No other group of animals on Earth is more successful than insects. There are over one and a half million known species of animal on this planet, with more being discovered daily. Of the 1.5 million + species, over 1 million of them are insects. In other words, there are twice as many kinds of insects as there are species of all other animals on the planet, combined.
Further, it is believed that there are about 10 million species of animals on Earth, counting those that haven’t been discovered yet. Of those, 9 million are suspected to be insects.