CHAPTER XIII
The military profession can hardly be said to favour the talents. Consider the Carabus, or Ground-beetle, that fiery warrior among the insect people. What can he do? In the way of industry, nothing or next to nothing. Nevertheless the dull butcher is magnificent in his indescribably sumptuous jerkin. It has the refulgency of copper pyrites, of gold, of Florentine bronze. While clad in black, he enriches his sombre costume with a vivid amethyst hem. On the wing-cases, which fit him like a cuirass, he wears little chains of alternate pins and bosses.
Of a handsome and commanding figure, slender and pinched in at the waist, the Carabus is the glory of our collections, but only for the sake of his appearance. He is a frenzied murderer; and that is all. We will ask nothing more of him. The wisdom of antiquity represented Hercules, the god of strength, with the head of an idiot. And indeed merit is not great when limited to brute force. And this is the case with the Carabus.
To see him so richly adorned, who would not wish to find him a fine subject for investigation, one worthy of history, a subject such as humbler natures provide with lavish generosity? From this ferocious ransacker of entrails we expect nothing of the kind. His art is that of slaying.
We may without trouble observe him at his bandit's work. I rear him in a large breeding-cage on a layer of fresh sand. A few potsherds scattered about the surface enable him to take shelter beneath the rocks; a tuft of grass planted in the centre makes a grove and enlivens the establishment.
Three species compose the population: the common Jardinière, or Golden Beetle, the usual inmate of our gardens; Procrustes coriaceus, the sombre and powerful explorer of the grassy thickets at the foot of walls; and the rare Purple Carabus, who trims the ebony of his wing-cases with metallic violet. I feed them on Snails, after partly removing the shell.
Hidden at first promiscuously under the potsherds, the Carabi make a rush for the wretched Snail, who, in his despair, alternately puts out and withdraws his horns. Three of them at a time, then four, then five begin by devouring the edge of his mantle, specked with chalky atoms. This is the favourite morsel. With their mandibles, those stout pincers, they lay hold of it through the froth; they tug at it, tear off a shred and retire to a distance to swallow it at their ease.
Meanwhile the legs, streaming with slime, pick up grains of sand and become covered with heavy gaiters, which are extremely cumbersome but to which the Beetle pays no attention. Heavy with mire, he staggers back to his prey and cuts off another morsel. He will think of polishing his boots presently. Others do not stir, but gorge themselves on the spot, with the whole fore-part of their body immersed in the froth. The feast lasts for hours on end. The guests do not leave the joint until the distended belly lifts the roof of the wing-cases and uncovers the nudities of the stern.
Fonder of shady nooks, the Procrustes form a separate company. They drag the Snail into their lair, under the shelter of a potsherd, and there, peacefully and in common, dismember the mollusc. They love the Slug, as easier to cut up than the Snail, who is defended by his shell; they regard the Testacella,1 who bears a chalky shell, shaped like a Phrygian cap, right at the hinder end of her foot, as a delicious tit-bit. The game has firmer flesh and is less nauseously slimy.
1 Or Shell-bearing Slug, found along the shores of the Mediterranean.—Translator's Note.
To feast gluttonously on a Snail whom I myself have rendered defenseless by breaking her shell is nothing for a warrior to boast about; but we shall soon see the Carabus display his daring. I offer a Pine-chafer, in the pink of strength, to the Golden Beetle, whose appetite has been whetted by a few days' fasting. The victim is a colossus beside the Golden Carabus; an Ox facing a Wolf.
The beast of prey prowls round the peaceful creature and selects its moment. It rushes forward, recoils, hesitates and returns to the charge. And lo, the giant is overthrown! Incontinently the other devours him, ransacking his belly. If this had happened in a higher order of the animal world, it would make one's flesh creep to watch the Carabus half immersed in the big Cockchafer and rooting out his entrails.
I test the eviscerator with a more difficult quarry. This time the victim is Oryctes nasicornis, the powerful Rhinoceros Beetle, an invincible giant, one would think, under the shelter of his armour. But the hunter knows the weak point of the horn-clad prey, the fine skin protected by the wing-cases. By means of attacks which the assailant renews as soon as they are repulsed by the assailed, the Carabus contrives to raise the cuirass slightly and to slip his head beneath it. From the moment that the pincers have made a gash in the vulnerable skin, the Rhinoceros is lost. Soon there will be nothing left of the colossus but a pitiful empty carcase.
Those who wish for a more hideous conflict must apply to Calosoma sycophanta, the handsomest of our flesh-eating insects, the most majestic in costume and size. This prince of Carabi is the butcher of the caterpillars. He is not to be overawed even by the sturdiest of rumps.
