THE GEOTRUPES: THE PUBLIC HEALTH

To complete the cycle of the year in the adult form, to see one’s self surrounded by one’s sons at the spring festival, to double and treble one’s family: that surely is a most exceptional privilege in the insect world. The Bees, the aristocracy of instinct, perish once the honey-pot is filled; the Butterflies, the aristocracy not of instinct but of dress, die when they have fastened their packet of eggs in a propitious spot; the richly-armoured Ground-beetles succumb when the germs of a posterity are scattered beneath the stones.

So with the others, except among the social insects, where the mother survives, either alone or accompanied by her attendants. It is a general law: the insect is born orphaned of both its parents. And lo, by an unexpected turn of fate, the humble scavenger escapes the catastrophes that devour the mighty! The Dung-beetle, sated with days, becomes a patriarch.

This longevity explains first of all a fact that struck me long ago, when, to learn a little about the tribes whose history attracted me so greatly, I used to stick rows of Beetles on pins in my boxes. Ground-beetles, Rose-chafers, Buprestes, Capricorns, Saperdæ1 and the rest were collected one by one, after prolonged search. Now and again a lucky find would make my cheeks glow with [190]excitement. Exclamations broke from our prentice band when one of these rarities was captured. A touch of jealousy accompanied our congratulations of the proud possessor. It was bound to be so; for think: there were not enough to go round.

A Scalary Saperda, the denizen of dead cherry-trees, clad in deep yellow with ladder-like markings of black velvet; a purply Ground-beetle, edged with amethyst along his ebony wing-cases; a brilliant Buprestis, wedding the sheen of gold and copper to the gorgeous green of malachite: these were great events, far too infrequent to satisfy us all.

With the Dung-beetles you can sing a different song! These are the ones if you want to fill the greediest of asphyxiating-phials to the neck. They, especially the smaller ones, are a numberless multitude when the others are few and far between. I remember Onthophagi and Aphodii swarming by the thousand under one shelter. You could have shovelled them up if you wished.

To this day I am still astonished when I see these crowds again; as of old, the abundance of the Dung-beetle family forms a striking contrast with the comparative scarcity of the others. If it occurred to me to go a-hunting once more and renew the quest to which I owe moments of such sheer delight, I should be certain of filling my flasks with Scarabæi, Copres, Geotrupes, Onthophagi and other members of the same corporation before achieving any measure of success with the rest of the series. By the time that May comes, the distiller of ordure is there in numbers; and in July and August, those months of blazing heat which see the suspension of labour in the fields, the dealer in unsavoury matter is still at work while the others have taken to earth and [191]are lying in motionless torpor. He and his contemporary, the Cicada,2 represent almost by themselves such activity as prevails during the torrid days.

May not this greater frequency of the Dung-beetles, at least in my part of the world, be due to the longevity of the adult form? I think so. Whereas the other insects are summoned to enjoy the fine weather only in successive generations, these receive a general invitation, father and sons together, daughters and mother together. Being equally prolific, they are therefore represented twice over.

And they really deserve it, in consideration of the services which they render. There is a general hygienic law which requires that every putrid thing shall disappear in the shortest possible time. Paris has not yet solved the formidable problem of her sewage, which sooner or later will become a question of life or death for the monstrous city. One asks one’s self whether the centre of light is not doomed to be extinguished some day in the reeking exhalations of a soil saturated with putrescence. What this agglomeration of millions of men cannot obtain, with all its treasures of wealth and talent, the smallest hamlet possesses without going to any expense or even troubling to think about it.

Nature, so lavish of her cares in respect of rural health, is indifferent to the welfare of cities, if not actively hostile to it. She has created for the fields two classes of scavengers, whom nothing wearies, whom nothing repels. One of these, consisting of Flies, Silphæ, Dermestes, Necrophori, Histers is charged with the dissection of corpses. They cut and hash, they elaborate the waste [192]matter of death in their stomachs in order to restore it to life.

A Mole ripped open by the ploughshare soils the path with its entrails, which soon turn purple; a Snake lies on the grass, crushed by the foot of a wayfarer who thought, the fool, that he was performing a good work; an unfledged bird, fallen from its nest, lies, a crushed and pathetic heap, at the foot of the tree that carried it; thousands of other similar remains, of every sort and kind, are scattered here and there, threatening danger through their effluvia, if no steps be taken to put things right. Have no fear: no sooner is a corpse signalled in any direction than the little undertakers come trotting along. They work away at it, empty it, consume it to the bone, or at least reduce it to the dryness of a mummy. In less than twenty-four hours, Mole, Snake, bird have disappeared and the requirements of health are satisfied.

