THE SPANISH COPRIS: THE LAYING OF THE EGGS
If we show instinct doing for the egg what would be done on the advice
of reason matured by study and experience, we achieve a result of no
small philosophic importance; and an austere scientific conscience
begins to trouble me with scruples. Not that I wish to give science a
forbidding aspect: I am convinced that one can say the wisest things
without employing a barbarous vocabulary. Clearness is the supreme
courtesy of the wielder of the pen. I do my best to observe it. No, the
scruple that stops me is of another kind.
I begin to wonder if I am not in this case the victim of an illusion. I
say to myself:
‘Gymnopleuri and Sacred Beetles, when in the open air, are
manufacturers of balls or pills. That is their trade, learnt we know
not how, prescribed perhaps by their structure, in particular by their
long legs, some of which are slightly curved. When they are making
preparations for the egg, is it so wonderful that they continue
underground their own ball-making speciality?’
If we leave out of the question the neck of the pear and the projecting
tip of the ovoid, details much more difficult to explain, there remains
the most important part so far as bulk is concerned, the globular part,
a repetition of the thing which the insect makes outside the burrow;
there remains the pellet with which the Sacred Beetle plays in the
sunshine, sometimes without making any other use of it, the ball which
the Gymnopleurus rolls peacefully over the turf.
Then what is the object here of the globular form, the best
preventative of desiccation during the heat of summer? This property of
the sphere and of its near neighbour, the ovoid, is an accepted
physical fact; but it is only by accident that these shapes are the
right ones to overcome that difficulty. A creature built for rolling
balls across the fields goes on making balls underground. If the grub
fare all the better for finding tender foodstuffs under its mandibles
to the very end, that is a capital thing for the grub, but it is no
reason why we should extol the instinct of the mother.
So I argued, saying to myself that, before I was convinced, I should
need to be shown a Dung-beetle who was utterly unfamiliar with the
pill-making business in everyday life and who yet, when laying-time was
at hand, made an abrupt change in her habits and shaped her provisions
into a ball. My Dung-beetle would have to be a good fat one too. Is
there any such in my neighbourhood? Yes, there is; and she is one of
the handsomest and largest, next to the Sacred Beetle. I speak of the
Spanish Copris (C. hispanus, Lin.), who is so remarkable on account of
the sharp slope of her corselet and the disproportionate size of the
horn surmounting her head.
Round and squat, the Spanish Copris with her ponderous gait is
certainly a stranger to gymnastics such as are performed by the Sacred
Beetle or the Gymnopleurus. Her legs, which are of insignificant length
and folded under her belly at the slightest alarm, bear no comparison
with the stilts of the pill-rollers. Their stunted form and lack of
flexibility are enough in themselves to tell us that their owner would
not care to roam about hampered by a rolling ball.
The Copris is indeed of a sedentary habit. Once he has found his
provisions, at night or in the evening twilight, he digs a burrow under
the heap. It is a rough cavern, large enough to hold an apple. Here is
introduced, bit by bit, the stuff that is just over his head or at any
rate lying on the threshold of the cavern; here is engulfed, in no
definite shape, an enormous supply of victuals, bearing eloquent
witness to the insect’s gluttony. As long as the hoard lasts, the
Copris, engrossed in the pleasures of the table, does not return to the
surface. The home is not abandoned until the larder is emptied, when
the insect recommences its nocturnal quest, finds a new treasure and
scoops out another temporary dwelling.
As his trade is merely that of a gatherer of manure, shovelling in the
stuff without any preliminary manipulation, the Copris is evidently
quite ignorant, for the time being, of the art of kneading and
modelling a globular loaf. Besides, his short, clumsy legs seem utterly
irreconcilable with any such art.
