Bramble-Bees and Others Part 14

To generalize and say that death is always near at hand when the sting is administered in the thoracic ganglia would be going too far: it occurs frequently, but there are a good many exceptions, resulting from circ.u.mstances impossible to define. I cannot control the direction of the sting, the depth attained, the quant.i.ty of poison shed; and the stump of the Bee is very far from making up for my shortcomings. We have here not the cunning sword-play of the predatory insect, but a casual blow, ill-placed and ill-regulated. Any accident is possible, therefore, from the gravest to the mildest. Let us mention some of the more interesting.

An adult Praying Mantis (Mantis religiosa, so-called because the toothed fore-legs, in which it catches and kills its prey, adopt, when folded, an att.i.tude resembling that of prayer.--Translator's Note.) is p.r.i.c.ked level with the attachment of the predatory legs. Had the wound been in the centre, I should have witnessed an occurrence which, although I have seen it many times, still arouses my liveliest emotion and surprise.

This is the sudden paralysis of the warrior's savage harpoons. No machinery stops more abruptly when the mainspring breaks. As a rule, the inertia of the predatory legs attacks the others in the course of a day or two; and the palsied one dies in less than a week. But the present sting is not in the exact centre. The dart has entered near the base of the right leg, at less than a millimetre (.039 inch.--Translator's Note.) from the median point. That leg is paralysed at once; the other is not; and the insect employs it to the detriment of my unsuspecting fingers, which are p.r.i.c.ked to bleeding-point by the spike at the tip. Not until to-morrow is the leg which wounded me to-day rendered motionless. This time, the paralysis goes no farther. The Mantis moves along quite well, with her corselet proudly raised, in her usual att.i.tude; but the predatory fore-arms, instead of being folded against the chest, ready for attack, hang lifeless and open. I keep the cripple for twelve days longer, during which she refuses all nourishment, being incapable of using her tongs to seize the prey and lift it to her mouth.

The prolonged abstinence kills her.

Some suffer from locomotor ataxy. My notes recall an Ephippiger who, p.r.i.c.ked in the prothorax away from the median line, retained the use of her six limbs without being able to walk or climb for lack of co-ordination in her movements. A singular awkwardness left her wavering between going back and going forward, between turning to the right and turning to the left.

Some are smitten with semiparalysis. A Cetonia-grub, p.r.i.c.ked away from the centre on a level with the fore-legs, has her right side flaccid, spread out, incapable of contracting, while the left side swells, wrinkles and contracts. Since the left half no longer receives the symmetrical cooperation of the right half, the grub, instead of curling into the normal volute, closes its spiral on one side and leaves it wide open on the other. The concentration of the nervous apparatus, poisoned by the venom down one side of the body only, a longitudinal half, explains this condition, which is the most remarkable of all.

There is nothing to be gained by multiplying these examples. We have seen pretty clearly the great variety of results produced by the haphazard sting of a Bee's abdomen; let us now come to the crux of the matter. Can the Bee's poison reduce the prey to the condition required by the predatory Wasp? Yes, I have proved it by experiment; but the proof calls for so much patience that it seemed to me to suffice when obtained once for each species. In such difficult conditions, with a poison of excessive strength, a single success is conclusive proof; the thing is possible so long as it occurs once.

A female Ephippiger is stung at the median point, just a little in front of the fore-legs. Convulsive movements lasting for a few seconds are followed by a fall to one side, with pulsations of the abdomen, flutterings of the antennae and a few feeble movements of the legs. The tarsi cling firmly to the hair-pencil which I hold out to them. I place the insect on its back. It lies motionless. Its state is absolutely the same as that to which the Languedocian Sphex (Cf. "Insect Life": chapter 10.--Translator's Note.) reduces her Ephippigers. For three weeks on end, I see repeated in all its details the spectacle to which I have been accustomed in the victims extracted from the burrows or taken from the huntress: the wide-open mandibles, the quivering palpi and tarsi, the ovipositor shuddering convulsively, the abdomen throbbing at long intervals, the spark of life rekindled at the touch of a pencil. In the fourth week, these signs of life, which have gradually weakened, disappear, but the insect still remains irreproachably fresh. At last a month pa.s.ses; and the paralysed creature begins to turn brown. It is over; death has come.

I have the same success with a Cricket and also with a Praying Mantis.

