Read Ebook: The Life of the Fly; With Which are Interspersed Some Chapters of Autobiography by Fabre Jean Henri Teixeira De Mattos Alexander Translator
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I have elsewhere, speaking of the Scolia devouring the Cetonia grub, enlarged upon this refined art of eating which consists in consuming the prey while killing it only at the last mouthfuls. The Anthrax has the same requirements as his competitors who dine off fresh viands. He needs meat of that day, taken from a single joint that has to last a fortnight without going bad. His method of consuming reaches the highest level of art: he does not cut into his prey, he sips it little by little through his sucker. In this way, any dangerous risk is averted. Whether he imbibe at this spot or at that, even if he abandon the sucking process and resume it later, by no accident can he ever attack that which it is incumbent upon him to respect lest corruption supervene. The others have a fixed position on the victim, a place at which their mandibles have to bite and enter. If they move away from it, if they miss the appointed path, they imperil their existence. The Anthrax, more highly favored, puts his mouth where it suits him; he leaves off when he pleases and when he pleases starts again.
Unless I labor under a delusion, I think that I see the necessity for this privilege. The egg of the carnivorous burrower is firmly fixed on the victim at a point which varies considerably, it is true, according to the nature of the prey, but which is uniform for the same species of prey; moreover--and this is an important condition--the point of adhesion of that egg is always the head, whereas the egg of a bee, of the Osmia, for instance, is fixed to the mess of honey by the hinder end. When hatched, the new born Wasp grub has not to choose for itself, at its risk and peril, the suitable point at which to take the first cut in the quarry without fear of killing it too quickly: all that it need do is to bite at the spot where it has just been born. The mother, with her unfailing instinct, has already made the dangerous choice; she has stuck her egg on the propitious spot and, by the very act of doing so, marked out the course for the inexperienced grub to follow. The tact of ripe age here guides the young larva's behavior at table.
The conditions are very different in the Anthrax' case. The egg is not placed upon the victuals, it is not even laid in the mason bee's cell. This is the natural consequence of the mother's feeble frame and of her lack of any instrument, such as a probe or auger, capable of piercing the mortar wall. It is for the newly hatched grub to make its own way into the dwelling. It enters, finds itself in the presence of ample provisions, the larva of the mason bee. Free of its actions, it is at liberty to attack the prey where it chooses; or rather the attacking point will be decided at haphazard by the first contact of the mouth in quest of food. Grant this mouth a set of carving tools, jaws and mandibles; in short, suppose the grub of the Fly to possess a manner of eating similar to that of the other carnivorous larvae; and the nursling is at once threatened with a speedy death. He will split open his nurse's belly, he will dig without any rule to guide him, he will bite at random, essentials as well as accessories; and, from one day to the next, he will set up gangrene in the violated mass, even as I myself do when I give it a wound. For the lack of an attacking point prescribed for him at birth, he will perish on the damaged provisions. His freedom of action will have killed him.
Certainly, liberty is a noble attribute, even in an insignificant grub; but it also has its dangers everywhere. The Anthrax escapes the peril only on the condition of being, so to speak, muzzled. His mouth is not a fierce forceps that tears asunder; it is a sucker that exhausts but does not wound. Thus restrained by this safety appliance, which changes the bite into a kiss, the grub has fresh victuals until it has finished growing, although it knows nothing of the rules of methodical consumption at a fixed point and in a predetermined direction.
The considerations which I have set forth seem to me strictly logical: the Anthrax, owing to the very fact that he is free to take his nourishment where he pleases on the body of the fostering larva, must, for his own protection, be made incapable of opening his victim's body. I am so utterly convinced of this harmonious relation between the eater and the eaten that I do not hesitate to set it up as a principle. I will therefore say this: whenever the egg of any kind of insect is not fastened to the larva destined for its food, the young grub, free to select the attacking point and to change it at will, is as it were muzzled and consumes its provisions by a sort of suction, without inflicting any appreciable wound. This restriction is essential to the maintenance of the victuals in good condition. My principle is already supported by examples many and various, whose depositions are all to the same effect. The witnesses include, after the Anthrax, the Leucospis and his rivals, whose evidence we shall hear presently; the Ephialtes mediator , who feeds, in the dry brambles, on the larva of the Black Psen ; the Myodites, that strange, fly-shaped beetle whose grub consumes the larva of the cockchafer. All--flies, ichneumon flies and beetles--scrupulously spare their foster mother; they are careful not to tear her skin, so that the vessel may keep its liquid good to the last.
