If we hold with Mr. Wallace that the chief difference between man and the lower animals is that of kind and not of degree—that man is possessed of an intelligent will that appoints its own ends, of a conscience that imposes upon him a "categorical imperative," of spiritual faculties that apprehend and worship the invisible—yet we must admit that his lower animal nature, which forms, as it, were, the platform of the spiritual, is built up of lower organisms.
If we hold with Professor Allman that thought, will, and conscience, though only manifesting themselves through the medium of cerebral protoplasm, are not its properties any more than the invisible earth elements which lie beyond the violet are the property of the medium which, by altering their refrangibility, makes them its own—then the study of the exact nature and properties of the transmitting medium is equally necessary. Indeed, the whole position can only be finally established of defining experimentally the necessary limitation of the medium, and proving the inefficiency of the lower data to account with the higher.
It is these considerations of the wider issues that give such a peculiar interest to the patient observations which have recently been brought to bear upon the habits of the social insects, especially of ants, which, living in communities, present so many of the conditions of human life, and the development of the "tribal self" from these conditions, to which Professor Clifford attributed the genesis of moral sense.
In order to pass in review these interesting observations and bring out their significance, I must go over ground which is doubtless familiar to most of my readers.
The winged ants, which often excite surprise, are simply the virgin queens and the males. They are entirely dependent upon the workers, and are reared in the same nest. September is the month usually selected as the marriage season, and in the early twilight of a warm day the air will be dark with the winged lovers. After the wedding trip the female tears off her wings—partly by pulling, but mostly by contortions of her body—for her life under ground would render wings not only unnecessary, but cumbersome; while the male is not exposed to the danger of being eaten by his cannibal spouse, as among spiders, nor to be set upon and assassinated by infuriated spinsters, as among bees, but drags out a precarious existence for a few days, and then either dies or is devoured by insectivorous insects. There is reason to believe that some females are fertilized before leaving the nest. I have observed flights of the common Formica rufa, in which the females flew away solitary and to great distances before they descended. In such cases it is certain that they were fertilized before their flight.
When a fertilized queen starts a colony it proceeds much in this way: When a shaft has been sunk deep enough to insure safety, or a sheltered position secured underneath the trunk of a tree or a stone, the queen in due time deposits her first eggs, which are carefully reared and nourished. The first brood consists wholly of workers, and numbers between twenty-five and forty in some species, but is smaller in others. The mother ant seeks food for herself and her young till the initial brood are matured, when they take up the burden of life, supply the rapidly increasing family with food, as well as the mother ant, enlarge the quarters, share in the necessary duties, and, in short, become the real workers of the nest before they are scarcely out of the shell. The mother ant is seldom allowed to peer beyond her dark quarters, and then only in company with her body guard. She is fed and cared for by the workers, and she in turn assists them in the rearing of the young, and has even been known to give her strength for the extension of the formicary grounds. Several queens often exist in one nest, and I have seen workers drag newly fertilized queens into a formicary to enlarge their resources. As needs be, the quantity of eggs laid is very great, for the loss of life in the ranks of the workers is very large; few survive the season of their hatching, although queens have been known to live eight years. (Lubbock.)
The ant life has four well marked periods: First, the egg; second, the grub or larva; third, the chrysalis or pupa; fourth, the imago, or perfect insect. The eggs are small, ovate, yellowish white objects, which hatch in about fifteen to thirty days. The larvæ are small legless grubs, quite large at the apex of the abdomen and tapering toward the head. Both eggs and pupa are incessantly watched and tended, licked and fed, and carried to a place of safety in time of danger. The larvæ are ingeniously sorted as regards age and size, and are never mixed. The larvæ period generally extends through a month, although often much longer, and in most species when the larvæ pass into pupæ they spin a cocoon of white or straw color, looking much like a shining pebble. Other larvæ do not spin a cocoon, but spend the pupal state naked. When they mature they are carefully assisted from their shells by the workers, which also assist in unfolding and smoothing out the legs. The whole life of the formicary centers upon the young, which proves they have reached a degree of civilization unknown even in some forms of higher life.
It is curious that, notwithstanding the labor of so many excellent observers, and though ants swarm in every field and wood, we should find so much difficulty in the history of these insects, and that so much obscurity should rest upon some of their habits. Forel and Ebrard, after repeated observations, maintain that in no single instance has an isolated female been known to bring her young to maturity. This is in direct contradiction to Lubbock's theory, who repeatedly tried introducing a new fertile queen into another nest of Lasius flavus, and always with the result that the workers became very excited and killed her, even though in one case the nest was without a queen. Of the other kinds, he isolated two pairs of Myrmica ruginodis, and, though the males died, the queens lived and brought their offspring to perfection; and nearly a year after their captivity, Sir John Lubbock watched the first young workers carrying the larvæ about, thereby proving the accuracy of Huber's statement, with some species at least. In spite of this convincing testimony, Lepeletier St. Fargeau is of the opinion that the nests originate with a solitary queen, as was first given.
The ants indigenous to Leadville, besides feeding on small flies, insects, and caterpillars—the carcasses of which they may be seen dragging to their nests—show the greatest avidity for sweet liquids. They are capable of absorbing large quantities, which they disgorge into the mouths of their companions. In winter time, when the ants are nearly torpid and do not require much nourishment, two or three ants told off as foragers are sufficient to provide for the whole nest. We all know how ants keep their herds in the shape of aphides, or ant cows, which supply them with the sweet liquid they exude. I have often observed an ant gently stroking the back of an aphide with its antennæ to coax it to give down its sweet fluid, much in the same way as a dairy maid would induce a cow to give down its milk by a gentle manipulation of its udders. Some species, principally the masons and miners, remove their aphides to plants in the immediate vicinity of their nest, or even introduce them into the ant home. In the interior of most nests is also found the small blind beetle (Claviger) glistening, and of a uniform red, its mouth of so singular a conformation that it is incapable of feeding itself. The ants carefully feed these poor dependent creatures, and in turn lick the sweet liquid which they secrete and exude. These little Coleoptera are only found in the nests of some species; when introduced into the nests of others they excite great bewilderment, and, after having been carefully turned over and examined, are killed in a short time as a useless commodity. Another active species of Coleoptera, of the family Staphylini, is also found in ant nests. I have discovered one in the nest of Formica rufa in the Jewish cemetery in Leadville. Furnished with wings, it does not remain in the nest, but is forced to return thither by the strange incapacity to feed itself. Like the Claviger, it repays its kind nurses by the sweet liquid it exudes, and which is retained by a tuft of hair on either side of the abdomen beneath the wings, which the creature lifts in order that the ant may get at its honeyed recompense. Such mutual services between creatures in no way allied is a most curious fact in the animal world.—Popular Science News.