Blue yoke (lat. Aeshna cyanea) belongs to the group of hetero-winged dragonflies (lat. Anisoptera). The beautiful dragonfly often attracts admiring glances, striking with the splendor of her dazzling outfit. Its unique beauty inspired more than one generation of jewelers, poets and artists.

In Asian countries, it has long been considered a symbol of victory, and in folk medicine medicinal preparations from dragonflies are used. In European countries, it has a completely different attitude. She was often mistaken for a dark force that brings misfortune on its wings.

Spreading

The blue rocker is common in North Africa, Central Asia, the Middle East and Europe, with the exception of Ireland, Greece and Turkey. The dragonfly lives at altitudes up to 1400 m above sea level. Her favorite habitat is located near the shores of lakes, swamps and ponds.

Adult individuals allow themselves to fly long distances for hunting in glades and along the edge of forest clearings. The antennae of the blue rocker are made up of granules of the mineral statolite, which helps the insect to navigate well in space.

Behavior

The dragonfly is a solitary hunter by nature. It can fly for many hours in a row at a speed of 9 m / s and with a frequency of wing flapping up to 20 times per second. This insect is capable of flying long distances, but it is a poor pedestrian. It can occasionally sit down to rest.

Large compound eyes consist of 28,000 simple ocelli.

The movable head and compound eyes make it much easier for this voracious person to find food. The oral apparatus is armed with a pair of powerful jaws. The basis of its diet are mosquitoes, butterflies and mayflies.

The blue rocker eats small insects on the fly, and having caught a larger one, it sits on the nearest plant and calmly eats it. After eating, it thoroughly cleans its paws and takes off again.

With the onset of dusk, numerous flocks of dragonflies hunt midges. In the heat of the hunt, they fly away to remote distances from the reservoir, and sometimes they can fly into human habitation.

reproduction

The breeding season runs from June to October. During this period, cavaliers actively patrol areas with ponds and lakes in search of females. Flying over the water surface, the male performs intricate acrobatic tricks in the air, trying to attract the attention of his partner. Females are limited to swift flights in a straight line.

After mating, the male flies away again to patrol the area. Females and males mate with different partners. After mating flights, the fertilized female is looking for a place for masonry. For this, wet moss or dead parts of the plant are suitable.

With her ovipositor, the female pierces the plant and lays eggs in several rows. Only in the spring of next year, 3 mm larvae will emerge from the eggs. Very soon they will begin the first molt. The larva of the blue rocker undergoes the process of molting 10 times.

Living in a reservoir, it actively eats fly larvae, caddisflies and various small invertebrates. She hunts with the help of a "mask", which has 2 claws. During rest, this device is neatly folded under the breast. At the right moment, the larva opens it and abruptly throws it forward, as a result, the victim falls into a trap.

10 days before moving to land, the larva goes through a preparatory period.

The way of breathing changes completely, the eyes become large. The wings, which are in small bags, increase.

With the onset of dusk, the larva leaves the reservoir and, having come ashore, climbs onto a blade of grass. After a while, a small crack forms on her back and head, and the last molt occurs. A completely adult insect is born. Its soft wings expand and harden after a while.

The blue rocker sets off on its first flight. The larvae that appeared at the beginning of the season, with the onset of cold weather, stop their growth and leave the reservoir only the next spring to complete the metamorphosis. The larvae that were laid at the end of the mating season develop very slowly. They complete the transformation within 2 years.

The life of an imago undergoes 3 periods of development. In the first period of maturation (for females up to 16 days, and for males up to 12), males show off in dazzling decoration.

The second stage lasts about 60 days and is completely dedicated to the continuation of a kind. During this period, many individuals die. With the advent of the third period, the dazzling attire of the dragonfly fades, the overworked wings refuse to serve, and the insect dies.

Description

The body length reaches 8 cm. The large head rotates in several directions. Huge compound eyes touch each other. The antennae, consisting of 7 segments, are equipped with spatial orientation organs.

The first pair of legs is directed forward and helps to climb plants, and during the hunt to grab insects. Two pairs of luxurious wings are attached to the insect's chest. The wings of the rear pair are slightly wider than the wings of the front pair.

The powerful chest consists of two segments of different sizes. The strongly elongated abdomen contains the reproductive organs. The abdomen ends with tick-like appendages, which the insect uses for self-defense.

The life span of the adult blue rocker is up to 6 months, and the larvae up to 2 years.

