13. The Water Supply
IN many parts of the world we find people studying the life-history of termites. In spite of this, no single observer seems to have discovered the psychological functions of the queen, but, more surprising still, no one seems to have realized the intriguing mystery of the constant supply of water of the termite. M. Barthellier, a Frenchman, has studied the termite in Indo-China, in districts probably as dry as Waterberg. An Englishman, Carpenter, studied certain termites for a long time in British East Africa; Maxwell Le Roy in India; Prell, a German, in German East Africa; the Belgians Hegh and Ghesguière in the Congo; Hill in Australia; and many others in parts of North and South America. The collected works of all these observers and many others would fill a library. Yet none of them ever sought to answer the questions:
- Why does community life of soldiers and workers cease when the queen is destroyed? and
- Where do the termites get their water?
The very facts seem to have escaped their notice: the never-ceasing supply of water during the dryest seasons, and the change of behaviour caused by the destruction of the queen. If one fails to notice these things, of course, the problems and unavoidable investigation of them will not arise. I want to describe my own observations on the conveyance of water. I was much impressed at the time by the result of my observations and also the effect they had on the other spectators. I think the behaviour of these people was as interesting as the behaviour of the termites. It was sheer chance which gave me the opportunity of watching for months the terrific struggle -- it was verily struggle between life and death -- unfold itself like a film on the screen. It was during the most severe drought which had ever stricken the Waterberg. That none such had occurred within human memory was certain, for on the farm Reitfontein 1638, where my observations took place, a sixty-year-old orange grove was entirely destroyed by the drought. Nature showed by many signs that it was the peak of a period of drought which had been gradually but systematically increasing for over three hundred years.
Just behind the farmhouse on Rietfontein was a range of hills which divided the farm in half. On the brow of the range were innumerable castles of the Waterberg termite. Many of these termitaries had been dead for some time but just as many were, during the very worst of the drought, alive and intact. I had often before pondered over their secret water supply, but at this time it became a bewildering riddle to me. The whole atmosphere was so dry that even at night there was not the least semblance of dew.
The whole surface of the farm was intersected with canals and ditches, and it could be confirmed by careful examination that along the range there was no trace of water in the earth to a depth of forty feet. With really hard labour we opened two termitaries situated on the summit of the hills. In one we found an eight-foot cobra which covered old Mr Gys van Rooyen and myself with venom. Both of us received it full in the face, but luckily our eyes escaped. [The 'ringhals', or ringneck, of the Boers, Naja nigricollis, which has the power of spitting its venom to a range of about six feet. It aims at the eyes and is very accurate.]
In both these termitaries the palace cavity was six feet below the surface of earth as hard as rock. Yet the whole of the palace cavity and the fungus gardens were moist. In the palace cavity the temperature was two degrees above the normal, blood temperature of the human. Water vapour was present in all the passages. The queen and all her subjects appeared to be perfectly normal.
The only unusual feature we found was that many of the gardens near the palace had dried up. Where did the termites obtain their water? I must confess that I came eventually to the solemn conviction, that the termites in some way or other manufactured water from oxygen and hydrogen. Where they obtained the hydrogen was another inexplicable mystery. But I knew the termites were capable of many wonderful things and my solution seemed the only possible one.
I first came on the track of the truth through an account given me by Mr Jan Wessel Wessels, one of the finest of practical naturalists. He told me that while he was living in Bechuanaland [Botswana] he had twice observed in wells vertical canals made by the termites to incredible depths in order to reach water. Even this I felt was a solution which was difficult to accept.
The termites on the range at Rietfontein would have had to go down vertically to a depth of at least a hundred feet to obtain water.
Then again all our attempts to find the beginning of such an aqueduct were unsuccessful. Later we discovered the reason for this. It was only the widely known and undoubted trustworthiness of Mr Wessels which allowed me to accept the explanation as the true one. Then mere chance ordained that I myself was able to see the whole business functioning.
In this terrible drought, it was not only the termites who were seeking water, but we humans too. On the brow of the aforementioned range was a clump of green bushes which contrasted agreeably with the parched veld. Mr Van Rooyen thought there must be water at this spot and his belief was upheld by a water diviner. Men immediately began excavating a square pit in the centre of the green dump. When the pit was about forty feet deep I was told by the labourers that a termite runway was visible on the north wall for its whole depth, and I lost no time in going to the spot to study the amazing work, in detail. The first fact I established was that the termitary connected with this canal was at least thirty feet away from the pit. I exposed the whole tunnel and also part of the gardens adjacent to the palace cavity. The latter I covered with a wooden lid, to enable me to observe them from time to time. I then discovered that the aqueduct did not descend vertically from the nest, but from the end of a long horizontal passage. This was the reason for our failing to discover it in the termitaries we opened.
I was then enabled also to discover a fact in relation to termite behaviour which would have helped me to infer the existence of a shaft into the depths, before actually seeing one, if only I had been able to reason clearly. When the ground is wet, in rainy seasons, the workers always begin repairing any damage to the outer crust immediately. In dry seasons, however, it takes hours, sometimes days, before the builders make their appearance and tackle the work. No wonder, if each little worker has to descend hundreds of feet to get his masonry. But this solution escaped me. I simply did not think of it!
A pagoda or mushroom termitary
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Another noteworthy point in connection with the vertical shaft was that in one plane, north and south, there were absolutely no bends. In the other plane, east and west, there were many unnecessary bends. This meant that the shaft was visible through its whole length on the north wall of the well, in spite of the turnings east and west. The vertical direction in one plane was of course a great labour-saving to the termites; but why did they not make the borehole absolutely vertical? Their method, like everything else they do, appeared almost but not absolutely perfect. They are extremely wise in some ways and so very stupid in others.
