Relations of Man to Insect World.—But Few Species Useful to Man.—Little Trace of Domestication.—Honey-bees: their Origin; Reasons for no Selective Work; Habits of the Species.—Silkworms: Singular Importance to Man; Intelligence of Species.—Cochineal Insect.—Spanish Flies.—Future of Man relative to Useful Insects.

Although the relations of man to the insect world are prevailingly those of hostility, there are a few of these multitudinous creatures which have been more or less completely adopted into his great society. Although not more than half a dozen out of the million or more species in this subkingdom have thus been brought to the uses of civilization, the forms are interesting not only for what they give, but for the promise of further contributions when this great problem of winning help from the insect world receives adequate consideration.

As a whole, the insects are not well fitted to serve the needs of man. Owing to certain peculiarities in their organic laws they, fortunately for ourselves, are very limited in size. Although some of them afford savory food and are occasionally eaten by savages, and even by civilized folk when pressed by hunger owing to the famines which the invasions of these animals occasionally produce, they can never be of any value as sources of provisions, except through the stores which they accumulate in the manner of the bees. All that we have won, or are likely to win, from this realm is from the filaments which the creatures spin, the wax or honey which they accumulate, the coloring or other matters which their bodies afford, or the help which they may give us in our struggle with invading species of their class.

Probably the first insect to be brought into friendly relations with man was the honey-bee. This creature, like the most of our domesticated animals, is a native of the great continent of the Old World, though it has now been conveyed to all the flowery lands of the world where the season is long enough for it to win its harvest. In its wild as well as in its tame state the honey-bee dwells in one of the most perfect and highly elaborated of insect societies. It is a member of the group of membranous-winged insects known to naturalists as Hymenoptera, an order which includes all the elaborate societies of the class except the colonies of white ants. It is characteristic of all these colonial insects that, from the experience of ages, they have learned the great principles of the division of labor and of profit sharing towards which mankind are now clumsily stumbling; the great work which their societies are able to do is accomplished by a complete specialization of function and a perfect share in the commonwealth. So far has this elaboration gone, that in the bees the work of reproducing the kind is allotted to forms which do no labor; all the work of the hive being effected by individuals which are sterile, and whose sole function it is to toil unendingly for the profit of the great household.

While the greater part of the kindred of the bees either construct the nests for their young in the manner of our wasps or hornets, building them entirely in the open air, or excavate underground chambers in the fashion of our bumble-bees, our domesticated form at some time in the remote past adopted the plan of choosing for its dwelling-place some chamber in the rocks, or cavity in a hollow tree which could be shaped to the needs of a habitation. Owing to the size of these cavities, they were enabled to form societies composed of many thousands of individuals; while the species which adopted nests, in other conditions, were much more limited as regards their numbers. Thus the bumble-bee, which abides underground, dwells in very small communities, probably for the reason that the conditions of the soil it inhabits make it difficult to excavate and maintain large rooms. It is this habit of resorting to hollow spaces, as well as the instinct to store up honey in wax cases, which has made the common bee valuable to man.

At best the opportunities which the wilderness affords, in the way of fit dwelling-places for the swarm which goes forth from a hive, are much less than can readily be provided by art. In almost all cases the wild bees have to expend a great deal of labor in searching for a fit residence; and after such is found it requires a great deal of toil and expenditure of the costly wax in order to shape the cavity so that it may comfortably accommodate the multitude, and be reasonably safe from the attacks of other insects. Thus it has come about that the bee has, in a way, welcomed the interference of man with his ancestral conditions; and, though the species exists in the wildernesses of its native land, the domesticated varieties have so far taken up with man that in other countries they do not wander far from the limits of civilization. Now and then an uncared-for swarm which cannot find accommodations about the parent hive will betake itself to the wilderness; though it generally continues to seek sustenance from the abundant flowers of the tilled fields where it finds species, such as clover and buckwheat, from which it has been long accustomed to win the harvest of pollen and honey.

In North America the honey-bees, which were brought by the early settlers, and which had been kept on the frontier by the pioneers of our civilization, have always extended, in wild swarms, a little distance into the wilderness. But, at most, they appear to have wandered only for a few miles beyond the homestead, going no further away than would permit their use of the cultivated plants. The aborigines early learned to regard the insect as the avant courier of European men. When they came upon an individual of the species they always knew that some white man's dwelling stood nearby. Those who are familiar with the solitudes of our Appalachian forests must often have remarked, in the stillness of a summer day, the hum of a swarm from some forest or domestic hive in its search for a dwelling-place. Those who have followed up the movements of these migrating colonies have had a chance to perceive how long is the search before they find a fit abiding place. Doubtless by far the greater part of these searchers for a home fail of their quest, and the wandering swarms perish without finding a suitable shelter.

