Part 8

It has come! tardily, it is true, but it has come. Ah! could one but observe now, in the peace of one’s study, isolated, absorbed, thinking only of what one is studying, far from the profane passer-by who will stop, seeing you so preoccupied where he sees nothing, will overwhelm you with questions and take you for a diviner of springs with the magic hazel wand, or worse, as a doubtful character, seeking by incantations old pots full of money hidden underground. Even if you seem to him to have the look of a Christian, he will come near, look at what you are looking at, and smile in a fashion which leaves no possible doubt as to his humble opinion of people who spend their time in watching flies. You would only be too happy if this annoying visitor would depart, laughing in his sleeve, but without disturbing everything and repeating the disaster caused by the soles of my two conscripts.

Or if it is not the passer-by who is perplexed by your unaccountable proceedings, it will be the garde-champêtre, that inexorable representative of the law amid the fallow fields. Long has he had his eye upon you. He has so often seen you wandering like a troubled ghost for no reason that he can perceive; has so often caught you seeking something in the ground, or knocking down some bit of wall in some hollow way with infinite precaution that he begins to look on you as a suspicious character, a vagabond, a gipsy, a tramp, or, at all events, a maniac. If you have a botanical tin, to him it is the ferret-cage of the poacher, and it will be impossible to convince him that you are not destroying all the rabbits in the neighbouring warrens, regardless of the laws of the chase and the rights of the owner. Beware! However thirsty you may be, lay no finger on a cluster in the vineyard hard by; the man of the municipal livery would be there, delighted to bear witness and get at last an explanation of your exasperatingly perplexing conduct.

I must do myself the justice to say that I have never committed such a misdeed, and yet one day when I was lying on the sand, absorbed in the domestic affairs of a Bembex, I heard beside me, “In the name of the law, I summon you to follow me!” It was the garde-champêtre of Les Angles, who having vainly watched for an opportunity of catching me in some offence, and being daily more desirous of an answer to the riddle which tormented him, had finally decided on a summons. An explanation became necessary. The poor man did not appear in the least convinced. “Bah! bah!” said he, “you’ll never get me to believe that you come and roast yourself in the sun just to watch flies. I keep my eye on you, you know, and the first time.... Well, that’s enough.” He departed. I have always believed that my red ribbon had a good deal to do with this departure, and I ascribe to that ribbon other similar services during my botanical or entomological rambles. It seemed to me—was it an illusion?—it did seem to me that during my botanical expeditions on Mont Ventoux, the guide was more manageable than usual and the donkey less obstinate.

The little dark red ribbon has not always protected me from the tribulations the entomologist must expect when carrying on experiments upon the highway. Since dawn I had been lying in ambush at the bottom of a ravine; Sphex occitanica was the object of my early visit. A party of three women vintagers passed on their way to work. A glance was cast on the seated figure apparently lost in thought. “Good day” was politely offered and politely answered. At sunset the women returned with full baskets. The man was still there, seated on the same stone, his eyes fixed on the same spot. My motionless figure, my persistent stay in that lonely place, must have struck them greatly. As they passed I saw one tap her forehead, and heard her whisper, “A poor innocent, pe’caïre! a poor innocent!” and all three made the sign of the cross.

An innocent, an idiot, a poor inoffensive creature who is deficient; and all three crossed themselves—an idiot being one to them marked by God’s seal. “How?” said I. “What cruel mockery of fate! You who are labouring to discover what is instinct and what reason in the animal; you yourself are a half-wit in the eyes of these women! What humiliation! However, pe’caïre, that term of supreme commiseration in Provençal, uttered from the bottom of the heart, made me quickly forget the Innocent.”

It is to that same ravine that I invite my reader, if he is not repelled by the small annoyances of which I have given him a foretaste. S. occitanica haunts these parts, not in numbers giving one another rendezvous when nidification is going on, but solitary individuals far apart, wherever their vagabond peregrinations have led them. Just as their relative S. flavipennis seeks the society of relations and the animation of a work-yard and company, so, on the other hand, does the Languedocian Sphex prefer calm, isolation, and solitude. Graver in behaviour, more formal in manner, more elegant of figure, and in more sombre attire, she always lives apart, careless of what others are doing, disdaining companionship, a very misanthrope among Sphegidæ. S. flavipennis is sociable; S. occitanica is unsociable—a profound difference, alone sufficient to characterise them.

