Of course, due to the great damage of human activities to the natural environment, including the reduction of green space, chemical pollution, the reduction of water area, and some people killing their larvae and selling them to people who regard them as food, the species and quantity of dragonflies are decreasing sharply, which is very regrettable.
It can be said that in my life of more than half a century, especially in my childhood, dragonflies are my favorite insects, none of them.
-It can kill pests.
Both adults and larvae of dragonflies feed on mosquitoes, flies, leafhoppers, moths, butterflies and flies. Adults prey in the air and larvae prey in the water. Of course, sometimes it eats the weak. It is said that a horsehead dragonfly can eat nearly 1000 small flying insects a day. A dragonfly can eat 40 flies or 840 mosquitoes in 1 hour. A dragonfly larva can eat more than 3000 mosquito larvae a year.
-Very talented.
It is said that there are 5000 kinds of dragonflies. There are many kinds of dragonflies, with beautiful colors, such as red, yellow, blue, purple, green and orange. All the colors are novel and dazzling.
There are big and small. The small ones I saw are about several inches long, the big ones are five inches long, and the common ones are about two to three inches long.
They are very light, and their flying posture is smart and beautiful. The posture of male and female mating is also so elegant. It looks like a water ballet with tail water movements (Dufu language: water dragonflies fly slowly), which is charming and moving. When it flies in the air in large groups, it is as innocent as a group of little fairies. The most amazing thing is the two big eyes on its round head, which are shiny and radiant. When resting on branches, they always turn around. Sometimes under the sunlight, its thin wings will give off colorful light.
-It's super capable.
Dragonfly's flying speed is amazing, it can fly 5? 10 meter, it can reach 40 meters per second when sprinting, and it can fly continuously 1 hour without rest. After all, flying hundreds of kilometers is not a problem.
When it flies, its wings can vibrate 30-50 times per second. It can fly at various angles or upside down. It just keeps flying, catching prey in flight.
Its compound eye can measure speed. When the prey moves in front of the compound eye, each "small eye" reacts in turn, and after processing, the moving speed of the target object can be determined, so as to lock and track the prey.
It is said that it is the hunter with the highest success rate in the animal kingdom, far higher than lions, tigers and leopards. In 100 hunting, it can catch its prey 95 times.
-It can forecast the weather.
When it is about to rain, some insects fly low to catch insects because of the low air pressure and high air humidity, but when the weather is good, they fly higher. Therefore, according to long-term observation experience, people have obtained the linear relationship between the flying height of dragonflies and the weather, just like swallows. When I was in the meteorological station of Hongjiang Xingfu Road Primary School, the meteorological teacher took us to the suburbs to observe the situation.
-It inspired poets and poets' poetic sentiment.
For example, Han Wo in the Tang Dynasty described dragonflies in detail: "The eye of jasper, the wing of mica, is lighter than a butterfly and thinner than a bee. Sitting in the waves for a long time, is it diligent? " In the Song Dynasty, Yang Wanli described dragonflies with poems: "Spring eyes are silent and precious, and the shade of trees loves sunny and soft." Xiao He only has sharp horns, and there are dragonflies standing on his head. " Zhu Xuanxian, a modern artist, created a vivid image in his Chinese painting Xiao He Cai Lou Jiao Jian.
-is a childhood playmate.
At our age, many people have experienced playing or catching dragonflies in childhood, which has brought us endless fun. Even as an adult, when I go to the countryside, I always look for dragonflies and take photos of them as a souvenir.
I remember when I was a child, my friends and I often went to streams, ponds and fields to watch dragonflies and see how they flew and caught insects.
From the observation, we know that a relatively small yellow dragonfly likes to fly and hover in groups; Blue, red, colorful, big people like to fly together, even alone. Big dragonflies are hard to see, and they pass by like comets in the air.
I don't know how dragonflies catch bugs in the air, but I know how to eat them. Look, it stops on a twig. The eyes moved a few times, and it suddenly flew straight. When it came back, there was a fly in its mouth. Then, it stopped on a twig, folded its wings slightly, chewed its prey slowly and tasted delicious food.
The most addictive thing is catching dragonflies. We have several capture methods.
One is to grasp by hand. Reach out and climb up from behind it. When your hand is an inch or two away from it, you suddenly reach out your thumb and forefinger and hold its tail or wings. There are many failures in this method, because it is too smart, it will bite people at the same time, and it will hurt to bite your fingers with your small mouth, so you still dare not grasp it with your hands.
The second is to sweep or net with dense bamboo branches to deal with groups of dragonflies.
The third is to catch it with cobwebs. Make a racket with a long bamboo pole in front, and then find a spider web to wrap around the racket, which becomes a spider web that can be taken away. Cover the dragonfly when you see it. The dragonfly can't escape because its wings are stuck.