His struggle with the huge caterpillar of the Great Peacock Moth2 is a thing to see once, not oftener: a single experience of such horrors is enough to disgust one. The contortions of the eviscerated insect, which, with a sudden heave of the loins, hurls the bandit in the air and lets him fall, belly uppermost, without managing to make him release his hold; the green entrails spilt quivering on the ground; the tramping gait of the murderer, drunk with slaughter, slaking his thirst at the springs of a horrible wound: these are the main features of the combat. If entomology had no other scenes to show us, I should without the least regret turn my back upon my insects.
2 Cf. The Life of the Caterpillar: chap. xi.—Translator's Note.
Next day, offer the sated Beetle a Green Grasshopper or a White-faced Decticus, serious adversaries both, armed with powerful lower jaws. With these big-bellied creatures the slaughter will begin anew, as eagerly as on the day before. It will be repeated later with the Pine-chafer and the Rhinoceros Beetle, accompanied by the usual atrocious tactics of the Carabi. Even better than these last does the Calosoma know the weak point of the armoured Beetles, concealed beneath the wing-cases. And this will go on so long as we keep him provided with victims, for this drinker of blood is never satiated.
Acrid exhalations, the products of a fiery temperament, accompany this frenzy for carnage. The Carabi elaborate caustic humours; the Procrustes squirts a jet of vinegar at any one who takes hold of him; the Calosoma makes the fingers smell of mouldy drugs; certain Beetles, such as the Brachini,3 understand explosives and singe the aggressor's whiskers with a volley of musketry.
3 Or Bombardier Beetles. When disturbed, they eject a fluid which volatilizes, on contact with the air, with a slight report.—Translator's Note.
Distillers of corrosives, gunners throwing lyddite, bombers employing dynamite: what can all these violent creatures, so well equipped for battle, do beyond committing slaughter? Nothing. We find no art, no industry, not even in the larva, which practices the adult's trade and meditates its crimes while wandering under the stones. Nevertheless it is to one of these dull-witted warriors that I am deliberately proposing to apply to-day, prompted by the wish to solve a certain question. Let me tell you what it is.
You have surprised this or that insect, motionless on a bough, blissfully basking in the sun. Your hand is raised, open, ready to descend on it and seize it. Hardly have you made the movement when the insect drops to the ground. It is a wearer of armoured wing-cases, slow to disengage the wings from their horny sheath, or perhaps an incomplete form, with no wing-surfaces. Incapable of sudden flight, the surprised insect lets itself fall. You look for it in the grass, often in vain. If you do find it, it is lying on its back, with its legs folded, without stirring.
It is shamming dead, people will tell you; it is pretending, in order to escape its enemy. Man is certainly unknown to it; we count for nothing in its little world. What does it care for our hunting, whether we be children or scientists? It does not fear the collector with his long pin; but it realizes danger in general; and it dreads its natural enemy, the insectivorous bird, which swallows it with a single snap. To outwit the assailant, it lies upon its back, draws up its legs and simulates death. The bird, or any other persecutor, will despise it in this condition; and its life will be saved.
This, we are assured, is how the insect would reason if suddenly surprised. The trick has long been famous. Once upon a time, two friends, at the end of their resources, sold the skin of a Bear before they had killed the brute. The encounter was unfortunate: they had to take to their heels. One of them stumbled, fell, held his breath and shammed dead. The Bear came up, turned the man over and over, explored him with his paw and his muzzle, sniffed at his face:
"He smells already," he said and, without more ado, turned away.
That Bear was a simpleton.
The bird would not be duped by this clumsy stratagem. In those happy days when the discovery of a nest marked a red-letter day, I never saw my Sparrows or Greenfinches refuse a Locust because he was not moving, or a Fly because she was dead. Any mouthful that does not kick is eagerly accepted, provided that it be fresh and pleasant to the taste.
If the insect, therefore, relies on the appearance of death, it would seem to me to be very badly inspired. More wary than the Bear in the fable, the bird, with its perspicacious eye, will recognize the fraud in a moment and proceed to business. Besides, had the object really been a corpse, but still fresh, it would none the less have gobbled it up.
More insistent doubts occur to my mind when I consider the serious consequences to which the insect's artfulness might lead. It shams dead, says the popular idiom, which recks little of weighing the value of its term; it simulates death, scientific language repeats, happy to find some gleams of reason in the insect. What truth is there in this unanimous statement, which in the one case is too unreflecting and in the other too much inclined to favour theoretical fancies?
