How many kinds of dragonflies are known?

In summer and autumn, people can often see dragonflies by the pond and on the grass. Dragonflies come in many colors, including red, yellow, black, grass green and colorful. There are more than 4,500 species in the world and about 300 species in China.

Dragonfly is the flying champion among insects. Its speed can reach 40 kilometers per hour, and the thorns on its feet are like daggers. It preys on about 1000 mosquitoes, flies and butterflies every day. When the dragonfly found the bug, it rushed over, aiming at the target with six feet and closing at the same time. The bug was firmly put into the "cage" and became a delicious meal for dragonflies.

Dragonflies can't change direction flexibly when flying forward. They must hold their bodies steady before turning around. If you have the heart, you will find that dragonflies mostly stay on branches or leaf tops, because their wings are still open when resting, that is, they don't fold their wings like birds, so there should be considerable space where they stay.

Dragonflies' long wings support their bodies smoothly and fly freely, and the wind will not make them waver. Why is this? It turns out that there is a beautiful horny thickening part above the leading edge of each dragonfly wing, which is biologically called wing nevus or wing eye, and it plays a role in smooth flight. According to this revelation, people added counterweights to the wings of the aircraft, thus avoiding the accident that the aircraft often can't control or even break the wings because of violent vibration when flying at high speed.

Dragonfly's compound eye is the largest compound eye in the insect world, accounting for 2/3 of the total head area, with about 28,000 at most, which is 10 times that of ordinary insects, and its structure is very strange: the upper part looks far away and the lower part looks very close. In this way, when they catch bugs in the air, they can be handy and they never fail. Scientists imitated the structure of dragonfly eyes and made a compound eye camera, which can take thousands of photos at a time.

dragonfly

In summer and autumn, when it rains or rains in Chuqing, colorful dragonflies can often be seen hovering at low altitude, flying for a while, gliding for a while, flapping their wings to stay in the sky for a while, and "dipping in the water" lightly for a while, and their flying skills are extremely superb. Dragonflies fly in erratic ways, and they can also predict sunny weather. In normal weather, dragonflies often inhabit trees or reeds by the water and rarely come out. Whenever dragonflies fly low in groups, it will rain soon. As the saying goes, "Dragonflies fly low and go out with hemp fiber." This is because the dragonfly's staple food is small insects. Before it rains, the air is wet and the wings of small insects are wet, so they can't fly very high. At this time, it is a good opportunity for dragonflies to hunt.

Different dragonflies will appear at different times, which also indicates different weather. Before and after the summer heat, the red dragonfly is flying in groups in the low altitude areas of the field, which is a sign that it is about to enter the summer drought and high temperature weather. Around beginning of autumn, yellow dragonflies circled low in the fields in groups, or dipped in water, which is a sign of rainy days in the near future.

dragonfly