Beetles: Facts, Identification & Control

Beetles belong to the insect order Coleoptera. This is the largest order of insects. There are more than a quarter of a million species of beetles in the world. In North America scientists have identified more than 25,000 beetle species.

Sometimes people mistake cockroaches for beetles. If the beetle is an adult, it can usually be identified by looking at the wings. Most adult beetles have two pairs of wings. The back wings are used for flying. They stay folded on the insect’s body when it is not flying.

The front wings are called elytra. These front wings are often very hard. The beetle folds the front wings so they cover the back wings. Most adult beetles seem to have a line down their back where the two front wings meet. Beetles come is many shapes. Some, like the click beetles, are long and slender. Some beetles like lady beetles and June beetles (also known as June bugs) have an oval or rounded shape. There are even beetles that resemble spiders.

Beetles Life Cycle

Beetles develop in a four-stage life cycle. Scientists call this a Complete Metamorphosis. The stages are Egg, Larva, Pupa, and Adult. The length of the life cycle also varies according to the type of beetle. Some beetles develop very quickly and they can produce more than one generation each year. Others, like the wood-boring beetles can take several years to develop from an egg to an adult insect. The length of the life cycle also depends on the amount of food that is available for the larvae to eat.

Beetles feed on many different plant and animal materials. Adult beetles often deposit their eggs near the food that the larvae will eat when they come out of the eggs.
Some beetles are destructive pests. Carpet beetle larvae eat natural fibers and feathers. They often damage woolens and other fabrics. Other beetles, like the Lyctidae, feed on hardwoods and bamboo. These pests attack furniture and other items made of wood.

Some, like the flour beetles and the grain beetles, attack food products in homes. They also damage food in production facilities and stores. Some beetles damage lawns and landscapes. Immature June beetles, called grubs, attack the roots of grass. The elm leaf beetle damages trees by eating the leaves.

Many beetles are beneficial insects. The lady beetle (often called ladybug) feeds on plant pests like aphids and mealybugs. Gardeners appreciate these beetles and try to keep them in the garden.
Sometimes beetles, including lady beetles and ground beetles, can become nuisances. In the late summer and fall, homeowners can find hundreds of these beetles clustered on the outside of the home. The beetles are trying to invade homes for shelter through the winter.

Types of Beetles

American Spider Beetle
The American Spider Beetle is shiny and reddish brown to almost black. When viewed from above, it resembles a spider.

Asian Lady Beetle
The Asian Lady Beetle is a small and round-to-oval insect. They are usually red or orange, but they can be yellow, brown, or black.

Cigarette Beetles
The Cigarette Beetle is often light brown. These beetles fly and can “play dead” for a few seconds if they are disturbed.

Dried Fruit Beetle
The Dried Fruit Beetle is a small oval black insect. It has two amber-colored spots on its wings and its legs or antennae are often reddish or amber.

Drugstore Beetle
The Drugstore Beetle is small brown and oval shaped pest that is typically about 1/10″ long. They have been known to infest many household items such as cereal, spices, books, leather and more.

Elm Leaf Beetle
The Elm Leaf Beetle is only about 1/4″ long. They are yellow to olive colored and have a dark band on the outside of each wing.

Flour Beetles
Flour Beetles are about 1/8″ long and are reddish brown. They are common in homes and grocery stores and are often found in flour and cereal products.

Foreign Grain Beetle
Foreign Grain Beetles are reddish brown. These beetles are often found in homes and businesses that have moisture or fungus problems.

Larder Beetle
Larder Beetles are usually black and have a yellow band across their wing covers. There are also several dark spots in the yellow area.

Plaster Beetles
Plaster Beetles are very small and less than 1/8″ long. They range in color from yellowish brown, to reddish brown, to almost black.

Sawtooth Grain Beetle
Sawtooth Grain Beetles have flat bodies and are about 1/10″ long. They have six tiny projections on each side, just behind the head.

Shiny Spider Beetle
Shiny Spider Beetles are small insects that range in size from 1/16″ to 1/8″ as adults. They are often dark red or black.