Nowadays, when night falls, those mosquitoes will still fly in the sky in the countryside, but the former insect catcher dragonfly can't see it. So what is the reason for the decrease of dragonflies in rural areas? There are four reasons:
First of all, in the past, ponds, canals, rivers and other places in rural areas were breeding places for dragonfly larvae. At that time, the ponds in the village were all ownerless, and villagers could bathe and wash clothes there. Later, with the development of rural aquaculture, the ponds in the village were contracted to individual aquaculture.
Farmers will put a lot of fish fry and shrimp fry in the original pond, and the density is also very high. It stands to reason that there will be no conflict between reproduction and dragonflies, but the larvae of dragonflies need to reproduce in water, and now the density of fish and shrimp in the pond is very high, and those dragonflies larvae become the food of fish and shrimp in the pond before the adults fly away.
This is equivalent to killing the goose that lays the golden egg. Dragonflies have just laid eggs, but before hatching adults, the fish and shrimp in the pond are completely eaten, which also causes the space for dragonfly larvae to grow to be squeezed.
Second, although there are still some rivers, ponds and reservoirs in rural areas, these have not been contracted by local farmers. But it also faces many problems.
After 1990s, with the increasing use of plastic bags in rural areas, several garbage bags are produced every day. In the past, there were no garbage dumps in rural areas, and there was no special person to regularly clean up the domestic garbage in the village. For the treatment of this kind of garbage, many villagers dump it in ponds, rivers and other waters in the village in order to save trouble.
The consequence of this is that the water quality is polluted. Dragonfly eggs can only breed in clean rivers. If the water quality is polluted, the breeding space of dragonflies will be squeezed.
Thirdly, I don't know if you have noticed that dragonflies sometimes bump into their own windows or the glass of cars parked on the side of the road. For this phenomenon, the elderly in rural areas are also very puzzled. In their memory, dragonflies don't do such "stupid things". Some superstitious people think this represents something. What does dragonfly want to tell people?
In fact, this phenomenon appears because glass is as transparent as water, and dragonflies are not smart. They are blind. For this modern craft glass, they are mistaken for ponds. Dragonflies hit the glass, but in fact they just want to "water" it. Dragonflies actually lay eggs.
Just glass is glass. Although they are transparent, they are not water. This practice of dragonflies is undoubtedly tantamount to "suicide". As long as you pay attention, you will find that after the dragonfly hits the glass, there will often be a transparent little wings that falls nearby, and even the dragonfly's body will be found. This shows that the widespread use of rural glass is also one of the reasons for the decrease of dragonflies.
Dragonflies are beneficial insects. They have a strong ability to catch mosquitoes and moths, and most people like dragonflies. But some people like dragonflies in another way, and that is to eat them. Usually no one eats adult dragonflies, but in some rural areas, the pupae and larvae of dragonflies have the custom of eating this food.
The larva of this dragonfly is a kind of hydra, which is called water scorpion in some local dialects. According to related books, the dragonfly larvae are rich in protein, which is higher than the pork we often eat, so the price sold in restaurants is also very expensive.
Some people are greedy for profits. In order to make a profit, they will catch dragonfly larvae in the water and sell them to restaurants or eat them themselves. Therefore, the reproduction of dragonflies is destroyed, and a large number of dragonflies are captured, which makes it impossible to complete the reproduction of the next generation, which will naturally reduce the number of dragonflies.