THE CIONUS

The Life of the Weevil by Jean-Henri Fabre and Alexander Teixeira de Mattos, is part of the HackerNoon Books Series. You can jump to any chapter in this book here. THE CIONUS

Chapter XV. THE CIONUS

An insect, well known to every one, is often but a stupid creature, while another, of which nothing is known, is of real value. When endowed with talents worthy of attention, it passes unrecognized; when richly clad and of handsome appearance, it is familiar to us. We judge it by its coat and its size, as we judge our neighbour by the fineness of his clothing and the importance of the position which he fills. The rest does not count.

Of course, if it is to be honoured by the historian, it is best that the insect should enjoy popular renown. This saves the reader trouble, as he at once knows precisely what we are speaking of; furthermore, it shortens the story, which is not hampered by long and tedious descriptions. Moreover, if size facilitates observation, if elegance of shape and brilliance of costume captivate the eye, we should be wrong not to take this magnificence into our reckoning.

But far more important are the habits, the ingenious devices, which give a real charm to entomological study. Now it so happens that among the insects it is the largest, the most magnificent, [247]that are generally the most inefficient: a freak of nature that recurs elsewhere. What can we expect of a Carabus, all shimmering with metallic gleams? Nothing but feasting amid the foam secreted by a murdered snail. What can we expect of the Cetonia, who looks as though she had escaped from a jeweller’s show-case? Nothing but drowsy slumbers in the heart of a rose. These magnificoes cannot do anything; they have no craft, no trade.

If, on the contrary, we wish to see original inventions, artistic masterpieces and ingenious contrivances, we must apply to the humble creatures that are oftener than not unknown to any one. And we must not allow ourselves to be disgusted by the spots frequented. Ordure has beautiful and curious things in store for us, the like of which we should never find on the rose. The Minotaur1 has edified us by his domestic habits. Long live the modest! Long live the little!

One of these little ones, smaller than a peppercorn, will set us a great problem, full of interest but probably insoluble. The official nomenclators call it Cionus thapsus, Fab. If you ask me what Cionus means, I shall reply frankly that I have not the least idea. Neither the writer of these lines nor the reader is any the worse off for that. [248]In entomology a name is all the better for meaning nothing but the insect named.

If an amalgam of Greek or Latin has a meaning that alludes to the insect’s manner of living, the reality is often inconsistent with the word, because the nomenclator, working in a necropolis, has preceded the observer, who is concerned with the living species. Moreover, rough guesses and even glaring mistakes too often disfigure the records of the insect world.

At the present moment, it is the word thapsus that deserves reproach, for the plant exploited by the Cionus is not the botanists’ Verbascum thapsus at all, but quite another plant, of wholly different character, Verbascum sinuatum. A lover of the way-side, having no fear of the ungrateful soil and the white dust, the scallop-leaved mullein is a southern plant which spreads over the ground a rosette of broad, fluffy leaves, the edges of which are gashed with deep, wavy incisions. Its flower-stalk is divided into a number of twigs bearing yellow blossoms whose staminal filaments are bearded with violet hairs.

At the end of May, let us open the umbrella, the collector’s chief engine of the chase, underneath the plant. A few blows of a walking-stick on the chandelier ablaze with yellow flowers will bring down a sort of hail. This is our friend the Cionus, a roundish little creature, huddled into a globule on its short legs. Its costume is not [249]lacking in elegance and consists of a scaly jacket flecked with black specks on an ash-grey background. The insect is distinguished above all by two large tufts of black velvet, one on its back and the other at the lower extremity of the wing-case. No other Weevil of our country-side wears the like. The rostrum is fairly long, powerful and depressed towards the thorax.

For a long while this Weevil, with her decoration of black spots, has occupied my mind. I should like to know her larva, which, as everything seems to prove, must live in the capsules of the scallop-leaved mullein. The insect belongs to the series that nibble at seeds contained in a shell; it ought to share their botanical habits. But vainly, whatever the season, do I open the capsules of the exploited plant: never do I find the Cionus there, nor its larva, nor its nymph. This little mystery increases my curiosity. Perhaps the dwarf has interesting things to tell us. I propose to wrest her secret from her.

