How, in your opinion, can explain such a variety of insects?

The variety of insects can be explained by their habitat. From an evolutionary point of view, all insects have adapted to changes in their environment. Some developed wings to cover great distances, some settled in the ground. Most insects have a color similar to the area in which they live, some, on the contrary, have a bright color, which warns of their toxicity. Predatory insects, such as a spider, can make nets to catch prey, and a grasshopper has long, strong legs that help quickly avoid danger.