Bramble-Bees and Others Part 13

We have here, recognized as of excellent standard by all the expert cla.s.sifiers, so fastidious in the arrangement of their lists, a generic group, called Anthidium, containing two guilds of workers entirely dissimilar in character: the cotton-fullers and the resin-kneaders. It is even possible that other species, when their habits are better known, will come and increase this variety of manufactures. I confine myself to the little that I know and ask myself in what the manipulator of cotton differs from the manipulator of resin as regards tools, that is to say, organs. Certainly, when the genus Anthidium was set down by the cla.s.sifiers, they were not wanting in scientific precision: they consulted, under the lens of the microscope, the wings, the mandibles, the legs, the harvesting-brush, in short, all the details calculated to a.s.sist the proper delimitation of the group. After this minute examination by the experts, if no organic differences stand revealed, the reason is that they do not exist. Any dissimilarity of structure could not escape the accurate eyes of our learned taxonomists. The genus, therefore, is indeed organically h.o.m.ogeneous; but industrially it is thoroughly heterogeneous. The implements are the same and the work is different.

That eminent Bordeaux entomologist, Professor Jean Perez, to whom I communicated the misgivings aroused in my mind by the contradictory nature of my discoveries, thinks that he has found the solution of the difficulty in the conformation of the mandibles. I extract the following pa.s.sage from his volume, "Les Abeilles":

'The cotton-pressing females have the edge of their mandibles cut out into five or six little teeth, which make an instrument admirably suited for sc.r.a.ping and removing the hairs from the epidermis of the plants. It is a sort of comb or teasel. The resin-kneading females have the edge of the mandible not toothed, but simply curved; the tip alone, preceded by a notch which is pretty clearly marked in some species, forms a real tooth; but this tooth is blunt and does not project. The mandible, in short, is a kind of spoon perfectly fitted to remove the sticky matter and to shape it into a ball.'

Nothing better could be said to explain the two sorts of industry: in the one case, a rake which gathers the wool; in the other, a spoon which scoops up the resin. I should have left it at that and felt quite content without further investigation, if I had not had the curiosity to open my boxes and, in my turn, to take a good look, side by side, at the workers in cement and the workers in cotton. Allow me, my learned master, to whisper in your ear what I saw.

The first that I examine is Anthidium septemdentatum. A spoon: yes, it is just that. Powerful mandibles, shaped like an isosceles triangle, flat above, hollowed out below; and no indentations, none whatsoever.

A splendid tool, as you say, for gathering the viscous pellet; quite as efficacious in its kind of work as is the rake of the toothed mandibles for gathering cotton. Here certainly is a creature potently-gifted, even though it be for a poor little task, the scooping up of two or three drops of glue.

Things are not quite so satisfactory with the second Resin-bee of the Snail-sh.e.l.ls, A. bellicosum. I find that she has three teeth to her mandibles. Still, they are slight and project very little. Let us say that this does not count, even though the work is exactly the same.

With A. quadrilob.u.m the whole thing breaks down. She, the queen of Resin-bees; she, who collects a lump of mastic the size of one's fist, enough to subdivide hundreds of her kinswomen's Snail-sh.e.l.ls: well, she, by way of a spoon, carries a rake! On the wide edges of her mandibles stand four teeth, as long and pointed as those of the most zealous cotton-gleaner. A. florentinum, that mighty manufacturer of cotton-goods, can hardly rival her in respect of combing-tools. And nevertheless, with her toothed implement, a sort of saw, the Resin-bee collects her great heap of pitch, load by load; and the material is carried not rigid, but sticky, half-fluid, so that it may amalgamate with the previous lots and be fas.h.i.+oned into cells.

A. Latreillii, without having a very large implement, also bears witness to the possibility of heaping up soft resin with a rake; she arms her mandibles with three or four sharply-cut teeth. In short, out of four Resin-bees, the only four that I know, one is armed with a spoon, if this expression be really suited to the tool's function; the three others are armed with a rake; and it so happens that the most copious heap of resin is just the work of the rake with the most teeth to it, a tool suited to the cotton-reapers, according to the views of the Bordeaux entomological expert.