The wholesomeness of the victuals is not the only condition imposed: I find a second, which is no less essential. The substance of the fostering larva must be sufficiently fluid to ooze through the unbroken skin under the action of the sucker. Well, the necessary fluidity is realized as the time of the metamorphosis draws near. When they wished Medea to restore Pelias to the vigor of youth, his daughters cut the old king's body to pieces and boiled it in a cauldron, for there can be no new existence without a prior dissolution. We must pull down before we can rebuild; the analysis of death is the first step towards the synthesis of life. The substance of the grub that is to be transformed into a bee begins, therefore, by disintegrating and dissolving into a fluid broth. The materials of the future insect are obtained by a general recasting. Even as the founder puts his old bronzes into the melting pot in order afterwards to cast them in a mould whence the metal will issue in a different shape, so life liquefies the grub, a mere digesting machine, now thrown aside, and out of its running matter produces the perfect insect, bee, butterfly or beetle, the final manifestation of the living creature.
Let us open a Chalicodoma grub under the microscope, during the period of torpor. Its contents consists almost entirely of a liquid broth, in which swim numberless oily globules and a fine dust of uric acid, a sort of off-throw of the oxidized tissues. A flowing thing, shapeless and nameless, is all that the animal is, if we add abundant ramified air ducts, some nervous filaments and, under the skin, a thin layer of muscular fibers. A condition of this kind accounts for a fatty transpiration through the skin when the Anthrax' sucker is at work. At any other time, when the larva is in the active period or else when the insect has reached the perfect stage, the firmness of the tissues would resist the transfusion and the suckling of the Anthrax would become a difficult matter, or even impossible. In point of fact, I find the grub of the fly established, in the vast majority of cases, on the sleeping larva and sometimes, but rarely, on the pupa. Never do I see it on the vigorous larva eating its honey; and hardly ever on the insect brought to perfection, as we find it enclosed in its cell all through the autumn and winter. And we can say the same of the other grub eaters that drain their victims without wounding them: all are engaged in their death dealing work during the period of torpor, when the tissues are fluidified. They empty their patient, who has become a bag of running grease with a diffused life; but not one, among those I know, reaches the Anthrax' perfection in the art of extraction.
Nor can any be compared with the Anthrax as regards the means brought into play in order to leave the cell. These others, when they become perfect insects, have implements for sapping and demolishing, stout mandibles, capable of digging the ground, of pulling down clay partition walls and even of reducing the mason bee's tough cement to powder. The Anthrax, in her final form, has nothing like this. Her mouth is a short, soft proboscis, good at most for soberly licking the sugary exudations of the flowers; her slim legs are so feeble that to move a grain of sand were an excessive task for them, enough to strain every joint; her great, stiff wings, which must remain full spread, do not allow her to slip through a narrow passage; her delicate suit of downy velvet, from which you take the bloom by merely breathing on it, could not withstand the rough contact of the gallery of a mine. Unable herself to enter the Mason bee's cell to lay her egg, she cannot leave it either, when the time comes to free herself and appear in broad daylight in her wedding dress. The larva, on its side, is powerless to prepare the way for the coming flight. That buttery little cylinder, owning no tools but a sucker so flimsy that it barely arrives at substance and so small that it is almost a geometrical point, is even weaker than the adult insect, which at least flies and walks. The Mason bee's cell represents to it a granite cave. How to get out? The problem would be insoluble to those two incapables, if nothing else played its part.
Among insects, the nymph, or pupa, the transition stage between the larval and the adult form, is generally a striking picture of every weakness of a budding organism. A sort of mummy tight bound in swaddling clothes, motionless and impassive, it awaits the resurrection. Its tender tissues flow in every direction; its limbs, transparent as crystal, are held fixed in their place, along the side, lest a movement should disturb the exquisite delicacy of the work in course of accomplishment. Even so, to secure his recovery, is a broken boned patient held captive in the surgeon's bandages. Absolute stillness is necessary in both cases, lest they be crippled or even die.
Well, here, by a strange inversion that confuses all our views on life, a Cyclopean task is laid upon the nymph of the Anthrax. It is the nymph that has to toil, to strive, to exhaust itself in efforts to burst the wall and open the way out. To the embryo falls the desperate duty, which shows no mercy to the nascent flesh; to the adult insect the joy of resting in the sun. This transposition of functions has as its result a well sinker's equipment in the nymph, an eccentric, complicated equipment which nothing suggested in the larva and which nothing recalls in the perfect insect. The set of tools includes an assortment of plowshares, gimlets, hooks and spears and of other implements that are not found in our trades nor named in our dictionaries. Let us do our best to describe the strange piercing gear.