The fourth is to wrap the spider web into a small ball with the top of a long bamboo pole, and then use this ball to stick dragonflies. My favorite is this one. It's interesting to catch dragonflies with it. The ball made of cobwebs should be very sticky, so it is best to look for cobwebs in the morning, because cobwebs are still very sticky at that time. When sticking dragonflies, keep your hands steady, your eyes accurate and your movements light. After you see it, quickly point the ball at the dragonfly's back, so that its wings are stuck, and no matter how hard you struggle, you can't throw it away. This method is more useful for those especially alert dragonflies and big dragonflies that are rarely seen.
The dragonflies I catch are mainly eaten by domestic chickens, or used to tease ants, or tied with strings to let them fly and play. Now it seems that this is an act of hurting beneficial insects, which is a bit cruel, but it was indeed a kind of play at that time.
I'll stop here about dragonflies. I hope that at present and in the future, the actions to protect the natural ecological environment can achieve the expected results, restore a good living environment for dragonflies and slow down their extinction. After all, it is an important part of the biological chain, and human beings should cherish it.
Written in He Cheng June 2022 17.
Information:
Dragonflies, invertebrates, Insecta, Odonata, Heteroptera. Generally, the body is large, the wings are long and narrow, and the membrane veins and reticular veins are extremely clear. Have compound eyes, extremely sensitive vision, 3 eyes; Antenna 1 pair, thin and short; Chewing mouthparts. Dragonflies are the insects with the most eyes in the world. Dragonfly's eyes are big and bulging, occupying more than half of its head. Each eye is made up of countless "small eyes". These "small eyes" are connected with photoreceptor cells and nerves, and can distinguish the shape and size of objects without turning their heads.
Dragonflies usually fly in ponds or rivers, and larvae (larvae) develop in water. Predatory, adult preys on flying insects. Mosquitoes and other harmful insects, but they have a wide range of feeding habits, so they can't be used to control some pests. There are no more than 5000 known species.
Larvae breathe through gills. Usually, when the prey approaches, it will shoot a lip that can wrap the prey. During the development process, the molting is 8 ~ 15 times, and the molting times within and between species are different, and there is no pupal stage. A few minutes after hatching, the sheath-like epidermis of the first instar larvae splits, releasing the spider-like second instar larvae, and the first instar larvae feed on aquatic animals such as crustaceans and protozoa. Later larvae eat mosquito larvae, water beetles, snails and even small fish. Wing buds appear in the early stage and grow with the increase of molting times. By the last age, adult organs have been formed in the body. A few days later, the larvae climbed out of the water, molted and emerged into adults (emergence). The biggest dragonfly usually leaves the water after sunset and takes off before sunrise, so it is rarely seen. Smaller species appear during the day. The newly emerged adult has soft body, immature reproductive system and imperfect color. One of its first activities was to fly out of the water. The life span of adults is divided into two stages: the first stage, about 2 days to 2 weeks, varies with species and climate; The other is the reproductive period, about 1 ~ 6 weeks. In the first stage, feed actively and stay away from water. The second stage begins with sexual maturity, when dragonflies fly to mating places (usually ponds and rivers, where they can lay eggs). The male bird arrived earlier, occupied a certain position on the river bank or water surface, defended his territory like a bird, and drove away other invading males. If a female bird flies near or into the field, the male will try to mate with it. Some species courtship before mating.
The mating posture is unique. The male holds the female's head or chest with the gripper at the end of the abdomen, and through its action, induces the female to bend the abdomen forward and touch the copulatory organ at the base of the male abdomen. When mating, land on the ground, but it can also be done in the air. Mating time varies from a few seconds to several hours. Females lay eggs immediately after mating, or after several hours or days. There are two ways to lay eggs. Developmental ovipositors lay eggs in or on water or aquatic plant tissues, and some climb to the surface to lay eggs, which can be soaked in water for more than 1 hour. Species without ovipositors wash eggs to the surface from the end of abdomen. There are several kinds of running water spawning, but there are attachment or winding devices to prevent them from being washed down. Adults need a warm climate, food suitable for spawning and water to reproduce. Fish and birds will prey on dragonfly larvae, and larvae will devour each other. When it appears, it may be preyed by birds and small crocodiles. However, after leaving the emergence scene, the adults are almost harmless, flying quickly and flexibly, and can avoid almost all enemies. Most species in temperate regions overwinter with larvae, the larval stage can reach 1 ~ 5 years, and the life span of adult stage is only a few weeks.
The eclosion adults have different colors, and the chromaticity varies from metallic color to pink. Compared with other insects, it is huge. Some species have a wingspan of 16 cm (about 6 inches), and even the smallest species has a wingspan of 2 cm (0.8 inches). Besides being extremely agile flying animals, they are also one of the fastest insects. Dragonfly wing muscles can only function best when it is warm, but if the weather is cool, this insect often expands its wings to generate heat before taking off. Dragonflies' speed and agility make them the most efficient flying predators. The prey is usually flying insects, but some dragonflies often eat 60% of their own weight.