It is possible that the magnetic poles of the earth may have had an influence on this work of the termites. In Australia is found a certain termite, the Magnetic White Ant, which builds an elongated termitary with the longer axis pointing north and south. In their case there is no doubt that building is determined by the magnetic poles of our sphere. So remarkable are the bends occurring only in one plane in the aqueduct of our termites that for the present we may accept the theory that the perpendicularity in one plane is due to the magnetism of the earth. East and West there is no magnetic power to keep the termites in the vertical direction. Every two or three feet in the shaft was situated a small white garden patch, dry and unplanted. It should not be forgotten, however, that I probably never saw more than half of the shaft. At a depth of forty feet, the well was abandoned because the ground even there was still as dry as a bone, whereas Mr Van Rooyen and the water diviner had thought a plentiful supply would be found at twenty-five feet. The distance of the nest from the bottom of the well was sixty-five feet, and here the shaft disappeared into the earth. There is no doubt that there were live gardens deeper down and nearer the water.
I constantly examined workers coming up the shaft under the microscope and nearly all of them had hyphae, seed ready for planting, in their bodies. During my observation I came to certain conclusions:
- That the community could not exist a single day in the terrible drought without water.
- That this could be the only shaft by which water was conveyed; for even for workers like the termites it would take years to reach that depth.
- That they were forced to use this shaft in spite of their intense aversion to light.
It was impossible for them to make a new shaft, and there was no chance of covering the old shaft, for haste, haste and haste again had to be the war-cry of the termites in the terrific struggle in which they were engaged.
In the end I was proved correct in all my conclusions. It was one of the few times when one could prophesy with certainty. I had the opportunity of watching their struggle for existence for months and of learning and understanding step by step all that was happening. During this time I visited the shaft at all hours of the day and night from sunset to sunrise, and never for one moment did I discover any cessation of the infinite labour. Nor was there even the least slackening. Once I marked a number of workers with aniline blue and could establish the fact that they never rested or slept, that they worked day and night, that the same workers who were marked by day were busy at night climbing up and down.
It is noteworthy that in the beginning I did not get the impression of haste and alarm which I received so clearly some time later. There were two streams of workers, those on the right going down, those on the left going up, and this order was maintained to the very last. The two streams were in single file, with a distance of about two inches separating each termite from the next one. The workers I marked took, in the beginning, about half an hour to reach the end of the shaft and return to the nest with their load from the depths. Later on this period shortened until it became about twenty minutes.
I then became aware that the whole character of the activity was changing. There was a slowly increasing concentration on the aqueduct, the streams of termites became thicker and thicker, and I got an impression of general consternation. It took me a long time to discover the real reason for this. I could see they were occupied with some task which taxed the energy and power of resistance of the community to the utmost. What exactly did it signify? There was a complete cessation of any repair work. No attempt was made to cover over the shaft. A breach made in the termitary was simply ignored, while all workers and soldiers in the neighbourhood disappeared. After a week or ten days a meagre cordon of soldiers appeared at the edge of the wound, and then sporadic attempts at repair were made by the workers. The necessary building materials were brought from the depths of the shaft. My own inference was that all the disturbance and heightened circulation was concentrated on the palace cavity, and that the object of it was to convey water to the queen, larvae and soldiers. I knew that the queen was merely a bag of liquid; that she laid on an average one hundred and fifty thousand eggs every twenty-four hours, and that for the purposes of all her functions she must require a constant and copious supply of water, while ninety per cent of the bodies of the rest of the termites consisted of water.
But the provision of water to the living termites was not the only reason for this quickened pulse. When I exposed the outer gardens, I noticed there, on a line dividing the gardens in two there was a constantly crawling throng of termites. I had forgotten that for the king and queen, for larvae and soldiers, these gardens were just as necessary as a water supply. The gardens, as I explained before, are digestive organs without which the community could not exist for even one day.
All the above-mentioned types are entirely dependent on the gardens, for the workers are the only type which can make use of partially digested food. The gardens are the stomach and the liver of the composite animal. The workers are the mouth and teeth. Long and very careful observation was necessary to enable me to understand what the enormous concentration on the gardens meant. At last I noticed that all the gardens external to the line I have mentioned were parched and that this death of the gardens was creeping inward from day to day. It was on this line dividing the dead gardens from the living that I found the greatest concentration of activity. It took the form of a terrific onslaught, engaged in with such fury that the workers and soldiers could spare no moment for rest. It was a mighty struggle against death's stealthy approach; there was no respite for the defenders day or night.
The workers were engaged in replanting hyphae round the living gardens, and in irrigating these freshly planted seeds; and every little seed, every drop of moisture had to be carried a hundred feet out of the depths of the earth. Sixty-five feet of this distance was visible to me. During the night the defenders would gain ground. During this cool period when evaporation was at its lowest ebb the line would be pushed outwards a half or a quarter of an inch. During the heat of the day, however, the enemy would press heavily and gain the hardly won advance.
It was at night, during the hours when the rest of nature was quietest, that the fierceness of the fight gained most frenzy. I could hear distinctly the unceasing alarm calls of the soldiers, a sound which roused even in me a feeling of terrible anxiety. My electric searchlight revealed the restless stream constantly passing to and fro, as sure and indomitable as fate itself. Nothing could turn them from their purpose, no external terror could distract them. The death of a thousand individuals made not the least impression on that living stream. Vaguely and faintly, I began to realize, as I watched, what the struggle for existence really means in nature.
Next: 14. The First Architects
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