Where are dragonflies distributed? What is the reason for the sudden increase in dragonflies?

Dragonflies are carnivorous insects that prey on a variety of agricultural, forestry and animal husbandry pests. They have brought great benefits to our lives, so they are an important type of natural enemy insect that is beneficial to humans. The most common dragonflies are the dragonflies and dragonflies. Where are they generally distributed? What is the reason for the sudden increase in dragonflies? Let's see what the Encyclopedia Knowledge Network says!

Contents of this article

1. Where are dragonflies distributed?

2. What is the reason for the sudden increase in dragonflies?

3. The relationship between dragonflies and helicopters

Where are dragonflies found?

Dragonflies are distributed all over the world, especially in tropical regions.

The larvae, also known as water scorpions, often live in sand, mud or water plants in the water, feeding on small aquatic animals such as mayflies and mosquito larvae. Large species can also prey on tadpoles and small fish. After emerging from the water, the mature larvae crawl onto stones and plants and often emerge at night.

Generally, they are large in size, with long and narrow wings, membranous, and with very clear reticular wing veins. They have extremely sensitive vision, three simple eyes, a pair of thin and short antennae, and chewing mouthparts. The abdomen is slender, flat or cylindrical, with an anal appendage at the end. The legs are thin and weak, with hooks on them, which can catch pests while flying in the air. The larvae develop in water and breathe in the water with rectal tracheal gills. Generally, they have to molt more than 11 times, and it takes 2 years or more to crawl out of the water along the water plants, and then undergo the final molt to emerge as adults. The larvae can prey on mosquito larvae or other small animals in the water, and sometimes they even cannibalize each other. Adults usually fly in ponds or rivers to prey on flying insects. In addition to being able to prey on mosquitoes, flies and other insects that are harmful to humans in large quantities, some can also prey on butterflies, moths, and bees, which are beneficial insects.

What is the reason for the sudden increase in dragonflies?

The sudden increase in the number of dragonflies is because it is about to rain. In the hot summer, when a rainstorm is approaching or just after a sudden rain, dragonflies often fly in groups at low altitudes.

dragonfly:

Dragonfly is a general term for invertebrates, insects, Odonata, Anisoptera. The base of the hind wings is slightly larger than that of the forewings, and the wing veins are slightly different. When at rest, the four wings are spread out and laid flat on both sides. The larvae are short and thick, with rectal gills and no caudal gills. There are three superfamilies, namely Aeshnoidea, Cordulegastroidea and Libelluloidea, with a total of 11 families. The dragonflies and dragonflies are the most common and are distributed throughout my country. Dragonflies are carnivorous insects. They prey on flies, mosquitoes, leafhoppers, horseflies, midges, small butterflies and moths and other agricultural, forestry and animal husbandry pests. Dragonflies are an important natural enemy insect that is beneficial to humans. "Dragonflies skimming the water" is the biological characteristic of dragonflies laying eggs in water. Their larvae (larvae) live in water, and their life span varies according to the species. Dragonflies are generally 2 years old, and some are as long as 3 to 5 years. It can be used to monitor environmental pollution and has medicinal, edible and ornamental value.

The relationship between dragonflies and helicopters

Dragonflies rely on their nervous system to control the tilt angle of their wings, which is subtly adapted to the flight speed and atmospheric pressure. The dragonfly's "autopilot" is much more agile than modern aircraft. People continue to study the characteristics of insect flight and structural functions from the perspective of bionics, and "transplant" them into aircraft design for application. For example, there is a "flutter" phenomenon in aerodynamics. If the aircraft feathers cannot eliminate "flutter", the feathers will break during fast flight, resulting in the destruction of the aircraft and the death of people. Dragonflies are "pioneers" in eliminating flutter. There is a dark and thickened part on the front edge of its wings, called a wing mole. This is the key to protecting the thin and tough dragonfly wings from breaking. People imitated the wing mole and designed a thickened part on the aircraft feathers, thus overcoming flutter and ensuring the safety of fast aircraft.