Although most beetles can fly, they generally do so only to move among low vegetation. They fly heavily and steer poorly. Often, as is the case with lady beetles, they have to climb to an elevated vantage point for a successful takeoff. Though some types of beetles (the tiger beetles or metallic wood-borers, for instance) are able to burst into flight rapidly when threatened, most others require lengthy preparations before becoming airborne.

Since beetles are cold-blooded, their body temperature is usually insufficient to permit the wing muscles to move rapidly enough for flight. So the beetle must raise its body temperature by vibrating its wings. This pumps air into the body and expends metabolic energy. Right after takeoff, the heavier beetles hang almost vertically in the air and only become more horizontal as top speed is reached. Beetles fly with between 30 to 90 wingbeats per second. The elytra are held diagonally erect, and act as gliding surfaces and stabilizers; the work of flying is done by the elastic hind wings (alae).

Chewing mouthparts with well-developed mandibles allow beetles to eat a broad range of materials. They are known to eat leaves, bark, dung, and other insects as well as man-made fabrics. Some beetles are predators, some are herbivores or scavengers, and some are parasites. Beetle larvae, called grubs, can be predacious or herbivorous and sometimes cover themselves with protective shelters. All grubs have biting mouthparts. Most species produce only one generation a year, mating in spring and summer.

Read our article on the Asian Longhorned Beetle, Anoplophora glabripennis.

Some beetles attack plants and stored foods, while others are beneficial as pollinators of flowering plants and predators of other insect pests. Ladybugs and lightning bugs and fireflies are all well-known misnamed insects; they are all beetles. The familiar huge brown June bug, often seen bumping against the porch light on summer nights, is a beetle. The infamous boll weevil, bane of cotton farmers throughout the United States, is a beetle.

The Asian Longhorned beetle is a newly introduced species to North America; its discovery in New York State and near Chicago Illinois in the late 1990's necessitated the destruction of thousands of trees in order to stop its spread. The bombardier beetle mixes volatile chemicals in a special combustion chamber in its abdomen and blasts would-be attackers with hot, toxic gases. The examples of fascinating (and destructive) beetle behavior and appearance makes them some of the most studied insects on the planet.