In all three cases, from the point of view of long-maintained freshness and of the signs of life proved by slight movements, the resemblance between my victim and those of the predatory insects is so great that no Sphex and no Tachytes would have disowned the product of my devices. My Cricket, my Ephippiger, my Mantis had the same freshness as theirs; they preserved it as theirs did for a period amply sufficient to allow of the grubs' complete evolution. They proved to me, in the most conclusive manner, they prove to all whom it may interest, that the poison of the Bees, leaving its hideous violence on one side, does not differ in its effects from the poison of the predatory Wasps. Are they alkaline or acid? The question is an idle one in this connection. Both of them intoxicate, derange, torpify the nervous centres and thus produce either death or paralysis, according to the method of inoculation. For the moment, that is all. No one is yet able to say the last word on the actions of those poisons, so terrible in infinitesimal doses. But on the point under discussion we need no longer be ignorant: the Wasp owes the preservation of her grub's provisions not to any special qualities of her poison but to the extreme precision of her surgery.

A last and more plausible objection is that raised by Darwin when he said that there were no fossil remains of instincts. And, if there were, O master, what would they teach us? Not very much more than what we learn from the instincts of to-day. Does not the geologist make the erstwhile carcases live anew in our minds in the light of the world as we see it? With nothing but a.n.a.logy to guide them, he describes how some saurian lived in the jura.s.sic age; there are no fossil remains of habits, but nevertheless he can tell us plenty about them, things worthy of credence, because the present teaches him the past. Let us do a little as he does.

I will suppose a precursor of the Calicurgi (The Calicurgus, or Pompilus, is a Hunting Wasp, feeding her larvae on Spiders. Cf. "The Life and Love of the Insect": chapter 12.--Translator's Note.) dwelling in the prehistoric coal-forests. Her prey was some hideous Scorpion, that first-born of the Arachnida. How did the Hymenopteron master the terrible prey? a.n.a.logy tells us, by the methods of the present slayer of Tarantulae. It disarmed the adversary; it paralysed the venomous sting by a stroke administered at a point which we could determine for certain by the animal's anatomy. Unless this was the way it happened, the a.s.sailant must have perished, first stabbed and then devoured by the prey. There is no getting away from it: either the precursor of the Calicurgi, that slaughterer of Scorpions, knew her trade thoroughly, or else the continuation of her race became impossible, even as it would be impossible to keep up the race of the Tarantula-killer without the dagger-thrust that paralyses the Spider's poison-fangs. The first who, greatly daring, pinked the Scorpion of the coal-seams was already an expert fencer; the first to come to grips with the Tarantula had an unerring knowledge of her dangerous surgery. The least hesitation, the slightest speculation; and they were lost. The first teacher would also have been the last, with no disciples to take up her work and perfect it.

But fossil instincts, they insist, would show us intermediary stages, first, second and third rungs; they would show us the gradual pa.s.sing from the casual and very incorrect attempt to the perfect practice, the fruit of the ages; with their accidental differences, they would give us terms of comparison wherewith to trace matters from the simple to the complex. Never mind about that, my masters: if you want varied instincts in which to seek the source of the complex by means of the simple, it is not necessary to search the foliations of the coal-seams and the successive layers of the rocks, those archives of the prehistoric world; the present day affords to contemplation an inexhaustible treasury realizing perhaps everything that can emerge from the limbo of possibility. In what will soon be half a century of study, I have caught but a tiny glimpse of a very tiny corner of the realm of instinct; and the harvest gathered overwhelms me with its variety: I do not yet know two species of predatory Wasps whose methods are exactly the same.

One gives a single stroke of the dagger, a second two, a third three, a fourth nine or ten. One stabs here and the other there; and neither is imitated by the next, who attacks elsewhere. This one injures the cephalic centres and produces death; that one respects them and produces paralysis. Some squeeze the cervical ganglia to obtain a temporary torpor; others know nothing of the effects of compressing the brain. A few make the prey disgorge, lest its honey should poison the offspring; the majority do not resort to preventive manipulations. Here are some that first disarm the foe, who carries poisoned daggers; yonder are others and more numerous, who have no precautions to take before murdering the unarmed prey. In the preliminary struggle, I know some who grab their victims by the neck, by the rostrum, by the antennae, by the caudal threads; I know some who throw them on their backs, some who lift them breast to breast, some who operate on them in the vertical position, some who attack them lengthwise and crosswise, some who climb on their backs or on their abdomens, some who press on their backs to force out a pectoral fissure, some who open their desperately contracted coil, using the tip of the abdomen as a wedge. And so I could go on indefinitely: every method of fencing is employed. What could I not also say about the egg, slung pendulum-fashion by a thread from the ceiling, when the live provisions are wriggling underneath; laid on a scanty mouthful, a solitary opening dish, when the dead prey requires renewing from day to-day; entrusted to the last joint stored away, when the victuals are paralysed; fixed at a precise spot, entailing the least danger to the consumer and the game, when the corpulent prey has to be devoured with a special art that warrants its freshness!