Logical arguments are insufficient here. It is essential that we should obtain the verdict of experiment, which alone can furnish a valid reply. But to which of the insects shall we go first?
I remember something that dates back some forty years. Delighted with a recent University triumph, I was staying at Cette, on my return from Toulouse, where I had just passed my examination as a licentiate in natural science. It gave me a fine chance of renewing my acquaintance with the seaside flora, which had delighted me a few years before on the shores of the wonderful Gulf of Ajaccio. It would have been foolish to neglect it. A degree does not confer the right to cease studying. If one really has a touch of the sacred fire in one's veins, one remains a student all one's life, not of books, which are a poor resource, but of the great, inexhaustible school of actual things.
One day, then, in July, in the cool stillness of the dawn, I was botanizing on the foreshore at Cette. For the first time I plucked the Convolvulus soldanella, which trails along the high-water mark its ropes of glossy green leaves and its great pink bellflowers. Withdrawn into his white, flat, heavily-keeled shell, a curious Snail, Helix explanata, was slumbering, in groups, on the bent grasses.
The dry shifting sands showed here and there long series of imprints, recalling, on a smaller scale and under another form, the tracks of little birds in the snow which used to arouse a delightful flutter in my youthful days. What do these imprints mean?
I follow them, a hunter on the trail of a new species. At the end of each track, by digging to no great depth, I unearth a magnificent Carabus, whose very name is almost unknown to me. It is the Giant Scarites (S. gigas, FAB.).
I make him walk on the sand. He exactly reproduces the tracks which put me on the alert. It was certainly he who, questing for game in the night, marked the trail with his feet. He returned to his lair before daylight; and now not a single Beetle is to be seen in the open.
Another characteristic thrusts itself upon my notice. If I shake him for a moment and then place him on the ground upon his back, he remains a long time without stirring. No other insect has yet displayed such persistent immobility, though I confess that my investigations in this respect have been only superficial. The detail is so thoroughly engraved on my memory that, forty years later, when I want to experiment on the insects which are experts in the art of simulating death, I at once think of the Scarites.
A friend sends me a dozen from Cette, from the very beach on which I once passed a delightful morning in the company of this skilful mimic of the dead. They reach me in perfect condition, mixed up in the same package with some Pimeliæ (P. bipunctata, FAB.), their compatriots in the sands beside the sea. Of these last, a pitiable crew, many have been disembowelled, absolutely emptied; others have merely stumps instead of legs; a few, but only a few, are unwounded.
It was what one might have expected of these Carabidæ, lawless hunters one and all. Tragic events took place in the box during the journey from Cette to Sérignan. The Scarites gormandized riotously on the peaceable Pimeliæ.
Their tracks, which I followed long ago on the actual spot, bore evidence to their nocturnal rounds, apparently in search of their prey, the pot-bellied Pimelia, whose sole defence consists of a strong armour of welded wing-cases.4 But what can such a cuirass avail against the bandit's ruthless pincers?
4 The Pimelia is a wingless Beetle.—Translator's Note.
He is indeed a mighty hunter, this Nimrod of the sea-shore. All black and glossy, like a jet bugle, his body is divided by a very narrow groove at the waist. His weapon of offence consists of a pair of claw-like mandibles of extraordinary vigour. None of our insects equals him in strength of jaw, if we except the Stag-beetle, who is far better armed, or rather decorated, for the antlered mandibles of the inmate of the oak are ornaments of the male's attire, not a panoply of battle.
The brutal Carabid, the eviscerator of the Pimeliæ, knows how strong he is. If I tease him a little on the table, he at once adopts a posture of defence. Well braced upon his short legs, especially the fore-legs, which are toothed like rakes, he dislocates himself in two, so to speak, thanks to the groove that divides him behind the corselet; he proudly raises the fore-part of the body, his wide, heart-shaped thorax and massive head, opening his threatening pincers to their full extent. He is now an awesome sight. More: he has the audacity to rush at the finger which has touched him. Here of a surety is one not easily intimidated. I look twice before I handle him.
I lodge my strangers partly under a wire-gauze cover and partly in glass jars, all supplied with a layer of sand. Each of them without delay digs himself a burrow. The insect bends his head a long way down and, with the points of his mandibles, brought together to form a pick-axe, he hews, digs and excavates with a will. The fore-legs, spread out and armed with hooks, gather the dust and rubbish into a load which is thrust backwards. In this way, a mound rises on the threshold of the burrow. The dwelling grows deeper quickly and by a gentle slope reaches the bottom of the jar.
Checked in the downward direction, the Scarites now digs against the glass wall and continues his work horizontally until he has obtained a length of nearly twelve inches in all.