In May, or June at latest, comes laying-time. The insect, so ready to
fill its own belly with the most sordid materials, becomes particular
where the portion of its family is concerned. Like the Sacred Beetle,
like the Gymnopleurus, it now wants the soft produce of the Sheep,
deposited in a single slab. Even when abundant, the cake is buried on
the spot in its entirety. Not a trace of it remains outside. Economy
demands that it be collected to the very last crumb.
You see: no travelling, no carting, no preparations. The cake is
carried down to the cellar by armfuls, at the very spot where it lies.
The insect repeats, with an eye to its grubs, what it did when working
for itself. As for the burrow, whose presence is indicated by a
good-sized mound, it is a roomy cavern excavated to a depth of some
eight inches. I observe that it is more spacious and better built than
the temporary abodes occupied by the Copris at times of revelry.
But let us turn from the insect in its wild state to the insect in
captivity. In the former case the evidence furnished by chance
encounters would be incomplete, fragmentary and of dubious relevancy;
and we shall do better to watch the Copris in my insect-house,
especially as she lends herself admirably to this sort of observation.
Let us observe the storing first.
In the soft evening light I see her appear on the threshold of her
burrow. She has come up from the depths, she is going to gather in her
harvest. She has not far to go: the provisions are there, outside the
door, a generous supply which I am careful to replenish. Cautiously,
ready to retreat at the least alarm, she makes her way to them with a
slow and measured step. Her shield does the rummaging and dissecting,
her fore-legs are busy extracting. An armful, quite a modest one, is
pulled away, crumbling to pieces. The Copris drags it backwards and
disappears underground. In less than two minutes, she is back again.
With feathery antennæ outspread, she warily scans the neighbourhood
before crossing the threshold of her dwelling.
A distance of two or three inches separates her from the heap of
provisions. It is a serious matter for her to venture so far. She would
have liked the victuals to be exactly overhead, forming a roof to her
house. That would have saved her from having to make these expeditions,
which are a source of anxiety. I have decided otherwise. To facilitate
observation, I have placed the supplies just on one side. By degrees
the nervous creature is reassured; it becomes accustomed to the open
air and to my presence, which, of course, I make as unobtrusive as
possible. Armful after armful goes down into the cellar. They are
always shapeless bits, shreds such as one might pick off with a small
pair of pincers.
Having learnt what I want to know about the insect’s method of
warehousing its provisions, I leave it to its work, which continues for
the best part of the night. On the following days, nothing happens; the
Copris goes out no more. Enough treasure has been laid up in a single
night. Let us wait a while and leave her time to stow away her stuff as
she pleases.
Before the week is out, I dig up the soil in my insect-house and bring
to light the burrow whose victualling I have been watching. As in the
fields, it is a spacious hall with an irregular, elliptic roof and an
almost level floor. In a corner is a round hole, similar to the orifice
in the neck of a bottle. This is the goods-entrance, opening on a
slanting gallery that runs up to the surface of the soil. The walls of
this house, which was hollowed out of fresh earth, have been carefully
compressed and are strong enough to resist any seismic disturbances
caused by my excavations. It is easy to see that the insect, toiling
for the future, has put forth all its skill, all its digging-powers, in
order to produce lasting work. The banqueting-tent may be a hole
hurriedly scooped out, with irregular and none too stable walls, but
the permanent dwelling is of larger dimensions and much more carefully
built.
I suspect that both sexes have a share in this architectural
masterpiece; at least, I often come upon the pair in the burrows
destined for the laying of the eggs. The roomy and luxurious apartment
was no doubt once the wedding-hall; the marriage was consummated under
the mighty dome in the building of which the lover had cooperated: a
gallant way of declaring his passion. I also suspect him of lending his
partner a hand with the collecting and storing of the provisions. From
what I have gathered, he too, strong as he is, shares in this finicking
work, collects his armfuls and descends into the crypt. It is a quicker
job when there are two to help. But, once the home is well stocked, he
retires discreetly, makes his way back to the surface and goes and
settles down elsewhere, leaving the mother to her delicate task. His
part in the family-mansion is ended.