It so happens that a few scallop-leaved mulleins are spreading their rosettes amid the pebbles of my enclosure. They are not populated, but I can easily colonize them with specimens from the country round about, obtained by a few battues over the umbrella. No sooner said than done. From May onwards I have before my door, without fear of disturbance by passing Sheep, the means [250]of following the Cionus’ doings, in comfort, at any hour of the day.

My colonies flourish. The strangers, satisfied with their new camping-ground, settle down on the twigs on which I have placed them. They browse and gently tease one another with their legs: many of them pair off and gaily spend their lives revelling in the sunshine. Those coupled together, one on top of the other, are subject to sudden lurches from side to side, as though impelled by the release of a vibrating spring. Pauses follow, of varying length; then the lurches are repeated, cease and begin again.

Which of the two supplies the motive force of this little piece of machinery? It seems to me that it is the female, who is rather larger than the male. The jerking would then be a protest on her part, an attempt to free herself from the embraces of her companion, who holds on despite all this shaking. Or again, it may be a common manifestation, the pair joyfully exulting in a nuptial rolling from side to side.

Those who are not coupled plunge their rostrum into the budding flowers and feast deliciously. Others bore little brown holes in the tiny twigs, whence oozes a drop of syrup which the Ants will come and lick up presently. And that, for the moment, is all. There is nothing to tell us where the eggs will be laid.

In July, certain capsules, still quite small, green [251]and tender, have at their base a brown speck which might well be the work of the Cionus placing her eggs. I have my doubts: most of these punctured capsules contain nothing. The grubs then left their cell shortly after the hatching, the aperture, still open, allowing them to pass.

This emancipation of the new-born grubs, this premature exposure to the dangers of the outside world, is not consistent with the habits of the Weevils, who are great stay-at-homes while in the larval state. Legless, plump, fond of repose, the grub shrinks from change of place; it grows up on the spot where it was born.

Another circumstance increases my perplexity. Among the capsules which the Weevil seems to have perforated with her rostrum, some contain eggs of an orange yellow, grouped into a single heap of five or six or more. This multiplicity gives us food for reflection. When fully matured, the capsules of the scallop-leaved mullein are small, greatly inferior in size to those of other plants of the same genus. When still very young, green and tender, those containing the eggs are hardly as big as half a grain of wheat. There is not food for so many feasters in so tiny a morsel; there would not be enough for one.

All mothers are provident. The exploiter of the mullein cannot have endowed her six or more nurselings with such scanty possessions. For these various reasons, I doubt at first whether these are [252]really the Cionus’ eggs. What follows is not calculated to decrease my hesitation. The orange eggs hatch out, producing grubs which within twenty-four hours abandon their exiguous natal chamber. They emerge through the orifice which has been left open; they spread over the capsule, cropping its down, a pasture sufficient for their first mouthfuls. They descend to the thin little twigs, which they strip of their bark, and gradually move on to the small adjacent leaves, where the banquet is continued. Let us leave them to grow. Their final transformation will tell me that I really have the authentic larva of the Cionus before my eyes.

They are bare, legless grubs, of a uniform pale yellow, excepting the head, which is black, and the first segment of the thorax, which is adorned with two large black spots. They are varnished all over their bodies with a glutinous humour, so much so that they stick to the paint-brush used to collect them and are difficult to shake off. When teased, they emit from the end of their intestine a viscous fluid, apparently the origin of their varnish.

They wander idly over the young twigs, whose bark they gnaw down to the wood; they also browse on the leaves growing from the twigs, which are much smaller than those upon the ground. Having found a good grazing-place, they stay there without moving, curved into a bow and held in [253]position by their glue. Their walk is an undulating crawl, based upon the support of their sticky behind. Helpless cripples, but coated with an adhesive varnish, they are firmly enough fixed to resist a shake of the bough that bears them without falling off. When you have no sort of grapnel to hold on by, the idea of clothing yourself in glue, so that you may shift your position without danger of falling, even in a gust of wind, is an original invention of which, as yet, I know no other instance.