This arrangement of the gallery, almost the whole of which runs just under the glass, is very useful to me, enabling me to follow the insect in the privacy of its home. If I wish to observe its underground operations, all that I need do is to remove the opaque sheath which I have been careful to put over the jar, in order to spare the creature the annoyance of the light.
When the house is deemed to be long enough, the Scarites returns to the entrance, which he works more carefully than the rest. He makes a funnel of it, a pit with shifting, sloping sides. It is the Ant-lion's crater on a larger scale and constructed in a more rustic fashion. This mouth is continued by an inclined plane, kept free of all rubbish. At the foot of the slope is the vestibule of the horizontal gallery. Here, as a rule, the hunter lurks, motionless, with his pincers half open. He is waiting.
There is a sound overhead. It is a specimen of game which I have just introduced, a Cicada, a luscious morsel. The drowsy trapper at once wakes; he moves his palpi, which quiver with cupidity. Cautiously, step by step, he climbs his inclined plane. He takes a glance outside the funnel. The Cicada is seen.
The Scarites darts out of his pit, runs forward, seizes the Cicada and drags her backwards. The struggle is brief, thanks to the trap of the entrance, which yawns like a funnel to receive even a bulky quarry and contracts into a crumbling precipice that paralyses all resistance. The slope is fatal: who crosses the brink can no longer escape the murderer.
Head first, the Cicada dives into the abyss, down which the spoiler drags her by successive jerks. She is drawn into the low-ceilinged tunnel. Here the wings cease to flutter, for lack of space. She reaches the knacker's cellar, at the end of the corridor. The Scarites now works at her for some time with his pincers, in order to reduce her to complete immobility, fearing lest she should escape; then he returns to the mouth of the charnel-house.
It is not everything to possess plenty of game; the question next arises how to consume it in peace. The door is therefore closed against importunate callers, that is to say, the insect fills the entrance to the tunnel with his mound of rubbish. Having taken this precaution, he goes back again and sits down to his meal. He will not reopen his hiding-place nor remake the pit at the entrance until later, when the Cicada has been digested and hunger makes its reappearance. Let us leave the glutton with his quarry.
The brief morning which I spent with him in his native place did not enable me to watch him at his hunting, on the sands of the beach; but the facts gathered in captivity are enough to tell us all about it. They show us in the Scarites a bold hero who is not to be intimidated by the biggest or strongest adversary.
We have seen him coming up from underground, falling on the passers-by, seizing them at some distance from the burrow and dragging them forcibly into his cut-throat den. The Rose-chafer, the Common Cockchafer are but small deer for him. He dares to attack the Cicada, he dares to dig his hooks into the corpulent Pine-chafer. He is a fearless ruffian, ready for any crime.
Under natural conditions his audacity can be no less. On the contrary, the familiar spots, freedom of movement, unlimited space and his beloved salt air excite the warrior to yet greater feats of daring.
He has dug himself a refuge in the sand, with a wide, crumbling mouth. This is not so that he may, like the Ant-lion, wait at the bottom of his funnel for the passing of a victim which stumbles on the shifting slope and rolls into the pit. The Scarites disdains these petty poachers' methods, these fowlers' snares; he prefers a run across country.
His long trails on the sand tell us of nocturnal rounds in search of big game, often the Pimelia, sometimes the Half-spotted Scarab.5 The find is not consumed on the spot. To enjoy it at his ease, he needs the peaceful darkness of the underground manor; and so the captive, seized by one leg with the pincers, is forcibly dragged along the ground.
5 Cf. The Sacred Beetle and Others: chaps. ii. and vii.—Translator's Note.
If no precautions were taken, the introduction of the victim into the burrow would be impracticable, with a huge quarry offering a desperate resistance. But the entrance to the tunnel is a wide crater, with crumbling walls. However large he be, the captive, tugged from below, enters and tumbles into the pit. The crumbling rubbish immediately buries him and paralyses his movements. The thing is done. The bandit now proceeds to close his door and empty his prey's belly.
CHAPTER XIV
The first insect that we will put to the question is that audacious disemboweller, the savage Scarites. To provoke his state of inertia is a very simple matter: I handle him for a moment, rolling him between my fingers; better still, I drop him on the table, twice or thrice in succession, from a small height. When the shock due to the fall has been administered and, if need be, repeated, I turn the insect on its back.
This is enough: the prostrate Beetle no longer stirs, lies as though dead. The legs are folded on the belly, the antennæ extended like the arms of a cross, the pincers open. A watch beside me tells me the exact minute of the beginning and the end of the experiment. Nothing remains but to wait and especially to arm one's self with patience, for the insect's immobility lasts long enough to become tedious to the observer watching for something to happen.