No, the explanation that appealed to me so much at first is not admissible. The mandible, whether supplied with teeth or not, does not account at all for the two manufactures. May we, in this predicament, have recourse to the general structure of the insect, although this is not distinctive enough to be of much use to us? Not so either; for, in the same stone-heaps where the Osmia and the two Resin-bees of the Snail-sh.e.l.ls work, I find from time to time another manipulator of mastic who bears no structural relations.h.i.+p whatever to the genus Anthidium. It is a small-sized Mason-wasp, Odynerus alpestris, SAUSS.

She builds a very pretty nest with resin and gravel in the sh.e.l.ls of the young Common Snail, of Helix nemoralis and sometimes of Bulimulus radiatus. I will describe her masterpiece on some other occasion. To one acquainted with the genus Odynerus, any comparison with the Anthidia would be an inexcusable error. In larval diet, in shape, in habits, they form two dissimilar groups, very far removed one from the other. The Anthidia feed their offspring on honey-bread; the Odyneri feed it on live prey. Well, with her slender form, her weakly frame, in which the most clear-seeing eye would seek in vain for a clue to the trade practised, the Alpine Odynerus, the game-lover, uses pitch in the same way as the stout and ma.s.sive Resin-bee, the honey-lover. She even uses it better, for her mosaic of tiny pebbles is much prettier than the Bee's and no less solid. With her mandibles, this time neither spoon nor rake, but rather a long forceps slightly notched at the tip, she gathers her drop of sticky matter as dexterously as do her rivals with their very different outfit. Her case will, I think, persuade us that neither the shape of the tool nor the shape of the worker can explain the work done.

I will go further: I ask myself in vain the reason of this or that trade in the case of a fixed species. The Osmiae make their part.i.tions with mud or with a paste of chewed leaves; the Mason-bees build with cement; the Pelopaeus-wasps fas.h.i.+on clay pots; the Megachiles made disks cut from leaves into urns; the Anthidia felt cotton into purses; the Resin-bees cement together little bits of gravel with gum; the Carpenter-bees and the Lithurgi bore holes in timber; the Anthophorae tunnel the roadside slopes. Why all these different trades, to say nothing of the others? How are they prescribed for the insect, this one rather than that?

I foresee the answer: they are prescribed by the organization. An insect excellently equipped for gathering and felting cotton is ill-equipped for cutting leaves, kneading mud or mixing resin. The tool in its possession decides its trade.

This is a very simple explanation, I admit, and one within the scope of everybody: in itself a sufficient recommendation for any one who has neither the inclination nor the time to undertake a more thorough investigation. The popularity of certain speculative views is due entirely to the easy food which they provide for our curiosity. They save us much long and often irksome study; they impart a veneer of general knowledge. There is nothing that achieves such immediate success as an explanation of the riddle of the universe in a word or two. The thinker does not travel so fast: content to know little so that he may know something, he limits his field of search and is satisfied with a scanty harvest, provided that the grain be of good quality. Before agreeing that the tool determines the trade, he wants to see things with his own eyes; and what he observes is far from confirming the sweeping statement. Let us share his doubts for a moment and look into matters more closely.

Franklin left us a maxim which is much to the point here. He said that a good workman should be able to plane with a saw and to saw with a plane.

The insect is too good a workman not to follow the advice of the sage of Boston. Its industry abounds in instances where the plane takes the place of the saw, or the saw of the plane; its dexterity makes good the inadequacy of the implement. To go no further, have we not just seen different artisans collecting and using pitch, some with spoons, others with rakes, others again with pincers? Therefore, with such equipment as it possesses, the insect would be capable of abandoning cotton for leaves, leaves for resin, resin for mortar, if some predisposition of talent did not make it keep to its speciality.

