AN INVADER.—THE HARICOT-WEEVIL

Social Life in the Insect World by Jean-Henri Fabre, is part of the HackerNoon Books Series. You can jump to any chapter in this book here. AN INVADER.—THE HARICOT-WEEVIL

CHAPTER XIX. AN INVADER.—THE HARICOT-WEEVIL

If there is one vegetable on earth that more than any other is a gift of the gods, it is the haricot bean. It has all the virtues: it forms a soft paste upon the tongue; it is extremely palatable, abundant, inexpensive, and highly nutritious. It is a vegetable meat which, without being bloody and repulsive, is the equivalent of the horrors outspread upon the butcher's slab. To recall its services the more emphatically, the Provençal idiom calls it the gounflo-gus—the filler of the poor.

Blessed Bean, consoler of the wretched, right well indeed do you fill the labourer, the honest, skilful worker who has drawn a low number in the crazy lottery of life. Kindly Haricot, with three drops of oil and a dash of vinegar you were the favourite dish of my young years; and even now, in the evening of my days, you are welcome to my humble porringer. We shall be friends to the last.

To-day it is not my intention to sing your merits; I wish simply to ask you a question, being curious: What is the country of your origin? Did you come from Central Asia with the broad bean and the pea? Did you make part of that collection of seeds which the first pioneers of culture brought us from their gardens? Were you known to antiquity?

Here the insect, an impartial and well-informed witness, answers: "No; in our country antiquity was not acquainted with the haricot. The precious vegetable came hither by the same road as the broad bean. It is a foreigner, and of comparatively recent introduction into Europe."

The reply of the insect merits serious examination, supported as it is by extremely plausible arguments. Here are the facts. For years attentive to matters agricultural, I had never seen haricots attacked by any insect whatever; not even by the Bruchidæ, the licensed robbers of leguminous seeds.

On this point I have questioned my peasant neighbours. They are men of the extremest vigilance in all that concerns their crops. To steal their property is an abominable crime, swiftly discovered. Moreover, the housewife, who individually examines all beans intended for the saucepan, would inevitably find the malefactor.

All those I have spoken to replied to my questions with a smile in which I read their lack of faith in my knowledge of insects. "Sir," they said, "you must know that there are never grubs in the haricot bean. It is a blessed vegetable, respected by the weevil. The pea, the broad bean, the vetch, and the chick-pea all have their vermin; but the haricot, lou gounflo-gus, never. What should we do, poor folk as we are, if the Courcoussoun robbed us of it?"

The fact is that the weevil despises the haricot; a very curious dislike if we consider how industriously the other vegetables of the same family are attacked. All, even the beggarly lentil, are eagerly exploited; whilst the haricot, so tempting both as to size and flavour, remains untouched. It is incomprehensible. Why should the Bruchus, which without hesitation passes from the excellent to the indifferent, and from the indifferent to the excellent, disdain this particularly toothsome seed? It leaves the forest vetch for the pea, and the pea for the broad bean, as pleased with the small as with the large, yet the temptations of the haricot bean leave it indifferent. Why?

Apparently because the haricot is unknown to it. The other leguminous plants, whether native or of Oriental origin, have been familiar to it for centuries; it has tested their virtues year by year, and, confiding in the lessons of the past, it bases its forethought for the future upon ancient custom. The haricot is avoided as a newcomer, whose merits it has not yet learned.

The insect emphatically informs us that with us the haricot is of recent date. It has come to us from a distant country: and assuredly from the New World. Every edible vegetable attracts its consumers. If it had originated in the Old World the haricot would have had its licensed consumers, as have the pea, the lentil, and the broad bean. The smallest leguminous seed, if barely bigger than a pin's head, nourishes its weevil; a dwarf which patiently nibbles it and excavates a dwelling; but the plump, delicious haricot is spared.

This astonishing immunity can have only one explanation: like the potato and the maize-plant, the haricot is a gift of the New World. It arrived in Europe without the company of the insect which exploits it in its native country; it has found in our fields another world of insects, which have despised it because they did not know it. Similarly the potato and the ear of maize are untouched in France unless their American consumers are accidentally imported with them.