The duration of the lifeless posture varies greatly on the same day, under the same atmospheric conditions and with the same subject, though I cannot fathom the causes which shorten or lengthen it. How to investigate the external influences, so numerous and often so slight, which intervene in such a case; above all, how to scrutinize the insect's private impressions: these are impenetrable mysteries. Let us confine ourselves to recording the results.
Immobility continues fairly often for as long as fifty minutes; in certain cases, even, it lasts more than an hour. The most frequent length of time averages twenty minutes. If nothing disturbs the Beetle, if I cover him with a glass shade, protecting him from the Flies, who are importunate visitors in the hot weather prevailing at the time of my experiment, the inertia is complete: not a quiver of the tarsi, nor of the palpi, nor of the antennæ. Here indeed is a simulacrum of death, with all its inertia.
At last the apparently deceased comes back to life. The tarsi quiver, those of the fore-legs first; the palpi and the antennæ move slowly to and fro: this is the prelude to the awakening. Now the legs begin to kick. The insect bends slightly at its pinched waist; it buttresses itself on its head and back; it turns over. There it goes, jogging away, ready to become an apparent corpse once more if I renew my shock tactics.
Let us repeat the experiment immediately. The newly resuscitated Beetle is for a second time lying motionless on his back. He prolongs his make-believe of death longer than he did at first. When he wakes up, I renew the test a third, a fourth, a fifth time, with no intervals of repose. The duration of the motionless condition increases each time. To quote the figures, the five consecutive experiments, from the first to the last, have continued respectively for 17, 20, 25, 33 and 50 minutes. Starting with a quarter of an hour, the attitude of death ends by lasting nearly a whole hour.
Without being constant, similar facts recur repeatedly in my experiments, the duration, of course, varying. They tell us that as a general rule the Scarites lengthens the period of his lifeless posture the oftener the experiment is repeated. Is this a matter of practice, or is it an increase of cunning employed in the hope of finally tiring a too persistent enemy? It would be premature to draw conclusions: the cross-examination of the insect has not yet been thorough enough.
Let us wait. Besides, we need not imagine that it is possible to go on like this until our patience is exhausted. Sooner or later, flurried by my pestering, the Scarites refuses to sham dead. Scarcely is he laid on his back after a fall, when he turns over and takes to his heels, as though he judged a stratagem which succeeded so indifferently to be henceforth useless.
If we were to stop here, it would certainly seem that the insect, a cunning hoaxer, seeks, as a means of defence, to cheat those who attack him. He counterfeits death; he repeats the process, becoming more persistent in his fraud in proportion as the aggression is repeated; he abandons his trickery when he deems it futile. But hitherto we have subjected him only to a friendly examination-in-chief. The time has come to put a string of searching questions and to trick the trickster if there be really any deception.
The Beetle under experiment is lying on the table. He feels beneath him a hard body which gives him no chance of digging. As he cannot hope to take refuge underground, an easy task for his nimble and vigorous tools, the Scarites lies low in his death-like pose, keeping it up, if need be, for an hour. If he were reclining on the sand, the loose soil with which he is so familiar, would he not regain his activity more rapidly, would he not at least betray by a few twitches his desire to escape into the basement?
I was expecting to see him do so; and I was mistaken. Whether I place him on wood, glass, sand or garden mould, the Beetle in no way modifies his tactics. On a surface readily excavated he continues his immobility as long as on an unassailable surface.
This indifference to the nature of the support half opens the door to doubt; what follows opens it wide. The patient is on the table before me and I watch him closely. With his gleaming eyes, overshadowed by his antennæ, he also sees me; he watches me; he observes me, if I may so express myself. What can be the visual impression of the insect when face to face with that monstrosity, man? How does the pigmy measure the enormous monument that is the human body? Seen from the depths of the infinitely little, the immense perhaps is nothing.
We will not go so far as that; we will admit that the insect watches me, recognizes me as his persecutor. So long as I am here, he will suspect me and refuse to budge. If he does decide to do so, it will be after he has exhausted my patience. Let us therefore move away. Then, since any trickery will be needless, he will hasten to take to his legs again and make off.
I move ten paces farther from him, to the other end of the room. I hide, I do not move a muscle, for fear of breaking the silence. Will the insect pick itself up? No, my precautions are superfluous. Alone, left to itself, perfectly quiet, it remains motionless for as long a time as when I was standing close beside it.
