One-fourth of all animals are beetles
Beetles are the dominant form of life on earth: one of every five living species is a beetle, and one fourth of all animal species are beetles. Coleoptera is the largest order in the animal kingdom, containing a third of all insect species. Aristotle described beetles as insects with wing cases, thus Coleoptera, from the Greek koleon “sheath” and pteron “wing.” There are about 300,000 known species of beetles worldwide, 30,000 of which live in North America. Various species live in nearly every habitat except the open sea, and for every kind of food, there’s probably a beetle species that eats it. Beetles first appeared during the lower Permian period, about 240 million years ago.