Is there any pattern in the occurrence of locust disasters?

The occurrence of locust disasters is both a natural disaster and a man-made disaster, and it has certain regularity. Natural disasters refer to factors such as global warming, uneven droughts and floods, and abnormal river flows that can easily lead to large-scale locust reproduction; man-made disasters refer to grassland degradation caused by poor management and inadequate climate monitoring. Multiple factors lead to locust disaster outbreaks. There are records in ancient Chinese books that "there are locusts in the extreme drought". Several major locust plagues in Africa in recent years have also been linked to severe local droughts. The main reason for this phenomenon is that locusts are insects that like warm and dry conditions. Dry environments have many benefits for their reproduction, growth, development and survival. Because locusts lay their eggs in the soil, the soil is relatively solid and has a moisture content of 10% to 20%, which is most suitable for them to lay eggs.

Extended information:

The main reasons for the rampant locusts:

1. The main locust species that caused the plague have fast reproduction speed, multiple reproduction and offspring , wide feeding range, large appetite, strong dispersal and migration capabilities and other physiological and ecological characteristics. East Asian migratory locusts have two to four generations in a year. After male and female locusts mate, adult females can lay eggs several times per generation. Generally speaking, locusts can lay 4 to 5 eggs in their lifetime, with a maximum of 12 eggs, 50 to 80 eggs per egg, and an average of 300 to 400 eggs.

2. The egg mass of desert locust contains 20 to 100 eggs, and the number of eggs laid by female locusts after dispersion can reach 120. The gregarious type can produce 1,000 per square meter. It should also be pointed out that both East Asian migratory locusts and desert locusts can parthenogenetically reproduce, that is, female locusts can lay eggs without mating. The hatchlings are all female, and the adult turtles can mate and lay eggs or continue parthenogenetic reproduction. There are about 20 kinds of food plants for East Asian migratory locusts, and their lifetime food intake is 60-80g. The food intake of adults is 3-7 times that of locusts.

3. All nymphs can disperse within short distances, and gregarious adults can also migrate long distances. The migration distance of desert locusts can reach 1,500 to 5,100 kilometers. Flight experiments show that desert locusts can fly continuously for 17 hours. For example, the eggs of Italian locusts in Xinjiang can reach 140 eggs/0.5 square meters, and the eggs of Siberian locusts can reach 486 eggs/square meters. The adults and adults of these two types of locusts also have the habit of gathering and flying.

Reference: Baidu Encyclopedia-Locust Disaster