Perhaps the clear-sighted Scarites has seen me in my corner, at the other end of the room; perhaps a subtle scent has revealed my presence to him. We will do more, then. I cover him with a bell-glass which will save him from being worried by the Flies and I leave the room; I go downstairs into the garden. There is no longer anything likely to disturb him. Doors and windows are closed. Not a sound from without; no cause for alarm indoors. What will happen in the midst of that profound silence?
Nothing more and nothing less than usual. After twenty, forty minutes' waiting out of doors, I come upstairs again and return to my insect. I find him as I left him, lying motionless on his back.
This experiment, many times repeated with different subjects, throws a vivid light upon the question. It expressly assures us that the attitude of death is not the ruse of an insect in danger. Here there is nothing to alarm the creature. Around him all is silence, solitude, repose. When he persists in his immobility it cannot now be to deceive an enemy. I have no doubt about it: there is something else involved.
Besides, why should he need special defensive artifices? I could understand that a weak, pacific, ill-protected insect might resort to ruses when in danger; but in him, the warlike bandit, so well armoured, it is more than I can understand. No insect on his native sea-shore has the strength to resist him. The most powerful of them, the Sacred Beetle and the Pimelia, are easy-going creatures which, so far from molesting him, are fine booty for his burrow.
Can he be threatened by the birds? It is very doubtful. As a Carabus, he is saturated with acrid humours which must make his body a far from pleasing mouthful. For the rest, he lives hidden from the light of day in a burrow where no one sees him; he emerges only at night, when the birds are no longer inspecting the beach. There are no beaks about for him to fear.
And this butcher of the Pimeliæ and even occasionally of the Sacred Beetles, this bully whom no danger threatens, is supposed to be such a coward as to sham death on the slightest alarm! I take the liberty of doubting this more and more.
I am confirmed in my doubts by the Smooth-skinned Scarites (S. lavigatus, FAB.), a denizen of the same shores. The first insect is a giant; the second, by comparison, is a dwarf. Otherwise he displays the same shape, the same jet-black costume, the same armour, the same habits of brigandage. Well, the Smooth-skinned Scarites, in spite of his weakness and his smallness, is almost ignorant of the trick of pretending to be dead. When molested for a moment and then turned on his back, he at once picks himself up and flees. I can hardly obtain a few seconds' immobility; once only, daunted by my obstinacy, the dwarf remains motionless for a quarter of an hour.
How different from the giant, motionless the moment that he is thrown upon his back, sometimes picking himself up only after an hour of inaction! It is the reverse of what ought to happen, if the apparent death were really a defensive ruse. The giant, confident in his strength, should disdain this cowardly posture; the timid dwarf should be quick to have recourse to it. And it is just the other way about. What is there behind all this?
Let us try the influence of danger. With what natural enemy shall I confront the big Scarites, motionless on his back? I know none. Let us then create a make-believe assailant. The Flies put me on the track of one.
I have spoken of their importunity during my investigations in the hot season. If I do not employ a bell-glass or keep an assiduous watch, rarely does the shrewish Dipteron fail to alight upon my patient and explore him with her proboscis. We will let her have her way this time.
Hardly has the Fly grazed this apparent corpse with her legs, when the Scarites' tarsi quiver as though twitched by a slight electric shock. If the visitor be merely passing, matters go no farther; but, if she persist, particularly near the Beetle's mouth, moist with saliva and disgorged secretions of food, the tormented Scarites promptly kicks, turns over and makes off.
Perhaps he did not think it opportune to prolong his fraud in the face of so contemptible an enemy. He resumes his activity because he has recognized the absence of danger. Then let us call in another interloper, one of formidable size and strength. I happen to have handy a Great Capricorn, with powerful claws and mandibles. That the long-horned insect is a peaceful creature I am well aware; but the Scarites does not know it; on the sands of the shore he has never encountered such a colossus as this, who is capable of impressing less timid creatures than he. Fear of the unknown will merely aggravate the situation.
Guided by the tip of my straw, the Capricorn sets his foot upon the prostrate insect. The Scarites' tarsi begin to quiver immediately. If the contact be prolonged or multiplied, or if it become aggressive, the dead insect gets on its legs again and scuttles off, just as the titillations of the Fly have already shown me. When danger is imminent and all the more to be dreaded because its nature is unknown, the trick of the simulation of death disappears and flight takes its place.
The following experiment is not without value. I take some hard substance and knock the foot of the table on which the insect is lying on its back. The shock is very slight, not enough to shake the table perceptibly. The whole thing is limited to the inner vibrations of a resilient body which has received a blow. But it is quite enough to disturb the insect's immobility. At each tap the tarsi are flexed and quiver for a moment.