This suggests how greatly the difficulty of observing the latter is increased. No long meditated experiment is possible, nor can one attempt to repeat it a second time if the first has failed. If you make preparations beforehand,—for instance, if you put in reserve a piece of game to substitute for that of the Sphex,—it is to be feared, indeed it is almost certain, that she will not appear, or if she comes, your preparations turn out useless. Everything must be improvised at once—conditions which I have not always been able to realise as I could have wished.

Let us take courage; the position is good. Many a time I have here surprised the Sphex reposing on a vine-leaf, exposed to the full rays of the sun. The insect, lying flat and spread out, is voluptuously enjoying the delights of warmth and light. From time to time a kind of frenzy of pleasure bursts forth in her; she thrills with well-being, drums rapidly on her resting-place with the points of her feet, and produces a sound somewhat like the roll of a drum, or heavy rain falling on foliage perpendicularly. You may hear this joyous drumming several paces off. Then again comes perfect stillness, followed by a fresh nervous commotion, and that waving of tarsi which is a sign of supreme happiness. I have known some of these ardent sun-worshippers suddenly leave a half-finished burrow to settle on a neighbouring vine and take a bath of sun and light, returning reluctantly to give a careless sweep to the hole, and finally abandon the workshop, unable longer to resist the temptation of luxuriating on a vine leaf. Perhaps this voluptuous resting-place is also an observatory whence to inspect the neighbourhood, and espy and choose prey. This Sphex catches only the ephippiger of the vine, scattered here and there on the leaves or on any convenient bush. The game is succulent—all the more that only females full of eggs are selected.

Let us pass over numerous expeditions, fruitless researches, and the tedium of long waiting, and present the Sphex to the reader just as she shows herself to the observer. Here she is, at the bottom of a hollow way with high sandy banks. She comes on foot, but aids herself with her wings in dragging along her heavy captive. The ephippiger’s antennæ, like long fine threads, are the harness ropes. With her mandibles and holding her head high, she grasps one of them, passing it between her feet, and the prey is dragged on its back. If some unevenness of ground should oppose itself to this style of haulage, she stops, clasps the ample provender, and transports it by very short flights, going on foot between whiles whenever this is possible. One never sees her undertake sustained flights for long distances carrying prey, as do those strong cruisers, the Bembex and Cerceris, which will carry perhaps for a good half mile through the air, the former their Diptera, the latter their weevils—very light prey compared with the huge ephippiger. The overwhelming size of its captive forces S. occitanica to convey it along the ground—a means of transit both slow and difficult. The same reason—namely, the great size and weight of the prey—entirely upsets the usual order followed by the Hymenoptera, in their labours,—an order well known, and consisting in first hollowing a burrow and then victualling it. The prey not being disproportioned to the size of the spoiler, facility of transport by flight allows the Hymenopteron a choice as to the position of her domicile. What matter if she has to hunt at considerable distances? Having made a capture, she returns home with rapid flight; it is indifferent to her whether she is near or far. Therefore she prefers the spot where she was born, and where her predecessors have lived; there she inherits deep galleries, the accumulated labour of former generations; with a little repair they can be used as avenues to new chambers, better defended than would be a single excavation a little below the surface made annually. Such is the case with Cerceris tuberculata and Philanthus apivorus, and even if the inherited dwelling should not be solid enough to resist wind and weather from one year’s end to another, and to be handed down to the next generation, at all events the Hymenopteron finds conditions of greater safety in spots consecrated by ancestral experience. There she hollows out galleries, each serving as corridors to a group of cells, thus economising the labour to be expended on the entire egg-laying.