Well, how can this mult.i.tude of varied instincts teach us anything about gradual transformation? Will the one and only dagger-thrust of the Cerceris and the Scolia take us to the two thrusts of the Calicurgus, to the three thrusts of the Sphex, to the manifold thrust of the Ammophila?

Yes, if we consider only numerical progression. One and one are two; two and one are three: so run the figures. But is this what we want to know? What has arithmetic to do with the case? Is not the whole problem subordinate to a condition that cannot be translated into cyphers? As the prey changes, the anatomy changes; and the surgeon always operates with a complete understanding of his subject. The single dagger-thrust is administered to ganglia collected into a common cl.u.s.ter; the manifold thrusts are distributed over the scattered ganglia; of the two thrusts of the Tarantula-huntress, one disarms and the other paralyses. And so with the others: that is to say, the instinct is directed each time by the secrets of the nervous organism. There is a perfect harmony between the operation and the patient's anatomy.

The single stroke of the Scolia is no less wonderful than the repeated strokes of the Ammophila. Each has her appointed game and each slays it by a method as rational as any that our own science could invent. In the presence of this consummate knowledge, which leaves us utterly confounded, what a poor argument is that of 1 + 1 = 2! And what is that progress by units to us? The universe is mirrored in a drop of water; universal logic flashes into sight in a single sting.

Besides, push on the pitiful argument. One leads to two, two lead to three. Granted without dispute. And then? We will accept the Scolia as the pioneer, the foundress of the first principles of the art. The simplicity of her method justifies our supposition. She learns her trade in some way or other, by accident; she knows supremely well how to paralyse her Cetonia-grub with a single dagger-thrust driven into the thorax. One day, through some fortuitous circ.u.mstance, or rather by mistake, she takes it into her head to strike two blows. As one is enough for the Cetonia, the repet.i.tion was of no value unless there was a change of prey. What was the new victim submitted to the butcher's knife? Apparently, a large Spider, since the Tarantula and the Garden Spider call for two thrusts. And the prentice Scolia, who used at first to sting under the throat, had the skill, at her first attempt, to begin by disarming her adversary and then to go quite low down, almost to the end of the thorax, to strike the vital point. I am utterly incredulous as to her success. I see her eaten up if her lancet swerves and hits the wrong spot. Let us look impossibility boldly in the face and admit that she succeeds. I then see the offspring, which have no recollection of the fortunate event save through the belly--and then we are postulating that the digestion of the carnivorous larva leaves a trace in the memory of the honey-sipping insect--I see the offspring, I say, obliged to wait at long intervals for that inspired double thrust and obliged to succeed each time under pain of death for them and their descendants. To accept this host of impossibilities exceeds all my faculties of belief. One leads to two, no doubt; the Ssingle blow of the predatory Wasp will never lead to the blow twice delivered.

In order to live, we all require the conditions that enable us to live: this is a truth worthy of the famous axioms of La Palice. (Jacques de Chabannes, Seigneur de La Palice [circa 1470-1525]), was a French captain killed at the battle of Pavia. His soldiers made up in his honour a ballad, two lines of which, translated, run:

Fifteen minutes before he died, He was still alive.

(Hence the French expression, une verite de La Palice, meaning an obvious truth.--Translator's Note.)

The predatory insects live by their talent. If they do not possess it to perfection, their race is lost. Hidden in the murk of the past ages, the argument based upon the non-existence of fossil instinct is no better able than the others to withstand the light of living realities; it crumbles under the stroke of fate; it vanishes before a La Palice plat.i.tude.

CHAPTER 12. THE HALICTI: A PARASITE.

Do you know the Halicti? Perhaps not. There is no great harm done: it is quite possible to enjoy the few sweets of existence without knowing the Halicti. Nevertheless, when questioned persistently, these humble creatures with no history can tell us some very singular things; and their acquaintance is not to be disdained if we would enlarge our ideas upon the bewildering swarm of this world. Since we have nothing better to do, let us look into the Halicti. They are worth the trouble.

How shall we recognize them? They are manufacturers of honey, generally longer and slighter than the Bee of our hives. They const.i.tute a numerous group that varies greatly in size and colouring. Some there are that exceed the dimensions of the Common Wasp; others might be compared with the House-fly, or are even smaller. In the midst of this variety, which is the despair of the novice, one characteristic remains invariable. Every Halictus carries the clearly-written certificate of her guild.

Examine the last ring, at the tip of the abdomen, on the dorsal surface.

