The Mason-Bees Part 9

Having perpetrated this child-murder, the depraved creature does a little provisioning. They all experience the same necessity to go backwards in the sequence of actions in order to pick up the thread of their interrupted occupations. Her next work is to lay her egg and then she conscientiously restores the demolished lid.

The havoc can be more sweeping still. One of these laggards is not satisfied with a single cell; she needs two, three, four. To reach the most remote, the Osmia wrecks all those which come before it.

The part.i.tions are broken down, the eggs eaten or thrown away, the provisions swept outside and often even carried to a distance in great lumps. Covered with dust from the loose plaster of the demolition, floured all over with the rifled pollen, sticky with the contents of the mangled eggs, the Osmia, while at her brigand's work, is altered beyond recognition. Once the place is cleared, everything resumes its normal course. Provisions are laboriously brought to take the place of those which have been thrown away; eggs are laid, one on each heap of food; the part.i.tions are built up again; and the ma.s.sive plug sealing the whole structure is made as good as new.

Crimes of this kind recur so often that I am obliged to interfere and place in safety the nests which I wish to keep intact. And nothing as yet explains this brigandage, bursting forth at the end of the work like a moral epidemic, like a frenzied delirium. I should say nothing if the site were lacking; but the tubes are there, close by, empty and quite fit to receive the eggs. The Osmia refuses them, she prefers to plunder.

Is it from weariness, from a distaste for work after a period of fierce activity? Not at all; for, when a row of cells has been stripped of its contents, after the ravage and waste, she has to come back to ordinary work, with all its burdens. The labour is not reduced; it is increased.

It would pay the Bee infinitely better, if she wants to continue her laying, to make her home in an unoccupied tube. The Osmia thinks differently. Her reasons for acting as she does escape me. Can there be ill-conditioned characters among her, characters that delight in a neighbour's ruin? There are among men.

In the privacy of her native haunts, the Osmia, I have no doubt, behaves as in my crystal galleries. Towards the end of the building-operations, she violates others' dwellings. By keeping to the first cell, which it is not necessary to empty in order to reach the next, she can utilize the provisions on the spot and shorten to that extent the longest part of her work. As usurpations of this kind have had ample time to become inveterate, to become inbred in the race, I ask for a descendant of the Osmia who eats her grandmother's egg in order to establish her own egg.

This descendant I shall not be shown; but I may be told that she is in process of formation. The outrages which I have described are preparing a future parasite. The transformists dogmatize about the past and dogmatize about the future, but as seldom as possible talk to us about the present. Transformations have taken place, transformations will take place; the pity of it is that they are not actually taking place. Of the three tenses, one is lacking, the very one which directly interests us and which alone is clear of the incubus of theory. This silence about the present does not please me overmuch, scarcely more than the famous picture of "The Crossing of the Red Sea" painted for a village chapel.

The artist had put upon the canvas a broad ribbon of brightest scarlet; and that was all.

'Yes, that's the Red Sea,' said the priest, examining the masterpiece before paying for it. 'That's the Red Sea, right enough; but where are the Israelites?'

'They have pa.s.sed,' replied the painter.

'And the Egyptians?'

'They are on the way.'

Transformations have pa.s.sed, transformations are on the way. For mercy's sake, cannot they show us transformations in the act? Must the facts of the past and the facts of the future necessarily exclude the facts of the present? I fail to understand.

I call for a descendant of the Chalicodoma and a descendant of the Osmia who have robbed their neighbours with gusto, when occasion offered, since the origin of their respective races, and who are working industriously to create a parasite happy in doing nothing. Have they succeeded? No. Will they succeed? Yes, people maintain. For the moment, nothing. The Osmiae and Chalicodomae of to-day are what they were when the first trowel of cement or mud was mixed. Then how many ages does it take to form a parasite? Too many, I fear, for us not to be discouraged.

If the sayings of the theorists are well-founded, going on strike and living by s.h.i.+fts was not always enough to a.s.sure parasitism. In certain cases, the animal must have had to change its diet, to pa.s.s from live prey to vegetarian fare, which would entirely subvert its most essential characteristics. What should we say to the Wolf giving up mutton and browsing on gra.s.s, in obedience to the dictates of idleness? The boldest would shrink from such an absurd a.s.sumption. And yet transformism leads us straight to it.