The head is round and large, separated from the thorax by a strangulated furrow, crowned on top and in front with a sort of diadem of six hard, sharp, black spikes, arranged in a semicircle whose concave side faces downward. These spikes decrease slightly in length from the summit to the ends of the arch. Taken together, they suggest the radial crowns which we see the Roman emperors of the Decadence wear on the medals. This six-fold plowshare is the chief excavating tool. Lower down, on the median line, the instrument is finished off with a separate group of two small black spikes, placed close together.
The thorax is smooth, the wing cases large, folded under the body like a scarf and coming almost to the middle of the abdomen. This has nine segments, of which four, starting with the second, are armed, on the back, down the middle, with a belt of little horny arches, pale brown in color, drawn up parallel to one another, set in the skin by their convex surfaces and finishing at both ends with a hard, black point. Altogether, the belt thus forms a double row of little thorns, with a hollow in between. I count about twenty-five twin-toothed arches to one segment, which gives a total of two hundred spikes for the four rings thus armed.
The use of this rasp, or grater, is obvious: it gives the nymph a purchase on the wall of its gallery as the work proceeds. Thus anchored on a host of points, the stern pioneer is able to hit the obstacle harder with its diadem of awls. Moreover, to make it more difficult for the instrument to recoil, long, stiff bristles, pointing backwards, are scattered here and there among the climbing belts. There are some besides on the other segments, both on the ventral and the dorsal surface. On the flanks, they are thicker and arranged as it were in clusters.
The sixth segment carries a similar belt, but a much less powerful one, consisting of a single row of unassuming thorns. The belt is weaker still on the seventh segment; lastly, on the eighth, it is reduced to a mere rough brown shading. Commencing with the sixth, the rings decrease in width and the abdomen ends in a cone, the extremity of which, formed of the ninth segment, constitutes a weapon of a new kind. It is a sheaf of eight brown spikes. The last two exceed the others in length and stand out from the group in a double terminal plowshare.
There is a round air hole in front, on either side of the thorax, and similar stigmata on the flanks of each of the first seven abdominal segments. When at rest, the nymph is curved into a bow. When about to act, it suddenly unbends and straightens itself. It measures 15 to 20 millimeters long and 4 to 5 millimeters across.
Such is the strange perforating machine that is to prepare an outlet for the feeble Anthrax through the Mason bee's cement. The structural details, so difficult to explain in words, may be summed up as follows: in front, on the forehead, a diadem of spikes, the ramming and digging tool; behind, a many bladed plowshare which fits into a socket and allows the pupa to slacken suddenly in readiness for an attack on the barrier which has to be demolished; on the back, four climbing belts, or graters, which keep the animal in position by biting on the walls of the tunnel with their hundreds of teeth; and, all over the body, long, stiff bristles, pointing backwards, to prevent falls or recoils.
A similar structure exists in the other species of Anthrax with slight variations of detail. I will confine myself to one instance, that of Anthrax sinuata, who thrives at the cost of Osmia tricornis. Her nymph differs from that of Anthrax trifasciata, the Anthrax of the mason bee, in possessing less powerful armor. Its four climbing belts consist of only fifteen to seventeen double spiked arches, instead of twenty-five; also, the abdominal segments, from the sixth onwards, are supplied merely with stiff bristles, without a trace of horny spikes. If the evolution of the various Anthrax flies were better known to us, the number of these arches would, I believe, be of great service to entomology in the differentiation of species. I see it remaining constant for any given species, with marked variations between one species and another. But this is not my business: I merely call the attention of the classifiers to this field of study and pass on.
About the end of May, the coloring of the nymph, hitherto a light red, alters greatly and forecasts the coming transformation. The head, the thorax and the scarf formed by the wings become a handsome, shiny black. A dark band shows on the back of the four segments with their two rows of spikes; three spots appear on the two next rings; the anal armor becomes darker. In this manner we foresee the black livery of the coming insect. The time has arrived for the pupa to work at the exit gallery.