Family of the Rocker (Aeschnidae)

Our largest dragonflies belong to rocker arms(Aeschniidae). One of common species in the Baikal region - rocker blue(Aeschna juncea), body length up to 70 mm, and in wingspan up to 95 mm. Males are brighter, with a predominance of blue coloration, especially on the abdomen. In females, green and yellowish tones predominate. These are wonderful flyers, capable of covering tens and even hundreds of kilometers, settling in new water bodies. Sometimes it is possible to observe the process of the dragonfly emerging from the larva, which for this purpose is selected from the water onto the protruding parts of plants. The wings of a young dragonfly are still fragile, cloudy, the integument is palely colored. But an hour after hatching, the dragonfly is ready to fly.

The exit of the dragonfly from the nymph

In calm weather, a large, slender nymph can be distinguished in the water. dragonflies(Aeschna), which crawls slowly among aquatic plants or perches on rocks, tracking prey with large compound eyes. If disturbed, the nymph ejects a jet of water from the hindgut with force and moves forward with a quick jump. In reservoirs, the rocker larva is a real thunderstorm for all inhabitants. It feeds on everything that it can overcome, even fish fry.

(Aeschniidae)

Large, colorfully colored dragonflies, one of the most beautiful representatives of the order. The eyes on the crown touch. Wings at rest are directed to the sides. Rocker arms can fly for hours without rest. At this time, they often fly away from water bodies. Females lay their eggs in living or dead plant tissues, lowering the end of the abdomen into the water. Larvae - active predators, sometimes even attacking fish fry. In some species, development is completed in 1 year, in others it lasts up to 4 years.

(Aeschna grandis)

The main body color is brownish-red. The wings are golden brown, with reddish veins. Chest above between wings with 4 blue spots, on the sides with yellow stripes. The abdomen of males is blue on the sides, with white spots on top. In females, the spots on the abdomen are light gray. Body length 70 - 80 mm, wingspan up to 105 mm.

Dragonflies are found from late June to September. Their flight is characterized by the fact that they often plan. They fly not only during the day, but also after sunset. Females lay their eggs in dead plant tissues submerged in water, or in accumulations of dead plant parts near the shores of water bodies.

Larvae reach a length of 50 mm, develop 2 - 3 years. They prefer stagnant or low-flowing water bodies. They live among aquatic vegetation.

12. Watcher Overlord(apah imperator)

The eyes are greenish-blue above, yellow-green below. The chest is greenish, without stripes. In females, the wings are golden yellow, in males they are colorless. In males, the abdomen is blue, with large blackish-brown spots, in females it is bluish-green, the spots are larger, with a reddish-brown tint. Body length up to 80 mm, wingspan up to 110 mm.

Dragonflies fly from mid-June to August. They can be found along the banks of small ponds and other stagnant and slow-flowing overgrown water bodies. Females lay their eggs mainly in dead, submerged parts of plants. The larvae live among aquatic vegetation. In a year they reach a length of 60 mm and complete their development.

13. White-haired yoke(Brachytron hafniense)

The dragonfly is covered in dense whitish hairs, hence its name. The eyes of males are blue, those of females are yellowish brown. Breast from above, brown-red, with 2 wide greenish-yellow longitudinal stripes. The lateral parts of the chest are green, with 2 oblique black stripes. Legs are black. The abdomen of males is black, with blue spots and narrow transverse green stripes. In females, the spots on the abdomen are yellow.

Body length up to 65 mm, wingspan up to 80 mm.

Dragonflies fly in May - July. For laying eggs, small stagnant and low-flowing reservoirs, including swampy ones, are chosen.

The larvae are massive and live among the dead parts of aquatic plants. They develop very slowly and hibernate three times.

14. Rocker blue(Aeschna cyanea)

The eyes of males are greenish-blue, those of females are yellowish-green. On the forehead there is a characteristic black spot in the form of the letter T. The chest is brown on top, with 2 wide green longitudinal stripes, green on the sides, with a black pattern. In males, the abdomen is black, with green dorsal and blue lateral spots; on the last abdominal segments, all spots are blue. In females, the abdomen is brownish-red, with green spots, or light gray, with light blue spots. Body length 65-80 mm, wingspan up to 110 mm.

Dragonflies are found from mid-June until late autumn. Females often fly in the evenings. They prefer large stagnant ponds, ponds and overgrown lakes.

The larvae live among aquatic plants. The development of larvae lasts 2 years. By the end of development, they reach a length of 50 mm.