Here is an example: in July, I split some bramble-stems in which Osmia tridentata has built her nests. In the long series of cells, the lower already hold the Osmia's coc.o.o.ns, while the upper contain the larva which has nearly finished consuming its provisions and the topmost show the victuals untouched, with the Osmia's egg upon them. It is a cylindrical egg, rounded at both extremities, of a transparent white and measuring four to five millimetres in length. (.156 to.195 inch.--Translator's Note.) It lies slantwise, one end of it resting on the food and the other sticking up at some distance above the honey.

Now, by multiplying my visits to the fresh cells, I have on several occasions made a very valuable discovery. On the free end of the Osmia's egg, another egg is fixed; an egg quite different in shape, white and transparent like the first, but much smaller and narrower, blunt at one end and tapering into a rather sharp point at the other. It is two millimetres long by half a millimetre wide. (.078 and.019 inch.--Translator's Note.) It is undeniably the egg of a parasite, a parasite which compels my attention by its curious method of installing its family.

It opens before the Osmia's egg. The tiny grub, as soon as it is born, begins to drain the rival egg, of which it occupied the top part, high up above the honey. The extermination soon becomes perceptible. You can see the Osmia's egg turning muddy, losing its brilliancy, becoming limp and wrinkled. In twenty-four hours, it is nothing but an empty sheath, a crumpled bit of skin. All compet.i.tion is now removed; the parasite is the master of the house. The young grub, when demolis.h.i.+ng the egg, was active enough: it explored the dangerous thing which had to be got rid of quickly, it raised its head to select and multiply the attacking-points. Now, lying at full length on the surface of the honey, it no longer s.h.i.+fts its position; but the undulations of the digestive ca.n.a.l betray its greedy absorption of the Osmia's store of food. The provisions are finished in a fortnight and the coc.o.o.n is woven. It is a fairly firm ovoid, of a very dark-brown colour, two characteristics which at once distinguish it from the Osmia's pale, cylindrical coc.o.o.n.

The hatching takes place in April or May. The puzzle is solved at last: the Osmia's parasite is a Wasp called the Spotted Sapyga (Sapyga punctata, V.L.)

Now where are we to cla.s.s this Wasp, a true parasite in the strict sense of the word, that is to say, a consumer of others' provisions. Her general appearance and her structure make it clear to any eye more or less familiar with entomological shapes that she belongs to a species akin to that of the Scoliae. Moreover, the masters of cla.s.sification, so scrupulous in their comparison of characteristics, agree in placing the Sapygae immediately after the Scoliae and a little before the Mutillae.

The Scoliae feed their grubs on prey; so do the Mutillae. The Osmia's parasite, therefore, if it really derives from a transformed ancestor, is descended from a flesh-eater, though it is now an eater of honey. The Wolf does more than become a Sheep: he turns himself into a sweet-tooth.

'You will never get an apple-tree out of an acorn,' Franklin tells us, with that homely common-sense of his.

In this case, the pa.s.sion for jam must have sprung from a love of venison. Any theory might well be deficient in balance when it leads to such vagaries as this.

I should have to write a volume if I would go on setting forth my doubts. I have said enough for the moment. Man, the insatiable enquirer, hands down from age to age his questions about the whys and wherefores of origins. Answer follows answer, is proclaimed true to-day and recognized as false tomorrow; and the G.o.ddess Isis continues veiled.

CHAPTER 10. THE TRIBULATIONS OF THE MASON-BEE.

To ill.u.s.trate the methods of those who batten on others' goods, the plunderers who know no rest till they have wrought the destruction of the worker, it would be difficult to find a better instance than the tribulations suffered by the Chalicodoma of the Walls. The Mason who builds on the pebbles may fairly boast of being an industrious workwoman. Throughout the month of May, we see her black squads, in the full heat of the sun, digging with busy teeth in the mortar-quarry of the road hard by. So great is her zeal that she hardly moves out of the way of the pa.s.ser-by; more than one allows herself to be crushed underfoot, absorbed as she is in collecting her cement.

