THE THREE DAGGER-THRUSTS

The Hunting Wasps by Jean-Henri Fabre, is part of the HackerNoon Books Series. You can jump to any chapter in this book here. THE THREE DAGGER-THRUSTS

Chapter V. THE THREE DAGGER-THRUSTS

There is no doubt that the Sphex displays her most cunning resources at the moment of immolating a Cricket; it is important, therefore, to ascertain the manner wherein the victim is sacrificed. Profiting by the repeated attempts which I had made when I was studying the tactics of the Cerceres, I at once applied to the Sphex the method which had succeeded with the other Wasps, a method that consisted in taking the prey from the huntress and forthwith replacing it by another, living prey. The substitution is all the easier inasmuch as we have seen the Sphex herself releasing her victim in order to go down the burrow for a moment alone. Her daring familiarity, which makes her come and take from your fingers and even out of your hand the Cricket whom you have stolen from her and now offer her again, also lends itself admirably to the successful issue of the experiment, by allowing you to observe every detail of the drama closely.

Again, to find live Crickets is an easy matter: we have but to lift the first stone that we see and we find them crouching underneath, sheltered from the sun. These Crickets are young ones, of the same year, who as yet boast but rudimentary wings and who, not possessing the industry of the full-grown insect, have not learnt to dig those cavernous retreats where they would be safe from the Sphex’ investigations. In a few moments I have as many live Crickets as I could wish for. This completes my preparations. I climb to the top of my observatory, establish myself on the level ground, in the centre of the Sphex village, and wait.

A huntress appears upon the scene, carts her Cricket to the entrance of the home and goes down her burrow by herself. I quickly remove the Cricket and substitute one of mine, placing him, however, some distance away from the hole. The kidnapper returns, looks round, and runs and seizes the victim, which is too far off for her. I am all eyes, all attention. Nothing would induce me to give up my part in the tragic spectacle which I am about to witness. The terrified Cricket takes to flight, hopping as fast as he can; the Sphex pursues him hot-foot, reaches him, rushes upon him. There follows, amid the dust, a confused encounter, wherein each champion, now victor, now vanquished, by turns is at the top or at the bottom. Success, for a moment undecided, at last crowns the aggressor’s efforts. Despite his vigorous kicks, despite the snaps of his pincer-like mandibles, the Cricket is laid low and stretched upon his back.

The murderess soon makes her arrangements. She places herself belly to belly with her adversary, but in the opposite direction, grasps one of the threads at the tip of the Cricket’s abdomen with her mandibles and masters with her fore-legs the convulsive efforts of his thick hinder thighs. At the same time, her middle-legs hug the heaving sides of the beaten insect; and her hind-legs, pressing like two levers on the front of the head, force the joint of the neck to open wide. The Sphex then curves her abdomen vertically, so as to offer only an unattackable convex surface to the Cricket’s mandibles; and we see, not without emotion, its poisoned lancet drive once into the victim’s neck, next into the joint of the front two segments of the thorax, and lastly towards the abdomen. In less time than it takes to relate, the murder is consummated; and the Sphex, after adjusting the disorder of her toilet, makes ready to haul home the victim, whose limbs are still quivering in the throes of death.

Let us consider for a moment the excellence of the tactics of which I have given a feeble glimpse. The Cerceris attacks a passive adversary, incapable of flight, almost devoid of offensive weapons, whose sole chances of safety lie in a stout cuirass, the weak point of which, however, is known to the murderess. But what a difference here! The quarry is armed with dreadful mandibles, capable of disembowelling the assailant if they succeed in seizing her; it sports a pair of powerful legs, regular clubs bristling with a double row of sharp spikes, which can be used either to enable the Cricket to hop out of his enemy’s reach, or to send her sprawling with brutal kicks. Observe, therefore, the precautions which the Sphex takes before setting her sting in motion. The victim, turned upon his back, cannot, for lack of any purchase, use his hind-levers to escape with, which he certainly would do if he were attacked in the normal position, as are the big Weevils of the Great Cerceris. His spurred legs, mastered by the Sphex’ fore-feet, cannot act as offensive weapons either; and his mandibles, kept at a distance by the Wasp’s hind-legs, open in wide menace without being able to seize a thing. But it is not enough for the Sphex to render her Cricket incapable of hurting her; she must also hold him so firmly pinioned that he cannot make the slightest movement capable of diverting the sting from the points at which the poison is to be injected; and it is probably with the object of stilling the movements of the abdomen that one of its terminal threads is grasped. No, if a fertile imagination had allowed itself free scope to invent a plan of attack at will, it could not have contrived anything better; and it is open to doubt whether the athletes of the classic palestræ, when grappling with an adversary, boasted more scientific attitudes.

I have said that the sting is driven several times into the patient’s body: first under the neck, then behind the prothorax, next and lastly towards the top of the abdomen. It is in these three dagger-thrusts that the infallibility and the intuitive science of instinct appear in all their splendour. Let us first recall the principal conclusions to which our earlier study of the Cerceris has led us. The victims of the Wasps whose larvæ live on prey are not proper corpses, in spite of their immobility, which is sometimes complete. They suffer simply from a total or partial locomotory paralysis, from a more or less thorough annihilation of animal life; but vegetable life, the life of the organs of nutrition, is maintained for a long while yet and preserves from decomposition the prey which the larva is not to devour for some time to come. To produce this paralysis the Hunting Wasps employ precisely the process which the advanced science of our own day might suggest to the experimental physiologists, that is to say, they injure, by means of their poisoned sting, the nerve-centres that control the locomotory organs. We know besides that the several centres or ganglia of the nervous system of articulate animals are, within certain limits, independent of one another in their action, so that an injury to any one of them does not, or at any rate not immediately, entail more than the paralysis of the corresponding segment; and this applies all the more when the different ganglia are farther apart. When, on the other hand, they are welded together, the lesion of this common centre induces paralysis of all the segments over which its ramifications are distributed. This is the case with the Buprestes and the Weevils, whom the Cerceres paralyse with a single thrust of the sting, aimed at the common mass of the nerve-centres of the thorax. But open a Cricket. What do we find to set the three pairs of legs in motion? We find what the Sphex knew long before the anatomists: three nerve-centres at a great distance one from the other. Hence the magnificent logic of her needle-thrusts thrice repeated. Proud science, bend the knee!