Our grubs are easily reared. Placed in a glass jar, with a few tender twigs of the plant that feeds them, they go on browsing for some time and then make themselves a pretty ampulla in which the transformation will take place. To observe this performance and discover the method employed was the chief purpose of my inquiry. I succeeded, though not without a great expenditure of assiduity.

All its life long, the larva is smeared, on both its dorsal and its ventral surface, with a viscous, colourless, strongly adhesive fluid. Touch the creature lightly, anywhere, with the tip of a camel-hair pencil. The glutinous matter yields and draws out into a thread of a certain length. Repeat the touch in the hot sunshine, in very dry weather. The viscosity is not diminished. Our varnishes dry up; the grub’s does not; and this is a property of the greatest value, enabling the feeble larva, without fear of being shrivelled by the wind or [254]the rays of the sun, to adhere firmly to its food-plant, which loves the open air and warm, sunny places.

The laboratory producing this sticky varnish is easily discovered; we have only to make the creature move along a slip of glass. We see from time to time a sort of treacly dew oozing from the end of the intestine and lubricating the last segment. The glue is therefore supplied by the digestive canal. Is there a special glandular laboratory there, or is it the intestine itself that prepares the product? I will leave the question unanswered, for nowadays I no longer have the steady hand or the keen sight required for delicate dissection. The fact remains that the grub daubs itself with a glue of which the end of the intestine is at least the storehouse, if it is not the actual source.

How is the sticky emission distributed over the whole body, both above and below? The larva is a legless cripple; it moves about by obtaining a hold with its behind. Moreover, it is well segmented. The back, in particular, has a series of fairly protuberant cushions; the ventral surface, on the other hand, is puckered by knotty excrescences, which change their shape considerably in the act of crawling. When moving, with the flexible fore-part of the body groping to find its way, the grub consists of a series of waves that follow one another in perfect order.

Each wave starts from the hinder extremity [255]and by swift degrees reaches the head. Straightway a second wave follows in the same direction, succeeded by a third, a fourth and so on, indefinitely. Each of these waves, proceeding from one end of the grub to the other, is a step. So long as the wave continues, the fulcrum, that is, the orifice of the intestine, remains in its place, at first a little before and then a little behind the movement as a whole. Hence the source of the sticky dew grazes first the tip of the abdomen and then the end of the back of the moving grub. In this way the tiny drop of gum is deposited above and below.

The glue has still to be distributed. This is done by crawling. Between the puckers, the cushions, which the locomotory wave brings together and then separates, alternately come into contact and open clefts into which the sticky fluid gradually makes its way by capillary action. The grub clothes itself in glue without exercising any special skill, merely by moving along. Each locomotory wave, each step, supplies its quota to the viscous doublet. This makes up for the losses which the larva cannot fail to suffer on the road as it roams from pasture to pasture; and, since the fresh material balances the wastage of the old, a suitable coat is obtained, neither too thin nor too thick.

The complete coating is rapidly effected. With the tip of a camel-hair pencil, I wash a grub in a [256]little water. The viscosity dissolves and disappears; and the water used for washing the larva, evaporated on a slip of glass, leaves a mark like that of a weak solution of gum arabic. I place the grub to dry on blotting-paper. When I now touch it with a straw, it no longer sticks to it; it has lost its coating of varnish.

How will it replace it? This is a very simple matter. I allow the grub to move about at will for a few minutes. No more is needed; the layer of gum is restored; the creature sticks to the straw that touches it. To sum up, the varnish with which the Cionus’ larva is covered, is a viscous fluid, soluble in water, quickly emitted and extremely slow to dry, even in an intensely hot sun and in the parching breath of the north-wind.

Having obtained these data, let us see how the ampulla is constructed in which the transformation will take place. On the 8th of July 1906, my son Paul, my zealous collaborator now that my once sturdy legs are failing me, brings me, on returning from his morning walk, a magnificent branching head of mullein peopled by the Cionus. It contains an abundance of larva. Two of them in particular delight me: while the others stand browsing, these two wander about restlessly, indifferent to their food. Beyond any doubt, they are looking for a spot favourable to the process of the nymphosis.

