The Amazons (Polyergus rufescens) act otherwise. Very skilful in obtaining slaves and powerfully armed for triumphant raids, their nests always contain legions of servants, and the custom of being waited upon has become so impressed on the race by heredity that it is an instinct stronger even than personal preservation. The master ant has not only lost the taste and the idea of work, but even the habit of feeding himself, and would die of hunger beside a pile of honey or sugar if a grey ant was not there to put it into his mouth. Thus Huber, the earliest accurate observer of these ants, enclosed thirty Amazons with several pupæ and larvæ of their own species, and twenty negro pupæ, in a glass box, the bottom of which was covered with a thick layer of earth; honey was given to them, so that, although cut off from their auxiliaries, the Amazons had both shelter and food. At first they appeared to pay some little attention to the young; this soon ceased, and they neither traced out a dwelling nor took any food; in two days one-half died of hunger, and the other remained weak and languid. Commiserating their condition, he gave them one of their black companions. This little creature, unassisted, formed a chamber in the earth, gathered together the larvæ, put everything into complete order, and preserved the lives of those which were about to perish.
All their industry is expended in the acquisition of captives. The Polyergus avoid introducing into their houses adults who would not become reconciled to the loss of liberty, and would prefer to die rather than work for others. They carry off the larvæ of Formica fusca and Formica cunicularia. When brought into the ant-hill these larvæ are placed in the jaws of slaves of their own species, who care for them; they are born captives, and have neither the regret nor the idea of a free life. Among the Amazons the slaves undertake every labour; it is they who build and who care for the larvæ of their masters, as well as those carried away in expeditions. They have also complicated personal services towards the Polyergus. They bring them food, lick off the dust from their hairs, clean them, carry them from one place to another, if there is need to emigrate, although they themselves are much smaller. The masters, by force of losing interest in work, lose also their votes when it is a question of taking a resolution concerning the whole colony. The servants act on their own initiative and their own responsibility, direct constructions according to their own ideas, and even in grave concerns, such as emigration, the idle masters do not seem to be consulted. The workers deliberate among themselves, and having come to a decision, proceed to execute it. They transport the household goods, the eggs, the future of the city, and the Amazons who have become its parasites. It is a most curious fact that the slaves should submit to this precarious fate when their masters are absolutely dependent on them. It is just to add that the robust mandibles of the latter may contribute to preserve the position they enjoy.[70]
CHAPTER V.
PROVISION FOR REARING THE YOUNG.
THE PRESERVATION OF THE INDIVIDUAL AND THE PRESERVATION OF THE SPECIES — FOODS MANUFACTURED BY THE PARENTS FOR THEIR YOUNG — SPECIES WHICH OBTAIN FOR THEIR LARVÆ FOODS MANUFACTURED BY OTHERS — CARCASSES OF ANIMALS STORED UP — PROVISION OF PARALYSED LIVING ANIMALS — THE CAUSE OF THE PARALYSIS — THE SURENESS OF INSTINCT — SIMILAR CASES IN WHICH THE SPECIFIC INSTINCT IS LESS POWERFUL AND INDIVIDUAL INITIATIVE GREATER — GENERA LESS SKILFUL IN THE ART OF PARALYSING VICTIMS.
The preservation of the individual and the preservation of the species. — In the previous chapter we have seen animals preparing for the future, and amassing materials for their own subsistence. In other cases these provisions are destined to feed the young. It is the same industry, sometimes exercised for the preservation of the individual, sometimes for the perpetuation of the race. We must expect to find acts of the last kind more instinctive and less reflective than those of the first, and this agrees well with what we know of natural selection. If we now see living beings display so many resources and calculate with such certainty all that will favour the healthy development of their descendants, we must not necessarily conclude that the species possess these instincts from the beginning. They are not to be regarded as mechanisms artfully wound up and functioning since the appearance of life on the earth with the same inevitable regularity. The qualities which we find in them were weak at first; they have developed in the course of ages, and have finally, by heredity, been impressed upon the creatures to manifest themselves by necessary acts from which there is no longer any escape. There is no need for surprise if we meet to-day, I do not say among all, but among a very large number of animals, this foresight for offspring in a well-marked form. It is easy to understand that the species that first acquired and fixed an instinct propitious to the increase of the race has rapidly prospered, stifling beneath its extension those that are less favoured from this point of view, which is of capital importance in a struggle for a place beneath the sun. At the present day if the struggle of animal life offers few facts of lack of foresight for the rearing of young, it is because this defect has killed the races who were subject to it; they have disappeared, or have only been saved by qualities of another order.
For the rest, if it is difficult to reconstitute except in imagination the different stages through which, in time, and in a determined species, acts at first imperfect, but designed, have become perfect and instinctive, we can at least find in space different degrees of the same instinct in allied genera which lead us by a succession of transitions from mechanical action to reflective action.
As I cannot quote all the facts showing this care for the future, I will select a few. It must be said at first that a considerable number of animals show nothing of the kind. Let us leave aside all the inferior beings to speak of those among whom we may expect some degree of method. Crustacea, fish, Batrachians, and many others lay their eggs, are contented to conceal them a little so that they may not become a too easy prey, and are altogether indifferent as to what may happen afterwards. As soon as they come out, the young obtain their own food from day to day; myriads are destroyed, and if the races remain so strong numerically it is because they are saved by the innumerable quantity of eggs produced by a single female. If it were not for this prodigious fecundity these species would have disappeared. Birds make no provision for their young; but, on the other hand, as long as the latter are weak and unable to obtain their own prey, the parents feed them every day by hunting both for themselves and the brood.
I will not insist on those beings who, like mammals, produce physiological reserves, not for their own use, but for the profit of their young. The females of these animals elaborate materials from their own organism and store them up in the form of milk to nourish the young. This fact is related to foresight, with a view to offspring, exactly in the same way as the Honey Ants show a transformation of foresight for the individual. In both cases industry is replaced by the function of a specially adapted organ.
Foods manufactured by the parents for the young. — It is especially insects with whose industries we are here concerned, and they are more or less instinctive in various cases. Every one knows how the Hymenoptera prepare honey from the pollen of flowers, to some extent for themselves, but especially in order that their young may at the moment of appearance possess a food which will enable them to undergo their first metamorphosis sheltered from the inclemencies outside. These foods are enclosed with great art, according to the species, either in skilfully-constructed cells of wax, as by Bees, or in nests of paper or cardboard which the Wasps fabricate, or again in huts built of earth in the manner of the Chalicodoma.