Now what do we find in this mansion, to which we have seen so many tiny
loads of provisions lowered? A mass of small pieces, heaped together
anyhow? Not a bit of it. I always find a simple lump, a huge loaf which
fills the dwelling except for a narrow passage all round, just wide
enough to give the mother room to move.
This sumptuous portion, a regular Twelfth-Night cake, has no fixed
shape. I come across some that are ovoid, suggesting a Turkey’s egg in
form and size; I find some that are a flattened ellipsoid, similar to
the common onion; I discover some that are almost round, reminding me
of a Dutch cheese; I see some that are circular with a slight swelling
on the upper surface, like the loaves of the Provençal peasant or,
better still, the egg-cake, the fougasso à l’iôu with which he
celebrates Easter. In every case the surface is smooth and nicely
curved.
There is no mistaking what has happened: the mother has collected and
kneaded into one lump the numerous fragments brought down one after the
other; out of all those particles she has made a homogeneous thing, by
mashing them, working them together and treading on them. Time after
time I come across the baker on top of the colossal loaf which makes
the Sacred Beetle’s pill look so insignificant; she strolls about on
the convex surface, which sometimes measures as much as four inches
across; she pats the mass, makes it firm and level. I just catch sight
of the curious scene, for, the moment she is perceived, the pastry-cook
slips down the curved slope and hides away under her cake.
For a further knowledge of the work, for a study of its innermost
detail, we shall have to resort to artifice. There is scarcely any
difficulty about it. Either my long practice with the Sacred Beetle has
made me more skilful in my methods of research, or else the Copris is
less reserved and bears the rigours of captivity more philosophically:
at any rate, I succeed, without the slightest trouble, in following all
the phases of the nest-making to my heart’s content.
I employ two methods, each of them adapted for enlightening me on some
special points. Whenever the vivarium supplies me with a few large
cakes, I take these out of the burrows, together with the mother
Copris, and place them in my study. The receptacles are of two sorts,
according to whether I want light or darkness. In the former case, I
use glass jars with a diameter more or less the same as that of the
burrows, say four to five inches. At the bottom of each is a thin layer
of fresh sand, quite insufficient to allow the Copris to bury herself
in it, but still serving the purpose of sparing the insect the slippery
foothold of the actual glass and giving it the illusion of a soil
similar to that of which I have just deprived it. With this layer the
jar becomes a suitable cage for the mother and her loaf.
I need hardly say that the startled insect would not undertake anything
while light prevailed, no matter how dim and tempered. It must have
complete darkness, which I produce by means of a cardboard sheath
enclosing the jar. By carefully raising this sheath a little, I can
surprise the captive at her work whenever I feel inclined, the light in
my study being a shaded one, and even watch operations for a time. The
reader will notice that this arrangement is much less complex than that
which I used when I wished to see the Sacred Beetle engaged in
modelling her pear, the simpler method being made possible by the
different temperament of the Copris, who is more easy-going than her
kinswoman. A dozen of these eclipsed appliances are thus arranged on my
large laboratory-table. Any one seeing them standing in a row would
take them for a collection of groceries in whity-brown paper bags.
For my dark apparatus I use flower-pots filled with fresh, well-packed
sand. The mother and her cake occupy the lower part, which is adapted
as a niche by means of a cardboard screen forming a ceiling and
supporting the sand above. Or else I simply put the mother on the
surface of the sand with a supply of provisions. She digs herself a
burrow, does her warehousing, makes herself a home; and things follow
the usual course. In all cases I rely upon a sheet of glass, which does
duty as a lid, to keep my prisoners safe. These different devices will,
I trust, give me information on a delicate point of which I will say
more later.
What do the glass jars covered with an opaque sheath teach us? A good
many things, all of them interesting, and this to begin with: the big
loaf does not owe its curve—which is always regular, no matter how much
the actual shape may vary—to any rolling process. Our inspection of the
natural burrow has already told us that so large a mass could not have
been rolled into a cavity of which it fills almost the whole space.