I place each of them singly in a small glass [257]tube which will allow me to observe them easily. In case they might find the food-plant useful, I supply them with a sprig of mullein. And now, lens in hand, from morning to evening and then by night, as far as drowsiness and the doubtful light of a candle will permit, let us be on the alert; for very interesting things are about to happen. Let me describe them hour by hour.

8 a.m.—The larva is not making use of the twig with which I provided it. It is crawling along the glass, darting its pointed head now this way, now that. With a gentle creeping movement that causes an undulation of the back and belly, it is trying to settle itself comfortably. After two hours of this effort, which is certain to be accompanied by an emission of viscous fluid, it finds a position to its taste.

10 a.m.—Being now fixed to the glass, the larva has shrunk into the semblance of a little barrel, or a grain of wheat with rounded ends. At one end is a shining black speck. This is the head, jammed into a fold of the first segment. The grub’s colour is unchanged: it is still a dirty yellow.

1 p.m.—A copious emission of fine black granules, followed by semifluid dejecta. To avoid soiling its future residence and to prepare the intestine for the delicate chemistry about to follow, the grub purges itself beforehand of its impurities. It is now a uniform pale yellow, without the cloudy [258]markings that disfigured it at first. It is lying at full length on its ventral surface.

3 p.m.—Under the skin, especially on the back, the lens reveals subtle pulsations, slight tremors, like those of a liquid surface on the point of boiling. The dorsal vessel itself is dilating and contracting, throughout its length, more actively than usual. This means a fit of fever. Some internal change must be preparing, which will affect the whole organism. Can it be the preparation for a moult?

5 p.m.—No, for the grub is no longer motionless. It leaves its heap of dirt and begins to move along impetuously, more restlessly than ever. What is happening that is in any way unusual? I think I can obtain some idea of it with the aid of logic.

Remember that the sticky coat in which the grub is clad does not dry up: this is a condition indispensable to liberty of movement. If changed into a hard varnish, a dry film, it would hamper, would indeed stop the crawling; but, so long as it remains liquid, it is the drop of oil that lubricates the locomotory machine. This moist coating will, however, constitute the material of the nymphosis-bladder: the fluid will become gold-beater’s-skin, the liquid will solidify.

This change of condition at first suggests oxidation. We must abandon this idea. If the hardening were really the result of oxidization, the grub, being sticky from its birth and always exposed to the air, would long ago have been clad not in a [259]delicate coat of adhesive, but in a stiff parchment sheath. Desiccation obviously must take place at the last moment and rapidly, when the grub is preparing to change its shape. Before then, this desiccation would be a danger; now, it is an excellent means of defence.

To ‘fix’ oil-paintings our ingenuity employs siccatives, that is to say, ingredients that act upon the oil, giving it a resinous consistency. The Cionus likewise has its siccative, as the following facts prove. It may be that the grub was labouring to produce this desiccating substance, by some profound change in the process of its organic laboratory, at the time when its poor flesh was quivering with feverish tremors; it may be that it was proceeding to spread the siccative over the whole surface of its body by taking a long walk, the last of its larval life.

7 p.m.—The larva is once more motionless, lying flat on its belly. Is this the end of its preparations? Not yet. The globular structure must have a foundation, a base on which the grub can support itself in order to dilate its ampulla.

8 p.m.—Round the head and the fore-part of the thorax, which, like the rest of the body, are touching the slip of glass, a border of pure white now appears, as though snow had fallen at these points. This forms a sort of horse-shoe enclosing an area in which the snowy deposit is continued in a vague mist. From the base of this border [260]some threads of the same white substance radiate in short tufts. This structure denotes work done with the mouth, a miniature wire-drawing. And in fact no such white substance is seen anywhere except around the head. Thus the creature’s two ends take part in the building of the hut: the one in front provides the foundations, the one behind provides the edifice.