The same zeal for their task exists in the second class of scavengers. The village hardly knows those ammonia-scented refuges to which the townsman repairs to relieve his sordid needs. A little bit of a wall, a hedge, a bush is all that the peasant asks as a retreat at the moment when he would fain be alone. I need say no more to suggest the encounters to which such free and easy manners expose you! Enticed by the patches of lichen, the cushions of moss, the tufts of houseleek and other pretty things that adorn old stones, you go up to a sort of wall that supports a vineyard. Faugh! At the foot of the daintily-decked shelter, what an unconcealed abomination! You flee: lichens, mosses and houseleek tempt you no more. But come back on the morrow. The thing has disappeared, the place is clean: the Dung-beetles have been that way.[193]

To preserve the eyes from a frequent recurrence of offensive sights is, to these stalwart workers, the least of their tasks: a loftier mission is incumbent on them. Science tells us that the most dreadful scourges of mankind have their agents of dissemination in tiny organisms, the microbes, near neighbours of must and mould, on the extreme confines of the vegetable kingdom. At times of epidemic, the terrible germs multiply by countless myriads in the intestinal discharges. They contaminate those main necessities of life, the air and the water; they spread over our linen, our clothes, our food and thus diffuse contagion. We have to destroy by fire, to sterilize with corrosives or to bury underground such things as are infected with them.

Prudence even demands that we should never allow ordure to linger on the surface of the ground. It may be harmless or it may be dangerous: when in doubt, the best thing is to put it out of sight. That is how ancient wisdom seems to have understood the thing, long before the microbe explained to us the need for vigilance. The nations of the east, more liable than we to epidemics, had formal laws in these matters. Moses, apparently echoing Egyptian knowledge in this case, tabulated the rules of conduct for his people wandering in the Arabian desert:

[194]

The simple precept touches a matter of grave concern; and we may well believe that, if Islam, at the time of its great pilgrimages to the Kaaba, were to take the same precaution and a few more of a similar character, Mecca would cease to be an annual seat of cholera and Europe would not need to mount guard on the shores of the Red Sea to protect herself against the scourge.

Heedless of hygiene as the Arab, who was one of his ancestors, the Provençal peasant does not suspect the danger. Fortunately, the Dung-beetle, that faithful observer of the Mosaic law, is at work. It is his to remove from sight, it is his to bury the microbe-laden matter. Supplied with digging-implements far superior to the paddle which the Israelite was to carry at his girdle when urgent business called him from the camp, he hastens to the spot and, as soon as man is gone, excavates a pit wherein the infection is swallowed up and rendered harmless.

The services rendered by these sextons are of the highest importance to the health of the fields; yet we, who are those most interested in this constant work of purification, hardly vouchsafe the sturdy toilers a contemptuous glance. Popular language overwhelms them with harsh epithets. This appears to be the rule: do good and you shall be misjudged, you shall be traduced, stoned, trodden underfoot, as witness the Toad, the Bat, the Hedgehog, the Owl and other helpers who, for their services, ask nothing but a little tolerance.

Now, of our defenders against the dangers of filth flaunted shamelessly in the rays of the sun, the most remarkable in our climes are the Geotrupes: not that they are more zealous than the others, but because their size makes them capable of heavier work. Moreover, when [195]it is simply a question of their nourishment, they resort by preference to the materials which we have most to fear.

My neighbourhood is worked by four species of Geotrupes. Two of them, G. mutator, Marsh, and G. sylvaticus, Panz., are rarities on which we had best not count for connected studies; the two others, on the contrary, G. stercorarius, Lin., and G. hypocrita, Schneid., are exceedingly common. Black as ink above, both of them are magnificently garbed below. We are quite surprised to find such a jewel-case among the professional scavengers. The under surface of the Stercoraceous Geotrupes is of a splendid amethyst-violet, while that of the Mimic Geotrupes makes a generous display of the ruddy gleams of copper pyrites. These two species are the inmates of my insect-houses.

Let us ask them first of what feats they are capable as buriers. There are a dozen of them in all. The cage is previously swept clean of what remains of the former provisions, hitherto supplied without stint. This time, I propose to find out what a Geotrupes can stow away in one night. At sunset, I serve to my twelve captives the whole of a heap which a Mule has just dropped in front of my door. There is plenty of it, enough to fill a basket.

