About dragonflies biography

Known from the coal period - a million years ago, and the dragonflies of that time reached giant sizes. In the modern fauna - near species, the majority lives in tropics and subtropics.

Development with incomplete transformation does not have the stage of the doll. Larvae of modern species live in water, although in the earliest fossil dragonflies, all development took place on land. Modern dragonflies are divided into three submarines: zygoptera is equivalent, anisoptera diverse and anisozygoptera. The first two differ in size, structure and type of flight. The third subordinate, combining the features of the first two, is represented by two species - in Japan and Himalayas, by the year, two more species discovered in China were described in this suborder.

Some species are at risk of disappearance mainly in connection with the destruction of habitats and are listed in the Red Book. Of course, dragonflies also cannot live all their lives in flight. From time to time they fall to a solid support, but almost never walk along it. And they usually prefer to sit on Earth, but on various elevations tall plants, stones, and a fence.

The dragonfly can sit at such an “airfield” from a couple of seconds to several hours, if she settled there for the night, all this time remaining almost motionless. Her strong and grabbed legs are needed not for movement, but for reliable adhesion to the support. But their main purpose is to catch prey, flying insects. This elegant creation fully justifies its name-a dragonfly-beautiful dragonfly.

The dark-metal shine of her body and darkened wings emphasize its fragility. But, like all other dragonflies, the beauty is a predator that caught his prey in the air, overtaking the victim, the dragonfly grabs her paws and brings it to the mouth, and there are already powerful jaws. Despite their frightening look, they serve only for food. Captured by a predator or a person, even large -sized dragonflies are not trying to bite the enemy.

Read also owls: a person flying on the wings of the night in different weight categories, who never specially interested in dragonflies, probably noticed that they have two very different types of physique. Small dragonflies - thin, lungs; When landing, they fold the wings in the vertical plane to the body. Their fluttering flight is deprived of swiftness and resembles the flight of butterflies or shadows.

Particularly similar to the butterflies of dragonflies, whose wings are painted in a thick dark blue color. In large dragonflies, the body is much more massive, the wings in a sitting position remain divorced to the sides. On each dragonfly wing, there is an opaque spot - Stigma - a section of a thickened chitin, which serves to prevent destructive vibration of the wing, but the most important difference is reflected in the scientific name of these groups - equivalent and diverse.

Indeed, in small dragonflies, all four wings are almost the same in shape, while the large wings have noticeably expanded at the base. Both large and small dragonflies, the front and rear wings are “equal”: during the flight they work uninchledly, although coordinated. It is generally accepted that this is an archaic, characteristic of ancient insects, the technique of movements, capable of providing only a slow and not too maneuverable flight.

Indeed, all the others are good and a lot of flying insects or learned to adapt the wings on each side into a single -bearing plane of the wasps, bees, many butterflies, or completely abandoned one of the pairs of wings of the fly, mosquitoes, or deprived it of mobility in the flight of beetles. However, large multi -winged dragonflies remained faithful to the ancient "Allura", while they managed to become the best flyers among insects.

Not every bird will stole after them, and almost no one can compete with large dragonflies among insects. In our latitudes, the morning dragonfly often begins with water procedures - drying from night dew. It will be ready for the flight after the droplets evaporate and the insect warms up so that the muscles are earned by the envy of the aircraft designers by high -speed possibilities are combined with enviable maneuverability: large dragonflies are no worse than the small ones can freeze in place or unfold at unthinkable corners, without reducing speed.

In addition, they can be cut in the air for hours without landing. Air hunter, the main trump card of which is speed, can confidently rely only on vision. It is no wonder that a characteristic feature of any dragonfly is huge eyes on the head out in a width. But even at the same time, the eyes make up most of the head, and in some large dragonflies merge together.

In front of the huge eyes of the dragonfly, short and thin antennae are located, in which hearing organs and receptors are placed that determine the speed of oncoming air flow, they consist of almost 30 elements-faces, providing almost a circular review. However, at the same time, all dragonflies must have three simple eyes - between “main” eyes or, if they merged, in front of them.There are also short, inconspicuous antennae, in which hearing organs and special receptors are placed that determine the speed of oncoming air flow.

Dragonflies live wherever two indispensable conditions are fulfilled: at least three to four months a year were warm enough and at the same time there were constant, unrestrained reservoirs. Although adult insects can do without water for a long time: in Central Asia, cases are described when dragonflies settled in places separated from the previous hundred kilometers of anhydrous desert.