Lastly, let us try the effect of light. So far, the patient has been treated in the shade of my cabinet, away from the direct sunlight. The sun is shining full upon the window. What will the motionless insect do if I carry it thither, from my table to the window, into the bright light? That we can find out in a moment. Under the direct rays of the sun, the Scarites immediately turns over and moves off.
This is enough. Patient, persecuted creature, you have half-betrayed your insect. When the Fly tickles you, drains your moist lip, treats you as a corpse whose juices she would like to suck; when the huge Capricorn appears to your horrified gaze and puts a foot on your belly, as though to take possession of his prey; when the table quivers, that is to say, when, for you, the ground shakes, undermined perhaps by some invader of your burrow; when a bright light surrounds you, favouring the designs of your enemies and imperilling your safety as an insect that loves the dark, then, in truth, it would be wiser not to move, if really your chief resource, when danger threatens you, is to simulate death.
On the contrary, at those critical moments, you give a start; you move, you resume your normal attitude, you run away. Your fraud is discovered; or, to put it more plainly, there is no trick. Your inertia is not simulated; it is real. It is a condition of temporary torpor into which you are plunged by your delicate nervous organization. A mere nothing makes you fall into it; a mere nothing withdraws you from it, above all a bath of light, that sovran stimulus of activity.
In respect of prolonged immobility as the result of emotion, I find a rival of the Giant Scarites in a large black Buprestis, with a flour-speckled corselet, a lover of the blackthorn, the hawthorn and the apricot-tree. His name is Capnodis tenebrionis, LIN. At times I see him, with his legs closely folded and his antennæ lowered, prolonging his motionless posture upon his back for more than an hour. At other times the insect is bent upon escaping, apparently influenced by atmospheric conditions of which I do not know the secret. One or two minutes' immobility is as much as I can then obtain.
Let me recapitulate: in my various subjects the attitude of death is of very variable duration, governed as it is by a host of unsuspected circumstances. Let us take advantage of favourable opportunities, which are fairly frequent. I subject the Cloudy Buprestis to the different tests undergone by the Giant Scarites. The results are the same. When you have seen the first, you have seen the second. There is no need to linger over them.
I will only mention the promptness with which the Buprestis, lying motionless in the shade, recovers his activity when I carry him away from my table into the broad sunlight of the window. After a few seconds of this bath of heat and light, the insect half-opens his wing-cases, using them as levers, and turns over, ready to take flight if my hand did not instantly snap him up. He is a passionate lover of the light, a devotee of the sun, intoxicating himself in its rays upon the bark of his blackthorn-trees on the hottest afternoons.
This love of tropical temperature suggests the following question: what would happen if I were to chill the creature in its immobile posture? I foresee a more prolonged inertia. The chill, of course, must not be great, for it would be followed by the lethargy into which insects capable of surviving the winter fall when benumbed by the cold.
On the contrary, the Buprestis must as far as possible retain his full vitality. The lowering of the temperature must be gentle, very moderate and such that the insect, under similar climatic conditions, would retain his powers of action in ordinary life. I have a convenient refrigerator at my disposal. It is the water of my well, whose temperature, in summer, is nearly twenty-two degrees Fahrenheit below that of the surrounding air.
The Buprestis, in whom I have just produced inertia by means of a few taps, is installed on his back in a little flask which I seal hermetically and immerse in a bucket full of this cold water. To keep the bath as cool as at first, I gradually renew it, taking care not to shake the flask in which the patient is lying, in his attitude of death.
The result rewards my pains. After five hours under water, the insect is still motionless. Five hours, I say, five long hours; and I might certainly say longer, if my exhausted patience had not put an end to the experiment. But this is enough to banish any idea of fraud on the insect's part. Here, beyond a doubt, the insect is not shamming dead. He is actually somnolent, deprived of the power of movement by an internal disturbance which my teasing produced at the outset and which is prolonged beyond its usual limits by the surrounding coolness.
I try the effect of a slight decrease in temperature upon the Giant Scarites by subjecting him to a similar sojourn in the cold water of the well. The result does not respond to the hopes which the Buprestis gave me. I do not succeed in obtaining more than fifty minutes' inertia. I have often obtained as long periods of immobility without resorting to the refrigerating artifice.
It might have been foreseen. The Buprestis, a lover of the burning sunshine, is affected by the cold bath in a different degree from the Scarites, who prowls about by night and spends his day in the basement. A fall of a few degrees in temperature takes the chilly insect by surprise and has no effect upon the one accustomed to the coolness underground.
