These foraging ants show a good deal of sympathy with one another, and if one is in distress the others will do their best to relieve him from his embarrassment. Mr. Belt, a naturalist who spent some time in Nicaragua, made some experiments with a view to testing these points. He took an ant, and placed it under a stone in the line of the marching column. The first of the marching ants that saw its plight hurried back, and soon returned with several companions, to whom it had evidently communicated the intelligence. Some seized and tugged the ant, whilst others bit and pushed the stone, and, between them, the prisoner was soon freed. Other ants Mr. Belt covered up with clay, leaving only their head or antennæ projecting, and all were rescued in the same way. Lord Avebury has tried similar experiments with our own English ants, but the results were not so satisfactory. Both in sympathy and intelligence, these foraging ants of America seem much superior to the various European species. More experiments, however, with a greater number of species are much to be desired.
Another ant of tropical America is the famous sauba or leaf-cutting ant. All day long these insects seem occupied in cutting out pieces of leaves, and carrying them off to their nests. New arrivals in the country are astonished to meet long columns of them marching down well-beaten paths, and all carrying circular pieces of green leaf, the size of a sixpence, held upright in their jaws. All these are marching homewards, but beside them, empty-handed, another stream goes hurrying back to the forest, from which their comrades are returning laden. What use do the ants make of these leaves, after they have carried them down into their nests? In regard to this there have been various opinions. Some naturalists used to think that they used them as food simply, others that they made a sort of underground roof to their nests with them; but Mr. Belt has almost proved that what the ants really do with their leaves, is to make them into mushroom-beds, the mushrooms—not the leaves themselves—being used as food by the community. He found, on excavating their nests, that they consisted of a number of chambers, as large, and almost as round, as a man’s head. In each of these lay a brown mass of vegetable matter, which, on examination, proved to be made of the leaves themselves, now withered and cut into a number of small pieces, amidst which, and holding them all together, grew a minute white fungus—the mushrooms of the ants. Mr. Belt proved that it was not the leaves themselves which the ants ate, because he found deserted chambers filled with these, which, now that their manuring properties had become exhausted, no longer supported any fungus. Yet that the ants require food in their nests must be assumed, since they are never seen feeding outside them; and, moreover, when they desert the nest and establish themselves in another, they take the fungus-bearing leaves, but not the others, with them. Clearly, then, this fungus, which they cultivate themselves, must be their food—the ants are mushroom-growers.
Mr. Belt concludes his very interesting account of the sauba ants with one more instance of their intelligence. “A nest,” he tells us, “was made near one of our tramways, and, to get to the trees, the ants had to cross the rails, over which the waggons were continually passing and repassing. Every time they came along, a number of ants were crushed to death. They persevered in crossing, for some time, but at last set to work and tunneled underneath each rail. One day, when the waggons were not running, I stopped up the tunnels with stones; but although great numbers carrying leaves were thus cut off from the nest, they would not cross the rails, but set to work making fresh tunnels underneath them. Apparently an order had gone forth, or a general understanding been come to, that the rails were not to be crossed.”
CHAPTER X
WHITE ANTS AND THEIR ARCHITECTURE—VERY WONDERFUL NESTS—“A PRISON AND A PALACE”—THE AARD VARK AND THE ANT-EATER—HOW ANTS ARE TRAPPED.
In the white ants, or termites—to use their more scientific name—we have insects greatly resembling ants in their general plan and mode of life, and also much like them in general appearance, but which really are not ants at all, but belong to another order, widely distinct from them. They are Neuroptera, and thus allied to the dragon-flies, may-flies, grasshoppers, etc., whereas the real ants belong to the Hymenoptera, in which the bees and wasps are included. Like the ants, the termites are divided into males, females, and undeveloped females, or workers, which last form two castes that work in different ways, the one in building the nest, the other in defending it from attack—the former are the masons or architects, the latter the soldiers. In the matter of the nest, these white or false ants surpass all real ones, and therefore all other insects; it is built above, instead of below, the ground, and attains such a size, and rises to such a height, that these termite nests become a marked feature of any landscape, and may almost be said to turn a flat country into a hilly one. Rising in huge conical or beehive-shaped mounds, of a red colour and with lesser mounds dotted about them, they often support a more or less dense vegetation, upon which, in South Africa, where they are the largest, antelopes, or even buffaloes, may be sometimes seen browsing. The base of such a structure may be twenty yards in circumference, the height from ten to twenty feet, or even more. The masonry composing it is a sort of red clay, and seems, to the touch, as hard and solid as brick; though that it is not really so, is shown by its yielding to the stout curved claws and muscular fore limbs of the aard vark, a creature who lives almost wholly on the termites.