In this way are formed, not true societies, there being no concerted effort to a common end, but at least gatherings where the sight of other Sphegidæ no doubt animates the labour of each. In fact, one can notice between these small tribes, sprung from one and the same stock, and the solitary miners, a difference in activity, recalling in one case the emulation of a populous workshop, and in the other the dulness of labourers in the tedium of isolation. For the animal as well as man activity is contagious, and excited by its own example. Let us sum up. Where there is a moderate weight for the spoiler, it is possible to carry it on the wing for a great distance, and then the Hymenopteron can arrange the burrows at pleasure, choosing by preference its birthplace. From this preference of the birthplace results an agglomeration—a coming together of insects of the same species, whence arises emulation in their work. This first step towards social life is the result of easy journeys. Is it not so with man? excuse the comparison! Men, where ways are bad, build solitary cottages, while where there are good roads, they collect in populous cities, served by railroads, which, so to say, annihilate distance; they assemble in immense human hives called London or Paris.

The Languedocian Sphex has quite another lot. Its prey is a heavy ephippiger—a single morsel representing the whole sum of provender amassed by the other predatory insects bit by bit. What the Cerceris and other strong-flying insects do by dividing their labour is accomplished by a single effort. The weight of the prey rendering flight impossible, it must be brought home with all the delays and fatigue of dragging it along the ground. This one fact obliges her to accommodate the position of her burrow to the chances of the chase: first the prey and then the dwelling. Hence no rendezvous at a general meeting-place; no living among neighbours, no tribes stimulating themselves by mutual example—only isolation where chance has led the Sphex—solitary labour, unenthusiastic, though always conscientious. First of all prey is sought, attacked, and paralysed. Then comes making the burrow. A favourable spot is chosen as near as possible to that where lies the victim, so as to abridge the toil of transport, and the cell of the future larva is rapidly hollowed to receive an egg and food as soon as possible. Such is the very different method shown by all my observations. I will mention the chief of them.

If surprised in its mining, one always finds this Sphex alone—sometimes at the bottom of some dusty niche a fallen stone has left in an old wall—sometimes in a shelter formed by a projecting bit of sandstone, such as is sought by the fierce-eyed lizard as a vestibule to its retreat. The sun falls full upon it; the place is a furnace. The soil is extremely easy to hollow, formed as it is by ancient dust which has dropped little by little from the roof. The mandibles, which act as pincers to dig with, and the tarsi, as rakes to clear away, soon hollow the cavity. Then the Sphex flies off, but in a leisurely way, and without any great expenditure of wing power, a manifest sign that the expedition is not a long one. One’s eye can easily follow the insect and discover where it alights, usually some ten yards off. Sometimes it decides to go on foot. It sets out, hurrying to a spot where we will be indiscreet enough to follow, our presence noways troubling it. Having arrived on foot or on the wing it hunts about for a while, as one may conclude from its indecision and short excursions on all sides. It seeks and at last finds, or rather finds anew. The object found is an ephippiger, half-paralysed, but still moving antennæ, tarsi, and ovipositor—a victim which the Sphex certainly poignarded a little while before with several stings, and then left her prey, an embarrassing burden, while she still hesitated as to the choice of a domicile. Perhaps she abandoned it on the very spot of the capture, leaving it rather obvious on a grass tuft the better to find it later, and trusting to her good memory to return where lies the booty, set to work to explore the neighbourhood and find a suitable spot to burrow. This done she came back for the game which was found without much hesitation, and now she prepares to convey it home. She bestrides the insect, seizes one or both antennæ and sets off, pulling and dragging with all the strength of loins and jaws.

Sometimes the journey is accomplished at one trial; more frequently she leaves her load and hurries home. Perhaps it occurs to her that the entrance door is not wide enough for this ample morsel, perhaps she bethinks her of some defect of detail that might interfere with provisioning the cell. Yes, she retouches her work, enlarges the doorway, levels the threshold, consolidates the arch, all with a few sweeps of the tarsi. Then she returns to the ephippiger, lying on its back a few paces distant, and drags it on again. But a new idea seems to flash across her lively mind. She had visited the gateway but had not looked within; who knows if all be well there? She hastens back, leaving the ephippiger midway. The interior is visited, and apparently some touches as with a trowel are given by the tarsi, to lend a last finish to the walls. Without lingering over these final touches the Sphex returns to her prey, and harnesses herself to the antennæ. Forward! Will the journey be accomplished this time? I would not answer for it. I have known a Sphex, perhaps more suspicious than others, or more forgetful of the minor details of architecture, set her omissions right or allay her suspicions by abandoning her prey five or six times successively, and hurrying to the burrow, which each time was touched up a little or simply entered. It is true that others go straight home, without even stopping to rest. I must add that when the Sphex comes home to perfect her dwelling, she does not fail to give an occasional, distant glance at the ephippiger left on the way, to make sure that nothing touches it. This prudence recalls that of the Scarabæus sacer issuing from the hole which it is digging to feel its dear ball, and bring it a little nearer.