The hardest and driest spots, which still retain the compactness imparted by the steam-roller, are the favourite veins; and the work of making the pellet is slow and painful. It is sc.r.a.ped up atom by atom; and, by means of saliva, turned into mortar then and there. When it is all well kneaded and there is enough to make a load, the Mason sets off with an impetuous flight, in a straight line, and makes for her pebble, a few hundred paces away. The trowel of fresh mortar is soon spent, either in adding another storey to the turret-shaped edifice, or in cementing into the wall lumps of gravel that give it greater solidity.

The journeys in search of cement are renewed until the structure attains the regulation height. Without a moment's rest, the Bee returns a hundred times to the stone-yard, always to the one spot recognized as excellent.

The victuals are now collected: honey and flower-dust. If there is a pink carpet of sainfoin anywhere in the neighbourhood, 'tis there that the Mason goes plundering by preference, though it cost her a four hundred yards' journey every time. Her crop swells with honeyed exudations, her belly is floured with pollen. Back to the cell, which slowly fills; and back straightway to the harvest-field. And all day long, with not a sign of weariness, the same activity is maintained as long as the sun is high enough. When it is late, if the house is not yet closed, the Bee retires to her cell to spend the night there, head downwards, tip of her abdomen outside, a habit foreign to the Chalicodoma of the Sheds. Then and then alone the Mason rests; but it is a rest that is in a sense equivalent to work, for, thus placed, she blocks the entrance to the honey-store and defends her treasure against twilight or night marauders.

Being anxious to form some estimate of the total distance covered by the Bee in the construction and provisioning of a single cell, I counted the number of steps from a nest to the road where the mortar was mixed and from the same nest to the sainfoin-field where the harvest was gathered.

I took such note as my patience permitted of the journeys made in both directions; and, completing these data with a comparison between the work done and that which remained to do, I arrived at nine and a half miles as the result of the total travelling. Of course, I give this figure only as a rough calculation; greater precision would have demanded more perseverance than I can boast.

Such as it is, the result, which is probably under the actual figure in many cases, is of a kind that gives us a vivid idea of the Mason-bee's activity. The complete nest will comprise about fifteen cells. Moreover, the heap of cells will be coated at the end with a layer of cement a good finger's-breadth thick. This ma.s.sive fortification, which is less finished than the rest of the work but more expensive in materials, represents perhaps in itself one half of the complete task, so that, to establish her dome, Chalicodoma muraria, coming and going across the arid table-land, traverses altogether a distance of 275 miles, which is nearly half of the greatest dimension of France from north to south.

Afterwards, when, worn out with all this fatigue, the Bee retires to a hiding-place to languish in solitude and die, she is surely ent.i.tled to say:

'I have laboured, I have done my duty!'

Yes, certainly, the Mason has toiled with a vengeance. To ensure the future of her offspring, she has spent her own life without reserve, her long life of five or six weeks' duration; and now she breathes her last, contented because everything is in order in the beloved house: copious rations of the first quality; a shelter against the winter frosts; ramparts against incursions of the enemy. Everything is in order, at least so she thinks; but, alas, what a mistake the poor mother is making! Here the hateful fatality stands revealed, aspera fata, which ruins the producer to provide a living for the drone; here we see the stupid and ferocious law that sacrifices the worker for the idler's benefit. What have we done, we and the insects, to be ground with sovran indifference under the mill-stone of such wretchedness? Oh, what terrible, what heart-rending questions the Mason-bee's misfortunes would bring to my lips, if I gave free scope to my sombre thoughts! But let us avoid these useless whys and keep within the province of the mere recorder.

There are some ten of them plotting the ruin of the peaceable and industrious Bee; and I do not know them all. Each has her own tricks, her own art of injury, her own exterminating tactics, so that no part of the Mason's work may escape destruction. Some seize upon the victuals, others feed on the larvae, others again convert the dwelling to their own use. Everything has to submit: cell, provisions, scarce-weaned nurselings.

The stealers of food are the Stelis-wasp (Stelis nasuta) and the Dioxys-bee (Dioxys cincta). I have already said how, in the Mason's absence, the Stelis perforates the dome of cell after cell, lays her eggs there and afterwards repairs the breach with a mortar made of red earth, which at once betrays the parasite's presence to a watchful eye.

The Stelis, who is much smaller than the Chalicodoma, finds enough food in a single cell for the rearing of several of her grubs. The mother lays a number of eggs, which I have seen vary between the extremes of two and twelve, on the surface, next to the Mason's egg, which itself undergoes no outrage whatever.

