CHAPTER XVII

Do ants sow and reap?—Rival observers—The Texanv.Macaulay’s schoolboy—More evidence wanted—How ants cross rivers—Tubular bridges—Ant armies—A world in flight—Living nests—Ants and plants—Mutual dependence—Nests in thorns and tubers—Ant honey-pots—Business humanity—Burial customs—A strange observation—Two views of ants.

MUSHROOM-GROWING, especially if the ants plant the mushrooms in the way stated by Mr. Tanner, is just as extraordinary, I think, as their habit of planting a field with ant-rice and reaping it at the proper time would be, did they really practise it. Up to a little while ago it certainly seemed as though they did, for there was Dr. Lincecum’s definite statement based upon twelve years’ observation, and this, if not confirmed by Mr. McCook, was, at any rate, not contradicted by him. On the contrary, McCook mentioned a good many facts pointing in the direction of Lincecum’s assertion, and though he did not consider them decisive, he could see no reason why the ants should not act in this way, as indeed there is none: so that as he had only stayed a few months where Lincecum had lived for twelve years, he seemed like a weaker witness supporting, according to his opportunities of observation, a much stronger one. Now, however, comes another witness, whose opportunities have also been great, and in a somewhat heavy-handed way, in a spirit ofmyth-slaying and irrelevant reference to supposed schoolboy knowledge, hardly required in face of all that ants are known to do, denies the whole thing.

First, however, let us have the assertion as originally made by Lincecum, which is, that on the summit of the mound of their nests, from which they carefully clear away all other vegetation, the harvesting ants sow the seed of a certain plant called ant-rice for the purpose of subsequently reaping a harvest of the grain. It is sown in time for the autumnal rains to bring up, and at the beginning of November a green row or ring of ant-rice, about four inches wide, is seen springing up round the circumference of thedisk(as the circular top of the mound is, for some reason, always called). In the vicinity of this circular ring the ants do not permit a single spire of any other grass or weed to remain a day, but leave the aristida or ant-rice untouched until it ripens, which occurs in June of the next year. After the maturing and harvesting of the seed, the dry stubble is cut away and removed from the disk, which is thus left unencumbered until the ensuing autumn, when the same species of grass again appears as before, and so on.[74]After stating in a letter to Darwin that he has seen all this taking place year after year, Dr. Lincecum adds:—“There can be no doubt of the fact that the particular species of grain-bearing grass mentioned above is intentionally planted. In farmer-like manner the ground upon which it stands is carefully divested of all other grasses and weeds during the time it is growing. When it is ripe the grain is taken care of, the dry stubble cut away andcarried off, the paved area being left unencumbered until the ensuing autumn, when the same ant-rice reappears within the same circle and receives the same agricultural attention as was bestowed upon the previous crop, and so on year after year, as Iknowto be the case in all situations where the ants’ settlements are protected from graminivorous animals.”[75]Lincecum also believed that the ants were able in some way to prevent the seed stored in their nests from germinating. This same fact has been asserted, and apparently proved, by Moggridge, in regard to the harvesting ant of southern Europe, and he also states that, if in spite of the precaution any seeds begin to sprout, the ants by gnawing off the tips of the radicles would prevent the germination from proceeding.