The deduction to be drawn from the facts just stated is evident. Since every Sphex occitanica we surprise while it burrows—be it at the very beginning, at the first stroke of her tarsi in the dust, or later, the dwelling being ready—makes a short expedition on foot or on the wing, and always finds a victim already stabbed, already paralysed, one may conclude with certainty that she first makes her capture, and later burrows, so that the place of capture decides that of the domicile.

This reversal of method which prepares the food before the larder, while previously we saw the larder precede the food, I attribute to the weight of the prey being too great to carry on the wing. It is not that S. occitanica is ill-organised for flight; on the contrary, she can soar splendidly, but her prey would overwhelm her if she depended only on her wings. She needs the support of the ground and must drag her prey, and displays wonderful vigour in doing this. Loaded with prey she always goes on foot, or takes very short flights when these spare time and toil. Let me quote an instance taken from my latest observations on this curious Hymenopteron.

A Sphex appeared suddenly, whence I know not, dragging an ephippiger apparently just caught hard by. As things were she had to burrow, but the position was as bad as possible—a highway, hard as stone. There was no time for difficult mining, since the prey must be stored as soon as possible; she needed light soil where the cell could be quickly made. I have already described her favourite soil—dust deposed by years at the bottom of some hole in a wall, or in some little hollow of a rock. The Sphex which I was observing stopped at the foot of a country house with a newly whitewashed façade, and measuring from six to eight metres in height. Instinct told her that under the roof tiles she would find hollows rich in ancient dust. Leaving her prey at the foot of the façade, she flew on to the roof. For some time I saw her seek vainly about. Then, having found a suitable position, she set to work under the hollow of a tile. In ten minutes or a quarter of an hour at most the domicile was ready; she flew down, promptly found the ephippiger, and then had to carry up her prey. Would it be on the wing, as circumstances suggest? Not at all; the Sphex adopted the difficult method of escalading a vertical wall with a surface smoothed by the mason’s trowel and from six to eight metres high. Seeing her take this road, dragging her game between her feet, I thought at first that it was impossible, but was soon reassured as to the outcome of this audacious attempt. Supporting herself by the little roughnesses of the mortar, the vigorous insect, in spite of the embarrassment of her heavy load, made her way up this vertical plane with the same security, the same speed, as on horizontal ground. The top is reached without any hindrance, and the prey provisionally deposited at the edge of the roof on the rounded bark of a tile. While the Sphex was retouching her burrow the ill-balanced prey slipped and fell to the foot of the wall. She must begin again, and again by means of an escalade. The same imprudence is repeated; once more left on the curved tile the prey slips and falls to the ground. With a calm which such accidents cannot disturb, the Sphex for the third time hoists the ephippiger by climbing the wall, and, better advised, drags it straight to the bottom of the hole.

If carrying the prey on the wing has not been attempted even in such conditions as the above, it is clear that the Sphex is incapable of flight with so heavy a load. To this impotence we owe the few details of habits which are the subject of this chapter. A prey not too heavy to be carried on the wing makes a semi-sociable species of S. flavipennis—that is to say, one seeking the company of its fellows; a heavy prey impossible to carry through the air renders S. occitanica a species devoted to solitary labour—a kind of savage, disdainful of the solace derived from neighbourhood of one’s fellows. The greater or lesser weight of their prey decides the fundamental character.

THE SCIENCE OF INSTINCT

I have no doubt that in order to paralyse her prey, Sphex occitanica follows the method of the one that hunts grasshoppers, plunging her sting repeatedly into the breast of the ephippiger in order to reach the thoracic ganglia. She must be familiar with the operation of injuring the nerve centres, and I am assured beforehand of her consummate skill in the learned operation. It is an art familiar to all the predatory Hymenoptera who bear a poisoned dagger, and it is not given them for nothing. But I must own that I have never yet beheld the deadly manœuvre, thanks to the solitary life of this Sphex.

