In this article, we suggest you talk about what kind of creature is a dragonfly. Building, nutrition, reproduction, benefits and harms - all these are our main questions, to which you will find the answer by reading this short article.
To begin with, we make a reservation: the dragonfly has six jointed limbs. This is an insect belonging to the subclass of winged insects. These many creatures even have their own squad - dragonflies.
Have you ever wondered how you got the name dragonflies? In Russian, it is a combination of two outdated words: egoza and chirping. The first word is translated as a fidget, and the second is to jump. This name fully characterizes the manner of flight of these fast creatures called dragonfly. Building is the first question that we will consider right now.
Structure
The dragonfly, the structure of which we consider in this material, has a long and very thin body. It, in turn, is connected to the cephalothorax. 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 have the same size and shape, as well as different. We will talk about 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 includes individuals that have wings of equal length and shape, while others are the other way around (one pair can be very different from the other). On the head of a dragonfly we can clearly distinguish large eyes and antennae. A little more about the senses. The eyes of these insects are complex. You can divide them into two departments:
- the top one responsible for recognizing an object;
- bottom, responsible for color recognition.
You must have noticed that the dragonfly’s transparent wings have streaks along their entire length, and there are darker spots on their tips than the color of the wings themselves. This device helps to avoid fractures of the wings, reducing vibration during flights.
Remember how the flight of other flying creatures occurs. This is a beautiful and synchronous movement of the wings. Dragonflies have also distinguished themselves here, the movements of the wings can be asynchronous when they balance, and synchronous to increase speed. It is important to know that these nimble creatures can reach flight speeds of up to 50 kilometers per hour.
Life span
We examined some structural features of dragonflies, but it is important to clarify that they can live up to ten years. These are real centenarians in the insect world. Let's talk about this in more detail.
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, at least two months, and the very long-livers can last about ten years. The full cycle of insect development is included in this period, and the development of the larva in some species may take more than one year.
Kinds
The external structure of a dragonfly directly depends on the species. There are only three suborders of these insects:
- winged;
- diverse wings;
- anisozygoptera.
How do they differ? The first species 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 they are spread out to the sides. The third suborder is the only genus; these insects are common in Japan and India. A feature of the latter is also that they combine the characteristics of the first and second suborder.
The most common representatives of equine dragonflies:
- Beauty
- Arrow.
- Dryut lyutka.
- 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 is nineteen.
Bright representatives of the suborder of diverse:
- Watchman Emperor.
- Cordulegaster ringed.
- The headstock is metal.
- The grandfather is ordinary.
- Dragonfly common.
Habitat
Features of the external structure of dragonflies and the method of reproduction directly depends on the habitat. These insects prefer to stay and conduct their activities near water. How can such an attraction to the water element be explained? Everything is very simple: dragonflies lay their eggs in water.
They choose places near mountain streams, at ponds, lakes, rivers and canals. There are also such types of dragonflies that prefer swamps. Dragonflies are sun-loving insects; they often bask under the sun in clearings and meadows. However, far from the water they do not fly away. On cloudy and rainy days, dragonflies do not fly out; they prefer to be in a "shelter".
Nutrition
Our next question is the internal structure of dragonflies and nutrition. As mentioned earlier, dragonfly is an arthropod type. 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 nerve chain represent the nervous system of insects.
What can a developed gnawing mouth apparatus, well-developed vision, an elongated body, and large, rather powerful wings speak of? Of course, dragonflies are predators. They prefer to eat their prey on the fly. They feed on insects, usually harmful. They catch large ones with their paws, and small ones (midges, mosquitoes) are caught directly with their jaws. To taste a large prey, the dragonfly has to descend to the ground. Hunting is a real sight. Even such good and brisk flyers, like flies, do not slip away 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).
Breeding
We examined the structural features of dragonflies, the way of feeding, and the habitat. Now briefly about the method of reproduction. Fertilization occurs in the air. Larvae are deposited by the female mainly in still water; their number reaches five hundred. Such an amount is needed due to the poor survival of the larvae. Larvae are deposited in various ways:
- dropping into 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 pronimfa appears (life cycle is a few seconds), then mollusk. 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 - protogonymosis. The larvae of some representatives are able to eat fry in fisheries.