Young dragonflies-called larvae, semi-metamorphosed through incomplete metamorphosis, sometimes called larvae-are aquatic animals and special predators in water, just like adults in the air. Functional wingless larvae are usually mottled or dull in color, just like sediments or aquatic plants in their living environment. Their prominent eyes are similar to those of adults, but they have amazing anatomical structures that adults do not have. This is called "mask", which is the fusion of the third pair of mouthparts of larvae. Masks are disproportionately large and are placed under the head and throat when not in use. At the end of the mask is a set of toothed clips, which are used to catch worms, crustaceans, tadpoles, small fish and other prey. Different kinds of dragonfly larvae are called creeping insects, burrowing insects, hiding insects or trapping insects-their body shape, metabolism and respiratory terminal depend on their micro-habitat.
Larvae crawl out of eggs in or near water, and there are three ways to lay eggs. Some species lay eggs in plant tissues, while others attach eggs to the bottom or top of surface water. Eggs may also fall from the abdomen or be washed into the water. Larvae use gills in rectum to draw oxygen from water. Water is sucked into the abdomen and then pressed out through the anus. Water may be forcefully discharged in this way, thus creating an escape method of jet propulsion. Solid waste is also discharged in this way. As the larva grows up, it will shed its skin, and about half of its future wings will first become obvious during the growth of the larva. Then, these wing sheaths increase rapidly in the subsequent molting process. Finally, the larvae climb out of the water (sometimes at night), shed their skin for the last time and become adults, leaving a layer of skin (molting shell), which is the shell of the body in the past.
The mating of dragonflies also takes place in flight. Male dragonflies grasp the neck of female dragonflies with hooks at the end of abdomen; The female dragonfly's abdomen bends from bottom to front, connecting the reproductive hole with the sperm storage organ below the second section of the male dragonfly's abdomen, and then the male dragonfly is fertilized.
teacher
Dragonflies, without feathers, are thin and transparent enough to share the world with birds of flesh and blood.
Dragonflies fly much better than birds.
Dragonflies are more similar in shape to airplanes created by humans.
Dragonflies used to be a big family and the closest one to us. It shuttles and stops freely on the road and in the countryside. Once upon a time, it also played hide-and-seek with the little urchins in the country.
Dragonflies are beautiful and lovely! Dragonflies are simple and hardworking!
Dragonflies try their best to "lay eggs" in a trembling posture. This reproductive instinct continues, and it is so rhythmic and wonderful. That kind of painting and poem is inadvertently created between mountains and rivers, and any praise will be inferior to it. Therefore, we should completely rehabilitate the traditional "dragonfly water".
Unfortunately, our good wishes will probably become empty talk, which reflects the lack of human morality!
You see, with the rapid growth of human beings, the species of Dragonflies are dying out one after another or dying out ... How many dragonflies are left dancing with us in our living area? You can still see several dragonflies hovering above us. Poor dragonflies, they died tragically in the magic weapon "pesticide" used by human beings to control pests. Can the surviving dragonflies spend too many teenagers in a harsh environment?
If the butterfly dies, there are moths as close relatives. Moth is a kind of insect, the vitality of which is particularly strong, and our human "pesticides" are helpless against it. This worm seems to be getting more and more deadly. If the dragonfly dies, it seems that nothing can replace it. As far as its wings are concerned, the dragonfly's wings are unique, and the grasshopper's wings look similar, but the shape and flying skills can't be compared with dragonfly's. Only dragonflies can be regarded as replicas of human planes.
Grasshopper and mantis hide in the grass, jumping and crawling for a short time, and the shape, quality and color of their wings are very different from those of dragonflies. Cicada's wings are most similar to dragonfly's, but its short and thick posture is far less slender and beautiful than dragonfly's. The meanness and ugliness of mosquitoes and flies should not be compared with dragonflies. Only this dragonfly, flying silently in the light from morning till night, can withstand the heat of the sun, and does not need to drink water or drink tea. Camels living in the desert should also bow to it.
The mating diagram of dragonflies is an extremely wonderful and awe-inspiring geometric figure. The arc formed by the two tails has a simple Hyunri and mystery. Parallel wings are the most tacit combination given to them by the creator. They can fly up and down in pairs, slide forward and sprint left and right, which is impossible for us humans to imitate.
Sadly, dragonflies die gloriously in batches under the arrogance of human beings, and their poisoning and extinction again and again are inseparable from their contribution to catching mosquitoes. The big team of dragonfly family could have competed with ants, but now it is rarer than birds, which is really heartbreaking!
In my small collection cabinet, there is a precious dragonfly specimen: tentacle dragonfly.
The biggest feature of tentacle dragonfly is that its head has a pair of tentacles almost as long as its body, which are hard, straight forward and spread out in a figure of eight. I clearly remember that when I caught it on the mountain, I was blushing all over, smaller than the common dragonfly, and looked like the "beauty" of the dragonfly country.
I have collected this tentacle dragonfly for ten years. I used paper and scotch tape to position it in a transparent plastic box. The secret is to use camphor tablets to protect its glorious image and its intact body and quality. I am also a member of mankind, and I have committed a deep sin against it. I have the right to write a few words as our confession and commemoration!