I was anxious to see it in action, not under natural conditions, which would be impracticable, but in a glass tube in which I confine it between two thick stoppers of sorghum pith. The space thus marked off is about the same size as the natal cell. The partitions front and back, although not so stout as the Chalicodoma's masonry, are nevertheless firm enough not to yield except to prolonged efforts; on the other hand, the side walls are smooth and the toothed belts will not be able to grip them: a most unfavorable condition for the worker. No matter: in the space of a single day, the pupa pierces the front partition, three quarters of an inch thick. I see it fixing its double plowshare against the back partition, arching into a bow and then suddenly releasing itself and striking the plug in front of it with its barbed forehead. Under the impact of the spikes, the sorghum slowly crumbles to pieces. It is slow in coming away; but it comes away all the same, atom by atom. At long intervals, the method changes. With its crown of awls driven into the pith, the animal frets and fidgets, sways on the pivot of its anal armor. The work of the auger follows that of the pickaxe. Then the blows recommence, interspersed with periods of rest to recover from the fatigue. At last, the hole is made. The pupa slips into it, but does not pass through entirely: the head and thorax appear outside; the abdomen remains held in the gallery.
The glass cell, with its lack of supports at the side, has certainly perplexed my subject, which does not seem to have made use of all its methods. The hole through the sorghum is wide and irregular; it is a clumsy breach and not a gallery. When made through the mason bee's walls, it is cylindrical, fairly neat and exactly of the animal's diameter. So I hope that, under natural conditions, the pupa does not give quite so many blows with the pickaxe and prefers to work with the drill.
Narrowness and evenness in the exit tunnel are necessary to it. It always remains half caught in it and even pretty securely fixed by the graters on its back. Only the head and thorax emerge into the outer air. This is a last precaution for the final deliverance. A fixed support is, in fact, indispensable to the Anthrax for issuing from her horny sheath, unfurling her great wings and extricating her slender legs from their scabbards. All this very delicate work would be endangered by any lack of steadiness.
The pupa, therefore, remains fixed by the graters of its back in the narrow exit gallery and thus supplies the stable equilibrium essential to the new birth. All is ready. It is time now for the great act. A transversal cleft makes its appearance on the forehead, at the bottom of the perforating diadem; a second, but longitudinal slit divides the skull in two and extends down the thorax. Through this cross-shaped opening, the Anthrax suddenly appears, all moist with the humors of life's laboratory. She steadies herself upon her trembling legs, dries her wings and takes to flight, leaving at the window of the cell her nymphal slough, which keeps intact for a very long period. The sand-colored fly has five or six weeks before her, wherein to explore the clay nests amid the thyme and to take her small share of the joys of life. In July, we shall see her once more, busy this time with the entrance into the cell, which is even stranger than the exit.
What can he be called, this creature whose style and title I dare not inscribe at the head of the chapter? His name is Monodontomerus cupreus, SM. Just try it, for fun: Mo-no-don-to-me-rus. What a gorgeous mouthful! What an idea it gives one of some beast of the Apocalypse! We think, when we pronounce the word, of the prehistoric monsters: the mastodon, the mammoth, the ponderous megatherium. Well, we are misled by the scientific label: we have to do with a very paltry insect, smaller than the common gnat.
There are good people like that, only too happy to serve science with resounding appellations that might come from Timbuktu; they cannot name you a midge without striking terror into you. O ye wise and revered ones, ye christeners of animals, I am willing, in my study, to make use--but not undue use--of your harsh terminology, with its conglomeration of syllables; but there is a danger of their leaving the sanctum and appearing before the public, which is always ready to show its lack of deference for terms that do not respect its ears. I, wishing to speak like everybody else, so that I may be understood by all, and persuaded that science has no need of this Brobdignagian jargon, make a point of avoiding technical nomenclature when it becomes too barbarous, when it threatens to lumber the page the moment my pen attempts it. And so I abandon Monodontomerus.
It is a puny little insect, almost as tiny as the midges whom we see eddying in a ray of sunshine at the end of autumn. Its dress is golden bronze; its eyes are coral red. It carries a naked sword, that is to say, the sheath of its drill stands out slantwise at the tip of its belly, instead of lying in a hollow groove along the back, as it does with the Leucospis. This scabbard holds the latter half of the inoculating filament, which extends below the animal to the base of the abdomen. In short, its utensil is that of the Leucospis, with this difference, that its lower half sticks out like a rapier.