This, then, is the caseforthe harvesting ant, as we may say; for if these things be true they are certainly much to its credit, whereas, if not, the scandal is so great that it ought to change its name. Let us now hear the case against, as stated by Professor Wheeler, after which readers may make up their minds, if they can, for I have not quite done so yet. I quote in full, so that the two statements may be balanced against each other, and this, I hope, will be more interesting than the usual “Mr. So and So, however, disputes this and thinks, etc.”—another line or two in which the contrary proposition of the one before is stated at about the same length. This is what Professor Wheeler, who “speaks home—you may relish him more (or at least as much) in the soldier as the scholar”—has to say: “It may not be altogether out of place in this paper to record a fewother observations onPogonomyrmex molifacieus, inasmuch as this form has been singled out among all the known members of the genus as presenting certain remarkable instincts. Lincecum is responsible for the myth that thisPogonomyrmexsows a certain species of grass, the ‘ant-rice’ (Aristida oligantha), protects it from harm and frees it from weeds while it is growing, for the purpose of reaping the grain. This notion, which even the Texan schoolboy (not Macaulay’s, who probably knew as much about it) has come to regard as a joke, has been widely cited, largely because the great Darwin stood sponsor for its publication in the Journal of the Linnean Society. McCook, after spending a few weeks in Texas observing the ant in question and recording his observations in a book of 310 pages, failed to obtain any evidence either for or against the Lincecum myth and merely succeeded in extending its vogue by admitting its plausibility. Two years of nearly continuous observation enable me to suggest the probable source of Lincecum’s and McCook’s misconceptions. In either case the observer has started with a few facts, and has then stopped short to draw inferences before gathering more facts. If the nests ofMolifacieusbe studied during the cool winter months—and this is the only time to study them leisurely and comfortably, since the cold subdues the fiery stings of their inhabitants—the seeds which the ants have garnered in many of their chambers will often be found to have sprouted. It is, therefore, certain that these ants are not able to prevent the seed from germinating, as Moggridge claims for the European species ofMessar, except by conveying them to drier chambers; and in protracted spells of wet weather even this precaution seems to be of no avail. On sunny days the ants may often be seen removing these seeds when they have sprouted too far to be left for food, and carrying them to the refuse heap, which is always at the extremity of the cleared earthern disk or mound. In this place the seeds thus cast away as inedible often take root, and, somewhat later, form an arc of tall grass more or less closely approximating to a complete circle round the nest. Since these ants feed largely, though by no means exclusively, on grass-seeds, and since these particular seeds are a very common and favourite article of food, it is easy to see how their grass should often predominate in the circle. In reality, however, only a small percentage of the nests, and only those situated in certain localities, present such circles. Now to state that the ant, like a provident farmer, sows this cereal, and guards and weeds it for the sake of garnering its grain, is as absurd as to say that the family cook is planting and maintaining an orchard when some of the peach-stones which she has carelessly thrown into the backyard, with the other kitchen refuse, chance to grow into peach trees.”[75]Certainly such a thing should have been observed before the statement was made, and, if it has not been, the facts seem more probably accounted for on the above explanation.

Professor Wheeler goes on to say that “there are several other facts which show that the special ring of grass about the nest is an unintentional and inconstant result of the activities of the ant colony. For instance, oneoften finds very flourishing ant-colonies that have existed for years in the midst of much-travelled roads, or in stone side-walls, often a hundred or more feet from any vegetation whatever (without any ant-rice on their mounds therefore). Again, it is very evident that even a complete circle of grass like those described by Lincecum and McCook would be entirely inadequate to supply more than a very small fraction of the grain necessary for the support of a flourishing colony of these ants. Hence they are always obliged to make long trips into the surrounding vegetation, and thereby wear out regular paths, which radiate in different directions, often to a distance of forty to sixty feet from the entrance of the nest. The existence of these paths, which are often found in connection with grass-encircled nests, is alone sufficient to disprove Lincecum’s statements.”[75]It certainly seems easier to suppose that Lincecum misinterpreted certain facts, not themselves in dispute, than that an explanation on which so many considerations seem to throw doubt is the correct one. One thing, at least, seems certain—if some of these ant communities grow grain of set purpose, all of them do not. This may be possible, but more proof of it than Lincecum has brought is demanded. If the ants really sow and reap the grain that grows upon their mounds, and, more especially, if they carefully keep the patch clear, it ought not to be difficult to see them doing so. This last would be decisive, whereas the other two are by no means so.