The verdict of the insect is confirmed by the negative testimony of the ancient classics; the haricot never appears on the table of the Greek or Roman peasant. In the second Eclogue of Virgil Thestylis prepares the repast of the harvesters:—

Thestylis et rapido fessis messoribus æstu
Allia serpyllumque herbas contundit olentes.

This mixture is the equivalent of the aïoli, dear to the Provençal palate. It sounds very well in verse, but is not very substantial. On such an occasion men would look for that fundamental dish, the plate of red haricots, seasoned with chopped onions. All in good time; this at least would ballast the stomach. Thus refreshed in the open air, listening to the song of the cigales, the gang of harvesters would take their mid-day rest and gently digest their meal in the shadows of the sheaves. Our modern Thestylis, differing little from her classic sister, would take good care not to forget the gounflo-gus, that economical resource of large appetites. The Thestylis of the past did not think of providing it because she did not know it.

The same author shows us Tityrus offering a night's hospitality to his friend Melibœus, who has been driven from his property by the soldiers of Octavius, and goes limping behind his flock of goats. We shall have, says Tityrus, chestnuts, cheese, and fruits. History does not say if Melibœus allowed himself to be tempted. It is a pity; for during the frugal meal we might have learned in a more explicit fashion that the shepherds of the ancient world were not acquainted with the haricot.

Ovid tells us, in a delightful passage, of the manner in which Philemon and Baucis received the gods unawares as guests in their humble cottage. On the three-legged table, which was levelled by means of a potsherd under one of the legs, they served cabbage soup, rusty bacon, eggs poached for a minute in the hot cinders, cornel-berries pickled in brine, honey, and fruits. In this rustic abundance one dish was lacking; an essential dish, which the Baucis of our countryside would never forget. After bacon soup would follow the obligatory plate of haricots. Why did Ovid, so prodigal of detail, neglect to mention a dish so appropriate to the occasion? The reply is the same as before: because he did not know of it.

In vain have I recapitulated all that my reading has taught me concerning the rustic dietary of ancient times; I can recollect no mention of the haricot. The worker in the vineyard and the harvester have their lupins, broad beans, peas, and lentils, but never the bean of beans, the haricot.

The haricot has a reputation of another kind. It is a source of flatulence; you eat it, as the saying is, and then you take a walk. It lends itself to the gross pleasantries loved of the populace; especially when they are formulated by the shameless genius of an Aristophanes or a Plautus. What merriment over a simple allusion to the sonorous bean, what guffaws from the throats of Athenian sailors or Roman porters! Did the two masters, in the unfettered gaiety of a language less reserved than our own, ever mention the virtues of the haricot? No; they are absolutely silent concerning the trumpet-voiced vegetable.

The name of the bean is a matter for reflection. It is of an unfamiliar sound, having no affinity with our language. By its unlikeness to our native combinations of sounds, it makes one think of the West Indies or South America, as do caoutchouc and cacao. Does the word as a matter of fact come from the American Indians? Did we receive, together with the vegetable, the name by which it is known in its native country? Perhaps; but how are we to know? Haricot, fantastic haricot, you set us a curious philological problem.

It is also known in French as faséole, or flageolet. The Provençal calls it faioù and favioù; the Catalan, fayol; the Spaniard, faseolo; the Portuguese, feyâo; the Italian, fagiuolo. Here I am on familiar ground: the languages of the Latin family have preserved, with the inevitable modifications, the ancient word faseolus.

Now, if I consult my dictionary I find: faselus, faseolus, phaseolus, haricot. Learned lexicographer, permit me to remark that your translation is incorrect: faselus, faseolus cannot mean haricot. The incontestable proof is in the Georgics, where Virgil tells us at what season we must sow the faselus. He says:—

Si vero viciamque seres vilemque faselum ...
Haud obscura cadens mittet tibi signa Bootes;
Incipe, et ad medias sementem extende pruinas.

Nothing is clearer than the precept of the poet who was so admirably familiar with all matters agricultural; the sowing of the faselus must be commenced when the constellation of Bootes disappears at the set of sun, that is, in October; and it is to be continued until the middle of the winter.

