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, Saperdæ [47] and
the rest were collected one by one, after prolonged search. Now and
again a lucky find would make my cheeks glow with 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 are lying in
motionless torpor. He and his contemporary, the Cicada, [48] 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 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.
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:
‘Thou shalt have a place without the camp,’ he says, ‘to which thou
mayst go for the necessities of nature, carrying a paddle at thy
girdle. And, when thou sittest down, thou shalt dig round about and
with the earth that is dug up thou shalt cover that which thou art
eased of’ (Deut. xxiii. 12–14).
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 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.
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 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
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 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, 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 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 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.