That ants should use their own larvæ like a shuttle, and for the same purpose, seems as strange a thing as one canwell imagine, but there is no doubt at all about it, the act having been witnessed on various occasions by competent observers, whose evidence is mutually corroborated. The species in question is common in Eastern Asia, and is accustomed to make little houses or arbours for itself by bending leaves round so that the edges meet, and then fixing them together, as some caterpillars do. Now the larva can do something which the grown ant cannot, which is to spin a cocoon from a sort of gummy, thread-like substance which issues from the mouth. Whilst one group of ants therefore join to keep the leaf bent in the proper position, another take each a larva in their jaws, and pass it from edge to edge of the leaf, applying its mouth to each edge, until the two are bound firmly together.[76]Whether this is a more or less remarkable habit than growing mushrooms it would be difficult, perhaps, to decide, nor is there any need to try, since such questions are more interesting left uncertain.

It is well known, or at least credibly asserted, that ants cross rivers by clinging one to another from the branch of a tree overhanging the water, till the end of this living chain, as it becomes longer and longer, is carried by the force of the current to the opposite bank, where a bridge is formed, over which the main body marches.[77]According to Du Chaillu the ants in Africa make, not only a bridge, but a tunnel—“a high, safe tubular bridge through which the whole vast regiment marches in regular order.”[78]These are the celebrated driver or bashikouay ants, who, when upon their terrible marauding marches, put every living creature, including man, to flight, thoughfor many flight is in vain. Size and strength are here no protection. “The elephant and gorilla fly before them; the black men run for their lives.” So says Du Chaillu, and, sure enough, when the skins of some of the poor gorillas he shot arrived in England, several of these ants were found amongst the hair.[79]In the forests of equatorial Africa, abounding—if they have not all been shot by this time—with large animals, these hunting-raids must give rise to some stirring scenes. What crashings through the trees and undergrowth! What uncouth sounds, perhaps, of mingled pain and rage! How a bitten gorilla would express himself! What a subject for a picture if a herd of elephants, a few families of gorillas, a score or so of lions, with a few leopards, and baboons, perhaps a rhinoceros, and any number of antelopes, were all to come rushing down together to where an artist stood ready for them! I should like to see the picture he would draw.

PURSUED BY DRIVER ANTS

The greatest beasts of the forest will fly before these terrible little insects,one of which is shown in the left-hand corner.

The greatest beasts of the forest will fly before these terrible little insects,

one of which is shown in the left-hand corner.

A more remarkable sight even than an ant-bridge is perhaps an ant-nest, by which I mean, not an ants’ nest in the ordinary sense of the term, but a nest made of ants. The following quotation from the much-containingNaturalist in Nicaragua, page 25, will explain this hard saying. “They make their temporary habitations in hollow trees, and sometimes underneath large fallen trunks that offer suitable hollows. A nest that I came across in the latter situation was open at one side. The ants were clustered together in a dense mass like a great swarm of bees hanging from the roof, but reaching to the ground below. Their innumerable long legs looked like brown threads binding together the mass, which must have been atleast a cubic yard in bulk, and contained hundreds of thousands of individuals, although many columns were outside, some bringing in the pupæ of ants, others the legs and dissected bodies of various insects. I was surprised to see in this living nest tubular passages leading down to the centre of the mass, kept open just as if it had been formed of inorganic materials. Down these holes the ants who were bringing in booty passed with their prey.” Of the many curiously constructed or strangely produced dwellings of ants, this made out of their own bodies is amongst the most remarkable.

