The Habits of Beetles
Beetles live in all parts of the world except in saltwater and the polar regions. Most varieties live on land; many are found in freshwater; and some are at home in either element. Beetles eat many kinds of animal and vegetable matter.The Colorado potato beetle eats leaves and can destroy crops.
Many beetles are destructive. Some feed on stored skins, furs, and woolens. The larvae of the carpet beetle damage rugs and carpets. May beetles and Japanese beetles devour the leaves of trees and crops. Some species bore into trees and deposit eggs. Other destructive beetles include the Mexican bean beetle, the sugarcane beetle, and various weevils.
Some beetles, such as the ladybugs, or ladybirds, are beneficial, since they destroy insects harmful to plants.
Beetles can be found in deserts, rain forests, grasslands, and freezing cold places. Beetles live on mountains, in lakes and streams, on plains, and in meadows. Beetles have adapted their bodies and their behavior to different climates and conditions. Beetles are great survivors. They were on the earth long before people were.
Some beetles camouflage (KAM uh flahzh), or cover themselves up, so that predators cannot see them. Cryptic (KRIHP tihk) beetles have bodies that blend into tree bark, leaves, and other parts of their environment. The darkling beetle you see here is one kind of cryptic beetle.
Most jewel beetles have bright, shiny colors. For some, these colors help attract their prey. Other jewel beetles have colors that fool their predators. For example, some have spots of bright color on their elytra that look like eyes. When they display their elytra, the “eyes” look right at the predator and startle it. This gives the beetle time to fly away to safety.
When it is trying to look like another insect, that’s when! This is called mimicry (MIM ihk ree). Mimicry is another weapon beetles use to keep predators away. They look and behave like other insects, such as ants, that predators know can fight back. Other beetles mimic flies and butterflies that are fast moving and hard to catch.
The wasp beetle has a long, tapered body that is yellow and black like a wasp’s. Another type of beetle looks like a bumblebee and will try to “sting” any animal that captures it. That should be enough to scare off even the bravest predator.
In its life cycle, a beetle goes through four stages—it begins as an egg, then becomes a larva, then a pupa, and, finally, an adult. This growth pattern is called a complete metamorphosis.
The female beetle lays her eggs where food is plentiful. After hatching, the larvae (grubs) resemble worms. As a larva grows, it sheds (or molts) its outer skin a number of times. The larvae of some species have protective coverings. When the larva of a tortoise beetle molts, its shed skin becomes attached to small prongs that hold the skin (and feces that the larva deposits on the skin) over the body like a shield.
The full-grown larva becomes a pupa, which does not eat or move about. The pupa slowly changes into an adult beetle, which then begins its search for food and a mate.
Some species of beetles produce several generations each year. Others require five years to complete their metamorphosis.