This mite that bears a sword upon her rump is yet another persecutor of the mason bees and not one of the least formidable. She exploits their nests at the same time as the Leucospis. I see her, like the Leucospis, slowly explore the ground with her antennae; I see her, like the Leucospis, bravely drive her dagger into the stone wall. More taken up with her work, less conscious perhaps of danger, she pays no heed to the man who is observing her so closely. Where the Leucospis flies, she does not budge. So great is her assurance that she comes right into my study, to my work table, and disputes my ownership of the nests whose occupants I am examining. She operates under my lens, she operates just beside my forceps. What risk does she run? What can one do to a thing so very small? She is so certain of her safety that I can take the Mason's nest in my hand, move it, put it down and take it up again without the insect's raising any objection: it continues its work even when my magnifying glass is placed over it.
One of these heroines has come to inspect a nest of the Chalicodoma of the Walls, most of whose cells are occupied by the numerous cocoons of a parasite, the Stelis. The contents of these cells, which have been partially ripped up to satisfy my curiosity, are very much exposed to view. The windfall appears to be appreciated, for I see the dwarf ferret about from cell to cell for four days on end, see her choose her cocoon and insert her awl in the most approved fashion. I thus learn that sight, although an indispensable guide in searching, does not decide upon the proper spot for the operation. Here is an insect exploring not the stony exterior of the mason's dwelling, but the surface of cocoons woven of silk. The explorer has never found herself placed in such circumstances, nor has any of her race before her, every cocoon, under normal conditions, being protected by a surrounding wall. No matter: despite the profound difference in the surfaces, the insect does not waver. Warned by a special sense, an undecipherable riddle to ourselves, it knows that the object of its search lies hidden under this unfamiliar casing. The sense of smell has already been shown to be out of the question; that of sight is now eliminated in its turn.
That she should bore through the cocoons of the Stelis, a parasite of the mason bee, does not surprise me at all: I know how indifferent my bold visitor is to the nature of the victuals destined for her family. I have noticed her presence in the homes of bees differing greatly in size and habits: Anthophorae, Osmiae, Chalicodomae, Anthidia. The Stelis exploited on my table is one victim more; and that is all. The interest does not lie there. The interest lies in the maneuvers of the insect, which I am able to follow under the most favorable conditions.
Bent sharply at right angles, like a couple of broken matches, the antennae feel the cocoon with their tips alone. The terminal joint is the home of this strange sense which discerns from afar what no eye sees, no scent distinguishes and no ear hears. If the point explored be found suitable, the insect hoists itself on tiptoe so as to give full scope to the play of its mechanism; it brings the tip of the belly a little forward; and the entire ovipositor--inoculating-needle and scabbard--stands perpendicular to the cocoon, in the center of the quadrilateral described by the four hind legs, an eminently favorable position for obtaining the maximum effect. For some time, the whole of the awl bears on the cocoon, feeling all round with its point, groping about; then, suddenly, the boring needle is released from its sheath, which falls back along the body, while the needle strives to make its entrance. The operation is a difficult one. I see the insect make a score of attempts, one after the other, without succeeding in piercing the tough wrapper of the Stelis. Should the instrument not penetrate, it retreats into its sheath and the insect resumes its scrutiny of the cocoon, sounding it point by point with the tips of its antennae. Then further thrusts are tried until one succeeds.
The eggs are little spindles, white and gleaming like ivory, about two-thirds of a millimeter in length. They have not the long, curved peduncle of the Leucospis' eggs; they are not suspended from the ceiling of the cocoon like these, but are laid without order around the fostering larva. Lastly, in a single cell and with a single mother, there is always more than one laying; and the number of eggs varies considerably in each. The Leucospis, because of her great size, which rivals that of her victim, the Bee, finds in each cell provisions enough for one and one alone. When, therefore, there is more than one set of eggs in any one cell, this is due to a mistake on her part and not a premeditated result. Where the whole ration is required for the meals of a single grub, she would take good care not to install several if she could help it. Her competitor is not called upon to observe the same discretion. A Chalicodoma grub gives the dwarf the wherewithal to portion a score of her little ones, who will live in common and in all comfort on what a single son of the giantess would eat up by himself. The tiny boring engineer, therefore, always settles a numerous family at the same banquet. The bowl, ample for a dozen or two, is emptied in perfect harmony.