When a number of burrows are made and then provisioned on some common ground, one has only to wait there to see now one insect return from the chase, now another, with her prey, and it is easy to substitute a live victim for the one sacrificed, renewing the experiment at will. Besides, the certainty that the subjects for experiment will not fail when wanted allows everything to be prepared beforehand, while with S. occitanica these conditions of success do not exist. To set out and look for her with one’s preparations made is all but useless, so sparsely are these solitary insects scattered. Moreover, if you do meet with one, it will probably be during her idle hour when nothing is to be learned. I repeat that it is almost always unexpectedly, when you are not thinking about it, that the Sphex appears with her ephippiger. This is the moment—the one propitious moment—to attempt a substitution of prey and to induce her to let you witness those dagger thrusts. Let us hasten; time presses; in a few moments the burrow will have enclosed the provender, and the grand chance will be lost.

Need I speak of my mortification in these promising moments—a mocking lure offered by fortune! Under my eyes is matter for curious observations, and I cannot profit by it! I cannot steal the Sphex’s secret, for I have no equivalent to offer for her prey. Just try, if you like, to go about looking for an ephippiger when there are but a few minutes to find it in! Why, it took me three days of wild search before I could find weevils for my Cerceris! Yet twice did I make that desperate attempt. Ah! if the garde-champêtre had caught me then rushing about the vineyards, what a chance he would have had to believe me guilty of theft, and of reporting me! Vines and grapes—nothing was respected by my hurried steps, fettered by the vine garlands. I must and would have an ephippiger, and have it then and there. And once I did find one during one of these rapid expeditions. I beamed with joy, little foreseeing the bitter disappointment awaiting me.

If only I can come in time! if only the Sphex is still dragging her victim! Thank heaven! all favours me. She is still at some distance from her hole, and is bringing along her prey. With my pincers I gently draw it back. She resists, clutches the antennæ and will not let go. I pull harder, even making her go backwards; it is in vain, she holds on. I had with me a pair of delicate little scissors, part of my entomological outfit, and I rapidly cut the harness, otherwise the long antennæ of the ephippiger. The Sphex still advanced, but soon paused, surprised by the sudden lightening of her load, which now indeed only consisted of the antennæ detached by my malicious artifice. The real burden, the heavy-bodied insect, remained behind, instantly replaced by my living one. The Sphex turned, let go the ropes, which now drew nothing, and retraced her steps. Now she is face to face with the prey substituted for her own. She examines it, walks round it with suspicious caution, stops, wets her foot with saliva and washes her eyes. While thus meditating does she say to herself something of this kind: “Well, am I awake or am I asleep? Do I see clearly or not? This thing is not mine. Of what or whom am I the dupe?” At all events she is in no haste to bite my prey. She holds aloof, and shows not the smallest wish to seize it. To excite her I offered the insect with the tips of my fingers, putting the antennæ almost in her jaws, well aware of her audacious tameness, and that she will take from your fingers prey withdrawn and then offered. What is this? She draws back, disdaining my offers and the prey put within her reach. I put down the ephippiger, which, unconscious of danger, goes straight to its assassin. Now for it. Alas! no; the Sphex continues to draw back, behaves like a veritable coward, and finally takes wing. I never saw her again. Thus ended to my confusion an experiment which had so excited my enthusiasm.

Later, and gradually, as I visited more burrows I came to understand my want of success and the obstinate refusal of the Sphex. I always, without exception, found stored a female ephippiger with an abundant and succulent store of eggs inside her. This, it would seem, is the favourite food of the larvæ. In my rush among the vines I had laid hands on one of the other sex. It was a male which I offered to the Sphex! More clear-sighted than I in the great victualling question, she would have nothing to say to my game. “A male! Is that the kind of dinner for my larvæ? And, pray, for whom do you take them?” How sensitive must be these dainty eaters who appreciate the difference between the tender flesh of the female and the comparatively dry body of the male! What a penetrating glance which can distinguish instantly the one sex from the other, though alike in form and colour! The female has an ovipositor to bury her eggs with, and this is almost the only outward difference between her and the male. This difference never escapes the keen-sighted Sphex, and that is why my experiment made her rub her eyes, immensely puzzled by a prey without an ovipositor, which she was perfectly sure had one when it was caught. At such a transformation what must have passed in her little Sphex brain?