Besides, the strength of the insect would be unequal to moving so great
a load.
From time to time I go to the jar for information and on every occasion
the same evidence is forthcoming. I see the mother, hoisted on top of
the lump, feeling here, feeling there, bestowing little taps, smoothing
away the projecting points, perfecting the thing; never do I catch her
looking as though she wanted to turn the block. It is clear as
daylight: rolling has nothing whatever to do with the matter.
The dough-maker’s assiduity, her patient care make me suspect an
industrial detail whereof I was far from dreaming. Why so many
after-touches to the mass, why so long a wait before making use of it?
It is, in fact, a week or more before the insect, still busy with its
pressing and polishing, makes up its mind to do something with its
hoard.
When the baker has kneaded his dough to the requisite extent, he
collects it into a single lump in a corner of the kneading-trough. The
leaven will work better in the depths of the voluminous mass. The
Copris knows this bakehouse secret. She heaps together all that she has
collected in her foraging; she carefully kneads the whole into a
provisional loaf and allows it time to improve by virtue of an internal
process that gives flavour to the paste and makes it of the right
consistency for subsequent manipulations. As long as this chemical
process remains unfinished, both the baker and the Copris wait. In the
case of the insect, it goes on for some time, a week at least.
At last it is ready. The baker’s man divides his lump into smaller
lumps, each of which will become a loaf. The Copris does the same
thing. By means of a circular cut made with the sharp edge of her
forehead and the saw of her fore-legs, she detaches from the mass a
piece of the prescribed size. With this stroke there is no hesitation,
no after-touches adding a bit here and taking off a bit there. Straight
away and with one sharp, decisive cut, she obtains the proper-sized
lump.
It now becomes a question of shaping it. Clasping it as best she can in
her short arms, so little adapted, one would think, to work of this
kind, the Copris rounds her lump of dough by means of pressure and of
pressure only. Gravely she moves about on the still shapeless pill,
climbs up, climbs down, turns to right and left, above and below; here
she methodically applies a little more pressure, there a little less,
touching and retouching with unvarying patience, and finally, after
twenty-four hours of it, the piece that was all corners has become a
perfect sphere, the size of a plum. There, in her crowded studio, with
scarcely room to move, the podgy artist has completed her work without
once shaking it on its base; by dint of time and patience she has
obtained the geometrical sphere which her clumsy tools and her confined
space seemed bound to deny her.
For a long time the insect continues to touch up its globe, polishing
it affectionately, passing its foot gently to and fro until the least
protuberance has disappeared. These meticulous finishing touches seem
endless. Towards the end of the second day, however, the sphere is
pronounced satisfactory. The mother climbs to the dome of her edifice
and there, still by simple pressure, hollows out a shallow crater. In
this basin the egg is laid.
Then, with extreme caution, with a delicacy that is most surprising
with such rough tools, the lips of the crater are brought together so
as to form a vaulted roof over the egg. The mother turns slowly, does a
little raking, draws the stuff upwards and finishes the
closing-process. This is the most ticklish work of all. A little too
much pressure, a miscalculated thrust might easily jeopardize the life
of the germ under its thin ceiling.
Every now and then the mother suspends operations. Motionless, with
lowered forehead, she seems to be sounding the cavity beneath, to be
listening to what is happening inside. All’s well, it seems; and once
again she resumes her patient toil: the careful, delicate scraping of
the sides towards the summit, which begins to taper a little and
lengthen out. In this way an ovoid with the small end uppermost takes
the place of the original sphere. Under the more or less projecting
nipple is the hatching-chamber with the egg. Twenty-four hours more are
spent in this minute work. Total: four times round the clock and
sometimes longer to construct the sphere, scoop out a basin, lay the
egg and shut it in by transforming the sphere into an ovoid.
