Which arthropod group is the most diversified animal group

Question

Which arthropod group is the most diversified animal group of the planet? How can this evolutionary achievement be described?

Answer 1

Insects are the animal group with most variety of species. Nearly 750000 insect species are recognized, around 55 percent of the total already cataloged species of living-beings (as compare with mammals, with no more than 4000 recognized species). It is evaluated however that the number of unknown species of insects might be over 2 million. The insect population on the planet is predicted to be more than 10 quintillion (1000000000000000000) individuals.
The huge evolutionary success of insects is due to factors like: small size and alimentary diversity, forming possible the exploration of numerous distinct ecological niches; wings which give more geographic spread; the tracheal respiration which gave them motor agility; high reproductive rates with production of big numbers of descendants.