10 p.m.—The larva shrinks. With its support, that is to say, its head anchored to the snowy cushion, it brings its hinder end a little nearer; it coils up, hunches its back and gradually turns itself into a ball. Though not yet perceptible, the ampulla is being prepared. The siccative has taken effect; the original gumminess has been transformed into a sort of skin, flexible enough at this moment to be distended by the pressure of the back. When its capacity is large enough, the grub will become unglued, throw off its envelope and find itself at liberty in a spacious enclosure.

I should much like to see this peeling, but things happen so slowly as to drive one to despair. Let us go to bed. What I have seen is enough to enable me to guess the little that remains to be seen.

Next day, when the pale dawn gives me sufficient light, I hasten to my two larvæ. The bladder is completed. It is a graceful ovoid of the finest gold-beater’s-skin, adhering at no point to the insect inside. It has taken some twenty hours to manufacture. [261]It has still to be strengthened with a lining. The transparency of the wall enables us to follow the operation.

We see the grub’s little black head rising and falling, swerving this way and that and from time to time gathering with its mandibles, at the door of the intestine, a particle of cement, which is instantly placed in position and meticulously smoothed. So the interior of the hut is plastered, point after point, by small touches. Lest I should not see clearly through the wall, I cut off the top of a bladder, partly uncovering the larva. The work is continued without much hesitation. The strange method is revealed as plainly as one could wish. The grub makes use of its behind as a store of consolidating cement; the end of the intestine serves as the equivalent of the hod from which the bricklayer takes his trowelful of mortar.

This original mode of procedure is familiar to me. At one time, a big Weevil, the Spotted Larinus, inhabiting the blue-headed globe-thistle (Echinops Ritro), enabled me to witness a similar method. The Larinus also expels its own cement. With the tips of its mandibles it gathers it from the evacuating orifice, applying it with strict economy. Moreover it has other materials at its disposal, the hairs and remnants of the florets of its thistle. Its cement is used only to plaster and glaze the work. The Cionus’ larva, on the other hand, employs nothing but the oozings of [262]its intestine; consequently the little hut resulting is of incomparable perfection.

Besides the Spotted Larinus, my notes mention other Weevils, for instance, the Garlic-weevil (Brachycerus algirus), whose larvæ possess the art of coating their cells with a thin glaze provided by the rump. This intestinal artifice seems, therefore, to be pretty frequently employed by the Weevils that build little chambers in which the metamorphosis is to take place; but none of them excel in it as does the Cionus. Its task becomes yet more interesting when we consider that, in the same factory, after a very brief interval, three different products are compounded: first a liquid glue, a means of adhesion to the swaying support of the mullein lashed by the winds; then a siccative fluid which transforms the sticky coating into gold-beater’s-skin; and lastly a cement which strengthens the bladder separated from the larva by a sort of moult. What a laboratory, what exquisite chemistry in a scrap of intestine!

What use are these minute details, noted hour by hour? Why these puerilities? What matters to us the industry of a wretched grub, hardly known even to the professional experts?

Well, these puerilities involve the most weighty problems that we are privileged to discuss. Is the world an harmonious creation, governed by a primordial force, a causa causarum? Or is it a chaos of blind conflicting forces, whose reciprocal [263]thrusts produce a chance equilibrium, for better or for worse? Minute entomological details examined with some thoroughness, may serve us better than syllogisms, in the scientific investigation of these trifles and others like them. The humble Cionus, for its part, tells us of a primordial force, the motive power of the smallest as of the greatest things.

A day is not too long to give the bladder a good lining. Next day the larva moults and passes into the nymphal state. Let us complete its story with the data gleaned in the fields. The cocoons are often found on the grass near the food-plant, on the stalks and dead blades of the Gramineæ. Generally, however, they occupy the little twigs of the mullein, stripped of their bark and withered. The adult insect emerges sooner or later in September. The gold-beater’s-skin capsule is not torn irregularly, at random; it is neatly divided into two equal parts, like the two halves of a soap-box.

Has the enclosed insect gnawed the casing with its patient tooth and made a fissure along the equator? No, for the edges of either hemisphere are perfectly clean-cut. There must, therefore, have been a circular line ready to facilitate the opening. All that the insect had to do was to hunch its back and give a slight push, in order to unfasten the roof of its cabin all in one piece and set itself free.