The insect goes back to the cut loaf and helps itself to a second
slice, which, by the same manipulations as before, becomes an ovoid
tenanted by an egg. The surplus suffices for a third ovoid, sometimes
even for a fourth. I have never seen this number exceeded when the
mother had at her disposal only the materials which she had accumulated
in the burrow.
The laying is over. Here is the mother in her retreat, which is almost
filled by the three or four cradles standing one against the other,
pointed end upwards. What will she do now? Go away, no doubt, to
recruit her strength a little in the open air after her prolonged fast.
He who thinks so is mistaken. She stays. And yet she has eaten nothing
since she came underground, taking good care not to touch the loaf,
which, divided into equal portions, will provide the sustenance of the
family. The Copris is touchingly scrupulous where the children’s
inheritance is concerned: she is a devoted mother, who braves hunger
rather than let her offspring suffer privation.
She braves it for a second reason: to mount guard around the cradles.
From the end of June onwards the burrows are difficult to find, because
the mounds disappear through the action of storm or wind or the feet of
the passers-by. The few which I succeed in discovering always contain
the mother dozing beside a group of pills, in each of which a grub, now
nearing its complete development, feasts on the fat of the land.
My dark appliances, flower-pots filled with fresh sand, confirm what
the fields have taught me. Buried with provisions in the first
fortnight in May, the mothers do not reappear on the surface, under the
glass lid. They keep hidden in the burrow after laying their eggs; they
spend the sultry dog-days with their ovoids, watching them, no doubt,
as the glass-jars, with their freedom from subterranean obscurity, tell
us.
They come up again at the time of the first autumnal rains in
September. But by then the new generation has attained its perfect
form. The mother, therefore, enjoys in her underground home that rare
privilege for an insect, the joy of knowing her family; she hears her
children scratching at the shell to obtain their liberty; she is
present at the bursting of the casket which she has fashioned so
conscientiously; maybe she helps the exhausted weaklings when the
ground has not been cool enough to soften the walls. Mother and progeny
leave the underworld together; and together they arrive at the autumn
banquets, when the sun is mild and the ovine manna abounds along the
paths.
The flower-pots teach us something else. I place on the surface a few
separate couples taken from their burrows at the outset of the
building-operations. They are given a generous supply of provisions.
Each couple buries itself, settles down and starts hoarding; then,
after ten days or so, the male reappears on the surface, under the
sheet of glass. The other does not stir an inch. The eggs are laid, the
food-balls are shaped, patiently rounded and grouped at the bottom of
the pot. And all the time, so that he may not disturb the mother in her
work, the father remains exiled from the gynæceum. He has climbed to
the surface with the intention of going and digging himself a shelter
elsewhere. Being unable to do so within the narrow confines of the pot,
he stays at the top, barely concealed from view by a modicum of sand or
a few scraps of food. A lover of darkness and of the cool underground
depths, he remains obstinately for three months exposed to the air and
drought and light; he refuses to go to earth, lest he should interfere
with the sacred things that are taking place below. The Copris shall
have a good mark for thus respecting the maternal apartments.
Let us come back to the jars, where the events hidden from us by the
soil are to be enacted before our eyes. The three or four pills, each
with its egg, stand one against another and occupy almost the whole
enclosure, leaving only narrow passages. Of the original lump very
little remains, at the most a few crumbs, which come in handy when
appetite returns. But that does not worry the mother much. She is far
more concerned about her ovoids.
Assiduously she goes from one to another, feels them, listens to them,
touches them up at points where my eye can perceive no flaw. Her
clumsy, horn-shod foot, more sensitive in darkness than my retina in
broad daylight, is perhaps discovering incipient cracks or defective
workmanship in the matter of consistency which must be attended to, in
order to prevent the air from entering and drying up the eggs. The
prudent mother therefore slips in and out of the narrow spaces between
the cradles, inspecting them carefully and remedying any accident, no
matter how trifling. If I disturb her, she sometimes rubs the tip of
her abdomen against the edge of her wing-cases, producing a soft
rustling noise, which is almost a murmur of complaint. Thus, between
scrupulous care and brief slumbers beside her group of cradles, the
mother passes the three months essential to the evolution of the
family.