Many ants live in the interior of various plants. The plant generally benefits as much as the insect by this arrangement, so that there is a mutual dependence between the two, which in some cases is carried to such an extent that the life of one or both seems a necessary part of that of the other. In Borneo, for instance, a certain large tuber which grows on the branches of aged trees is always found inhabited by a certain red ant, of small size, but fierce disposition, which rushes out and attacks anyone who ventures at all near its dwelling. The seed of this tuber is disseminated in the same way as is our own mistletoe, through the agency of birds, that is to say, the seed being surrounded by a similar pulpy mass, which adheres to the branch on which it falls. Soon after germination the tuber, which is shaped something like a carrot, begins to develop, but whilst still quite small its growth ceases and in this state it would remain, and before long, die, if it should not happen to be found by the ants in question. If it should be, however, its life isassured. They immediately bore a hole at the base of the stem, upon which this enlarges to a great degree, so that soon there is room for them to excavate galleries in the cellular tissue of the interior, and to form a populous colony. The whole tuber is soon perforated in all directions, and becomes a living and growing formicarium, the great accretion of cellular tissue which has made this possible having been caused by the poison—if we may call it so—of the ant’s bite, in the same way as the sting of the gall-fly raises galls upon the oak.[80]Of course, from the moment that the ants appear the tuber is safe from any other insect, or small bird, or mammal that might otherwise do it harm. The ants in defending their nest would defend it, and it is on this principle of mutual advantage that such ant and plant alliances have been brought about.

Thus the dry, arid plains, called savannahs, of tropical America support a species of acacia of which the thorns, characteristic of the family, grow in pairs and are shaped exactly like the horns of some oxen. Every pair of these horns becomes in time an ants’ nest, and if the tree be touched or shaken, the ants rush out full of fury in defence of their habitations. Thus every tree is tenanted by a large army of retainers, who almost more than the thorns themselves, which have been developed for the same purpose, protect it against browsing quadrupeds. Its thorns, however, would be no protection against the leaf-cutting ants in search of materials for their mushroom-beds, whereas these are kept at bay by a hostile species, smaller indeed, but armed with a powerful sting. “Forthese services,” says Belt, “the ants are not only securely housed by the plant, but are provided with a bountiful supply of food; and to secure their attendance at the right time and place, this food is so arranged and distributed as to effect that object with wonderful perfection. The leaves are bi-pinnate (double, that is to say), and at the base of each pair of leaflets, on the mid-rib, is a crater-formed gland, which, when the leaves are young, secretes a honey-like liquid. Of this the ants are very fond; and they are constantly running about from one gland to another to sip up the honey as it is secreted. But this is not all; there is a still more wonderful provision of solid food. At the end of each of the small divisions of the compound leaflet there is, when the leaf first unfolds, a little yellow, fruit-like body, united to it by a point at its base. Examined through a microscope, this little appendage looks like a golden pear. When the leaf first unfolds the little pears are not quite ripe, and the ants are continually employed going from one to another examining them. When an ant finds one sufficiently advanced it bites the small point of attachment; then, bending down the fruit-like body, it breaks it off and bears it away in triumph to the nest. All the fruit-like bodies do not ripen at once, but successively, so that the ants are kept about the young leaf for some time after it unfolds. Thus the young leaves are always guarded by the ants; and no caterpillar or larger animal could attempt to injure them without being attacked by the little warriors.” Thus, as Mr. Belt very aptly puts it, “the ants are really kept by the acacia as a standing army toprotect its leaves from the attacks of herbivorous mammals and insects.”[81]

As for the honey or honey-pot ants, they were first heard of in America, and various floating stories, which seemed more or less hard to credit, having got into circulation about them, without there being any positive knowledge to check them, Dr. McCook, to remove this grave reproach to transatlantic entomology, started off one day to observe them. He soon found that the main fact which had been stated was correct, viz. that a certain sect or caste of these ants, disregarding the Italian warning, were in the habit of making themselves all honey, to be swallowed in consequence by the rest of the community. These are the so-called honey-pots, and so well do they deserve their name, that when full the abdomen becomes almost perfectly circular, like a glass globe, and so enormously swollen that the body in proportion to it is like a grain of wheat stuck into a cherry or gooseberry.[82]The legs dangle towards the ground, but hardly, or only by a great effort, reach it, and in this last state of distension the insect may find it impossible to get about, though as a rule by dragging or pushing herself along sideways, she is able to do so to a certain extent. These honey-jars have special chambers for their accommodation, and here they hang in clusters from the roof, awaiting the visit of any worker, who upon signifying his wants—it would seem after climbing up to them—is fed, after the ordinary ant manner, by regurgitation. In the same way the honey-bearers are themselves filled, or more properlyspeaking, feed themselves, since the mouth arrangement, in spite of the direction in which things seem hastening, has not yet become so simple as in the case of a real jar.