Description

Head and chest close-up

Body length 65-80 mm, wingspan up to 110 mm. The eyes of males are greenish-blue, those of females are yellowish-green. There is a black spot on the forehead in the form of the letter T. Chest from above Brown, with 2 wide green longitudinal stripes. On the sides of the chest Green colour, with black pattern. Males have a black belly, green on the back, with blue lateral spots. On the last segments of the abdomen, all spots are blue. In the male, the upper anal appendages of the abdomen are distinctly bent down at the apices. In females, the abdomen is brownish-red with green spots or light gray with light blue spots.

area

Biology

Adults occur from the 2nd decade of June until November (in the south of the range). Females often fly in the evenings. They can reach speeds up to 60 km/h. They hunt flying insects, even other dragonflies, looking out for prey with huge eyes. They prefer large stagnant ponds, ponds and overgrown lakes.

reproduction

Unlike other closely related species, females of the blue rocker do not lay their eggs in water from aquatic vegetation, but on dry ground or moss near the water level. Wintering eggs. The larvae hatch in April. The body of the larvae is wide, thick, stocky, there are no caudal gills. The larvae live among aquatic plants. Active predators - eat small crustaceans, mosquito larvae, aquatic insects, fish fry. The development of larvae is 2 years old, they turn into adults after 13 molts. By the end of their development, they reach a length of 50 mm.

Gallery

Notes

Wikimedia Foundation. 2010 .

> Blue rocker (Aeschna juncea),		Blue rocker (Aeschna juncea), female
Blue rocker, male	Blue yoke, female

In calm weather, a large, slender nymph of the rocker dragonfly (Aeschna) can be distinguished in the water, which slowly crawls among aquatic plants or sits on stones, stalking prey with the help of large compound eyes. If disturbed, the nymph ejects a jet of water from the hindgut with force and moves forward with a quick jump. In reservoirs, the rocker larva is a real thunderstorm for all inhabitants. It feeds on everything that it can overcome, even fish fry. AAAAAAAAAAAAAAAAAAAAAAAAAAA

Watcher - Anax imperator Leach

One of the most large species dragonflies with powerful flight. The chest is green with wide black stripes at the seams. The wings are transparent, large (wing length 50 mm). Wing membrane of contrasting gray-white color. Legs with long spikes, with the help of which they fold into a trapping "basket" for insects in flight. The abdomen of an adult male is blue, that of a female is green or bluish-green, with a continuous black jagged longitudinal stripe on the dorsal side. The eyes are large, compound, blue-green in color.

The species has an unusually wide range, crossing almost all natural areas Lands from the Scandinavian Peninsula to southern Africa, but in most areas within the range, its distribution is local. In Russia, the range is limited to the southern half of the European part.

Inhabits water bodies both in open and forest landscapes. The larvae develop in stagnant and slow-flowing water bodies; by way of life, they are overgrown ambush predators. The feeding spectrum of larvae is very wide and includes almost all small aquatic organisms from cladocerans to tadpoles and fish fry. The development cycle is 1-2 years, depending on the photoperiodic and temperature conditions of a particular habitat, as well as on the abundance and availability of food. Emergence of adults from larvae in the south of Russia at the end of May. The imago flight continues until mid-August. Adult dragonflies are active predators, chasing prey in the air. They feed on a wide variety of flying insects, but the diet is usually based on chironomids. There are big differences in the biotopic distribution of males and females: the former are more concentrated near water bodies, the latter are dispersed over large areas, preferring the edges of forests, shrubs, and forest belts. During the reproductive period, males are characterized by territorial behavior - patrol flights within an individual area where mating and oviposition take place.

In Russia, the population dynamics is steadily declining. The dispersion of adults from breeding sites is wide; dragonflies in feeding habitats can be found at a distance of 3-4 km from the nearest reservoir.

Conclusion

Our region is rich in dragonflies. The largest of them are eshna, or simply a yoke, and an anaks-watcher.

The most graceful and elegant of dragonflies, of course, must be recognized as a beauty girl and a bride-bride.

In this term paper dragonflies of the Astrakhan region were considered.

The species composition of dragonflies is diverse and interesting not only for science, but also for any person. However, in the oblast, the dynamics of the number of dragonflies is steadily declining, apparently due to pollution of water bodies. In most of its range, the species very quickly and easily colonizes ponds, reservoirs, and other newly created water bodies. Natural limiting factors in the distribution of the species temperature regime reservoirs and competition with dragonflies of the genus Aeschna, numerous Anax. Anthropogenic limiting factor - pollution of water bodies, the use of pesticides.

With their graceful shape, and many species and their coloration, dragonflies play a big role in the aesthetic perception of the world by man.

The importance of representatives of this order of insects in nature is determined by their predatory nature of behavior, the beauty of species diversity, as well as the habitat of the larval phase of development: dragonflies maintain species balance in ecosystems not only by eating various representatives of the animal world, but also by the fact that their larvae are intermediate hosts of various diseases (up to 160 species), including such a disease as prostogoniasis.