These conditions put the haricot out of the running: it is a delicate plant, which would never survive the lightest frost. Winter would be fatal to it, even under Italian skies. More refractory to cold on account of the country of their origin, peas, broad beans, and vetches, and other leguminous plants have nothing to fear from an autumn sowing, and prosper during the winter provided the climate be fairly mild.

What then is represented by the faselus of the Georgics, that problematical vegetable which has transmitted its name to the haricot in the Latin tongues? Remembering that the contemptuous epithet vilis is used by the poet in qualification, I am strongly inclined to regard it as the cultivated vetch, the big square pea, the little-valued jaïsso of the Provençal peasant.

The problem of the haricot stood thus, almost elucidated by the testimony of the insect world alone, when an unexpected witness gave me the last word of the enigma. It was once again a poet, and a famous poet, M. José-Maria de Heredia, who came to the aid of the naturalist. Without suspecting the service he was rendering, a friend of mine, the village schoolmaster, lent me a magazine[9] in which I read the following conversation between the master-sonneteer and a lady journalist, who was anxious to know which of his own works he preferred.

"What would you have me say?" said the poet.

"I do not know what to say, I do not know which sonnet I prefer; I have taken horrible pains with all of them.... But you, which do you prefer?"

"My dear master, how can I choose out of so many jewels, when each one is perfect in its beauty? You flash pearls, emeralds, and rubies before my astonished eyes: how should I decide to prefer the emerald to the pearl? I am transported by admiration of the whole necklace."

"Well, as for me, there is something I am more proud of than of all my sonnets, and which has done much more for my reputation than my verses."

I opened my eyes wide, "What is that?" I asked. The master looked at me mischievously; then, with that beautiful light in his eyes which fires his youthful countenance, he said triumphantly—

"It is my discovery of the etymology of the word haricot!"

I was so amazed that I forgot to laugh.

"I am perfectly serious in telling you this."

"I know, my dear master, of your reputation for profound scholarship: but to imagine, on that account, that you were famed for your discovery of the etymology of haricot—I should never have expected it! Will you tell me how you made the discovery?"

"Willingly. See now: I found some information respecting the haricot while studying that fine seventeenth-century work of natural history by Hernandez: De Historia plantarum novi orbis. The word haricot was unknown in France until the seventeenth century: people used the word feve or phaséol: in Mexican, ayacot. Thirty species of haricot were cultivated in Mexico before the conquest. They are still known as ayacot, especially the red haricot, spotted with black or violet. One day at the house of Gaston Paris I met a famous scholar. Hearing my name, he rushed at me and asked if it was I who had discovered the etymology of the word haricot. He was absolutely ignorant of the fact that I had written verses and published the Trophées."—

A very pretty whim, to count the jewellery of his famous sonnets as second in importance to the nomenclature of a vegetable! I in my turn was delighted with his ayacot. How right I was to suspect the outlandish word of American Indian origin! How right the insect was, in testifying, in its own fashion, that the precious bean came to us from the New World! While still retaining its original name—or something sufficiently like it—the bean of Montezuma, the Aztec ayacot, has migrated from Mexico to the kitchen-gardens of Europe.

But it has reached us without the company of its licensed consumer; for there must assuredly be a weevil in its native country which levies tribute on its nourishing tissues. Our native bean-eaters have mistaken the stranger; they have not had time as yet to grow familiar with it, or to appreciate its merits; they have prudently abstained from touching the ayacot, whose novelty awoke suspicion. Until our own days the Mexican bean remained untouched: unlike our other leguminous seeds, which are all eagerly exploited by the weevil.

This state of affairs could not last. If our own fields do not contain the insect amateur of the haricot the New World knows it well enough. By the road of commercial exchange, sooner or later some worm-eaten sack of haricots must bring it to Europe. The invasion is inevitable.

According to documents now before me, indeed, it has already taken place. Three or four years ago I received from Maillane, in the Bouches-du-Rhône, what I sought in vain in my own neighbourhood, although I questioned many a farmer and housewife, and astonished them by my questions. No one had ever seen the pest of the haricot; no one had ever heard of it. Friends who knew of my inquiries sent me from Maillane, as I have said, information that gave great satisfaction to my naturalist's curiosity. It was accompanied by a measure of haricots which were utterly and outrageously spoiled; every bean was riddled with holes, changed into a kind of sponge. Within them swarmed innumerable weevils, which recalled, by their diminutive size, the lentil-weevil, Bruchus lenti.

