Did you know there are over a million different kinds of insects, more than twice the number of all the other kinds of animals on Earth put together! Insects can be found everywhere on land and in fresh water. Some insects live at sea, in the driest deserts, in the icy Arctic, and a few insects are even found in Antarctica. Insects also live in any kind of human dwelling place, from grass huts to brick houses. No matter where you live or travel, insects are part of your world.
Why are these creepy, crawly creatures so plentiful? One big advantage they have is their small size. Because they are so small, they need little space and little food. Consequently, they can live where other creatures cannot. A single breadcrumb can provide a day's food for several ants. About 21 acres of land is needed to grow enough food for one person for a year, but the same space can feed more than a billion insects!
Another reason why insects are so successful is that they reproduce so rapidly. A single fly lays hundreds of eggs at a time. These eggs can hatch in as few as eight hours. In 3 to 6 days these flies are full-grown and capable of laying hundreds more eggs.
Although there are many different kinds of insects, all of them have a body structure that sets them apart from other animals. Insects are "hexapods." This name means "six-footed." All insects have three pairs of jointed legs.
Insects are alike in other ways, too. They all have a hard outer covering called an exoskeleton, to protect their soft organs inside. This is covered with a waxy, waterproof substance called chitin, to keep them from drying out.
Insect bodies are divided into three parts: the head, thorax (middle), and abdomen (rear). On every insect's head is a pair of antennas, or feelers. Along each side of an insect's body is a row of tiny holes, called spiracles, through which they breathe air. Branching tubes carry the air to all parts of their bodies.
It is easy to tell insects from other animals. But there are many differences between various insects. Insects differ from one another in shape, size, and color. Beetles, grasshoppers, and butterflies certainly don't look much alike. Insects also have different lifestyles. Some insects such as bees, ants, and termites live together in large colonies. Other insects lead solitary lives.
Most insects have wings, but some kinds of insects, such as fleas and silverfish, have no wings. Some of the winged insects have two pairs of wings, while others have only one pair. Insect wings may be transparent as with dragonflies, or covered with brightly colored scales, as in moths and butterflies. Some wings are made for carrying insects over long distances, while others are used only for short, quick flights from danger. While flying is the usual insect way of getting about, you may also see insects crawling, hopping, swimming, jumping, or walking.
Most insects, but not quite all, have two big eyes made up of hundreds of smaller ones. These are called compound eyes. Compound eyes detect movement much better than they make out shapes.
Some insects have special organs. Insects that make sound, like grasshoppers and crickets, have organs of hearing. These are located either on the front legs or in the first segment of the abdomen. Some insects have special glands that produce poisons. Other insects have special organs, such as stingers, to defend themselves.
Insects have different types of mouths depending on what kinds of foods they eat. Mouthparts of insects are either one of two types: jaws used for chewing, or tubes used for piercing and sucking. Leaves, plant sap, nectar, blood, wool, wood, and other insects are all insect food.
Some insects go through four stages as they grow. For example, a butterfly is first an egg. The egg hatches into a caterpillar, or larva. The caterpillar grows, sheds its skin several times, and at last forms a case around itself. It is now called a pupa. The pupa then changes into a butterfly.
A grasshopper, on the other hand, is never a larva. When it hatches from an egg it looks just like a grown-up grasshopper except that it does not have wings. It sheds its skin several times, grows wings, and finally reaches its full size.
Many insects are experts at hiding from their enemies. Camouflage keeps them from being eaten. For example, a walking stick mimics a tree branch. If threatened, the walking stick freezes and is barely visible. Have you ever tried to catch an insect? Many insects are quick escape artists.
There are many insect pests. Mosquitoes bite us. Ants and cockroaches eat our food. Caterpillars, grasshoppers, and beetles eat plants and food crops. Moths eat clothes. Carpet beetles eat woolen rugs. Silverfish eat books. Termites eat the wood in our houses. Flies and fleas transmit disease.