Curiosity made me count the brood, to see if the mother was able to estimate the victuals and to proportion the number of guests to the sumptuousness of the fare provided. My notes mention fifty-four larvae in the cell of a masked Anthophora . No other census attained this figure. Possibly, two different mothers had laid their eggs in this crowded habitation. With the Mason bee of the Walls, I see the number of larvae vary, in different cells, between four and twenty-six; with the mason bee of the Sheds, between five and thirty-six; with the three-horned Osmia, who supplied me with the largest number of records, between seven and twenty-five; with the blue Osmia , between five and six; with the Stelis , between four and twelve.
The first return and the last two seem to point to some relation between the abundance of provisions and the number of consumers. When the mother comes upon the bountiful larva of the masked Anthophora, she gives it half-a-hundred to feed; with the Stelis and the blue Osmia, niggardly rations both, she contents herself with half-a-dozen. To introduce into the dining room only the number of boarders that the bill of fare will allow would certainly be a most deserving performance, especially as the insect is placed under very difficult conditions to judge the contents of the cell. These contents, which lie hidden under the ceiling, are invisible; and the insect can derive its information only from the outside of the nest, which varies in the different species. We should therefore have to admit the existence of a particular power of discrimination, a sort of discernment of the species, which is recognized as large or small from the outward aspect of its house. I refuse to go to this length in my conjectures, not that instinct seems to me incapable of such feats, but because of the particulars obtained from the three-horned Osmia and the two mason bees.
In the cells of these three species, I see the number of larvae put out to nurse vary in so elastic a fashion that I must abandon all idea of proportionate adjustment. The mother, without troubling unduly whether there be an excess or a dearth of provisions for her family, has filled the cells as her fancy prompted, or rather according to the number of ripe ovules contained in her ovaries at the time of the laying. If food be over-plentiful, the brood will be all the better for it and will grow bigger and stronger; if food be scarce, the famished youngsters will not die, but will remain smaller. Indeed, with both the larva and the full grown insect, I have often observed a difference in size which varies according to the density of the population, the members of a small colony being double the size of their overcrowded neighbors.
The grubs are white, tapering at both ends, sharply segmented and covered all over their bodies with a coat of fine, soft hairs which is invisible except under the lens. The head consists of a little knob much smaller in diameter than the body. In this head, the microscope reveals mandibles consisting of fine spikes of a tawny red, which spread into a wide, colorless base. Deprived of any indentation, incapable of chewing anything between their awl-shaped ends, these two tools serve at best to fix the grub slightly at some point of the fostering larva. Useless for carving, therefore, the mouth is a pure osculatory sucker, which drains the provisions by a process of exudation through the skin. We see here repeated what the Anthrax and the Leucospis have already shown us: the gradual exhaustion of a victim which the parasite consumes without killing it.
It is a curious spectacle even after that of the Anthrax. We have here twenty or thirty starvelings, all with their mouths pressed, as for a kiss, to the body of the plump larva, which, from day to day, fades and shrinks without the least appreciable wound, thus keeping fresh until reduced to a shriveled slough. If I disturb the gluttonous swarm, all, with a sudden recoil, let go, drop off and flounder around the foster mother. They are no less prompt in resuming their savage kisses. I need not add that neither at the point where they leave off nor at the point where they recommence is there the faintest trace of liquid. The oily exudation occurs only when the pump is at work. To linger over this strange method of feeding is superfluous after what I have said about the Anthrax.
The appearance of the full grown insect takes place at the beginning of summer, after nearly a whole year's stay in the invaded dwelling. The large number of inhabitants of one and the same cell led me to think that the work of deliverance ought to present a certain interest. They are all equally anxious to clear the walls of the prison at the earliest possible moment and to come forth into the great festival of the sun: do they all at the same time, in a confused horde, attack the ceiling which has to be pierced? Is the work of deliverance arranged in the general interest? Or is individual selfishness the only rule? These are the questions which observation will answer.
A little in advance of the proper season, I transfer each family into a short glass tube, which will represent the natal cell. A good, thick cork, quite a centimeter deep, is the obstacle to be pierced for an outlet. Well, instead of the mad haste and the ruinous lack of organization which I expected to find, my broods show me in their glass prison an exceedingly well regulated workshop. One insect, one only, works at perforating the cork. Patiently, with its mandibles, grain by grain, it digs a tunnel the width of its body. The gallery is so narrow that, in order to return to the tube, the worker has to move backwards. It is a slow process; and it takes hours and hours to dig the hole, a hard job for the frail miner.