Things do not go so badly at first. The feasters swim--it is the only word--in the midst of plenty; they eat and digest like brothers.

Presently, times become hard for the hostess' son; the food decreases, dearth sets in; and at length not an atom remains, although the Mason's larva has attained at most a quarter of its growth. The others, more expeditious feeders, have exhausted the victuals long before the victim has finished his normal repast. The swindled grub shrivels up and dies, while the gorged larvae of the Stelis begin to spin their strong little brown coc.o.o.ns, pressed close together and lumped into one ma.s.s, so as to make the best use of the scanty s.p.a.ce in the crowded dwelling. Should you inspect the cell later, you will find, between the heaped coc.o.o.ns on the wall, a little dried-up corpse. It is the larva that was such an object of care to the mother Mason. The efforts of the most laborious of lives have ended in this lamentable relic. It has happened to me just as often, when examining the secrets of the cell which is at once cradle and tomb, not to come upon the deceased grub at all. I picture the Stelis, before laying her own eggs, destroying the Chalicodoma's egg and eating it, as the Osmiae do among themselves; or I picture the dying thing, an irksome ma.s.s for the numerous spinners at work in a narrow habitation, being cut to pieces to make room for the medley of coc.o.o.ns.

But to so many deeds of darkness I would not like to add another by an oversight; and I prefer to admit that I failed to perceive the grub that died of hunger.

Let us now show up the Dioxys. At the time when the work of construction is in progress, she is an impudent visitor of the nests, exploiting with the same effrontery the enormous cities of the Mason-bee of the Sheds and the solitary cupolas of the Mason-bee of the Pebbles. An innumerable population, coming and going, humming and buzzing, strikes her with no awe. On the tiles hanging from the walls of my porch I see her, with her red scarf round her body, stalking with sublime a.s.surance over the ridged expanse of nests. Her black schemes leave the swarm profoundly indifferent; not one of the workers dreams of chasing her off, unless she should come bothering too closely. Even then, all that happens is a few signs of impatience on the part of the hustled Bee. There is no serious excitement, no eager pursuits such as the presence of a mortal enemy might lead us to suspect. They are there in their thousands, each armed with her dagger; any one of them is capable of slaying the traitress; and not one attacks her. The danger is not suspected.

Meanwhile, she inspects the workyard, moves freely among the ranks of the Masons and bides her time. If the owner be absent, I see her diving into a cell, coming out again a moment later with her mouth smeared with pollen. She has been to try the provisions. A dainty connoisseur, she goes from one store to another, taking a mouthful of honey. Is it a t.i.the for her personal maintenance, or a sample tested for the benefit of her coming grub? I should not like to say. What I do know is that, after a certain number of these tastings, I catch her stopping in a cell, with her abdomen at the bottom and her head at the orifice. This is the moment of laying, unless I am much mistaken.

When the parasite is gone, I inspect the home. I see nothing abnormal on the surface of the ma.s.s. The sharper eye of the owner, when she gets back, sees nothing either, for she continues the victualling without betraying the least uneasiness. A strange egg, laid on the provisions, would not escape her. I know how clean she keeps her warehouse; I know how scrupulously she casts out anything introduced by my agency: an egg that is not hers, a bit of straw, a grain of dust. So, according to my evidence and that of the Chalicodoma, which is more conclusive, the Dioxys's egg, if it is really laid then, is not placed on the surface.

I suspect, without having yet verified my suspicion--and I reproach myself for the neglect--I suspect that the egg is buried in the heap of pollen-dust. When I see the Dioxys come out of a cell with her mouth all over yellow flour, perhaps she has been surveying the ground and preparing a hiding-place for her egg. What I take for a mere tasting might well be a more serious act. Thus concealed, the egg escapes the eagle eye of the Bee, whereas, if left uncovered, it would inevitably perish, would be flung on the rubbish heap at once by the owner of the nest. When the Spotted Sapyga lays her egg on that of the Bramble-dwelling Osmia, she does the deed under cover of darkness, in the gloom of a deep well to which not the least ray of light can penetrate; and the mother, returning with her pellet of green putty to build the closing part.i.tion, does not see the usurping germ and is ignorant of the danger. But here everything happens in broad daylight; and this demands more cunning in the method of installation.

