Duane Wilkum, age 10, of Milwaukee, Wis.., for the question:
How many different insects are there?
Some 670,000 different insects have been named and classified. Imagine a parade of these small creatures hopping, crawling or flitting past you at the rate of one every six seconds, just long enough for you to get a good look. This parade could go on for longer than 46 days and nights without you seeing the same insect twice. And it would include only those insects so far classified. New ones are being discovered and named at the rate of about 5,000 each year.
The experts who study insects are called entomologists. Some entomologists estimate that so far we have tabbed only a third of the different insects in the world. This estimate would put the total number of different insects at about two million. Other estimates suggest that we have only classified about one tenth. We cannot give a definite number but we know for certain that there are countless more insects in the world waiting to be classified.
The insects belong in the Arthropoda Phylum of animals ‑ the joint‑footed ones. They form the huge class Insecta of this Phylum ‑ the largest of any class of animals. To be classed an insect an animal must have six legs and a segmented body in three clearly defined sections. He must have a head, a chest or thorax and an abdomen. These rules apply onl7 to the adult insect and not to the various caterpillar and pupa stages.
The huge class Insecta is broken down into 26 orders. The insects in each order have certain features in common which other insects do not have. The name of the order gives a clue to these features. The order Coleoptera. means sheath‑wings. It is the order of the beetles, whose hard front wings form a sheath over the body. There are a quarter of a million different members of the Coleoptera order.
The order Lepidoptera means the scaly‑winged ones. Under the microscope the lovely wings of the moth and the butterfly are seen to be composed of tiny scales. Lepidoptera is their order. The ptera part of this long word means wings and it occurs in several of the insect orders. Dermaptern, meaning skin‑wings, is the order of the earwigs and their kin. Diptera, two‑wings, is the order of flies, A true fly has but two gauzy flying wings. Grasshoppers, crickets and mantids belong in the Orothptera, or straight‑winged, order.
There are some 7,000 different members of the Lepidoptera order in North America alone. An order is subdivided into families for convenience in classifying. There are 80 family units in Lepidoptera, 75 families of moths and five of butterflies.
When fully classified each different insect is in his own order, his own family and his own genus, He is then given a species name, an individual name of his own. The house fly is rated in the order Diptera, the family Muscidae and the genus Musca. His species name is domestica and his proper scientific name is Musca domestica.