These few lines, which are the outcome not of a heedless pen but of mature reflection, will set people talking of hateful paradoxes. We will let them talk and we will submit the following proposition to our adversaries: take an entomologist of the highest merit, a Latreille (Pierre Andre Latreille (1762-1833), one of the founders of modern entomological science.--Translator's Note.), for instance, versed in all the details of the structure of insects but utterly unacquainted with their habits. He knows the dead insect better than anybody, but he has never occupied himself with the living insect. As a cla.s.sifier, he is beyond compare; and that is all. We ask him to examine a Bee, the first that comes to hand, and to name her trade from her tools.

Come, be honest: could he? Who would dare put him to such a test? Has personal experience not fully convinced us that the mere examination of the insect can tell us nothing about its particular industry? The baskets on its legs and the brush on its abdomen will certainly inform us that it collects honey and pollen; but its special art will remain an utter secret, notwithstanding all the scrutiny of the microscope. In our own industries, the plane denotes the joiner, the trowel the mason, the scissors the tailor, the needle the seamstress. Are things the same in animal industry? Just show us, if you please, the trowel that is a certain sign of the mason-insect, the chisel that is a positive characteristic of the carpenter-insect, the iron that is an authentic mark of the pinking-insect; and as you show them, say:

'This one cuts leaves; that one bores wood; that other mixes cement.'

And so on, specifying the trade from the tool.

You cannot do it, no one can; the worker's speciality remains an impenetrable secret until direct observation intervenes. Does not this incapacity, even of the most expert, proclaim loudly that animal industry, in its infinite variety, is due to other causes besides the possession of tools? Certainly, each of those specialists requires implements; but they are rough and ready implements, good for all sorts of purposes, like the tool of Franklin's workman. The same notched mandible that reaps cotton, cuts leaves and moulds pitch also kneads mud, sc.r.a.pes decayed wood and mixes mortar; the same tarsus that manufactures cotton and disks cut out of leaves is no less clever at the art of making earthen part.i.tions, clay turrets and gravel mosaics.

What then is the reason of these thousand industries? In the light of facts, I can see but one: imagination governing matter. A primordial inspiration, a talent antecedent to the actual form, directs the tool instead of being subordinate to it. The instrument does not determine the manner of industry; the tool does not make the workman. At the beginning there is an object, a plan, in view of which the animal acts, unconsciously. Have we eyes to see with, or do we see because we have eyes? Does the function create the organ, or the organ the function? Of the two alternatives, the insect proclaims the first. It says:

'My industry is not imposed upon me by the implement which I possess; what I do is to use the implement, such as it is, for the talent with which I am gifted.'

It says to us, in its own way:

'The function has determined the organ; vision is the reason of the eye.'

In short, it repeats to us Virgil's profound reflection:

'Mens agitat molem'; 'Mind moves matter.'

CHAPTER 11. THE POISON OF THE BEE.

I have discussed elsewhere the stings administered by the Wasps to their prey. Now chemistry comes and puts a spoke in the wheel of our arguments, telling us that the poison of the Bees is not the same as that of the Wasps. The Bees' is complex and formed of two elements, acid and alkaline. The Wasps' possess only the acid element; and it is to this very acidity and not to the 'so-called' skill of the operators that the preservation of the provisions is due. (The author's numerous essays on the Wasps will form the contents of later works. In the meantime, cf.

"Insect Life," by J.H. Fabre, translated by the author of "Mademoiselle Mori": chapters 4 to 12, and 14 to 18; and "The Life and Love of the Insect," by J. Henri Fabre, translated by Alexander Teixeira de Mattos: chapters 11, 12 and 17.--Translator's Note.)

