The occurrence of locust plague is both a natural disaster and a man-made disaster, which has certain regularity. Natural disasters refer to global warming, uneven drought and flood, abnormal river flow and other factors that easily lead to large-scale reproduction of locusts; Man-made disasters refer to grassland degradation caused by poor management and inadequate climate monitoring. Multiple factors lead to locust plague. 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.

Extended data:

The main reasons for the rampant locusts are:

1. The main locust species that form plague have the physiological and ecological characteristics of fast reproduction, more reproduction, more offspring, wide feeding range, large food intake and strong transmission and migration ability. There are two or four generations of migratory locusts in East Asia a year. After mating, adult females can lay eggs several times per generation. Generally speaking, locusts can lay 4-5 eggs in a lifetime, with a maximum of 12, 50-80 eggs per egg, with an average of 300-400 eggs.

2. The egg mass of desert locust contains 20 ~ 100 eggs, and the dispersed female locust can produce 120 eggs. Social type can produce 1000 per square meter. It should also be pointed out that both oriental migratory locust and desert locust can parthenogenesis, that is, female locusts can lay eggs without mating. Young turtles are all females, and adult turtles can mate and lay eggs or continue parthenogenesis. There are about 20 species of edible plants of Locusta migratoria manilensis, with a lifetime food intake of 60-80g, and the adult food intake is 3-7 times that of midges.

3. All midges can be dispersed in a short distance, and social adults can also migrate in a long distance. The migration distance of desert locusts can reach 1500 ~ 5 100 km, and flight experiments show that desert locusts can fly continuously17 hours. For example, the eggs of Italian locust in Xinjiang can reach 140 /0.5 m2, and those of Siberian locust can reach 486/m2. The adults and adults of these two kinds of locusts also have the habit of flying together.

References:

Baidu encyclopedia-locust plague