If your capture be an Halictus, there will be here a smooth and shiny line, a narrow groove along which the sting slides up and down when the insect is on the defensive. This slide for the unsheathed weapon denotes some member of the Halictus tribe, without distinction of size or colour. No elsewhere, in the sting-bearing order, is this original sort of groove in use. It is the distinctive mark, the emblem of the family.

Three Halicti will appear before you in this biographical fragment. Two of them are my neighbours, my familiars, who rarely fail to settle each year in the best parts of the enclosure. They occupied the ground before I did; and I should not dream of evicting them, persuaded as I am that they will well repay my indulgence. Their proximity, which allows me to visit them daily at my leisure, is a piece of good luck. Let us profit by it.

At the head of my three subjects is the Zebra Halictus (H. zebrus, WALCK.), which is beautifully belted around her long abdomen with alternate black and pale-russet scarves. Her slender shape, her size, which equals that of the Common Wasp, her simple and pretty dress, combine to make her the chief representative of the genus here.

She establishes her galleries in firm soil, where there is no danger of landslips which would interfere with the work at nesting-time. In my garden, the well-levelled paths, made of a mixture of tiny pebbles and red clayey earth, suits her to perfection. Every spring she takes possession of it, never alone, but in gangs whose number varies greatly, amounting sometimes to as many as a hundred. In this way she founds what may be described as small townships, each clearly marked out and distant from the other, in which the joint possession of the site in no way entails joint work.

Each has her home, an inviolable manor which none but the owner has the right to enter. A sound buffeting would soon call to order any adventuress who dared to make her way into another's dwelling. No such indiscretion is suffered among the Halicti. Let each keep to her own place and to herself and perfect peace will reign in this new-formed society, made up of neighbours and not of fellow-workers.

Operations begin in April, most un.o.btrusively, the only sign of the underground works being the little mounds of fresh earth. There is no animation in the building-yards. The labourers show themselves very seldom, so busy are they at the bottom of their pits. At moments, here and there, the summit of a tiny mole-hill begins to totter and tumbles down the slopes of the cone: it is a worker coming up with her armful of rubbish and shooting it outside, without showing herself in the open.

Nothing more for the moment.

There is one precaution to be taken: the villages must be protected against the pa.s.sers-by, who might inadvertently trample them under foot.

I surround each of them with a palisade of reed-stumps. In the centre I plant a danger-signal, a post with a paper flag. The sections of the paths thus marked are forbidden ground; none of the household will walk upon them.

May arrives, gay with flowers and sunshine. The navvies of April have turned themselves into harvesters. At every moment I see them settling, all befloured with yellow, atop of the mole-hills now turned into craters. Let us first look into the question of the house. The arrangement of the home will give us some useful information. A spade and a three-p.r.o.nged fork place the insect's crypts before our eyes.

A shaft as nearly vertical as possible, straight or winding according to the exigencies of a soil rich in flinty remains, descends to a depth of between eight and twelve inches. As it is merely a pa.s.sage in which the only thing necessary is that the Halictus should find an easy support in coming and going, this long entrance-hall is rough and uneven. A regular shape and a polished surface would be out of place here. These artistic refinements are reserved for the apartments of her young. All that the Halictus mother asks is that the pa.s.sage should be easy to go up and down, to ascend or descend in a hurry. And so she leaves it rugged. Its width is about that of a thick lead-pencil.

Arranged one by one, horizontally and at different heights, the cells occupy the bas.e.m.e.nt of the house. They are oval cavities, three-quarters of an inch long, dug out of the clay ma.s.s. They end in a short bottle-neck that widens into a graceful mouth. They look like tiny vaccine-phials laid on their sides. All of them open into the pa.s.sage.

The inside of these little cells has the gloss and polish of a stucco which our most experienced plasterers might envy. It is diapered with faint longitudinal, diamond-shaped marks. These are the traces of the polishing-tool that has given the last finish to the work. What can this polisher be? None other than the tongue, that is obvious. The Halictus has made a trowel of her tongue and licked the wall daintily and methodically in order to polish it.

This final glazing, so exquisite in its perfection, is preceded by a tr.i.m.m.i.n.g-process. In the cells that are not yet stocked with provisions, the walls are dotted with tiny dents like those in a thimble. Here we recognize the work of the mandibles, which squeeze the clay with their tips, compress it and purge it of any grains of sand. The result is a milled surface whereon the polished layer will find a solid adhesive base. This layer is obtained with a fine clay, very carefully selected by the insect, purified, softened and then applied atom by atom, after which the trowel of the tongue steps in, diapering and polishing, while saliva, disgorged as needed, gives pliancy to the paste and finally dries into a waterproof varnish.

