One out of every four animal species on Earth is a beetle.

Beetles belong to the order Coleoptera, which is the largest group in the entire animal kingdom. As of current biological records, scientists have described approximately 400,000 different species of beetles. This number represents roughly 40% of all described insects and 25% of all known animal species globally.The evolutionary success of beetles began over 300 million years ago during the Carboniferous period. One of their most significant evolutionary advantages is the development of elytra. These are hardened forewings that protect the delicate hindwings and the beetle's soft abdomen from predators and environmental hazards.The famous quote regarding an 'inordinate fondness for beetles' is attributed to the British evolutionary biologist J.B.S. Haldane. He reportedly made the comment in the 1940s when asked what could be inferred about the mind of the Creator from the works of Creation. This diversity is driven by their ability to exploit specialized ecological niches, from desert floors to freshwater ponds.Recent studies, including a 2015 report published in the journal 'Proceedings of the Royal Society B', suggest that beetle diversity is even higher than previously thought. Some researchers estimate there could be millions of beetle species still waiting to be discovered in tropical rainforests. Their adaptability allows them to feed on everything from dung and decaying wood to living plants and other insects.