Wikijunior:Bugs/Beetle
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[edit] What does it look like?
Beetles belong to the order Coleoptera. There are about 350,000 named species. They are an amazingly large and varied group of insects. Beetles living in the tropics can be up to 5-1/8 inches long. Smaller species are less than 1/16 inch in length. Many have bright colors or iridescent hues. Some have bold dots, stripes, and unusual patterns. The vast majority, however, are somber shades of brown and black. Their shapes can be rounded or long and thin. The Stag Beetle has “antlers” and the Horned Fungus Beetle has bumps.
Diving Beetles are usually brownish-black or dark green with smooth, oval bodies. They can be large or small, ranging in size from 1/16 inch to 1-5/8 inches long. Some are equipped with hind legs that can be converted into paddles for swimming. Most water beetles move their legs alternately, but Diving Beetles flex their hind legs together simultaneously, using them as oars. They have a chamber that holds trapped air so they can breathe underwater. Their sickle-shaped jaws are very strong and are often used to attack prey larger than themselves.
Small Flat Diving Beetles are only about ½ inch long. They have an oval, flattened brown-colored body with brownish-yellow markings. A fringe of golden yellow hairs widens and flattens the surface of the hind legs so they can be used as paddles. Most beetles have bodies that are similar to each other in structure. They generally have a hard covering called an exoskeleton. Numerous plates provide armored defense and flexibility. The body is divided into three sections: the head, the thorax, and the abdomen. They have large prominent compound eyes. Beetle antennae may be threadlike or clubbed.
Beetles have chewing mouthparts with well-developed jaws called mandibles. They have wings and most can fly. They belong to the order Coleoptera which means “sheath wings.” The name refers the elytra that cover and protect the wings. When the beetle is resting, the elytra usually meet in the middle of the back. They often have bright colors or patterns.
[edit] Where does it live?
North America is home to over 3,000 species of the Carabidae family known as Ground Beetles. They can be found in dark, moist places under logs, rocks, and leaves, in gardens and in grain fields. Bombardier Beetles are found throughout the United States and southern Canada. European Ground Beetles are found in New Jersey, Wisconsin, Oregon, and British Columbia.
Predacious diving beetles belong to the Dytiscidae family. Small Flat Diving Beetles live in ponds, and weedy margins of slow streams and rivers. They range from southern Canada to northern United States. Large Diving Beetles live in ponds, pools, streams, and rivers. They are found throughout North America. The Marbled Diving Beetle is found in the southwestern United States and Mexico.
[edit] What does it eat?
Beetles have kept their primitive mouth parts designed for chewing solid foods, so their diet is broader than other kinds of insects. Some beetles are “generalists,” eating both plants and animals. Others are limited in what they can eat and have highly specialized diets. Many beetles feed only on a single kind of plant. Some are able to eat and digest solid wood. Others eat resin or drink sap—some beetles don't eat solids and drink only the liquids of plants, trees, and fruits.
Ground Beetles are carnivores and eat small prey such as earthworms and snails. Certain Scarab Beetles eat dung and Carrion Beetles eat dead animals. Clown Beetles eat the larvae of other insects.
[edit] How does it defend itself?
Beetles have various defense strategies, including camouflage, mimicry, and poison. Using camouflage, beetles blend into their surroundings to hide from predators. Mimicry is the use of color or shape to deceive enemies by appearing to be another animal. Many Longhorn Beetles look like wasps, even though they are harmless. Some beetle species give off distasteful or toxic substances. Others spray acidic gas from their abdomen to repel predators.
The beetle’s soft body and membranous wings are protected by the elytra, the front pair of wings. The elytra are thickened into hard covers which fold back to make an effective shield.
[edit] What stages of metamorphosis does it go through?
Beetles undergo complete metamorphosis with an immature larval stage and a pupal stage. Larvae (grubs) are often worm-like and lack compound eyes. They usually have biting mouthparts. They can be predacious or vegetarian. Wings develop internally during the juvenile stages.
The last resting stage before the final molt is called a pupa. Pupae do not feed and are usually relatively inactive. They are vulnerable to predators and parasites. The pupal case is shed when the adult beetle is ready to emerge.
Beetles mate in spring or summer. Most species produce one generation a year. Some may produce as many as four.
[edit] What special behavior does it exhibit?
Scarab Beetles push or roll balls of dung to their brood sites. It is thought that this behavior inspired the design in Egyptian art showing the Scarab Beetle pushing the sun along its course in the sky.
Although most beetles have a hard time righting themselves when turned upside down, the Click Beetle does not. It has a special mechanism on the underside of its body to help it spring into the air to right itself. It is named for the clicking sound it makes when doing this.
Many beetles make noises by tapping on hard surfaces or by rubbing parts of the body together. These beetles seem to have better hearing than beetles that do not make such sounds.
Burying Beetles are known to hide small animal carcasses from mammalian scavengers. A small dead animal, such as a mouse, supplies food for a whole brood of larvae that a pair of beetles will care for together.
[edit] How does it affect people?
They are among the most important of the insect recyclers. Many beetle species are decomposers that feed on dung or dead plants and animals. Ladybird beetles eat aphids and other insects that harm crops. Ground Beetles feed on Potato Beetles that ruin potatoes in the field.
Beetle pests cause millions of dollars in damage to plant products and sometimes transmit disease. Woodworm beetles can eat furniture and wood floors.
lucianae and dynastine are used for fighting as they have horns,they are sold at high prices in the far-east and south-eastern asia.
[edit] References
Milne, L. & Milne, M. (2003). National Audubon Society field guide to North American insects and spiders. NY: Alfred A. Knopf.
Newton, B. (2005). Stag beetles. [1]
Raven, P. H. & Johnson, G. B. (1999). Biology, (5th Ed.). Boston, MA: WCB/McGraw-Hill.
Thomas, J. (2001). Beetles. In Nature’s children. (Set 7). Danbury, CT: Grolier Educational.
Zim, H. S. (1987). Insects, A guide to familiar American insects. NY: Golden Press, NY.