Outwardly, the termite-mound is dotted with little round holes, which are the orifices of so many passages leading into the interior, whilst the interior itself presents the most wonderful arrangement of galleries, halls, nurseries, cells, and chambers that exists in the insect world. First, comes a well-aired, empty attic, situated in the crown of the dome, or, rather, the peak of the sugar-loaf, to take the more typical shape. Beneath it, with a passage between them, is a nursery where, on shelves round the walls, the young termites are hatched. Beneath this, again, is a wide hall supported by lofty pillars, and, lastly, upon the ground floor, a royal chamber, shaped like a beehive, in which the king and queen—being respectively the father and mother of the entire colony—are confined. Around this palace-prison, as it may be called, are clustered the much smaller cells of the workers, from which, as from the other compartments, a number of tunnels, or galleries, lead to the outer circumference of the mound. From the floor[7] of the termitary—as the nest is sometimes called—holes perforate the earth, becoming larger as they descend; but these do not represent any addition to the architecture of the building, being merely the pits from which the materials that have gone to make it, have been extracted. Except the royal cell, the whole of this great edifice—equally remarkable in regard to its size and its architecture—is reared by the worker termites: but this, as being the foundation-stone of the whole, must necessarily, it would seem, be the work of the two founders, there being no one else to help them till after the hatching of the eggs.
Both the male and female are at first winged—as is the case with the real ants—but after the marriage flight they voluntarily break them off, as do these, and then set to work to found a colony. Whether the two entirely immure themselves in the cell, or chamber, referred to, or whether they only partially do so, and are assisted afterwards by the workers yet unborn, I cannot state, inasmuch as I have not watched the founding of a nest myself, and such authorities as I have been able to turn to, though writing as observers, say nothing on this head. Evidently they don’t know, but they don’t tell you that, either. However, be this as it may, the royal pair are, at some point in the earlier part of their career, enclosed in a compartment which may, at first, be roomy, but which, in this case, rapidly becomes, by the swelling of the queen’s body, now stored with thousands of eggs, only just able to contain them. The queen herself, in fact, whose abdomen has now become a long, white cylindrical object, like the blown-out finger-stall of a white kid glove, almost fills the space with this alone, her head and thorax being, in comparison with it, of as contemptible dimensions as are those of a bean-stalk, compared with its bean. Yet, besides herself, there is room not only for the male, but for some of the workers, which are very small, and enter the cell through a line of small holes, running round it, longitudinally, in the centre. Through these holes the king and queen are fed by the workers, which have probably bored them, since they but just admit their own bodies.
This, however, is the least part of their duties. Very soon the queen begins to lay her eggs, and continues to do so day and night, without intermission, at the astonishing rate of from sixty to eighty thousand in the twenty-four hours. All are carried out by the workers, and deposited, eventually, in the nursery which they themselves have prepared for them. Since, however, the very workers which do this have first to be born, it seems evident that the earlier eggs must for some time lie where they fall, and perhaps be afterwards stored somewhere else, whilst the nursery is a-making. The great size that the nest becomes seems to suggest that it is the gradual work of many generations of termites, brought forth by successive queens. It must, however, have had a beginning, and it is this beginning, as made by a single royal pair, that I have here been considering. It is quite possible that nobody may yet have watched it, or both watched and written about it. Probably it is most difficult—perhaps impossible—to do so; but it is irritating to read that the nest is founded in this way, and find not so much as an allusion to these obvious difficulties. It is quite as incumbent, I think, on those who watch creatures, to say what they have not been able to find out, as what they have.