The vital activity of earthworms has a beneficial effect on the environment. They make the land more fertile by pushing nutrients deeper into the soil. And under the influence of some factors, worms can be seen in large numbers on the surface after rain.
One of the reasons for the appearance of worms on the surface after rain can be called a change in soil temperature, to which these creatures are very susceptible. After rain, it usually drops by a few degrees. Most species of worms live deep underground, since a temperature that is warm enough and comfortable for their life always prevails under the layers of soil. Another possible cause is a change in the acid-base balance. After precipitation occurs, the soil becomes more acidic, which negatively affects the worms and encourages them to crawl to the surface to avoid mass extinction. In addition, it is believed that during rain in some types of soil a high concentration of cadmium is formed, which can also affect the behavior of worms. The next reason for the appearance of these creatures on the surface after rain is associated with the phenotypic variability of nature, that is, inconstancy. Because of this, such types of worms arise that cannot stay in the water for a long time. Lack of air is also considered to be one of the reasons for the appearance of worms on the surface after rain. Some can lead normal life only when there is a sufficient content of oxygen in the earth, and the water just enriches the upper layers of the soil with it. Another reason why worms crawl to the surface lies in the behavioral structure of animals. There is a version according to which, after rain, worms behave in this way, as they simply follow most of their relatives. One of the simplest reasons for the abundance of earthworms on earth is their relationship to moisture. Scientists believe that these creatures appear on the surface in order to enjoy moisture. Other animals, for example, isopods, behave in the same way in the rainy season.