Other experiments on these lines tell me nothing more. I see the inert condition persisting sometimes for a longer, sometimes for a shorter period, according as the insect seeks the sunlight or avoids it. Let us change our method.
I evaporate a few drops of sulphuric ether in a glass jar and put in a Stercoraceous Geotrupes and a specimen of Buprestis tenebrionis, at the same time. In a few moments both subjects are motionless, anæsthetized by the etheric vapour. I take them out quickly and lay them on their backs in the open air.
Their attitude is exactly that which they would have assumed under the influence of a shock or any other cause of alarm. The Buprestis has his legs symmetrically folded against his chest and belly; the Geotrupes has his outspread, stretched in disorder, rigid and as though attacked by catalepsy. You could not tell if they were dead or alive.
They are not dead. In a minute or two, the Geotrupes' tarsi twitch, the palpi quiver, the antennæ wave gently to and fro. Then the fore-legs move; and a quarter of an hour has not elapsed before the other legs are struggling. The activity of the insect made motionless by the concussion of a shock would reawaken in precisely the same fashion.
As for the Buprestis, he is in a state of inertia so profound that at first I really believe him to be dead. He recovers during the night; and next day I find him in possession of his usual activity. The ether experiment, which I took care to stop at the moment when it produced the desired effect, has not been fatal to him; but it has had much more serious consequences for him than for the Geotrupes. The insect more sensitive to the alarm due to concussion or to a fall of temperature is also the more sensitive to the action of ether.
Thus the enormous difference which I observe in these two insects, with regard to the inertia provoked by a shock or by handling them in one's fingers, is explained by nice differences of impressionability. Whereas the Buprestis remains motionless for nearly an hour, the Geotrupes is struggling violently after a minute or two. And even then I rarely attain this limit.
In what respect has the Geotrupes, to defend itself, less need of the stratagem of simulated death than the Black Buprestis, well protected by his massive build and his armour, which is so hard that it resists the point of a pin and even of a needle? We should be perplexed by the same question in respect of a multitude of insects, some of which remain motionless while others do not; and we could not possibly foresee what would happen from the genus of the subject, its form, or its way of living.
Buprestis tenebrionis, for example, exhibits a persistent inertia. Will it be the same, because of similarity of structure, with other members of the same group? Not at all. My chance finds provide me with the Brilliant Buprestis (B. rutilans, FAB.), and the Nine-spotted Buprestis (Ptosima novemmaculata, FAB.). The first resists all my attempts. The splendid creature grips my fingers, grips my tweezers and insists on getting up the moment that I lay it on its back. The second readily becomes immobile; but how brief is its attitude of death! Four or five minutes at most.
A Melasoma-beetle, Omocrates abbreviatus, OLIV., whom I frequently discover under the broken stones on the neighbouring hills, continues motionless for over an hour. He rivals the Scarites. We must not forget to add that very often the awakening takes place within a few minutes.
Can he owe his long period of inertia to the fact that he is one of the Tenebrionidæ, or Darkling Beetles? By no means, for here in the same group is Pimelia bipunctata, who turns a somersault on his round back and finds his feet the moment he has turned over; here is a Cellar-beetle (Blaps similis, LATR.), who, unable to turn with his flat back, his big belly and his welded wing-cases,1 struggles desperately after a minute or two of inertia.
1 The Cellar-beetle is one of the wingless Beetles.—Translator's Note.
The short-legged Beetles, trotting along with tiny steps, ought, one would think, to make up in cunning, more fully than the others, for their incapacity for rapid flight. The facts do not correspond with this apparently well-founded forecast. I have consulted the genera Chrysomela,2 Blatta,3 Silpha, Cleonus,4 Bolboceras,5 Cetonia, Hoplia, Coccinella,6 and so on. A few minutes or a few seconds are nearly always long enough for the return to activity. Several of them even obstinately refuse to sham death.
2 Golden-apple Beetles.—Translator's Note.
3 Blackbeetles or Cockroaches.—Translator's Note.
4 A genus of Weevils.—Translator's Note.
5 A mushroom-eating Beetle. Cf. The Life of the Fly: chap. xviii.—Translator's Note.
6 Ladybirds.—Translator's Note.
As much must be said of the Beetles well-equipped for pedestrian escape. Some remain motionless for a few seconds; others, more numerous still, behave in an ungovernable fashion. In short, there is no guide to tell us in advance:
"This one will readily assume the posture of a dead insect; this one will hesitate; that one will refuse."
There is nothing but shadowy probabilities, until experiment has given its verdict. From this muddle shall we draw a conclusion which will set our minds at rest? I hope so.