Admitting that there is a difference in the nature of the venom, I fail to see that this has any bearing on the problem in hand. I can inoculate with various liquids--acids, weak nitric acid, alkalis, ammonia, neutral bodies, spirits of wine, essence of turpentine--and obtain conditions similar to those of the victims of the predatory insects, that is to say, inertia with the persistence of a dull vitality betrayed by the movements of the mouth-parts and antennae. I am not, of course, invariably successful, for there is neither delicacy nor precision in my poisoned needle and the wound which it makes does not bear comparison with the tiny puncture of the unerring natural sting; but, after all, it is repeated often enough to put the object of my experiment beyond doubt. I should add that, to achieve success, we must have a subject with a concentrated ganglionic column, such as the Weevil, the Buprestis, the Dung-beetle and others. Paralysis is then obtained with but a single p.r.i.c.k, made at the point which the Cerceris has revealed to us, the point at which the corselet joins the rest of the thorax. In that case, the least possible quant.i.ty of the acrid liquid is instilled, a quant.i.ty too small to endanger the patient's life. With scattered nervous centres, each requiring a separate operation, this method is impracticable: the victim would die of the excess of corrosive fluid. I am quite ashamed to have to recall these old experiments. Had they been resumed and carried on by others of greater authority than I, we should have escaped the objections of chemistry.

When light is so easy to obtain, why go in search of scientific obscurity? Why talk of acid or alkaline reactions, which prove nothing, when it is so simple to have recourse to facts, which prove everything?

Before declaring that the hunting insects' poison has preservative properties merely because of its acid qualities, it would have been well to enquire if the sting of a Bee, with its acid and its alkali, could not perchance produce the same effects as that of the paralyser, whose skill is categorically denied. The chemists never gave this a thought.

Simplicity is not always welcome in our laboratories. It is my duty to repair that little omission. I propose to enquire if the poison of the Bee, the chief of the Apidae, is suitable for a surgery that paralyses without killing.

The enquiry bristles with difficulties, though this is no reason for abandoning it. First and foremost, I cannot possibly operate with the Bee just as I catch her. Time after time I make the attempt, without once succeeding; and patience becomes exhausted. The sting has to penetrate at a definite point, exactly where the Wasp's sting would have entered. My intractable captive tosses about angrily and stings at random, never where I wish. My fingers get hurt even oftener than the patient. I have only one means of gaining a little control over the indomitable dart; and that is to cut off the Bee's abdomen with my scissors, to seize the stump instantly with a fine forceps and to apply the tip at the spot where the sting is to enter.

Everybody knows that the Bee's abdomen needs no orders from the head to go on drawing its weapon for a few instants longer and to avenge the deceased before being itself overcome with death's inertia. This vindictive persistency serves me to perfection. There is another circ.u.mstance in my favour: the barbed sting remains where it is, which enables me to ascertain the exact spot pierced. A needle withdrawn as soon as inserted would leave me doubtful. I can also, when the transparency of the tissues permits, perceive the direction of the weapon, whether perpendicular and favourable to my plans, or slanting and therefore valueless. Those are the advantages.

The disadvantages are these: the amputated abdomen, though more tractable than the entire Bee, is still far from satisfying my wishes.

It gives capricious starts and unexpected p.r.i.c.ks. I want it to sting here. No, it balks my forceps and goes and stings elsewhere: not very far away, I admit; but it takes so little to miss the nerve-centre which we wish to get at. I want it to go in perpendicularly. No, in the great majority of cases it enters obliquely and pa.s.ses only through the epidermis. This is enough to show how many failures are needed to make one success.

Nor is this all. I shall be telling n.o.body anything new when I recall the fact that the Bee's sting is very painful. That of the hunting insects, on the contrary, is in most cases insignificant. My skin, which is no less sensitive than another's, pays no attention to it: I handle Sphex, Ammophilae and Scoliae without heeding their lancet-p.r.i.c.ks. I have said this before; I remind the reader of it because of the matter in hand. In the absence of well-known chemical or other properties, we have really but one means of comparing the two respective poisons; and that is the amount of pain produced. All the rest is mystery. Besides, no poison, not even that of the Rattlesnake, has. .h.i.therto revealed the cause of its dread effects.

