 facets. Это маленькие глазки, при необходимости функционирующие отдельно друг от друга. Верхние ряды отвечают за распознавание форм и объемов, нижние предназначены для определения цвета. Глаза способны воспринимать ультрафиолетовый свет.
At the back of the head, in the crown of the crown, the dragonfly has three additional simple eyes lined up in a triangle. Having the ability to see, analyze the world in front of her, on either side, behind herself, the predator notices the victim even after a distance of more than eight meters.
How many wings?
Two pairs of dense, independently functioning wings, consisting of two transparent layers of chitin, are connected to the chest with a unique system of veins. When the flap of each wing can occur alternately and in any sequence, only dragonflies have such an aircraft. The wingspan of some species exceeds 18 cm. High maneuverability allows the insect to reach speeds of up to 60 km / h, but usually it does not exceed 30 km / h.
Where does the dragonfly live?
The habitat of a chirping insect is as huge as the variety of coloring options. But you can meet spotted individuals, yellow, green, blue, pearl blue. There are also interesting blackouts on the abdomen against the background of the main color.
For dragonflies, maximum proximity to water bodies, plenty of food, a rather warm tropical climate are preferable. This expands the places of their possible habitat on almost all continents of the globe. They are common in:
In dry dry places do not survive.
The squad differs in an extraordinary way of life, in comparison with other representatives of the class Insects. Winged predators attract attention to themselves from the moment of their turning into a naiad, which shakes by its gluttony, duration of stay in this transition stage for an insect. Transformed into an adult, dragonflies acquire the skills of a particular style of flight.
How many live dragonflies?
A short period of existence, only 3-5 months, obviously assumes a very active lifestyle. Dragonflies are diurnal, solitary insects moving and hunting during the sunny time of the day. At night, in inclement weather, they hide in shelters. Wintering is also sent there.
After hatching from an egg in the form of a larva, the insect lives in the water column up to 5 years, molts more than 10 times. If during this time the dragonfly is not eaten, the larva grows wings, it crawls out onto the surface stem of some plant, where the real dragonfly hatch. It spreads its wings, flies, becomes an adult.
Large species overwinter, endure the dry season in a daze, come to life after the first rain. Some representatives make grand flights over many kilometers from breeding sites.
In the fall, most of the dragonflies die. In spring, new larvae hatch out of eggs. The life circle of this amazing insect begins again.
You should not be deceived by careless elegant flight: a cruel winged predator hides behind the chatter and bright coloring. Endowed with the body of an ideal flying hunter, he is almost unmistakably oriented in space. Hunting for fly, dragonflies attack the victim from below. This is due to the special structure of vision, which opens the best view on the background of a clear sky. Insects make interception, calculating almost 100% of the trajectory of the victim. It is calculated by reading the information with all eyes.
Having caught the prey, the insect fixes it with its front paws, denying the chance to make any movement. Then the middle pair of legs lifts the wings. Having lost the hope of salvation, the victim is practically ground by powerful jagged jaws to a mushy state, and is sent for further digestion.
Having swallowed prey, the predator again proceeds to active hunting.
In conditions of endless arrival of easy prey, the dragonfly can eat 40 or even more small insects without stopping.
The main danger for dragonflies - birds, some fish, large spiders that can cause harm. However, dragonflies as typical predators are protected to the last: bite, sting.