These invertebrates are distinguished, in the adult stage, by a body consisting of three segments, head, thorax and abdomen, with six legs, a pair of feelers and generally two or four wings. Insects develop in one of two different ways. The transformation from egg to larva, to pupa and then finally to adult, as in the case of butterflies and moths, is termed complete metamorphosis. Other insects, such as the locusts, pass through only three stages (incomplete or gradual metamorphosis); the nymph hatches from the egg and after a series of successive molts the change to adult insect is complete.
The picturesque language of the Bible refers to insects as ‘going on all fours.’ Obviously Moses was familiar with the fact that insects have six legs. So the reference is undoubtedly to their mode of travel rather than to the number of their legs. There are winged insects, including the bees, flies and wasps, that walk with their six legs in the manner of four-legged animals. Other insects, such as the locusts, are equipped with two leaper legs and thus literally use the other four legs for crawling.—Lev. 11:20-23.
The more than 800,000 known varieties of insects present a panorama of contrast. While some are somberly colored, others are arrayed in bright hues and with beautiful designs. All the shades of the rainbow are represented. In size, insects vary from beetles that are small enough to get through the eye of a needle to curious “walking sticks” that measure more than a foot (c. .3 meter) in length. Among the insects can be found organized communities, builders, agriculturists, manufacturers, long-distance fliers, expert jumpers, swimmers and burrowers. Through study and observation man can learn much from the insects, most importantly that they are God’s creations, endowed with instinctive wisdom, not by chance, but by the Source of all wisdom, Jehovah.—Job. 12:7-9.
Although many are inclined to view insects as pests that damage crops and man’s possessions as well as spread disease, actually only a very small percentage of insects can be designated as harmful under present circumstances. The majority can be termed either as neutral or as directly or indirectly beneficial to man.
Even insects that attack trees and other plants are not always injurious but may be performing a valuable service. In Australia, for instance, the prickly-pear cactus rendered millions of acres of land practically unsuitable for agriculture. But this circumstance changed within a few years, chiefly because of introducing a variety of moth whose caterpillars mine the joints of this cactus. Then, too, the pruning of trees resulting from the activities of certain forest insects benefits man in contributing to better-quality lumber, reducing the fire hazard and making the forest more suitable as a home for wildlife.
Insects stand in an important relationship to plants. It has been estimated that 85 percent of flowering plants are either completely or partly dependent on insect pollination. Besides the honeybee and bumblebee, flies, beetles, moths, butterflies and other insects carry out this important function.
Insects also play a beneficial role as soil builders and scavengers. Dead plant and animal matter attracts many insects that help to break this down into different chemical combinations that can be used again as food by succeeding plant generations. The subterranean tunnels of insects aid water passage, capillary action and soil aeration. Their excreta and, eventually, their dead bodies fertilize the soil. The thickness of the rich topsoil is increased as insects continually bring up particles of subsoil to the surface.
Man has been able to use insects directly in research and to some degree in medicine. Dyes and shellac are produced from scale insects. In the Near East, insects, such as locusts, have for centuries been used as an item of diet. Were it not for the existence of insects, honey and natural silk would be unknown.
Then there is the good that insects perform in destroying, either as predators or parasites, other insects that are presently harmful to man. Besides the insect-eating insects, there are many birds, freshwater fishes, reptiles and small animals that now largely depend on insects for their food. Hence the disappearance of insects would place the life of these creatures in jeopardy.
Insects indeed occupy an important place in relation to the rest of the earthly creation. Observed Carl D. Duncan, professor of entomology and botany: “It is not too much to say that insects determine the character of man’s world to a far greater extent than he does himself, and that if they were suddenly to disappear completely the world would be changed so extensively that it is extremely doubtful that man would be able to maintain any sort of organized society whatever.”—Annual Report of the Smithsonian Institution, 1947, p. 346.
For the insects mentioned in the Bible see ANT; BEE; CATERPILLAR; COCKROACH; CRICKET; FLEA; FLY; GADFLY; GNAT; GRASSHOPPER; LOCUST; MAGGOT; MOSQUITO; MOTH.