I can just see this line of easy rupture on certain [264]intact capsules. It is a faint line ringing the equator. What does the insect do beforehand to contrive that its cell shall open in this way? A humble plant, flowering early in the spring, the blue or scarlet pimpernel, has also its soap-box, its pyxidium, which splits easily into two hemispheres when the time comes for the seed to be scattered. In either case it is the work of an unconscious ingenuity. The grub does not plan its methods any more than the pimpernel: it has hit upon its ingenious scheme of joining the halves of its capsule by the inspiration of instinct alone.

More numerous than the capsules which burst accurately are others which are clumsily torn by a shapeless breach. Through this some parasite must have emerged, some ruthless creature which, unacquainted with the secret of the delicate joint, has released itself by tearing the gold-beater’s-skin. I find its larva in cells which are not yet perforated. It is a small, white grub, fixed to a discoloured tit-bit which is all that remains of the Cionus’ nymph. The intruder is sucking dry the rightful occupant, whose budding flesh is still quite tender. I think I can identify the murderess as a bandit of the Chalcid tribe, which is addicted to such massacres.

Her appearance and her gluttonous ways have not misled me. My rearing-jars provide me with abundant supplies of a small bronze-coloured [265]Chalcid with a large head and a round, tapering body, but with no visible boring-tool. To inquire her name of the experts will not help me much. I do not ask the insect, ‘what are you called?’ but ‘what are you able to do?’

The anonymous parasite hatched in my jars has no implement similar to that of the Leucospis,2 the chief of the Chalcididæ; it has no probe which is able to penetrate a wall and place the egg, at some distance, on the food-ration. Her germ, therefore, was laid in the very flanks of the Cionus’ larva, before the latter had built its shell.

The methods of these tiny brigands appointed to the task of thinning out the too numerous are extremely varied. Each guild has its own method, which is always horribly effective. How should so small a creature as the Cionus cumber the earth? No matter: it has to be massacred, to perish in its cradle, a victim of the Chalcid. Like other creatures, the peaceful dwarf must furnish its share of organizable matter, which will be further and further refined as it passes from stomach to stomach.

Let us recapitulate the habits of the Cionus, very strange habits in an insect of the Weevil series. The mother entrusts her eggs to the swelling capsules of the scallop-leaved mullein. So far, everything is according to rule. Other Weevils, as a matter of fact, prefer, when setting [266]their children up in life, the pods of some other mullein, or those of the figwort or of the snap-dragon, two plants belonging to one and the same botanical family. But now we are suddenly confronted with the strange and exceptional. The mother Cionus chooses the mullein with the smallest capsules, whereas in the neighbourhood and at the same season there are others loaded with fruit whose dimensions would provide spacious lodgings and abundance of food. She prefers dearth to plenty and narrow to spacious quarters.

Worse still. Indifferent to leaving provision for her brood, she nibbles the tender seeds, destroys them, extirpates them, in order to obtain a cavity in the heart of the tiny globule. Into this she slips more or less half a dozen eggs. With the edible substance left, were the whole cell to be consumed, there would not be enough to feed a single grub.

When the bread-pan is empty, the house is deserted. The young abandon their famine-stricken dwelling on the day when they are hatched. They are bold innovators and practise a method which is held in detestation among the Weevils, who are all pre-eminently stay-at-homes: they dare the dangers of the outer world: they travel, passing from one leaf to another in search of food. This strange exodus, unprecedented in a Weevil, is not a mere caprice but a necessity imposed on them by hunger; they migrate because their mother has not provided them with anything to eat.[267]

If travelling has its pleasures, enough to make the insect forget the delights of the cell in which it digests at peace, it also has its drawbacks. The legless grub can progress only by a sort of creeping gait. It has no instrument of adherence which will enable it to remain fixed to the twig, whence the least breath of wind may make it fall. Necessity is the mother of invention. To guard against the danger of falling, the wanderer smears itself with a viscous fluid, which varnishes it and makes it adhere to the trail which it is following.