However, it was water that attracted them there: the drilling of artesian wells and irrigation of underground water of fields and pastures created ponds in which dragonflies could multiply. Read also the dwelling for everyone for envy: 3 main architects in the world of insects Strong embrace of the breeding of dragonflies is also unique. The abdomen of the male ends with a kind of three -fingered “tweezers”.

Once these were the external genitalia, but in modern “dragonflies” they are not connected with the sex glands that produce a spermatofor-a compact container with sperm. Brown, the male puts him in the deepening of the secondary copulative body - special education in the second segment of the abdomen - after which he goes in search of a girlfriend. Finding, he grabs her by the “neck” - the first segment of the chest, immediately behind his head - the very appendages at the end of the abdomen.

Clouling in this way, a happy couple flies together for a while. The next move makes the female - she bends her abdomen, capturing it with the tip of the secondary copulative organ of the male. All this happens right in the air, and the couple clinging in two places forms a figure similar to a carelessly drawn heart, the so -called marriage ring. At this moment, insects are especially vulnerable to birds and other predators, so the ring does not exist for long - exactly as much as it is necessary to transfer the spermatofor to the female.

After that, the female releases the male, but he continues to hold it: a lady without a gentleman will immediately attract the attention of other boyfriends who can persuade her to treason and certainly prevent her from laying eggs. In many species, males do not disconnect from friends to the end of the masonry. The male does not let go of his girlfriend even during the laying of eggs, because the insidious rivals do not doze and their courtship can prevent her from laying eggs of eggs of eggs of different types of dragonflies are quite diverse.

Some swim the precious capsules simply into the water, touching its surface with the tip of the abdomen or directly from a shaving flight. Others place them on floating leaves of aquatic plants or on moist ground at the edge of the water. Some make the eggs in the stems of plants sticking out of the water or even in the bark of woody branches hanging over water.

In some shooters, the family of small dragonflies the female descends a stem deep under the water, dragging the male a rare situation when the dragonfly uses his legs to move! Such a caring mother quite really risks drowning herself and her spouse. Like adult dragonflies, larvae are active predators attacking all the animals with whom they can cope at this stage of development - from cadennials to tadpoles and fry of fish.

All of them are armed with powerful jaws, and in larvae of large species, the lower jaws are part of the so -called mask: the lower lip, at the end of which they are located, is strongly stretched and capable of folding in half, like a feather knife. Approaching the prey, the larva throws forward the lip, grabs the victim with the jaws and pulls up to the mouth, where the upper jaws enter into business.

The last molt - a young dragonfly appears from the shell of the larva. The transformation takes several hours and requires an insect of great work. In this state, the dragonfly is defenseless, however, if adult insects hunt only in the air, then the larvae rush, walking along the bottom, looking up from it only when they feel in danger. In this case, they launch a real jet engine, pushing water from an expanded rectum with force.

The desired volume of water is almost always there, since the same mechanism serves as breathing larvae: the so -called rectal gills are located in the expansion of the rectum, through which gas exchange goes. It is unnecessary to say that a similar method of breathing is unknown not only in all other insects, but also in any other animals. Freed from its “spacesuit”, the dragonfly remains next to him for a long time, waiting for her soft wrinkled wings to deal, harden and turn into elastic sparkling planes from the larvae of small dragonflies besides rectal there are also external gills - three elegant leaves at the end of the abdomen.

On occasion, they also serve as an organ of movement, acting like a fish tail. And on occasion, they can be left as a keepsake of the predator clinging to them, distracting his attention from the larva itself. In the smallest dragonflies, the larva spends almost a year in the water, for larger ones - from two to four years, having been driving 10-25 times during this time.Typically, such a long water "childhood" is characteristic of those insects that in adulthood either do not eat underlying, springwood, or feed on some kind of low-novel juice, suitable only for maintaining strength, but not for the formation of many eggs.

It would seem that adult dragonflies with their purely meat diet could not rely on reserves made by a larva. But, barely leaving the larval skin, they immediately proceed to reproduction. They need to hurry: in the vast majority of species, an adult form lives only one summer. Photo: Nikolai Spynok, if other material is not indicated in May, partially updated in January the author of the text: Ivan Streltsov.