Now let us follow her when, the burrow being ready, she returns to find her victim, deserted not far from the place of capture, and after the operation which paralysed it. The ephippiger is in a state like that of the cricket slain by S. flavipennis—a certain proof that stings have been darted into the ganglia of the thorax. Nevertheless, many movements continue, but disconnected, though endowed with a certain vigour. Unable to stand, the insect lies on one side or on its back, moving its long antennæ and palpi rapidly, opening and closing its mandibles, and biting as hard as in its normal condition. The abdomen pants fast and deeply; the ovipositor is suddenly brought under the stomach, which it almost touches. The feet move, but languidly and irregularly, the middle ones seemingly more benumbed than the others. If touched with a needle, the whole body starts wildly; efforts are made to rise and walk without success. In short, the creature would be full of life but for the impossibility of locomotion and even of getting on its feet. There is then a paralysis altogether local—paralysis of the feet, or rather partial abolition and ataxy of movement in them. Is this very incomplete inertia caused by some special disposition of the victim’s nervous system, or is it that only a single stab is given, instead of wounding each ganglion of the thorax, as does the huntress of grasshoppers? I cannot say.

However, for all its starts, its convulsions, its irregular movements, the victim is none the less unable to harm the larvæ destined to devour it. I have taken from the Sphex’s burrow ephippigers struggling just as much as in the first moments of their semi-paralysis, and yet the feeble grub, born but a few hours earlier, was biting the gigantic victim with entire immunity. This striking result is caused by the mother laying her egg in one particular spot. I have already told how S. flavipennis glues her egg on the cricket’s breast, rather on one side, between the first and second pairs of feet. S. albisecta chooses the same place, and S. occitanica an analogous one, rather further back toward the base of one of the large hind thighs, all three thus evincing admirable knowledge as to where the egg will be safe.

For consider the ephippiger shut in the burrow. It is on its back, absolutely incapable of turning over. Vainly does it struggle; the irregular movements of its feet are useless, the cell being too wide for them to gain support from the walls. What do the victim’s convulsions matter to the larva? It is on a spot where it cannot be reached by tarsi, mandibles, ovipositor, or antennæ—a point absolutely motionless, where there is not even a shudder of the skin. There is entire security unless the ephippiger can move, turn, and get on its feet, and that one condition is admirably guarded against.

But with several, all in the same degree of paralysis, there would be great risk for the larva. Though there would be nothing to fear from the first insect attacked, as the larva is out of its reach, there would be peril from the neighbourhood of the others, which in stretching out their legs hither and thither might strike it and tear it up with their spurs. Perhaps this is why S. flavipennis, which heaps three or four grasshoppers in one cell, almost entirely paralyses them, while S. occitanica, providing each burrow with a single victim, leaves great power of motion to the ephippiger, simply preventing change of place or rising to its feet, thus—though I cannot affirm it—economising dagger thrusts.

If the half-paralysed ephippiger be harmless for the larva established on a point of its body where defence is impossible, things are otherwise for the Sphex itself, which has to get it home. First, the prey clutches bits of grass with its tarsi as it is dragged along, being still able to use them pretty freely, causing considerable difficulty in getting it onward. The Sphex, heavily weighted by her load, is exposed to exhaustion by her efforts to make her prey let go its desperate hold on grassy places. But that is the least of the difficulties; it has full use of its mandibles, which snap and bite with their old vigour. Just in front of these terrible pincers is the slender body of the spoiler, as the latter draws the victim along. The antennæ are grasped not far from their root, so that the ephippiger, lying on its back, has its mouth now opposite the abdomen, and now the thorax of the Sphex, who, standing high on her long legs, watches, I am convinced, in order not to be seized by the mandibles gaping beneath. A moment of forgetfulness, a slip, a mere nothing, might bring her within reach of a pair of strong nippers which would not let slip the chance of a pitiless vengeance. In certain specially difficult cases, if not always, the movement of these redoubtable pincers must be stopped, and the harpoon-like tarsi prevented from adding to the difficulties of transport.