But this is not all. When the ticklish moment of the nymphosis arrives, a retreat in which the grub can undergo its transformation in peace becomes indispensable. The vagabond has nothing of the sort. It is homeless, it sleeps in the open air; yet it is able, when the time comes, to make itself a tent, a capsule, the materials for which are supplied by its intestine. No other insect of its order can build a home like this. Let us hope that the hateful Chalcid, the murderer of nymphs, will not visit it in its pretty little tent.

The grub that lives on the scallop-leaved mullein has shown an utter revolution in the habits of the Weevil clan. The better to judge of this, let us consult a cognate species, placed not far from the Cionus by the classifiers; let us compare the two kinds of life, on the one hand the exception and on the other the rule. The comparison will be all the more useful inasmuch as the new witness also [268]exploits a mullein. It is known as Gymnetron thapsicola, Germ.

Dressed in russet homespun, with a plump round body and about the size of the Cionus: there you have the creature. Note the qualifying thapsicola, meaning an inhabitant of the thapsus. On this occasion, I am glad to see, the term could not possibly be happier: it enables the novice to identify the insect exactly, without other data than the name of the plant on which it lives.

The botanist gives the name of Verbascum thapsus to the common mullein, or shepherd’s club, a lover of the tilled fields in both the north and the south. Its bloom, instead of branching out like that of the scallop-leaved mullein, consists of one thick cone of yellow flowers. These flowers are followed by close-packed capsules about as big as a fair-sized olive. Here we no longer have the niggardly pods in which the grub of the Cionus would die of starvation if it did not abandon them as soon as it is hatched; these caskets contain plenty of victuals for one larva and even for two. A partition divides them into two equal compartments, both of them crammed with seeds.

The fancy took me to estimate roughly the mullein’s wealth of seeds. I have counted as many as 321 in a single shell. Now a spike of ordinary size contains 150 capsules. The total number of seeds is therefore 48,000. What can the plant want with such abundance? Allowing [269]for the small number of seeds required to maintain the species in a thriving state, it is evident that the mullein is a hoarder of nutritive atoms; it creates foodstuffs; it summons guests to its opulent banquet.

Knowing these facts, the Gymnetron, from May onwards, visits the luxuriant flower-spike and there installs her grubs. The inhabited capsules may be recognized by the brown speck at their base. This is the hole bored by the mother’s rostrum, the aperture needed for inserting the eggs. Usually there are two, corresponding with the two cells of the fruit. Soon the oozings from the cell set hard and dry and obstruct the tiny window; and the capsule is closed again, without any communication with the outer world.

In June and July, let us open the shells marked with brown specks. Nearly always we find two grubs, looking fat as butter, with their fore-parts swollen and their hinder parts shrunken and curved like a comma. Not a vestige of legs, which members would be very useless in such a lodging. Lying at its ease, the grub has plenty of food ready to its mouth: first the tender, sugary seeds; then the placenta, their common support, which is likewise fleshy and highly flavoured. It is pleasant to live under such conditions, motionless and devoting one’s self entirely to the joys of the stomach.

It would take a cataclysm to upset the smug [270]hermit. This cataclysm I bring about by opening the cell. Then and there, the grub begins to twist and wriggle desperately, hating any exposure to the air and light. It takes more than an hour to recover from its excitement. Here assuredly is a grub that will never be tempted to leave its home and go wandering about like the Cionus’ larva. It is most highly domestic by inheritance and domestic it will remain.

It refuses even to go next door. In the same capsule, on the other side of the partition, a neighbour is nibbling away. Never does it pay the neighbour a visit, though it could easily do so by perforating the partition, which at this moment is an actual sort of cake, no less tender than the seeds and the placenta. Each holds the other’s share of the capsule inviolable. On the one hand is one grub; on the other hand is another; and never do the two hold the least communication through the little skylight. A grub’s home is its castle.