I seem to catch a glimpse of the reason for this long watch. The
pill-rollers, whether Scarabs or Gymnopleuri, never have more than a
single pear, a single ovoid in their burrows. The mass of foodstuff,
which at times is rolled from a great distance, is necessarily limited
by the insect’s own limitations of strength. It is enough for one
larva, but not enough for two. An exception must be made with respect
to the Broad-necked Scarab, who brings up her family very frugally and
divides her rolling booty into two modest portions.
The others are obliged to dig a special burrow for each egg. When
everything is in order in the new establishment—and this does not take
long—they leave the underground vault and go off somewhere else,
wherever chance may lead them, to begin their pill-rolling, excavating
and egg-laying once more. With these nomadic habits, any prolonged
supervision on the mother’s part becomes impossible.
The Scarab suffers by it. Her pear, which is magnificently regular at
the outset, soon shows cracks and becomes scaly and swollen. Various
cryptogams invade it and undermine it; the material expands and the
resultant splitting causes the pear to lose its shape. We have seen how
the grub combats these troubles.
The Copris has other ways. She does not roll her stores from a
distance; she warehouses them on the spot, bit by bit, which enables
her to accumulate in a single burrow enough to satisfy all her brood.
As there is no need for further expeditions, the mother stays and keeps
watch. Under her never-failing vigilance, the pill does not crack, for
any crevice is stopped up as soon as it appears; nor does it become
covered with parasitic vegetation, for nothing can grow on a soil that
is constantly being raked. The two or three dozen ovoids which I have
before my eyes all bear witness to the mother’s watchfulness: not one
of them is split or cracked or infested with tiny fungi. In all of them
the surface is irreproachable. But, if I take them away from the mother
to put them into a bottle or tin, they suffer the same fate as the
Sacred Beetle’s pears: in the absence of supervision, destruction more
or less complete overtakes them.
Two examples will be instructive to us here. I take from a mother two
or three pills and place them in a tin, which prevents them from
getting dry. Before a week has passed, they are covered with a fungous
vegetation. More or less everything grows in this fertile soil; the
lesser fungi delight in it. To-day it is an infinitesimal crystalline
plant swollen into a bobbin-shape, bristling with short, dew-beaded
hairs and ending in a little round head as black as jet. I have not the
leisure to consult books and microscope and give a name to the tiny
apparition which attracts my attention for the first time. This
botanical detail is of little importance: all that we need know is that
the dark green of the pills has disappeared under the thick white
crystalline growth stippled with black specks.
I restore the two pills to the Copris keeping watch over her third. I
replace the opaque sheath and leave the insect undisturbed in the dark.
In an hour’s time or less, I look to see how things are getting on. The
parasitic vegetation has entirely disappeared, cut down, extirpated to
the last stalk. The magnifying-glass fails to reveal a trace of what, a
little while before, was a dense thicket. The insect has used its rake,
those notched legs, to some purpose; and the surface of the pill is
once more in the unblemished condition necessary for health.
The other experiment is a more serious one. With the point of my
penknife I make a gash in a pill at the upper end and lay bare the egg.
Here we have an artificial breach not unlike those which might be
caused naturally, but of much greater size. I give back to the mother
the violated cradle, threatened with disaster unless she intervenes.
But she does intervene and that quickly, once darkness comes. The
ragged edges slit by the penknife are brought together and soldered.
The small amount of stuff lost is replaced by scrapings taken from the
sides. In a very short time the breach is so neatly repaired that not a
trace remains of my onslaught.
I repeat it, making the danger graver and attacking all four pills with
my desecrating penknife, which cuts right through the hatching-chamber
and leaves the egg only an incomplete shelter under the gaping roof.