The honey which the rotunds, as McCook calls them, receive from the workers is gathered at night, and is obtained almost entirely from the galls of oak trees, which, when pierced by the ant’s mandibles, exude a white transparent liquid in minute globules. This is greedily licked up by the ants and distributed by them after the return home, not only to the rotunds, but to such of their fellow-workers as may not have taken part in the expedition.[83]The honey thus obtained is pleasant to ant and human taste alike, and the Indians of New Mexico, as no doubt elsewhere, obtain it by the simple process of squeezing the insect—breaking the honey-jar, as one may say. They also make from it a fermented liquor having intoxicating powers, so that one need not wonder that the idea of farming the honey-ant, like the honey-bee, has been seriously discussed in the United States. McCook, however, has pointed out that “the limited quantity of the product would prevent a profitable industry,” and he adds: “Besides, the sentiment against the use of honey thus taken from living insects, which is worthy of all respect, would not be overcome.”[83]Personally I think it would be overcome, and pretty quickly, too, as are most other sentiments that stand in the way of pleasure or profit. Women would get it under first, as in the case of birds, seals, etc., and the world would soon follow, with “woman’s influence” upon its lips. But let me not be unjust. I do not believe in sentiment as a working forcein the case at all. If the ants are not to be squeezed it will be on commercial considerations.

That the worker-ants—and for that matter the others also—are extremely fond of the honey so curiously stored by them, will be easily believed, and an unpleasant illustration of their greediness in this respect was often observed by McCook when capturing a nest. The swollen bodies of the rotunds, on these occasions, were sometimes unavoidably ruptured, whereupon such workers as happened to be near these unfortunates, forgetting their alarm, which had hitherto been great, and the ruin and confusion all around them, paused in their flight, or aimless movements, and greedily lapped up the overflowing honey.[84]It is all the more interesting, therefore, to learn that when the “little life” of these poor honey-pots is at length “rounded with a sleep,” their contained treasure, though so easily obtainable, goes with them to the grave, the idea of opening the full crop, and imbibing the contents, never seeming to occur to any ant. This is all the more remarkable in that the workers, when they recognise that life is extinct, carefully separate the abdomen from the thorax by sawing through, with their mandibles, the little connecting stalk called the petiole. The two parts are then removed separately, that representing the head half being carried, whilst the “golden bowl” of the body “unbroken,” though with “the spirit fled for ever,” is rolled along the various chambers and galleries of the nest, till it finally finds a resting-place in the cemetery just beyond its precincts.[84]To what are we to attribute the non-utilisation of the honey in the dead body? Evenwere it possible that the ants could forget that it was there, they cannot be unconscious of what must be smelt, as well as seen, through the semi-transparent walls of the abdomen. Some feeling must restrain them—what, I am not prepared to say in a work which does not aim at being scientific.

Here, then, we have one most suggestive illustration—“suggestive,” I think, is a very useful word—of the funeral habits of ants. Many others could be instanced, but I will end this chapter, and small account of ant doings, generally, with the following extract from theProceedings of the Linnæan Society(1861). The observer was a Mrs. Hutton, of Sydney; and Romanes, who quotes her account in hisAnimal Intelligence, remarks that though she is not a well-known observer the facts reported were such as scarcely to admit of a mistake. Personally, I attach no weight whatever to anybody’s not being known as an observer. Want of leisure, or unpropitious circumstances generally, must prevent large numbers of people from seeing what they would be very well able to note accurately if they did, or from recording what they do see; whilst, on the other hand, leisure, joined to taste in a certain direction, makes many a quite average observer known as a good one. A good observer, in fact, is rather one who is always keeping on, and does not weary, than one who can see a single salient thing more plainly than most other people; and, again, it is easy to set a fictitious value merely on being before the public.