The Gymnetron is so happy in her cell that she stays there a long time after assuming her adult form. For ten months out of the twelve she does not leave it. In April, when the buds of the new twigs are swelling, she pierces the natal capsule, now a mighty donjon; she comes out and revels in the sun on the recent flower-spikes, which grow daily longer and thicker; she frisks in couples and, in May, establishes her family, which will [271]obstinately repeat the sedentary habits of the elders.

With these data before us, let us philosophize awhile. Every Weevil spends its larval life on the spot where the egg was laid. Various larvæ, it is true, when the time of metamorphosis approaches, migrate and make their way underground. The Brachycerus abandons its clove of garlic, the Balaninus its nut or acorn, the Rhynchites its vine-leaf or poplar-leaf cigar, the Ceuthorhynchus its cabbage stalk. But these instances of desertion on the part of grubs which have attained their full growth do not in any way invalidate the rule: all Weevil-larvæ grow up in the actual place where they are born.

Now here, by a most unexpected change of tactics, the Cionus-grub, while still quite young, quits its natal cell, the capsule of the mullein; it longs for the outer world, that it may browse in the open air on the bark of a twig; and this entails upon it two inventions elsewhere unknown: the sticky coat, which gives it a firm hold when it moves from place to place, and the gold-beater’s-skin ampulla, which serves to house the nymph.

What is the cause of this aberration? Two theories are suggested, one based on decadence, the other on progress. Of old, we tell ourselves, the mother Cionus, far back in the ages, used to obey the conventions of her tribe. Like the other Weevils that munch unripe seeds, she favoured [272]large capsules, enough to feed a sedentary family. Later, by inadvertence or flightiness or for some other reason, she turned her attention to the stingy scollop-leaved mullein. Faithful to ancient custom she rightly chose for her domain a plant of the same family as that which she first exploited; but it unfortunately happens that the mullein adopted is incapable of feeding a single grub in its fruit, which is too small for the purpose. The mother’s ineptitude has led to decadence; the perils of a wandering life have taken the place of a peaceful, sedentary existence. The species is on the high road to extinction.

Again, we might argue as follows, at the outset, the Cionus had the scallop-leaved mullein as her portion; but, since the grubs do not thrive when thus installed, the mother is searching for a better means of setting them up in life. Gradual experiment will one day show her the way. From time to time, indeed, I find her on Vervascum maiale or Verbascum thapsus, both of which have large capsules; only she is there by accident, in the course of a trip, thinking of obtaining a good drink and not of laying her eggs. Sooner or later, the future will establish her there for the sake of her family. The species is in process of improvement.

By dressing up the matter in uncouth phrases, calculated to conceal the vagueness of the thought behind them, we might represent the Cionus as [273]a magnificent example of the changes which the centuries bring about in the habits of insects. This would sound extremely learned, but would it be very intelligible? I doubt it. When my eyes fall upon a page bristling with barbarous and so-called scientific locution, I say to myself:

‘Take care! The author has not quite grasped what he is saying, or he would have found, in the vocabulary hammered out by so many brilliant minds, words that would express his thought more plainly.’

Boileau,3 who has been denied poetic inspiration, but who certainly possessed common-sense and plenty of it, tells us:

‘Ce que l’on conçoit bien s’énonce clairement.’4

Just so, Nicolas! Yes, clearness, clearness always! He calls a spade a spade. Let us do as he does, let us qualify as gibberish any over-learned prose that reminds us of Voltaire’s witty sally:

‘When the listener does not understand and the speaker does not himself know what he is saying, then they are talking metaphysics.’

‘And advanced science,’ let us add.

We will confine ourselves to stating the problem of the Cionus, without much hope that some day it will be clearly solved. For that matter, if the [274]truth be told, it may be that there is no problem at all. The grub of the Cionus was a vagabond in the beginning and a vagabond it will remain, among the other Weevil-grubs, which are all essentially stay-at-home larvæ. Let us leave it at that: it is the simplest and most lucid explanation.

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This book is part of the public domain. Jean-Henri Fabre and Alexander Teixeira de Mattos (2021). The Life of the Weevil. Urbana, Illinois: Project Gutenberg. Retrieved https://www.gutenberg.org/cache/epub/66844/pg66844-images.html

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