On the morning of the next day, the mass has disappeared underground. There is nothing left outside, or very nearly nothing. I am able to make a fairly close estimate and I find that each of my Geotrupes, presuming each of the twelve to have done an equal share of the work, has buried pretty nearly sixty cubic inches of matter: a Titanic task, when we remember the insignificant size of the insect, which, moreover, has to dig the warehouse to which the booty must be lowered. And all this is done in the space of a night.[196]

Having feathered their nests so well, will they remain quietly underground with their treasure? Not they! The weather is magnificent. The hour of twilight comes, gentle and calm. Now is the time when long flights are undertaken, when joyous humming fills the air, when the insects go afar, searching the roads by which the herds have lately passed. My lodgers abandon their cellars and mount to the surface. I hear them buzzing, climbing up the wirework, bumping wildly against the walls. I have anticipated this twilight animation. Provisions have been collected during the day, plentiful as those of yesterday. I serve them. There is the same disappearance during the night. On the morrow, the place is once again swept clean. And this would continue indefinitely, so fine are the evenings, if I always had at my disposal the wherewithal to satisfy these insatiable hoarders.

Rich though his booty be, the Geotrupes leaves it at sunset to dally in the last gleams of daylight and to go in search of a new workplace. With him, one would say, the wealth acquired does not count; the only thing of value is that to be acquired. Then what does he do with his warehouses, renewed each twilight in favourable weather? It is obvious that the Dung-beetle is incapable of consuming all those provisions in a single night. He has such a superabundance of victuals in his larder that he does not know how to dispose of them; he is surfeited with good things by which he will not profit; and, not satisfied with having his store crammed, the acquisitive plutocrat slaves, night after night, to store away more.

From each warehouse, set up here, set up there, as things happen, he deducts the daily meal beforehand; the rest, which means almost the whole, he abandons. My cages testify to the fact that this instinct for burying [197]is more imperative than the consumer’s appetite. The ground is soon raised, in consequence; and I am obliged, from time to time, to lower the level to the desired limits. If I dig it up, I find it choked throughout its depth with hoards that have remained intact. The original earth has become a hopeless conglomeration, which I must prune freely, if I would not go astray in my future observations.

Allowing for errors, either of excess or deficiency, which are inevitable in a subject that does not admit of exact measurement, one point stands out very clearly as the result of my enquiry: the Geotrupes are enthusiastic buriers; they take underground a great deal more than is necessary for their consumption. As this work is performed, in varying degrees, by legions of collaborators, large and small, it is evident that the purification of the soil must benefit to a considerable extent and that the public health is to be congratulated on having this army of auxiliaries in its service.

In addition, the plant and, indirectly, a host of different existences are interested in these interments. What the Geotrupes buries and abandons the next day is not lost: far from it. Nothing is lost in the world’s balance-sheet; at stock-taking, the total never varies. The little lump of dung buried by the insect will make the nearest tuft of grass grow a luxuriant green. A Sheep passes, crops the bunch of grass: all the better for the leg of mutton which man is waiting for; the Dung-beetle’s industry has procured us a savoury mouthful.

Even that is something, though we are making our usual mistake of comparing everything with our own standard. How much more it becomes, once we begin to think and get away from this narrow point of view! To [198]enumerate all those who benefit, directly or indirectly, by the Dung-beetle’s work would be impossible, so inextricably interlinked is all that exists. I think of the Warbler, who will stuff the mattress of his nest with the tiny stalks retted by the rain and sun; the caterpillar of some Psyche, which will construct its Moth-case by imbricating the remnants of those same stalks; little Cockchafers, who will nibble the anthers of the tall grasses; tiny Weevils, who will turn the ripe seeds into cradles for their grubs; tribes of Aphides, who will settle under the leaves; and Ants, who will come and slake their thirst at the sugary cornicles of the last-named herd.

Let us be content with this list, or we shall never have done. A whole world is benefited by the agricultural industry of the Dung-beetle, that burier of manure: first the plant and then all that live upon the plant. A small world, a very small world, as small as you please, but after all not a negligible world. It is of such trifles that the great integral of life is composed, even as the integral of the mathematicians is composed of quantities neighbouring on 0.

Agricultural chemistry teaches us that, to employ the stable-dung to the best purpose, we should put it into the ground, so far as possible, while fresh. When diluted by the rain and dissipated by the air, it becomes lifeless and devoid of fertilizing elements. This highly important agronomic truth is quite familiar to the Geotrupes and his colleagues. In their burying-work they invariably aim at materials of recent date. Just as they are eager to put away the produce of the moment, all saturated with its potassium, its nitrates and its phosphates, even so do they scorn the stuff hardened into [199]brick by the sun or rendered infertile by long exposure to the air. The valueless residue does not interest them; they leave this barren rubbish to others.