Acting, therefore, under the instruction of that one guide, pain, I place the Bee's sting far above that of the predatory insects as an offensive weapon. A single one of its thrusts must equal and often surpa.s.s in efficaciousness the repeated wounds of the other. For all these reasons--an excessive display of energy; the variable quant.i.ty of the virus inoculated by a wriggling abdomen which no longer measures the emission by doses; a sting which I cannot direct as I please; a wound which may be deep or superficial, the weapon entering perpendicularly or obliquely, touching the nerve-centres or affecting only the surrounding tissues--my experiments ought to produce the most varied results.

I obtain, in fact, every possible kind of disorder: ataxy, temporary disablement, permanent disablement, complete paralysis, partial paralysis. Some of my stricken victims recover; others die after a brief interval. It would be an unnecessary waste of s.p.a.ce to record in this volume my hundred and one attempts. The details would form tedious reading and be of very little advantage, as in this sort of study it is impossible to marshal one's facts with any regularity. I will, therefore, sum them up in a few examples.

A colossal member of the Gra.s.shopper tribe, the most powerful in my district, Decticus verrucivorus (This Decticus has received its specific name of verrucivorus, or Wart-eating, because it is employed by the peasants in Sweden and elsewhere to bite off the warts on their fingers.--Translator's Note.), is p.r.i.c.ked at the base of the neck, on the line of the fore-legs, at the median point. The p.r.i.c.k goes straight down. The spot is the same as that pierced by the sting of the slayer of Crickets and Ephippigers. (A species of Green Gra.s.shopper. The Sphex paralyses Crickets and Gra.s.shoppers to provide food for her grubs. Cf.

"Insect Life": chapters 6 to 12.--Translator's Note.) The giantess, as soon as stung, kicks furiously, flounders about, falls on her side and is unable to get up again. The fore-legs are paralysed; the others are capable of moving. Lying sideways, if not interfered with, the insect in a few moments gives no signs of life beyond a fluttering of the antennae and palpi, a pulsation of the abdomen and a convulsive uplifting of the ovipositor; but, if irritated with a slight touch, it stirs its four hind-legs, especially the third pair, those with the big thighs, which kick vigorously. Next day, the condition is much the same, with an aggravation of the paralysis, which has now attacked the middle-legs.

On the day after that, the legs do not move, but the antennae, the palpi and the ovipositor continue to flutter actively. This is the condition of the Ephippiger stabbed three times in the thorax by the Languedocian Sphex. One point alone is missing, a most important point: the long persistence of a remnant of life. In fact, on the fourth day, the Decticus is dead; her dark colour tells me so.

There are two conclusions to be drawn from this experiment and it is well to emphasise them. First, the Bee's poison is so active that a single dagger-thrust aimed at a nervous centre kills in four days one of the largest of the Orthoptera (An order of insects including the Gra.s.shoppers, Locusts, c.o.c.kroaches, Mantes and Earwigs, in addition to the Stick- and Leaf-insects, Termites, Dragon-flies, May-flies, Book-lice and others.--Translator's Note.), though an insect of powerful const.i.tution. Secondly, the paralysis at first affects only the legs whose ganglion is attacked; next, it spreads slowly to the second pair; lastly, it reaches the third. The local effect is diffused. This diffusion, which might well take place in the victims of the predatory insects, plays no part in the latters' method of operation. The egg, which will be laid immediately afterwards, demands the complete inertia of the prey from the outset. Hence all the nerve-centres that govern locomotion must be numbed instantaneously by the virus.

I can now understand why the poison of the predatory Wasps is comparatively painless in its effects. If it possessed the strength of that of the Bee, a single stab would impair the vitality of the prey, while leaving it for some days capable of violent movements that would be very dangerous to the huntress and especially to the egg. More moderate in its action, it is instilled at the different nervous centres, as is the case more particularly with the caterpillars.