Should her fatigue become too great, the excavator leaves the forefront and mingles with the crowd, to polish and dust herself. Another, the first neighbor at hand, at once takes her place and is herself relieved by a third when her task is done. Others again take their turn, always one at a time, so much so that the works are never at a standstill and never overcrowded. Meanwhile, the multitude keeps out of the way, quietly and patiently. There is no anxiety as to the deliverance. Success will come: of that they are all convinced. While waiting, one washes her antennae by passing them through her mouth, another polishes her wings with her hind legs, another frisks about to while away the period of inaction. Some are making love, a sovran means of killing time, whether one be born that day or twenty years ago.
Some, I said, make love. These favored ones are rare; they hardly count. Is it through indifference? No, but the gallants are lacking. The sexes are very unequally represented in the population of a cell: the males are in a wretched minority and sometimes even completely absent. This poverty did not escape the older observers. Brulle , the author of many works on natural history and one of the founders of the Societe entomologique de France, the only author whom I am able to consult in my hermitage, says, literally: 'The males do not appear to be known.'
I, for my part, know them; but, considering their feeble number, I keep asking myself what part they play in a harem so disproportionate to their forces. A few figures will show us what my hesitations are based upon.
In twenty-two Osmia cocoons , the total census of the inmates yields three hundred and fifty-four, of whom forty-seven are males and three hundred and seven females. The average number of inmates, therefore, is sixteen individuals; and there are six females at least to one male. This disparity is maintained, in more or less marked proportions, whatever the species of the bee invaded. In the cocoons of the Mason bee of the Sheds, I discover the average proportion to be six females to one male; in those of the Mason bee of the Walls, I find one male to fifteen females.
These facts, which I am unable to state with any greater precision, are enough to give rise to the suspicion that the males, who are even tinier dwarfs than the females and who, moreover, like all insects, are injured by a single act of pairing, must, in most cases, remain strangers to the females. Can the mothers, in fact, dispense with their assistance, without being deprived of offspring on that account? I do not say yes, but I do not say no. The duality of the sexes is a hard problem. Why two sexes? Why not just one? It would have been much simpler and saved a great deal of foolery. Why such a thing as sex, when the tuber of the Jerusalem artichoke can do without it? These are the pregnant questions suggested to me, in the end, by Monodontomerus cupreus, the insect so infinitesimal in body and so overpowering in name that I had really vowed never to speak of it again by its official designation.
If the reader has paid any attention to the story of the Anthrax, he must have perceived that my narrative is incomplete. The fox in the fable saw how the lion's visitors entered his den, but did not see how they went out. With us, it is the converse: we know the way out of the mason bee's fortress, but we do not know the way in. To leave the cell of which he has eaten the owner, the Anthrax becomes a perforating machine, a living tool from which our own industry might take a hint if it required new drills for boring rocks. When the exit tunnel is opened, this tool splits like a pod bursting in the sun; and from the stout framework there escapes a dainty fly, a velvety flake, a soft fluff that astounds us by its contrast with the roughness of the depths whence it ascends. On this point, we know pretty well what there is to know. There remains the entrance into the cell, a puzzle that has kept me on the alert for a quarter of a century.
To begin with, it is evident that the mother cannot lodge her egg in the cell of the mason bee, which has been long closed and barricaded with a cement wall by the time that the Anthrax makes her appearance. To penetrate it, she would have to become an excavating tool once more and resume the cast-off rags which she left behind in the exit window; she would have to retrace her steps, to be reborn a pupa; and life knows none of these retrogressions. The full grown insect, if endowed with claws, mandibles and plenty of perseverance, might at a pinch force the mortar casket; but the fly is not so endowed. Her slender legs would be strained and deformed by merely sweeping away a little dust; her mouth is a sucker for gathering the sugary exudations of the flowers and not the solid pincers needed for the crumbling of cement. There is no auger either, no bore copied from that of the Leucospis, no implement of any kind that can work its way into the thickness of the wall and dispatch the egg to its destination. In short, the mother is absolutely incapable of settling her eggs in the chamber of the Mason bee.
Can it be the grub that makes its own way into the storeroom, that same grub which we have seen draining the Chalicodoma with its leech-like kisses? Let us call the creature to mind: a little oily sausage, which stretches and curls up just where it lies, without being able to shift its position. Its body is a smooth cylinder; its mouth simply a circular lip. Not one ambulatory organ does it possess; not even hairs, protuberances or wrinkles to enable it to crawl. The animal is made for digestion and immobility. Its organization is incompatible with movement; everything tells us so in the clearest fashion. No, this grub is even less able than the mother to make its way unaided into the mason's dwelling. And yet the provisions are there; those provisions must be reached: it is a matter of life or death; to be or not to be. Then how does the fly set about it? It would be vain for me to question probabilities, too often illusory; to obtain a reply of any value, I have but one resource; I must attempt the nearly impossible and watch the Anthrax from the egg onwards.
