Versamelde werke

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7 The Wonders of the White Ant

If ant-hills on the veld about Johannesburg are opened, three out of four would probably belong to the Eutermes group, of which there are representatives throughout Africa and Asia. A small opening through the skin of the ant-hill at this time of the year will speedily bring to view first the soldiers and then the workers of the community. In the Eutermes group these two classes are so widely differentiated that no one who did not know would ever imagine them to belong to the same species. They differ even more widely from their parents. A thousand soldiers would not equal their mother in size or weight.

The soldiers appear first. The worst creations of a nightmare cannot equal them for sheer gruesomeness. They are quite blind and sexless. The head looks like a semi-translucent stone - a reddish piece of highly polished amber, with no sign of an external sense organ. On the under side of this polished stone is the mouth, surrounded by leg-like jaws. Quite clearly, the soldiers are unable to ingest food that is not liquid or semi-liquid. For offensive or defensive purposes, the jaws are negligible. But the soldier has a more effective weapon. In the centre of the forehead there is a sharp, hollow needle, which connects with a bottle-shaped cavity in the head. This is filled with a sticky, colourless fluid. When need arises, the insect is able to eject through this needle a single drop of the fluid, and woe betide the unfortunate insect which it touches. Such an intruder is at once put out of action. Besides the entangling stickiness, the fluid contains some sort of irritant poison. It stains the human skin purple and smarts in open wounds.

The soldiers form a cordon round the nest opening, waving their deadly syringes in circles as if ‘trying the air’ for the presence of an enemy. Immediately afterwards, behind the protecting cordon, the workers appear in the opening. They, too, are sexless and blind; about the same size as the soldiers, but without the syringe. Their jaws are much more effective than those of the soldiers. It is they who cut and collect the grass-hay which forms the basic food supply of the community.

And now commences an operation as astonishing, as inexplicable, as anything in the world of insects - namely, the concerted architecture of the workers. With a fairly strong magnifying-glass it can be seen that workers, in an unending stream, are hurrying up from the dark interior of the ant-hill, each with a microscopic pebble in its jaws. This species employs only actual stone for building purposes. The completed work resembles soil, but it really consists of microscopic stones. There are other species which employ mud for building, but the process is quite different.

Arriving on the edge of the opening, each worker rolls the pebble which it

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has brought from the depths round and round in its jaws, covering it with the same sticky secretion which the soldier squirts through its syringe. Hurriedly, and apparently without design or forethought, the stone is stuck on to the broken edge, and the little worker disappears once more into the darkness of the ant-hill. The work goes on ceaselessly night and day, for neither soldiers nor workers ever rest or sleep as long as the weather remains warm. Cold alone drives them to the warmth of the fungus gardens and the central cavities.

Up to this point there is nothing more wonderful in these building operations than can be seen in the structural work of most insects. But patient observation and a few experiments disclose circumstances that ‘puzzle the understanding’ and leave the observer beating the void for an explanation. Take this first simple circumstance: the break in the ant-hill might be miles wide - that is, termite miles. The workers build from all sides simultaneously. It can easily be ascertained that they carry their stones from different extremities of the ant-hill. Each one works quite independently, and yet from all sides of this (to them) immense gulf they build in the same curve. When the work is completed there is no fault or ridge at the line of junction. Now, if the surface of an ant-hill is examined, it will be seen that it consists of a number of different curves. If the insects always built in the same curve the thing would be more or less comprehensible. But that is not so. Occasionally, instead of the usual ‘skin’, they build a vertical turret. When this happens, the workers on opposite sides of the opening never engage in different kinds of work. It is as if the structure had previously been planned and drawings supplied to each group of workers.

Sometimes they have to do extensive roofing, which rests on solid, vertical pillars. In the same way as with the turrets and skin-repairing, the work is started from all sides simultaneously, and when completed, the pillars are always in perfect co-ordination with the roof. Unlike all other insects, they do not build one structural design only - like the web of the spider or the bird's nest. Their engineering problems are infinitely varied, and it is seldom that they make fundamental mistakes. When they do, strangely enough, they persist in them with a stupidity as great as their cleverness is in other directions.