The mother’s counter-move is swift and effective. In one brief spell of
work everything is put right again. Yes, I can quite believe that with
this vigilant supervisor, who never sleeps except with one eye open,
there is no possibility of the cracks and the puffiness which so often
disfigure the Sacred Beetle’s pear.
Four pills containing eggs are all that I have been able to obtain from
the big loaf which I took from the burrow at the time of the nuptials.
Does this mean that the Copris can lay only that number? I think so. I
even believe that usually there are less, three, two, or possibly only
one. My boarders, installed in separate potfuls of sand at
nesting-time, did not reappear on the surface once they had stored away
the necessary provisions; they never came out to dip into the
replenished stock and enable themselves to increase the always
restricted number of ovoids lying at the bottom of the pot under the
mother’s watchful care.
This limitation of the family might very well be due partly to lack of
space. Three or four pills completely fill the burrow; there is no room
for more; and the mother, a stay-at-home alike from duty and
inclination, does not dream of digging another dwelling. It is true
that greater breadth in the one which she has would solve the problem
of room; but then a ceiling of excessive length would be liable to
collapse. Suppose I were myself to intervene, suppose I provided space
without the risk of the roof falling in, could there be an increase in
the number of eggs?
Yes, the number is almost doubled. My trick is quite simple. In one of
the glass jars, I take away her three or four pills from a mother who
has just finished the last. None of the loaf remains. I substitute for
it one of my own making, kneaded with the tip of a paper-knife. A new
type of baker, I do over again very nearly what the insect did at the
beginning. Reader, do not smile at my baking: science shall give it the
odour of sanctity.
My cake is favourably received by the Copris, who sets to work again,
starts laying anew and presents me with three of her perfect ovoids,
making seven in all, the greatest number that I obtained in my various
attempts of this kind. A large piece of the bun remains available. The
Copris does not utilize it, at least not for nest-building; she eats
it. The ovaries appear to be exhausted. This much is proved: the
pillaging of the burrow provides space; and the mother, taking
advantage of it, nearly doubles the number of her eggs with the aid of
the cake which I make for her.
Under natural conditions nothing of a similar kind can happen. There is
no obliging baker at hand, to shape and pat a new cake and slip it into
the oven that is the Copris’ cellar. Everything therefore tells us that
the stay-at-home Beetle, who makes up her mind not to reappear until
the cool autumn days, is of very limited bearing-capacity. Her family
consists of three or four at most. Occasionally, in the dog-days, long
after laying-time is past, I have even dug up a mother watching over a
solitary pill. This one, perhaps for lack of provisions, had reduced
her maternal joys to the narrowest limits.
The loaves kneaded with my paper-knife are readily accepted. We will
take advantage of this fact to make a few experiments. Instead of the
big, substantial cake, I fashion a pill which is a replica in shape and
size of the three or four which the mother is guarding after confiding
the egg to them. My imitation is a fairly good one. If I were to mix up
the two products, the natural and the artificial, I might easily fail
to distinguish between them afterwards. The counterfeit pill is placed
in the jar, beside the other. The disturbed insect at once hides in a
corner, under a little sand. I leave it in peace for a couple of days.
Then how great is my surprise to find the mother on the top of my pill,
digging a cup into it! In the afternoon the egg is laid and the cup
closed. I can only tell my pill from those of the Copris by the place
which it occupies. I had put it at the extreme right of the group, and
at the extreme right I find it, duly operated on by the insect. How
could the Beetle know that this ovoid, so like the others in every
respect, was untenanted? How did she allow herself unhesitatingly to
scoop the top into a crater when, judging by appearances, there might
be an egg just underneath? She takes good care not to do any fresh
excavating on the finished pills. What guide leads her to the
artificial one, which is extremely deceptive in appearance, and bids
her dig into that?
