Locust belongs to Insecta Acridoidea, commonly known as grasshopper or grasshopper. There are many kinds of locusts, including more than 4500 species. The longest part of a locust's body is its hind foot, which is almost the same as its body length. It can jump out of its body eight times as long in one jump. The hind foot of a locust is also its best musical instrument, and it can make a sound by rubbing its wings.
Its adults have a pair of developed jaws, mainly eating grass, especially like to eat gramineous plants, such as rice, wheat, sorghum, corn and bamboo leaves. Gramineous weeds are dense here, which is a vast wasteland and an ideal habitat for locusts. Where locusts swept, Gramineae plants were eaten up, and almost everything it could bite was spared. Swarms of locusts can turn green land into wasteland. Locusts are good at flying and jumping, and a pair of tentacles in the head are organs that combine smell and touch. Its chewing mouthparts have a pair of developed jaws with teeth, which can bite off the stems and leaves of plants. Its hind foot is very strong, and it mainly depends on it when jumping. When locusts fly, their hind wings play a major role, and when they rest, their front wings cover their rear wings for protection. The female insect has a strong "ovipositor" at the end of her abdomen, which can be inserted into the soil to lay eggs. Locust spawning sites are mostly wet river banks, lakes, foothills and ridges. Every 30 to 60 eggs are grouped together. Immature locusts hatched from eggs are called "locusts" and need to molt five times to develop into adults. A large number of eggs can be hatched after the rain clears. Locusts also have amazing flying ability, which can fly continuously 1~3 days. When locusts fly by, the sound of swarms of locusts flapping their wings is amazing, just like the roar of a storm in the ocean.
The life of locusts begins with fertilized eggs. The larvae just hatched from eggs have no wings and can jump, which is called jumping insects. The flea is similar in shape and living habits to adults, but smaller in size and immature in reproductive organs, so it is also called nymph. If an insect grows up gradually, it will shed its original exoskeleton when it is restricted by the exoskeleton and can no longer grow up. This is called molting. Nymphs molt five times in their lives. From hatching to molting for the first time, the age is 1, and every molting thereafter, the age increases 1. After the 3rd instar, the wing buds are remarkable. Become a flying adult after 5 years old. It can be seen that the individual development process of locusts goes through three stages: egg, nymph and adult. A developmental process like this is called incomplete metamorphosis. When an insect develops from a fertilized egg to an adult, it can produce the whole individual development history of its offspring, which is called the first generation. Locusts can produce two generations of summer locusts and autumn locusts a year in some parts of China, so there are two generations.
People have long noticed that serious locust plagues are often accompanied by serious droughts. There is a record of "drought locust" in ancient books in China. In recent years, several major locust plagues in Africa are also related to the severe drought in the region. The main reason for this phenomenon is that locusts are warm and dry insects, and the arid environment has many benefits for their reproduction, growth and survival. Because locusts lay eggs in the soil, the soil is relatively solid, and the water content is 10% ~ 20%, which is most suitable for them to lay eggs.
Drought makes locusts multiply and grow rapidly, and there are two reasons for the disaster. On the one hand, in dry years, due to the drop of water level, the soil becomes more solid, the water content decreases, the ground vegetation is sparse, and the number of eggs laid by locusts increases greatly, reaching 4000-5000 eggs per square meter of soil in many cases, with 500-80 eggs in each egg block, that is, 200,000-400,000 eggs per square meter. At the same time, in dry years, the water surface of rivers and lakes shrinks and the low-lying land is exposed, which also provides more suitable places for locusts to lay eggs. On the other hand, plants that grow in arid environment have low water content, and locusts feed on it, which makes them grow faster and have higher fertility.
On the contrary, the rainy and humid environment has many adverse effects on the reproduction of locusts. The plants eaten by locusts have high water content, which will delay the growth of locusts and reduce their fertility. Rainy and humid environment will also make locusts epidemic diseases, and rain and snow can directly kill locust eggs. In addition, the increase of natural enemies such as frogs will also increase the mortality rate of locusts.