The insect world explored
What do most people think of when you mention”insects”? Well, they may think of pests, such as flies, mosquitoes, moths, and beetles. Or they may think of ants and bees and wasps; and attractive insects like butterflies. And then if you ask if they can think of any other insects, they might be able to think of a few more.
But do you know how many different kinds of insects there actually are? Get ready for a surprise. There are somewhere between two and four million different kinds of insects! Scientists have actually described in scientific language as many as 625,000 different kinds. They practically have no hope of ever being able to classify every single kind of insect that exists. There is no other class of animals on earth that even comes close to having as many kinds as so insects.
When it comes to trying to estimate how many insects are living in the world today, the number is so vast that the human mind cannot imagine it! The only way scientists can even begin to count the insect population in any one area is to count all the insects that can be found in and on a square meter of rich, moist soil. That can be anywhere from five hundred to two thousand. So it can be said that in a single hectare of good soil, about eight million insects live in cozy comfort!
Remember that if you, who are untrained in observing insects, were to go over this hectare and count insects, you would see only an occasionally butterfly, bumblebee, or beetle. But the majority of insects are so small that the human eye does not readily notice them. Many are microscopic. And there are only a few thousand insects of all those that exist that become annoying enough to man for him to try to control them.
When you think of it this way, you realize that man really moves about in a world of insects but he has no idea that most of them exist or how many there are!
By the way, there are two things most insects have in common: their body is divided into three parts; and they usually have six legs. This is true of most, but not all of them.
As we look at living creatures much smaller than ourselves, many of us imagine that they must lack organs and functions that we have. How can something as tiny as an insect have a heart? How can it have a circulatory system and blood in its tiny body?
But the miracle of life is not only that these creatures have organs, but that these organs are perfect for each insect’s way of life.
Adult insects have bodies with three sections: head, thorax, and abdomen. The head has a pair of antennae in front that are feelers, and that usually have some tiny organs of smell. The eyes and mouth are part of the head, too.
Not only does an insect have a hearty, but it also has blood and a circulatory system. The blood passes into the heart by means of holes equipped with valves. When the heart contracts, these holes close, and the blood is driven out the through the arteries. Insects don’t have a system of capillaries and veins as we do.
The reason their circulatory system is not greatly developed is that they don’t depend on the circulation of the blood for their supply of oxygen. In our bodies, as you know, the blood carries oxygen to every part and enables it to function. But insects have s different system of breathing. They have tiny branching tubes that end in little air holes in the sides of the body. The air comes in right from the surface of the body and goes directly to the cells.
A more complicated system would be too much for their size. On the other hand, a simple system like theirs wouldn’t be enough for larger animals. It’s not too bad a system, though, considering that more than half of all lining animals have it! Did you know that one name for an insect is hexapod? The term is from two Greek words meaning “six” and “foot”. If you count the feet of an insect, you can see why hexapod is a good what to describe most insects. The legs are usually in three pairs, and are attached to the thorax.
There are thousands and thousands of different species of insects, among them some of man’s best friends as well as some of his worst enemies.