The impact of cicada number is mainly due to the increase in the use and cost of pesticides in rural areas this year. But the life span of cicadas is not affected by these factors after they break through the ground. After they come to this world, it is the natural environment that can affect their life. In nature, summer and autumn, the weather is often changeable. They often go through three days of exposure and three days of thunderstorms. This kind of "ice-fire blending" day makes their bodies quickly become brittle and then die. Cicadas that can live for two months often inadvertently find an environment that is extremely suitable for their own survival, which is extremely rare.