The humidity of the subsoil, at the time of the spring showers, would reduce the little earthen alcove to a sort of pap. The coating of saliva is an excellent preservative against this danger. It is so delicate that we suspect rather than see it; but its efficacy is none the less evident. I fill a cell with water. The liquid remains in it quite well, without any trace of infiltration.

The tiny pitcher looks as if it were varnished with galenite. The impermeability which the potter obtains by the brutal infusion of his mineral ingredients the Halictus achieves with the soft polisher of her tongue moistened with saliva. Thus protected, the larva will enjoy all the advantages of a dry berth, even in rain-soaked ground.

Should the wish seize us, it is easy to detach the waterproof film, at least in shreds. Take the little shapeless lump in which a cell has been excavated and put it in sufficient water to cover the bottom of it. The whole earthy ma.s.s will soon be soaked and reduced to a mud which we are able to sweep with the point of a hair-pencil. Let us have patience and do our sweeping gently; and we shall be able to separate from the main body the fragments of a sort of extremely fine satin. This transparent, colourless material is the upholstery that keeps out the wet. The Spider's web, if it formed a stuff and not a net, is the only thing that could be compared with it.

The Halictus' nurseries are, as we see, structures that take much time in the making. The insect first digs in the clayey earth a recess with an oval curve to it. It has its mandibles for a pick-axe and its tarsi, armed with tiny claws, for rakes. Rough though it be, this early work presents difficulties, for the Bee has to do her excavating in a narrow gully, where there is only just room for her to pa.s.s.

The rubbish soon becomes c.u.mbersome. The insect collects it and then, moving backwards, with its fore-legs closed over the load, it hoists it up through the shaft and flings it outside, upon the mole-hill, which rises by so much above the threshold of the burrow. Next come the dainty finishing-touches: the milling of the wall, the application of a glaze of better-quality clay, the a.s.siduous polishing with the long-suffering tongue, the waterproof coating and the jarlike mouth, a masterpiece of pottery in which the stopping-plug will be fixed when the time comes for locking the door of the room. And all this has to be done with mathematical precision.

No, because of this perfection, the grubs' chambers could never be work done casually from day to day, as the ripe eggs descend from the ovaries. They are prepared long beforehand, during the bad weather, at the end of March and in April, when flowers are scarce and the temperature subject to sudden changes. This thankless period, often cold, liable to hail-storms, is spent in making ready the home. Alone at the bottom of her shaft, which she rarely leaves, the mother works at her children's apartments, lavishing upon them those finishing-touches which leisure allows. They are completed, or very nearly, when May comes with the radiant sunshine and wealth of flowers.

We see the evidence of these long preparations in the burrows themselves, if we inspect them before the provisions are brought. All of them show us cells, about a dozen in number, quite finished, but still empty. To begin by getting all the huts built is a sensible precaution: the mother will not have to turn aside from the delicate task of harvesting and egg-laying in order to perform rough navvy's work.

Everything is ready by May. The air is balmy; the smiling lawns are gay with a thousand little flowers, dandelions, rock-roses, tansies and daisies, among which the harvesting Bee rolls gleefully, covering herself with pollen. With her crop full of honey and the brushes of her legs befloured, the Halictus returns to her village. Flying very low, almost level with the ground, she hesitates, with sudden turns and bewildered movements. It seems that the weak-sighted insect finds its way with difficulty among the cottages of its little township.

Which is its mole-hill among the many others near, all similar in appearance? It cannot tell exactly save by the sign-board of certain details known to itself alone. Therefore, still on the wing, tacking from side to side, it examines the locality. The home is found at last: the Halictus alights on the threshold of her abode and dives into it quickly.

What happens at the bottom of the pit must be the same thing that happens in the case of the other Wild Bees. The harvester enters a cell backwards; she first brushes herself and drops her load of pollen; then, turning round, she disgorges the honey in her crop upon the floury ma.s.s.

This done, the unwearied one leaves the burrow and flies away, back to the flowers. After many journeys, the stack of provisions in the cell is sufficient. This is the moment to bake the cake.

The mother kneads her flour, mingles it sparingly with honey. The mixture is made into a round loaf, the size of a pea. Unlike our own loaves, this one has the crust inside and the crumb outside. The middle part of the roll, the ration which will be consumed last, when the grub has acquired some strength, consists of almost nothing but dry pollen.

The Bee keeps the dainties in her crop for the outside of the loaf, whence the feeble grub-worm is to take its first mouthfuls. Here it is all soft crumb, a delicious sandwich with plenty of honey. The little breakfast-roll is arranged in rings regulated according to the age of the nurseling: first the syrupy outside and at the very end the dry inside. Thus it is ordained by the economics of the Halictus.