Besides, it is the one favourable moment for the Dioxys. If she waits for the Mason-bee to lay, it is too late, for the parasite is not able to break down doors, as the Stelis does. As soon as her egg is laid, the Mason-bee of the Sheds comes out of her cell and at once turns round and proceeds to close it up with the pellet of mortar which she holds ready in her mandibles. The material is employed with such method that the actual sealing is done in a moment: the other pellets, the object of repeated journeys, will serve merely to increase the thickness of the lid. The chamber is inaccessible to the Dioxys from the first touch of the trowel. Hence it is absolutely necessary for her to see to her egg before the Mason-bee of the Sheds has disposed of hers and no less necessary to conceal it from the Mason's watchful eye.

The difficulties are not so great in the nests of the Mason-bee of the Pebbles. After this Bee has laid her egg, she leaves it for a time to go in search of the cement needed for closing the cell; or, if she already holds a pellet in her mandibles, this is not enough to seal it properly, as the orifice is larger. More pellets are needed to wall up the entrance entirely. The Dioxys would have time to strike her blow during the mother's absences; but everything seems to suggest that she behaves on the pebbles as she does on the tiles. She steals a march by hiding the egg in the ma.s.s of pollen and honey.

What becomes of the Mason's egg confined in the same cell with the egg of the Dioxys? In vain have I opened nests at every season; I have never found a vestige of the egg nor of the grub of either Chalicodoma. The Dioxys, whether as a larva on the honey, or enclosed in its coc.o.o.n, or as the perfect insect, was always alone. The rival had disappeared without a trace. A suspicion thereupon suggests itself; and the facts are so compelling that the suspicion is almost equal to a certainty. The parasitic grub, which hatches earlier than the other, emerges from its hiding-place, from the midst of the honey, comes to the surface and, with its first bite, destroys the egg of the Mason-bee, as the Sapyga does the egg of the Osmia. It is an odious, but a supremely efficacious method. Nor must we cry out too loudly against such foul play on the part of a new born infant: we shall meet with even more heinous tactics later. The criminal records of life are full of these horrors which we dare not search too deeply. An infinitesimal creature, a barely-visible grub, with the swaddling-clothes of its egg still clinging to it, is led by instinct, at its first inspiration, to exterminate whatever is in its way.

So the Mason's egg is exterminated. Was it really necessary in the Dioxys' interest? Not in the least. The h.o.a.rd of provisions is too large for its requirements in a cell of the Chalicodoma of the Sheds; how much more so in a cell of the Chalicodoma of the Pebbles! She eats not a half, hardly a third of it. The rest remains as it was, untouched. We see here, in the destruction of the Mason's egg, a flagrant waste which aggravates the crime. Hunger excuses many things; for lack of food, the survivors on the raft of the Medusa indulged in a little cannibalism; but here there is enough food and to spare. When there is more than she needs, what earthly motive impels the Dioxys to destroy a rival in the germ stage? Why cannot she allow the larva, her mess-mate, to take advantage of the remains and afterwards to s.h.i.+ft for itself as best it can? But no: the Mason-bee's offspring must needs be stupidly sacrificed on the top of provisions which will only grow mouldy and useless! I should be reduced to the gloomy lucubrations of a Schopenhauer if I once let myself begin on parasitism.

Such is a brief sketch of the two parasites of the Chalicodoma of the Pebbles, true parasites, consumers of provisions h.o.a.rded on behalf of others. Their crimes are not the bitterest tribulations of the Mason-bee. If the first starves the Mason's grub to death, if the second makes it perish in the egg, there are others who have a more pitiable ending in store for the worker's family. When the Bee's grub, all plump and fat and greasy, has finished its provisions and spun its coc.o.o.n wherein to sleep the slumber akin to death, the necessary period of preparation for its future life, these other enemies hasten to the nests whose fortifications are powerless against their hideously ingenious methods. Soon on the sleeper's body lies a nascent grub which feasts in all security on the luscious fare. The traitors who attack the larvae in their lethargy are three in number: an Anthrax, a Leucopsis and a microscopic dagger-wearer. (Monodontomerus cupreus. For this and the Anthrax, cf. "The Life of the Fly": chapters 2 and 3. The Leucopsis is a Hymenopteron, the essay upon whom forms the concluding chapter of the present volume.--Translator's Note.) Their story deserves to be told without reticence; and I shall tell it later. For the moment, I merely mention the names of the three exterminators.