The first thing apparent from this engineering work of the termites is the fact that there is a predetermined design. This is quite certain. The completed structure is never the result of chance. To the human observer the intention is clear right from the start, and from this ‘intention’ in their labour the little, blind engineers never deviate by any chance. And then come the baffling questions: Where is this design formulated? Where does it exist, during the carrying out of the work, as a psychological exercise of will? What is it that directs each fraction to the final design?

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Is it to be wondered at that different naturalists have from time to time suggested extremely anthropocentric and often fantastic answers to these questions? Professor Bugnion of Lausanne is satisfied that the soldiers direct the labour of the workers just as human military officers direct their files of soldiers. Even if this view were not utterly untenable on psychological grounds, its fallacy can be demonstrated very simply. The whole cordon of soldiers can be destroyed and each one removed as it appears in the opening, and still the work continues as if nothing had happened. Quite clearly soldiers and workers exercise entirely different functions independently of each other. Maeterlinck suggests the ‘Spirit of the Universe’, which means nothing, and such childish fantasies as ‘intelligent communication’ between individuals and even - in the case of the audible signals of soldiers and workers - the employment of ‘an articulate language’. Every experienced behaviourist knows there are no such things in nature outside the order of the primates and their absence can be demonstrated by the simplest of experiments.

It is only by means of carefully devised experiments that the exploration of this dark mental world is possible. We already know that destruction of the queen entails the death sooner or later of the entire community. The first thing to be done, therefore, is to subject the queen in situ to such observation as circumstances will permit. The way to set about this is to drive a narrow trench right to the royal cavity without actually exposing it. Two small peepholes can then be made, one for admitting a ray of light, and the other for observation. If too great and too continuous a stream of light is admitted, a very singular thing occurs, the significance of which has not been determined: the workers at once set about the destruction of the queen. They cover her in dense masses and, puncturing the skin of her fluid bag with thousands of holes, absorb all the moisture that constitutes practically her entire body. After a time she dies, and with her dies the community. It seems like the suicide of utter despair. If care is taken to prevent too much light penetrating and too great an evaporation of moisture, the queen's cell can be kept under some degree of observation.

It is true that this observation amounts to no more than occasional glimpses, but the sum total of them will, after many repetitions, give some idea of what takes place in the royal cavity and about the fungus gardens. The first thing that one ascertains is that millions of her subjects probably never come into contact with the queen, and that seems to be so in the case of all species where the queen is walled up.

The group that feeds her and removes the eggs appears to be specially adapted for this purpose. The mass of the population never enter the royal cell. They cannot, by direct experience, know of the existence of the queen. One also discovers that tremendous damage may be inflicted on all parts of the nest, or millions of workers and soldiers destroyed, without jeopardizing the exist-

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ence of the community as a whole - so long as the royal cavity and the queen are left intact. On the other hand if, with the smallest possible degree of destruction, the queen is reached and removed, a difference will speedily be noticed in the behaviour of soldiers and workers in every part of the community, even in portions yards away from the central cavity. Their movements become languid and uncertain. There is a tendency to collect in groups. Gradually all work ceases; feeding stops. Even the workers, who can feed themselves, do not do so. No repairs are done. Both soldiers and workers become utterly helpless, and in the end die of hunger or the want of that supreme essential - moisture.

How do these groups in outlying parts of the ant-hill become aware of the removal of the queen?

Naturally the answer that first suggests itself is that the news is communicated from one individual to another in termite language. That, however, is not so. By a conclusive experiment it can be demonstrated that the removal of the queen becomes known to parts of the nest with which there is no possibility of communication. If the queen is separated from half the nest by means of a metal plate driven down through the nest (the ground must be previously well drenched for this purpose), it will be found that work continues on both sides of the plate without any apparent interruption, but if the queen is then removed the fact is known on the far side of the plate as soon as on her own side. One concludes from this that the ‘instincts’ of workers and soldiers are entirely dependent on - in fact, emanate from - the queen. In themselves, without the presence of the queen, they are the most helpless of insects. In the midst of abundant food they cannot even eat.