Despite the appearances that might make us think otherwise, the Crickets immolated by the Yellow-winged Sphex are no more dead than the Weevils pierced by the Cerceris’ dart. The flexibility of the victims’ integuments, faithfully revealing the slightest internal movement, enables us in this case to dispense with the artificial methods which I employed to demonstrate the presence of a remnant of life in the Cleoni of the Great Cerceris. In fact, if we assiduously observe a Cricket stretched on his back, a week, a fortnight even or more after the murder, we see the abdomen heaving deeply at long intervals. Pretty often we can still perceive a few quiverings in the palpi and exceedingly-pronounced movements on the part of both the antennæ and the abdominal threads, which diverge and separate and then suddenly come together. I have succeeded, by placing the sacrificed Crickets in glass tubes, in keeping them perfectly fresh for a month and a half. Consequently, the Sphex-grubs, which live for less than a fortnight before shrouding themselves in their cocoons, are certain of fresh meat until their banquet is finished.

The chase is over; the three or four Crickets that are the allotted portion of each cell are stacked methodically, lying on their backs, with their heads at the far end of the cell and their feet at the entrance. An egg is laid on one of them. The burrow must now be closed. The sand resulting from the excavation, which is lying in a heap outside the front-door, is quickly swept backwards down the passage. From time to time some fair-sized bits of gravel are picked out singly, by scratching the heap of rubbish with the fore-feet, and carried with the mandibles to strengthen the crumbly mass. Should the Wasp find none within reach to suit her, she goes and searches for them in the neighbourhood, and seems to choose them as conscientiously as a mason would choose the chief stones for his building. Vegetable remains, tiny fragments of dead leaves, are also employed. In a few moments every outward trace of the underground dwelling has disappeared; and, if we have not been careful to mark the site of the abode, it becomes impossible for the most watchful eye to find it again. When this is finished, a new burrow is dug, provisioned and walled up as often as the teeming ovaries demand. Having completed the laying of her eggs, the Sphex resumes her careless, vagrant life, until the first cold snap puts an end to her well-filled existence.

The Sphex’ task is accomplished; and I will finish mine with an examination of her weapon. The organ destined for the elaboration of her poison consists of two prettily-ramified tubes, ending separately in a common reservoir or phial, shaped like a pea. From this phial starts a slender channel which runs down the axis of the sting and conducts the little drop of poison to its tip. The dimensions of the lancet are very small and not such as one would expect from the size of the Sphex, and especially from the effects which its prick produces on the Crickets. The point is quite smooth and entirely deprived of those backward indentations which we find in the Hive-bee’s sting. The reason for this is obvious. The Bee uses her sting only to avenge an injury, even at the cost of her life; and the teeth of the dart resist its withdrawal from the wound and thus cause mortal ruptures in the viscera at the extremity of the abdomen. What would the Sphex have done with a weapon that would have been fatal to her on her first expedition? Supposing that the dart could be withdrawn in spite of its teeth, I doubt whether any Hymenopteron using her weapon chiefly to wound the game destined for her larvæ would be supplied with a toothed sting. With her, the dirk is not a show weapon, unsheathed to satisfy revenge: revenge, the so-called pleasure of the gods, but a very costly pleasure, for the vindictive Bee sometimes pays for it with her life; it is an implement for use, a tool, on which the future of the grubs depends. It must therefore be one easy to wield in the struggle with the captured prey; it must be capable of being inserted in the flesh and withdrawn without the least hesitation, a condition much better fulfilled by a smooth than by a barbed blade.

I wished to find out at my own expense if the Sphex’ sting is very painful, this sting which lays low sturdy victims with terrible rapidity. Well, I confess with profound admiration that it is insignificant and bears no comparison, for intensity of pain, with the stings of the irascible Bees and Social Wasps. It hurts so little that, instead of using the forceps, I would not scruple to take in my fingers any live Sphex-wasps that I needed in my experiments. I can say the same of the different Cerceres, of the Philanthi,1 of the Palari, of even the huge Scoliæ,2 whose very view inspires dismay, and, generally speaking, of all the Hunting Wasps that I have been able to observe. I make an exception of the Spider-huntresses, the Pompili;3 and even then their sting is much less painful than the Bees’.

One last word: we know how furiously the Hymenoptera armed with a purely defensive dart—the Social Wasps, for instance—rush upon him who is bold enough to disturb their dwelling-house and punish him for his temerity. On the other hand, those whose sting is intended for killing game are very pacific, as though they were aware of the importance which the little drop of poison in their phial possesses for their family. This tiny drop is the safeguard of their race, I might say, its livelihood; and so they are very economical in its use, reserving it for the serious business of the chase, without any parade of vindictive courage. I was not once punished with a sting when I established myself amid the villages of our various Hunting Wasps, though I overturned their nests and stole the larvæ and the provisions. You must lay hold of the insect to make it use its weapon; and even then it does not always pierce the skin, unless you place within its reach a part more delicate than the fingers, such as, for instance, the wrist.

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