We now know about the Geotrupes as a sanitary expert and a collector of manure. We are going to see him in a third aspect, that of the sagacious weather-prophet. It is popularly believed, in the country-side, that a swarm of agitated Geotrupes, skimming the ground with an air of great business in the evening, is a sign of fine weather on the morrow. Is this rustic prognostication worth anything? My cages shall tell us. I watch my boarders closely all through the autumn, the period when they build their nests; I note the state of the sky on the day before and register the weather of the next day. I use no thermometer, no barometer, none of the scientific implements employed in the meteorological observatories. I confine myself to the summary information derived from my personal impressions.

The Geotrupes do not leave their burrows until after sundown. With the last glimmer of daylight, if the air be calm and the temperature mild, they roam about, flying low with a humming noise, seeking the materials which have accumulated for them in the course of the day. If they come upon something that suits them, they drop down heavily, tumbling over in their clumsy eagerness, thrust themselves into their new treasure and spend the best part of the night in burying it. In this way the dirt of the fields is made to disappear in a single night.

There is one condition indispensable to this purging-process: the atmosphere must be still and warm. Should it rain, the Geotrupes will not stir out of doors. They have sufficient resources underground for a prolonged holiday. Should it be cold, should the north-wind blow, [200]they will not sally forth either. In both cases my cages remain deserted on the surface. We will leave out of the question these periods of enforced leisure and consider only those evenings on which the atmospheric conditions are favourable to foraging-expeditions, or at least seem to me as though they ought to be. I will summarize the details in my note-book in three general cases.

First case. A glorious evening. The Geotrupes fuss about the cages, impatient to hasten to their nocturnal task. Next day, magnificent weather. The prophecy, of course, is of the simplest. To-day’s fine weather is only the continuation of yesterday’s. If the Geotrupes know nothing more than this, they hardly deserve their reputation. However, let us pursue the experiment before drawing any conclusions.

Second case. Again a fine evening. My experience seems to say that the condition of the sky forebodes a fine morning. The Geotrupes think otherwise. They do not come out. Which of the two will be right, man or Dung-beetle? The Dung-beetle: thanks to the keenness of his perceptions, he foresees, he scents a downpour. Rain comes during the night and lasts for part of the day.

Third case. The sky is overcast. Will the south-wind, gathering its clouds, bring us rain? I am of that opinion, appearances seem so much to point that way. The Geotrupes, however, fly and buzz around their cages. Their prophecy is correct and I am wrong. The threat of rain is dispelled and the sun next morning rises radiantly.

They seem to be influenced above all by the electric tension of the atmosphere. On hot and sultry evenings, when a storm is brewing, I see them moving about even [201]more than usual. The morrow is always marked by violent claps of thunder.

There you have the upshot of my observations, which were continued for three months. Whatever the condition of the sky, whether clear or clouded, the Geotrupes announce fair weather or storm by their excited movements in the evening twilight. They are living barometers, more worthy of belief perhaps, in such contingencies, than the barometer of our scientists. The exquisite sensitiveness of life is mightier than the brute weight of a column of mercury.

I will end by mentioning a fact that well deserves further investigation when circumstances permit. On the twelfth, thirteenth and fourteenth of November 1894, the Geotrupes in my cages are in an extraordinarily agitated condition. Never before and never since have I seen such animation. They clamber wildly up the wires; at every moment they take wing and at once bump against the walls and are flung to the ground. Their restlessness continues until a late hour of the night, a very unusual thing with them. Out of doors, a few free neighbours run up and complete the riot in front of my house. What can be happening to bring these strangers here and especially to throw my cages into such a state of excitement?

After a few hot days, which are most exceptional at this time of the year, the south-wind prevails, foretelling that rain is at hand. On the evening of the fourteenth, an endless procession of broken clouds passes before the face of the moon. It is a magnificent sight. During the night the wind drops. There is not a breath of air. The sky is a uniform grey. The rain pours straight down, monotonously, continuously, depressingly. It looks as [202]though it would never stop. And it goes on, in fact, until the eighteenth of the month.

Did the Geotrupes, who were so restless on the twelfth, foresee this deluge? They did. But as a rule they do not quit their burrows at the approach of rain. Something very extraordinary must have happened, therefore, to upset them in this way.

The newspapers explained the riddle. On the twelfth a storm of unprecedented violence burst over the north of France. The great barometrical depression which caused it was echoed in my district; and the Geotrupes marked this profound disturbance by their exceptional display of emotion. They told me of the hurricane before the papers did, had I but been able to understand them. Was this simply a chance coincidence, or was it a case of cause and effect? In the absence of sufficient evidence, I will end on this note of interrogation.