Seeing as there's about 400,000 species of beetle it's no wonder they come in a variety of sizes and shapes, ranging from 0.3mm to 17cm, and are perhaps one of the most diverse species on the planet.
Most beetles, though, are at the diminutive end of the scale. The average size across all known beetle species is a fraction under 7mm
At an implausible 0.3mm long, the Bolivian feather-wing beetle, Scydosella musawasensis, could scurry around quite happily within this letter ‘O’. It is smaller than many single-celled animals.
At the other end of the spectrum, the huge Brazilian longhorn, Titanus giganteus, is one of the largest beetles in the world, reaching nearly 17cm and will only just sit in the fully extended palm of your hand; if goaded, it can break a pencil in its jaws. This gives a size differential of at least 130 million times.
Other giants include the shorter but bulkier goliath beetles (Goliathus) of Africa, at up to 11cm, and the elephant beetles (Megasoma) of South America, which reach nearly 14cm. But unlike the more familiar mammalian giants, such as whales, whose life in the oceans has allowed them to evolve supermassive size, aquatic beetles are much smaller than their terrestrial counterparts.
The biggest water beetle ever found – the ducal, Megadytes ducalis, of Brazil – is only 5cm long. This is for complex reasons, to do with the need for diffusional gas-exchange gradients across small-bodied organisms that lack central lungs, heart and haemoglobin-based blood systems to transport oxygen.
Did you know there's a beetle species named after The Beatles?
Main image: A red-brown longhorn Beetle © Getty Images
