The United States will welcome 30 billion cicadas, and cicada warnings have been issued in the eastern region. As for why cicadas hibernate for 17 years, neither the Internet nor scientists have given an accurate answer. At present, there are two most reliable theories. One is that in order to avoid natural enemies, cicadas climb the ground in fixed years and die after reproducing; the other is that in order to prevent species from interbreeding, each cicada appears in different years.

The 13-year cicada and the 17-year cicada are common in North America. Relevant scientists have divided them according to the year. There are group numbers 30 in a ***, among which numbers 1 to 17 are 17-year cicadas, and numbers 18 to 30 are 13-year cicadas. The reincarnation cycle of this cicada is very strange. Whether 13 or 17 are both prime numbers, many scientists can't figure it out. 1. 30 billion cicadas emerge from the ground

A large number of cicadas emerge from the ground in the United States every year, and it is said that there are tens of billions of cicadas every year. 2021 is no exception. The eastern United States has issued an early warning, reminding people that 300 cicadas will emerge from the ground and that they must take precautions in advance.

Despite their large numbers, cicadas do not cause much impact. Generally speaking, cicadas only live on the ground for about half a month to a month, and they die after breeding. In addition, cicadas themselves are not considered pests. The biggest impact is their cicadas, which may make people unable to sleep at night. People living in rural areas should be accustomed to this. 2. Two views

Many people think that the life span of a cicada is only one month. In fact, this view is wrong. The so-called 13-year cicada or 17-year cicada, 13 and 17 are their life cycles. Only in the final stages of their lives do they choose to crawl to the ground to reproduce.

As for why this special number was chosen, scientists gave two explanations. First, in order to avoid natural enemies, choose to appear when there are the least natural enemies and the ground temperature is 18 degrees Celsius. At present, this statement is believed by most people and is also the most widely circulated. The second is to avoid species hybridization. Different cicadas will appear in different years so that everyone doesn't get together.

At present, these two statements are theoretical speculations without accurate basis. 3. There are almost no cicadas in China

This kind of long-term dormant cicada only exists in North America and can even be said to be unique. In China, most cicadas are annuals and their life cycle is only one year. The reason for this situation is that there are fewer natural enemies. In our lives, there are only some common birds, and lizards are basically invisible. In this case, they simply reproduce every year.

Although there are few natural enemies in China, some people like to eat it. In the early days, they were just rural people, and in summer they would catch cicadas. With the popularity of fried cicadas, many restaurants and restaurants have launched similar meals. in the country, there are even cicada farmers.