Although Anthrax flies are fairly common, in the sense of there being several different species, they are not plentiful when it is a case of wanting a colony populous enough to admit of continuous observation. I see them, now here, now there, in the fiercely sun-scorched places, flitting hither and thither on the old walls, the slopes and the sand, sometimes in small platoons, most often singly. I can expect nothing of those vagabonds, who are here today and gone tomorrow, for I know nothing of their settlements. To keep a watch on them, one by one, in the blazing heat, is very painful and very unfruitful, as the swift-winged insect has a habit of disappearing one knows not whither just when a prospect of capturing its secret begins to offer. I have wasted many a patient hour at this pursuit, without the least result.
There might be some chance of success with Anthrax flies whose home was known to us beforehand, especially if insects of the same species formed a pretty numerous colony. The inquiries begun with one would be continued with a second and with more, until a complete verdict was forthcoming. Now, in the course of my long entomological career, I have met with but two species of Anthrax that fulfilled this condition and were to be found regularly: one at Carpentras; the other at Serignan. The first, Anthrax sinuata, FALLEN, lives in the cocoons of Osmia tricornis, who herself builds her nest in the old galleries of the hairy-footed Anthophora; the second, Anthrax trifasciata, MEIGEN, exploits the Chalicodoma of the Sheds. I will consult both.
Once more, here am I, somewhat late in life, at Carpentras, whose rude Gallic name sets the fool smiling and the scholar thinking. Dear little town where I spent my twentieth year and left the first bits of my fleece upon life's bushes, my visit of today is a pilgrimage; I have come to lay my eyes once more upon the place which saw the birth of the liveliest impressions of my early days. I bow, in passing, to the old college where I tried my prentice hand as a teacher. Its appearance is unchanged; it still looks like a penitentiary. Those were the views of our mediaeval educational system. To the gaiety and activity of boyhood, which were considered unwholesome, it applied the remedy of narrowness, melancholy and gloom. Its houses of instruction were, above all, houses of correction. The freshness of Virgil was interpreted in the stifling atmosphere of a prison. I catch a glimpse of a yard between four high walls, a sort of bear pit, where the scholars fought for room for their games under the spreading branches of a plane tree. All around were cells that looked like horse boxes, without light or air; those were the classrooms. I speak in the past tense, for doubtless the present day has seen the last of this academic destitution.
Here is the tobacco shop where, on Wednesday evening, coming out of the college, I would buy on credit the wherewithal to fill my pipe and thus to celebrate on the eve the joys of the morrow, that blessed Thursday which I considered so well employed in solving hard equations, experimenting with new chemical reagents, collecting and identifying my plants. I would make my timid request, pretending to have come out without my money, for it is hard for a self-respecting man to admit that he is penniless. My candor appears to have inspired some little confidence; and I obtained credit, an unprecedented thing, with the representative of the revenue. Ah, why did not I open a shop and expose for sale some packets of candles, a dozen dried cod, a barrel of sardines and a few cakes of soap! I am no more of a fool nor any less industrious than another; and I should have made my way. But, as it was, what could I expect? As an accoucheur of brains, a molder of intellects, I had no claim even to bread and cheese.
Here is my former habitation, occupied since by droning monks. In the embrasure of that window, sheltered from profane hands, between the closed outer shutters and the panes, I used to keep my chemicals, bought for a few sous cheated out of the weekly budget in the early days of our housekeeping. The bowl of a pipe was my crucible, a sweet jar my retort, mustard pots my receptacles for oxides and sulfides. My experiments, harmless or dangerous, were made on a corner of the fire beside the simmering broth.
Though all my efforts, which were the more deserving because I had to work alone, led to almost nothing in that congenial calling, I would begin it all over again if I could. I should love to be conversing for the first time with Leibnitz and Newton, with Laplace and Lagrange, with Cuvier and Jussieu, even if I had afterwards to solve that other arduous problem: how to procure one's daily bread. Ah, young men, my successors, what an easy time you have of it today! If you don't know it, then let me tell you so by means of these few pages from the life of one of your elders.
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