In certain kinds of woods, as, for instance, those occupied by pine trees or other species which do not develop spacious hollows in their trunks, and where there are no crannied rocks—all the swarms which seek habitations there are foredoomed to destruction. If by chance the colonies wander too far, they generally find the wilderness so ill provided with plants which may furnish them with the sources of wax, honey, or other necessaries, that they cannot maintain their life. Thus it is that the bee, though domiciled with us rather than domesticated, has become united in its fortunes with civilization. In this position they have shown a remarkable adaptation to extremely varied conditions. They can withstand any climate which permits the development of the vegetation to which they need have access, provided the growing season continues long enough to accumulate their store. In the tropical lands they harvest so little honey that they are not profitable to man, and in the high north they need all their summer's accumulation to maintain them through the long winter. Thus, though they may range almost as far as man through the gamut of climates, they are profitable to their masters only in the middle latitudes. They commonly do not do well close to the sea, and cannot be kept on inconsiderable islands for the reason that they are, in their wanderings, likely to be lost in the waters.

The bee, like the other social insects, evinces a wide range of instincts which are intimately related to the economy of the hive; but these motives appear to be of an unchangeable character. They show no tendency to undergo the modifications which we observe to take place in our birds and mammals when they are brought under the influence of man. The only case in which they show any distinct effect from their contact with man is found in their evident recognition of those who care for them. They soon learn that their master is not to be feared, and, therefore, need not be resisted; but, beyond this dumb acceptance of a situation, they exhibit no trace of sympathetic recognition of our kind. It is clear that their mental endowments, though considerable, are very much more remote from our own than are those of the vertebrated animals with which we have formed a friendly association. Moreover, the type of life of the creatures in a way excludes them from any kind of share in human society. Each of them is, from its birth to its death, entirely devoted to the interests of its little commonwealth. Every impulse of their being relates to the economy of their hive. While we know little about instinct, we know enough of its manifestations to state that the real unit of this species is not the individual insect, but the colony to which it belongs. The separate form is hardly more than a bit of machinery so arranged that it may operate at a distance from the engine of which it forms a part. On this account it appears to be impossible for us ever to attain to any kind of sympathetic relations with these creatures.

Even more important than the bees are those insects which, in their immature state, yield us silk. The so-called silkworms, like the bees, originated in Asia, and have long been in the care of man. Beginning their experiments in spinning with the wool of animals and the various accessible vegetable fibres, men have ever been seeking materials which could serve them in the weaver's art. At one time or another they have tried an exceeding variety of materials; in modern days more than a score of insects have been experimented with in the endeavor to obtain fibres which could be turned to use. So far, however, the Bombyx mori—the form which, as its specific name indicates, feeds upon the leaves of the mulberry tree—is the only one which proves really serviceable. The advantages of this species are found in a peculiar assemblage of qualities, each of which is necessary to make it fit for the ends it attains at the hand of man.

The mulberry silkworm can readily be bred in confinement. The eggs are easily gathered and preserved, and are so readily kept that they may be sent the world about. At a given temperature they with infrequent failures hatch; and if sufficiently fed with the fresh leaves of the mulberry, will in a short time attain to as perfect a development as though they grew, not in close rooms, but in the open conditions of the trees. When of adult size, the grubs proceed to spin themselves in, forming a thick cocoon composed of threads of a material which, though as soft as paste when emitted from the body, hardens so as to form a strong and even thread. If the insect be allowed to remain for a sufficient time in the cradle which it has spun for its second birth, the body within the chrysalis case will proceed in a manner to dissolve; and in the milky fluid thus produced, where only faint traces of its former state remain, the beautiful image or perfect form will arise. In the economic use of the creature, however, except as far as a supply of eggs may be desired, it is necessary to prevent the completion of its development; for in escaping from the chrysalis case, the butterfly cuts many of the delicate threads, so that the silk is made unserviceable. It is necessary to wind it off before the insect escapes. In this part of the work we notice the most perfect adaptation of the creature to the needs of man. While the silk threads from the cocoons of other species which might prove of value cannot be easily reeled off, those of the silkworm, when placed in hot water, readily separate, and can be gathered in a condition for spinning. Thus, while some success has been attained by carding the cocoons of other species, thereby making a fibre which has a certain utility, the silkworm alone yields material fitted for delicate fabrics.

The Farmer's Apiary