It's no secret why people see more insects than any other animal; they outnumber us by 200 to 1. The name insect comes from the Latin insectum, which means "cut into sections." There are 900,000 known species of insects in the world today, but some scientists believe the species count could be as high as three million.
An insect is an animal that:
Although insects have multiple life stages which may not exhibit one or more of the above characteristics, these characterisitics will be present in at least one life stage, usually the adult stage.
In addition, insects:
Did You Know?
A spider is not an insect because it has a two-part body and eight legs.
For Students - What Do You Think?
Is a worm an insect? Is a ladybug an insect? Is a butterfly an insect? Is a snake an insect? Explain your answer.
With their 3-D vision (called stereopsis), barbed raptorial forelegs, and lightning fast reflexes, praying mantises are expert hunters.
At right: The first three pairs of legs on this monarch caterpillar will become the butterfly's legs;the last five pairs (called prolegs) are not present in the adult.
At right: The mason bee (Megachile inermis) sees with two large compound eyes (sides of head) and three small simple eyes, called ocelli (top center of head).
At left: Near its mandibles (jaws), this moth larva (Helicoverpa zea) has six pairs of simple eyes (called stemmata), which can only differentiate between light and dark.
The click beetle (Megapenthes limbalis) deploys a unique "click" mechanism to jump out of harm's way.