Having thus defended Mrs. Hutton, I proceed now to quote her account: “I saw,” she says, “a large numberof ants surrounding the dead ones” (soldier ants which she had herself killed and left lying on the ground some half-hour previously), “and determined to watch their proceedings closely. I followed four or five that started off from the rest towards a hillock a short distance off, in which was an ants’ nest. This they entered, and in about five minutes they reappeared, followed by others. All fell into rank, walking regularly and slowly, two by two, until they arrived at the spot where lay the dead bodies of the soldier ants. In a few minutes two of the ants advanced and took up the dead body of one of their comrades; then two others, and so on, until all were ready to march. First walked two ants bearing a body, then two without a burden; then two others with another dead ant, and so on, until the line was extended to about forty pairs, and the procession now moved slowly onwards, followed by an irregular body of about two hundred ants. Occasionally the two laden ants stopped, and laying down the dead one, it was taken up by the two walking unburdened behind them, and thus, by occasionally relieving each other, they arrived at a sandy spot near the sea. The body of ants now commenced digging with their jaws a number of holes in the ground, into each of which a dead ant was laid, where they now laboured on until they had filled up the graves. This did not quite finish the remarkable circumstances attending this funeral of the ants. Some six or seven individuals had attempted to run off without performing their share of the task of digging; these were caught and brought back, when they were at once attacked by the body of ants and killed upon the spot.A single grave was quickly dug, and they were all dropped into it.”

“Prodigious!” as Dominie Sampson would have said, and certainly I think this is one of the most remarkable observations upon ants that has ever been made. As far as the burying is concerned, it has been corroborated by the Rev. W. Farrar White, who, at the same time, corroborates Pliny; but how strange are all the circumstances! What was it, one wonders, that made just a few of the crowd shirk their share of the labour—for this is not like ants. Some strange, uncanny feeling in connection with the dead bodies may be suspected; but seeing that, as the Russian proverb truly says, “Another man’s soul is darkness,” it is not very likely that we shall ever know what ants feel.

One interesting question is suggested in this connection, though I have never known it raised yet. Two views of what ants are, excluding compromises, may be taken—the automatic one, tempered with “psychic plasticity,” of Professor Wheeler, and that formed by Mr. Belt, who, having fully satisfied himself—from the keenest observation, be it remembered—of their reasoning powers and capacities, remarks, “When we see these intelligent insects dwelling together in orderly communities of many thousands of individuals, their social instincts developed to a high degree of perfection, making their marches with the regularity of disciplined troops, showing ingenuity in the crossing of difficult places, assisting each other in danger, defending their nests at the risk of their own lives, communicating information rapidly to a greatdistance, making a regular division of work, the whole community taking charge of the rearing of the young, and all imbued with the strongest sense of industry, each individual labouring not for itself alone, but for all its fellows, we may imagine that Sir Thomas More’s description of Utopia might have been applied with greater justice to such a community than to any human society.”[85]Now, if Belt’s view be the correct one, or if the evidence in favour of it be at all strong, is it not time for us to ask ourselves, merely as a moral problem, how far we, in our clumsy and imperfect human state, have a right to kill ants and tumble Utopia to pieces, simply for our amusement, intellectual or otherwise? Ought we to do this? Or ought we, like a lady who lives in America and writes to very scientific papers, to imprison queens who do no harm, and make ourselves learned at the expense of one, or both of their antennæ, during the term of their natural lives? However simply and sweetly we may talk of this, however much true womanly feeling may enter into the narrative, nay, even though we give the queens pet names, is it really right?

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