(Caterpillars are the prey of the Ammophila, which administers a separate stab to each of the several ganglia.--Translator's Note.) In this way, the requisite immobility is obtained at once; and, notwithstanding the number of wounds, the victim is not a speedy corpse.

To the marvels of the paralysers' talent we must add one more: their wonderful poison, the strength of which is regulated by delicate doses.

The Bee revenging herself intensifies the virulence of her poison; the Sphex putting her grubs' provender to sleep weakens it, reduces it to what is strictly necessary.

One more instance of nearly the same kind. I prefer to take my subjects from among the Orthoptera, which, owing to their imposing size and the thinness of their skin at the points to be attacked, lend themselves better than other insects to my delicate manipulations. The armour of a Buprestis, the fat blubber of a Rosechafer-grub, the contortions of a caterpillar present almost insuperable obstacles to the success of a sting which it is not in my power to direct. The insect which I now offer to the Bee's lancet is the Great Green Gra.s.shopper (Locusta viridissima), the adult female. The p.r.i.c.k is given in the median line of the fore-legs.

The effect is overwhelming. For two or three seconds the insect writhes in convulsions and then falls on its side, motionless throughout, save in the ovipositor and the antennae. Nothing stirs so long as the creature is left alone; but, if I tickle it with a hair-pencil, the four hind-legs move sharply and grip the point. As for the fore-legs, smitten in their nerve-centre, they are quite lifeless. The same condition is maintained for three days longer. On the fifth day, the creeping paralysis leaves nothing free but the antennae waving to and fro and the abdomen throbbing and lifting up the ovipositor. On the sixth, the Gra.s.shopper begins to turn brown; she is dead. Except that the vestige of life is more persistent, the case is the same as that of the Decticus. If we can prolong the duration, we shall have the victim of the Sphex.

But first let us look into the effect of a p.r.i.c.k administered elsewhere than opposite the thoracic ganglia. I cause a female Ephippiger to be stung in the abdomen, about the middle of the lower surface. The patient does not seem to trouble greatly about her wound: she clambers gallantly up the sides of the bell-jar under which I have placed her; she goes on hopping as before. Better still, she sets about browsing the vine-leaf which I have given her for her consolation. A few hours pa.s.s and the whole thing is forgotten. She has made a rapid and complete recovery.

A second is wounded in three places on the abdomen: in the middle and on either side. On the first day, the insect seems to have felt nothing; I see no sign of stiffness in its movements. No doubt it is suffering acutely; but these stoics keep their troubles to themselves. Next day, the Ephippiger drags her legs a little and walks somewhat slowly. Two days more; and, when laid on her back, she is unable to turn over. On the fifth day, she succ.u.mbs. This time, I have exceeded the dose; the shock of receiving three stabs was too much for her.

And so with the others, down to the sensitive Cricket, who, p.r.i.c.ked once in the abdomen, recovers in one day from the painful experience and goes back to her lettuce-leaf. But, if the wound is repeated a few times, death ensues within a more or less short period. I make an exception, among those who pay tribute to my cruel curiosity, of the Rosechafer-grubs, who defy three and four needle-thrusts. They will collapse suddenly and lie outstretched, flabby and lifeless; and, just when I am thinking them dead or paralysed, the hardy creatures will recover consciousness, move along on their backs (This is the usual mode of progression of the Cetonia- or Rosechafer-grub. Cf. "The Life and Love of the Insect": chapter 11.--Translator's Note.), bury themselves in the mould. I can obtain no precise information from them. True, their thinly scattered cilia and their breastplate of fat form a palisade and a rampart against the sting, which nearly always enters only a little way and that obliquely.

Let us leave these unmanageable ones and keep to the Orthoperon, which is more amenable to experiment. A dagger-thrust, we were saying, kills it if directed upon the ganglia of the thorax; it throws it into a transient state of discomfort if directed upon another point. It is, therefore, by its direct action upon the nervous centres that the poison reveals its formidable properties.