One concludes further that this mysterious emanation from the queen is certainly not ‘material’ in the commonly accepted sense. It is something that penetrates matter. Neither rock nor earth, nor even fairly thick metal, can obstruct its passage. By means of this dividing metal plate some idea of the nature of the concerted work can also be ascertained. If a break in the skin of an ant-hill is divided into two by means of a metal plate driven down through the middle of the break and into the earth past the royal cavity, so that the whole community is divided into two portions, it will be found that repair proceeds on both sides of the plate. By marking workers and soldiers on one side with a bright dye it can be demonstrated that they never by any chance appear on the other side of the metal. All communication between the two sides is shut off. And yet, not only does work on both sides of the plate continue undisturbed, but the workers on both sides follow the same design. They build in the same mathematical curve, or erect separate halves of an identical chimney. When the work is completed and the plate removed it will be found that the two halves join (allowing for the aperture made by the plate) without the least ridge or irregularity. The unavoidable conclusion from all this is that the workers on

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both sides of the plate are directed by an identical influence; that there is no need for ‘communication’; that this directing influence comes from without their own organisms and is dependent on the presence of the queen in her cell; that in themselves workers and soldiers are pure automatons with no individual instinct.

With removal of the queen all their ‘cleverness’ in construction, gardening, feeding and defence departs. It is she - motionless in her dark cell - who directs their work; in her are centred all those wonderful instincts. She is both the sexual and psychological centre of this vast community of blind and sexless individuals who work without end in darkness, and never for themselves. One begins to find an answer to the puzzling question: What makes them labour thus without pause or rest? For them there are none of the incentives that operate throughout the organic world: love, hunger or danger. Sex they have none. One half of the community is fed by the other half and that other half collects food for the community and not for themselves. The question of life or death for the individual is never decided by his own efforts on his own behalf. His safety, his life is entirely dependent upon the presence or absence of the queen, whom he has probably never come in contact with and whom in the human sense of the word, he does not know.

Here, too, one begins to catch glimpses of a solution to a more far-reaching enigma. We know that all instincts are as surely and as invariably inherited from parents as bodily shape. The knowledge of what to eat, how to construct a habitation, how to provide for young - this knowledge which is not dependent on experience or ‘learning’ - is always no more and no less than similar knowledge possessed by parents. Whence, then, do termite soldiers and workers get their instincts - their engineering knowledge, their gardening and their communal defence? Their parents had none of these and they themselves cannot transmit these instincts to other individuals because they never have any progeny. The first broad answer to the question is that it is the queen who inherits and transmits all these properties and instincts to other queens descended from her. It is she who inherits and transmits the power of giving birth to individuals as different from her in bodily shape as the soldiers and workers. It is she who inherits and transmits the power of influencing and directing them at a distance as if they were in reality part and parcel of her own body. The line of heredity can run through the queens only and not through soldiers and workers, because it is only they who have offspring.

Is there anything in nature that resembles this mysterious entity with its coordinating groups? The least consideration will reveal that all the principles involved are identical with those that govern the growth, repair and control of the mammalian body - or, for that matter, the body of any of the more complex organisms. The mammalian body, for instance, originates from the sexual con-

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jugation of two individual and independent single-cell organisms, one male and the other female. From these two other single-cell organisms originate, unlike the parents in form and function, until through their proliferation the entire complex body is built up. The growth and repair of the body are dependent upon the presence and life of the brain. Many groups of apparently independent organisms - such as the bone-weaving cells - are directed in some unknown manner by the brain.

In fact, to the minutest detail one will find analogies in the life of the ant-hill. It is an old theory that the mammalian body is the evolved product of a community of, originally, independent animals which came into being in the same way that the siphonophora form one complex animal out of a large number of simple individuals. Once these facts are established it is not difficult to follow the probable course of evolution in the formation of the termite community. Communal life at some time or other became more advantageous to the species than solitary life. The differentiation thereafter of classes in conformity with difference of function is easily understood. The vast economy of labour entailed would be sufficient to ensure the natural selection of class and functional differentiation. Once it is accepted as a fact that each entity of communal insects is in reality a separate and independent animal in a certain stage of evolution, then at once the inexplicable problems of termite behaviour are no longer insoluble.