This further segmentation is usually best seen on the abdomen.

They may not mate at all if they do not perform the precopulatory ritual.

A few species of beetles are ectoparasitic on mammals. Instead, they’ll weasel their way into your home to escape the oncoming winter, buzz around your light bulbs for a while, then drop dead before spring. Another Old English name for beetle is ceafor, chafer, used in names such as cockchafer, from the Proto-Germanic *kabraz- (compare German Käfer).

Most beetles, however, do not cause economic damage and many, such as the lady beetles and dung beetles are beneficial by helping to control insect pests. The heaviest beetle, indeed the heaviest insect stage, is the larva of the goliath beetle, Goliathus goliatus, which can attain a mass of at least 115 g (4.1 oz) and a length of 11.5 cm (4.5 in).

In the Permian-Triassic extinction event at the end of the Permian, some 30% of all insect species became extinct, so the fossil record of insects only includes beetles from the Lower Triassic 220 mya. Longhorn beetles (Cerambycidae) and weevils have divided eyes, while many have eyes that are notched, and a few have ocelli, small, simple eyes usually farther back on the head (on the vertex); these are more common in larvae than in adults. For example, the tansy beetle walks between habitats despite being physically capable of flight. During the Jurassic (210 to 145 mya), there was a dramatic increase in the diversity of beetle families, including the development and growth of carnivorous and herbivorous species. Anoxia tolerance in the adult Carabid beetle Pelophilia borealis was tested in laboratory conditions and it was found that they could survive a continuous period of up to 127 days in an atmosphere of 99.9% nitrogen at 0 °C.

Most recent plant-eating beetles feed on flowering plants or angiosperms, whose success contributed to a doubling of plant-eating species during the Middle Jurassic.

However, the increase of the number of beetle families during the Cretaceous does not correlate with the increase of the number of angiosperm species. Copulation is generally quick, but in some cases lasts for several hours.

Anoxia tolerance in the larvae may have been sustained by switching to anaerobic metabolic pathways or by reducing metabolic rate.

Beetles are prominent in human culture, from the sacred scarabs of ancient Egypt to beetlewing art and use as pets or fighting insects for entertainment and gambling.

Moisture harvesting behavior by the Namib desert beetle (Stenocara gracilipes) has inspired a self-filling water bottle which utilises hydrophilic and hydrophobic materials to benefit people living in dry regions with no regular rainfall. Some species of beetle have evolved immunity to insecticides.

Some elateriform larvae of click beetles are known as wireworms. Predatory ground beetles (Carabidae) and rove beetles (Staphylinidae) began to distribute into different patterns; the Carabidae predominantly occurred in the warm regions, while the Staphylinidae and click beetles (Elateridae) preferred temperate climates. The Australian Dung Beetle Project (1965-1985), introduced species of dung beetle to Australia from South Africa and Europe to reduce populations of Musca vetustissima, following successful trials of this technique in Hawaii. These crawling worms are 1/4-inch long with bristly tufts of hair and yellowish white and brown alternating horizontal stripes. African carabid beetles (for example, Anthia and Thermophilum - Thermophilum is sometimes included within Anthia) employ the same chemicals as ants: formic acid.

about 1 a day in the house, usually around the stairs, landing area but has also been seen in other areas.

The fogstand beetle of the Namib Desert, Stenocara gracilipes, is able to collect water from fog, as its elytra have a textured surface combining hydrophilic (water-loving) bumps and waxy, hydrophobic troughs.

During copulation, sperm cells are transferred to the female to fertilize the egg. For example, the Colorado potato beetle, Leptinotarsa decemlineata, is a destructive pest of potato plants. Myxophaga contains about 65 described species in four families, mostly very small, including Hydroscaphidae and the genus Sphaerius.