The provisions are stolen, the egg is destroyed. The young grub dies of hunger, the larva is devoured. Is that all? Not yet. The worker must be exploited thoroughly, in her work as well as in her family. Here are some now who covet her dwelling. When the Mason is constructing a new edifice on a pebble, her almost constant presence is enough to keep the aspirants to free lodgings at a distance; her strength and vigilance overawe whoso would annex her masonry. If, in her absence, one greatly daring thinks of visiting the building, the owner soon appears upon the scene and ousts her with the most discouraging animosity. She has no need then to fear the entrance of unwelcome tenants while the house is new. But the Bee of the Pebbles also uses old dwellings for her laying, as long as they are not too much dilapidated. In the early stages of the work, neighbours compete for these with an eagerness which shows the value attached to them. Face to face, at times with their mandibles interlocked, now both rising into the air, now coming down again, then touching ground and rolling over each other, next flying up again, for hours on end they will wage battle for the property at issue.

A ready-made nest, a family heirloom which needs but a little restoring, is a precious thing for the Mason, ever sparing of her time. We find so many of the old homes repaired and restocked that I suspect the Bee of laying new foundations only when there are no secondhand nests to be had. To have the chambers of a dome occupied by a stranger therefore means a serious privation.

Now several Bees, however industrious in gathering honey, building party-walls and contriving receptacles for provisions, are less clever at preparing the resorts in which the cells are to be stacked. The abandoned chambers of the Chalicodoma, now larger than they were originally, through the addition of the hall of exit, are first-rate acquisitions for them. The great thing is to occupy these chambers first, for here possession is nine parts of the law. Once established, the Mason is not disturbed in her home, while she, in her turn, does not disturb the stranger who has settled down before her in an old nest, the patrimony of her family. The disinherited one leaves the Bohemian to enjoy the ruined manor in peace and goes to another pebble to establish herself at fresh expense.

In the first rank of these free tenants, I will place an Osmia (Osmia cyanoxantha, PEREZ) and a Megachile, or Leaf-cutting Bee (Megachile apicalis, SPIN.) (Cf. "Bramble-dwellers and Others": chapter 8.--Translator's Note.), both of whom work in May, at the same time as the Mason, while both are small enough to lodge from five to eight cells in a single chamber of the Chalicodoma, a chamber increased by the addition of an outer hall. The Osmia subdivides this s.p.a.ce into very irregular compartments by means of slanting, upright or curved part.i.tions, subject to the dictates of s.p.a.ce. There is no art, consequently, in the acc.u.mulation of little cells; the architect's only task is to use the breadth at her disposal in a frugal manner. The material employed for the part.i.tions is a green, vegetable putty, which the Osmia must obtain by chewing the shredded leaves of a plant whose nature is still uncertain. The same green paste serves for the thick plug that closes the abode. But in this case the insect does not use it unadulterated. To give greater power of resistance to the work, it mixes a number of bits of gravel with the vegetable cement. These materials, which are easily picked up, are lavishly employed, as though the mother feared lest she should not fortify sufficiently the entrance to her dwelling. They form a sort of coa.r.s.e stucco, on the more or less smooth cupola of the Chalicodoma; and this unevenness, as well as the green colouring of its mortar of masticated leaves, at once betrays the Osmia's nest. In course of time, under the prolonged action of the air, the vegetable putty turns brown and a.s.sumes a dead-leaf tint, especially on the outside of the plug; and it would then be difficult for any one who had not seen them when freshly made to recognize their nature.

The old nests on the pebbles seem to suit other Osmiae. My notes mention Osmia Morawitzi, PEREZ, and Osmia cyanea, KIRB., as having been recognized in these dwellings, although they are not very a.s.siduous visitors. Lastly, to complete the enumeration of the Bees known to me as making their homes in the Mason's cupolas, I must add Megachile apicalis, who piles in each cell a half-dozen or more honey-pots constructed with disks cut from the leaves of the wild rose, and an Anthidium whose species I cannot state, having seen nothing of her but her white cotton sacks.