I do it again and yet again. The result is the same: the mother does
not confuse her work with mine and takes advantage of the presence of
my pill to install an egg in it. On only one occasion, when her
appetite seems suddenly to have come back, did I see her feeding on my
loaf. But her discrimination between the tenanted and the untenanted
was just as clearly marked here as in the previous instance. Instead of
attacking, in her hunger, the pills with eggs, by what miracle of
divination does she turn, in spite of their exact outward similarity,
to the pill which contains nothing?
Can my handiwork be defective? Did the wooden blade not press hard
enough to impart the proper consistency? Is there something wrong with
the dough as the result of insufficient kneading? These are delicate
questions, of which I, who am no expert in this kind of confectionery,
am not competent to judge. Let us have recourse to a master of the
pastry-cook’s art. I borrow from the Sacred Beetle the pill which he is
beginning to roll in the vivarium. I choose a small one, of the size
affected by the Copris. True, it is round; but the Copris’ pills also
are pretty often round, even after receiving the egg.
Well, the Sacred Beetle’s loaf, that loaf of irreproachable quality,
kneaded by the king of bread-makers, meets with the same fate as mine.
At one time it is provided with an egg, at another it is eaten, while
no accident ever happens by inadvertence to the exactly similar pills
kneaded by the Copris.
That the insect, finding itself in this mixed assembly, should rip open
what is still inanimate matter and respect what is already a cradle,
that it should discriminate between the lawful and the unlawful, in
circumstances such as these, seems to me incapable of explanation, if
there be no guide but senses resembling our own. It is useless to say
that it is a case of sight: the Beetle works in absolute darkness. Even
if she worked in the light, that would not lessen the difficulty. The
shape and appearance of the pill are alike in both instances; the
clearest sight would be at fault once the pills were mixed up.
It is impossible to suggest that smell has anything to do with it: the
substance of the pill does not vary; it is always the produce of the
Sheep. Impossible likewise to say that she is exercising the sense of
touch. What delicacy of touch can there be under a coat of horn?
Besides, the most exquisite sensitiveness would be required. Even if we
admit that the insect’s feet, particularly the tarsi, or the palpi, or
the antennæ, or anything you please, possess a certain faculty for
distinguishing between hard and soft, rough and smooth, round and
angular, still our experiment with the Sacred Beetle’s sphere warns us
to look where we are going. There surely we had the exact equivalent of
the Copris’ sphere—made of the same materials, kneaded to the same
consistency, given the same outline—and yet the Copris makes no
mistake.
To drag the sense of taste into the problem would be absurd. There
remains that of hearing. Later on, I might not deny the possibility
that this has something to do with it. When the larva is hatched, the
mother, ever attentive, might conceivably hear it nibbling the wall of
the cell, but for the present the chamber contains merely an egg; and
an egg is always silent.
Then what other means does the mother possess, I will not say of
thwarting my machinations—the problem is on a loftier plane and animals
are not endowed with special aptitudes in order to dodge an
experimenter’s wiles—what other means does she possess of obviating the
difficulties attendant upon her normal labours? Do not lose sight of
this: she begins by shaping a sphere; and the globular mass often does
not differ from the pills that have received the egg, in respect of
either form or size.
Nowhere is there peace, not even below ground. When, in a moment of
panic, the too-timid mother falls off her sphere and forsakes it to
seek refuge elsewhere, how can she afterwards find her ball again and
distinguish it from the others, without running the risk of crushing an
egg when she is pressing in the top of a pill to make the necessary
crater? She needs a safe guide here. What is that guide? I do not know.
I have said it many a time and I say it again: insects possess
sense-faculties of exquisite delicacy attuned to their special trade,
faculties of which we can form no conception because we have nothing
similar within ourselves. A man blind from birth can have no notion of
colour. We are as men blind from birth in the face of the unfathomable
mysteries that surround us; and myriads of questions arise to which no
answer can ever be given.