Not all insects are harmful, however. Some are true helpers. Bees, wasps, moths, and other insects are important pollen carriers. Many products that we use are made by insects. Silkworms make silk. Bees make beeswax and honey. Carmine, a red food coloring, is derived from cochineal scale insects. Fast-breeding insects help scientists study genetics and biological change. Insects are also an important source of food for other animals such as birds and fish. Some beneficial insects prey on insects that are harmful to food and flower crops.
Types of Insects
It is amazing how many varieties of insects there are. Scientists have grouped the hundreds of thousands of kinds of insects into big groups called orders. The chief orders are shown below. The scientists' names for many of these orders end in "ptera." "Ptera" comes from a Greek word meaning "wings." (Thus, lepidoptera means scaly wings, diptera means two wings, and so on.)
Insects or Bugs?
Many people call any kind of insect a bug. True bugs, however, are a specific kind of insect. They have two pairs of overlapping wings (leathery forewings and transparent underwings), and a pointed snout with sucking mouthparts. There are chinch bugs, squash bugs, stink bugs, and cone-nosed bugs.
Is it an Insect, or Not?
Which of these creepy crawlies are insects and which ones are not? Spider, Fly, Scorpion, Bee, Centipede, Ladybug, Earthworm, Caterpillar, Millipede, Grasshopper, Snail, Silverfish, Sowbug, Wasp, Slug, Moth, Tick, Lice. Check your answers at the end of this article.
While we see insects outside all the time, it can be fascinating to examine them up close. A net can be used for catching winged insects or for scooping up water insects. Make your own "bug jar" by adding bits of the insect's environment to a wide-mouthed jar. Be sure to poke holes in the lid or cover the jar with a mesh screen or cheesecloth, to allow air in and keep the insects from escaping. Return the creatures to their home after a brief visit. As an alternative, be on the lookout for insects whose life cycles have ended. To catch insects at night, take a large white cloth (like an old bed sheet) and hang it, shaping the bottom into a funnel, over an empty jar. Position a light so it shines on the cloth. Insects will fly into the cloth and slide down into the jar.
Katydid Insect Museum
Located at 5060 W. Bethany Home Road in Glendale, this museum features all kinds of insects and arachnids, both native and exotic. Visit their website at www.insectmuseum.com or call 623-931-8718 for more info or to arrange a field trip. Open on weekdays only; admission is $0 - $3.
Recommended Videos, Books & Websites
A BUG'S LIFE (G) - An entertaining computer-animated view into the miniature world of insects.
MICROCOSMOS (G) - Spectacular close-up photography reveals a breathtaking view of dueling stag beetles, ants gathering food, the transformation of a caterpillar to a butterfly, the birth of a mosquito, and other tiny miracles of the insect world.
INSECTS (A GOLDEN GUIDE), by Herbert S. Zim and Clarence Cottam. (Classic guide to the most common, important, and showy North American species, with maps showing their ranges.)
INSECTS DO THE STRANGEST THINGS, by Leonora and Arthur Hornblow. (An easy-to-read book featuring stranger-than-fiction true stories about some of the things that insects do.)
JOYFUL NOISE: POEMS FOR TWO VOICES, by Paul Fleischman. (A Newbery Medal book; read these poems aloud with a partner, and make the different insects come to life.)
THE ICKY BUG ALPHABET BOOK, by Jerry Pallotta. (The lighthearted text and vivid illustrations make this alphabetical exploration of insects both informative and entertaining.)
WHAT'S INSIDE? INSECTS, by Dorling Kindersley. (Describes and illustrates the anatomy of a beetle, honeybee, caterpillar, fly, cricket, ladybug, butterfly, and stick insect for young children.)
ZOOBOOKS: INSECTS & INSECTS 2, by John Bonnett Wexo. (Beautiful close-up photographs, informative text, and activities.)
(Answer - The insects are: Fly, Bee, Ladybug, Caterpillar, Grasshopper, Silverfish, Wasp, Moth, Lice.)
ARTICLES & REVIEWS |
NOT JUST FOR KIDS |
These pages are a continuous work in progress.
These pages are a continuous work in progress.