The senders told me of the loss experienced at Maillane. The odious little creature, they said, had destroyed the greater portion of the harvest. A veritable plague, such as had never before been known, had fallen upon the haricots, leaving the housewife barely a handful to put in the saucepan. Of the habits of the creature and its way of going to work nothing was known. It was for me to discover them by means of experiment.

Quick, then, let us experiment! The circumstances favour me. We are in the middle of June, and in my garden there is a bed of early haricots; the black Belgian haricots, sown for use in the kitchen. Since I must sacrifice the toothsome vegetable, let us loose the terrible destroyer on the mass of verdure. The development of the plant is at the requisite stage, if I may go by what the Bruchus pisi has already taught me; the flowers are abundant, and the pods are equally so; still green, and of all sizes.

I place on a plate two or three handfuls of the infested haricots, and set the populous heap in the full sunlight by the edge of my bed of beans. I can imagine what will happen. Those insects which are already free, and those which the stimulus of the sunshine will presently liberate, will emerge and take to their wings. Finding the maternal haricot close at hand they will take possession of the vines. I shall see them exploring pods and flowers, and before very long they will lay their eggs. That is how the pea-weevil would behave under similar conditions.

But no: to my surprise and confusion, matters do not fall out as I foresaw. For a few minutes the insects bustle about in the sunlight, opening and closing their wing-covers to ease the mechanism of flight; then one by one they fly away, mounting in the luminous air; they grow smaller and smaller to the sight, and are quickly lost to view. My persevering attentions have not met with the slightest success; not one of the weevils has settled on my haricots.

When the joys of liberty have been tasted will they return—to-night, to-morrow, or later? No, they do not return. All that week, at favourable hours, I inspect the rows of beans pod by pod, flower by flower; but never a Bruchus do I see, nor even an egg. Yet the season is propitious, for at this very moment the mothers imprisoned in my jars lay a profusion of eggs upon the dry haricots.

Next season I try again. I have at my disposal two other beds, which I have sown with the late haricot, the red haricot; partly for the use of the household, but principally for the benefit of the weevil. Arranged in convenient rows, the two crops will be ready, one in August and one in September or later.

With the red haricot I repeat the experiment already essayed with the black haricot. On several occasions, in suitable weather, I release large numbers of weevils from my glass jars, the general headquarters of the tribe. On each occasion the result is plainly negative. All through the season, until both crops are exhausted, I repeat my search almost daily; but I can never discover a single pod infested, nor even a single weevil perching on leaf or flower.

Certainly the inspection has not been at fault. The household is warned to respect certain rows of beans which I have reserved for myself. It is also requested to keep a look-out for eggs on all the pods gathered. I myself examine with a magnifying-glass all the haricots coming from my own or from neighbouring gardens before handing them over to the housewife to be shelled. All my trouble is wasted: there is not an egg to be seen.

To these experiments in the open air I add others performed under glass. I place, in some tall, narrow bottles, fresh haricot pods hanging from their stems; some green, others mottled with crimson, and containing seeds not far from mature. Each bottle is finally given a population of weevils. This time I obtain some eggs, but I am no further advanced; they are laid on the sides of the bottles, but not on the pods. Nevertheless, they hatch. For a few days I see the grubs wandering about, exploring the pods and the glass with equal zeal. Finally one and all perish without touching the food provided.

The conclusion to be drawn from these facts is obvious: the young and tender haricot is not the proper diet. Unlike the Bruchus pisi, the female of the haricot-weevil refuses to trust her family to beans that are not hardened by age and desiccation; she refused to settle on my bean-patch because the food she required was not to be found there. What does she require? Evidently the mature, dry, hard haricot, which falls to earth with the sound of a small pebble. I hasten to satisfy her. I place in the bottles some very mature, horny pods, thoroughly desiccated by exposure to the sun. This time the family prospers, the grubs perforate the dry shell, reach the beans, penetrate them, and henceforth all goes well.

To judge by appearances, then, the weevil invades the granary. The beans are left standing in the fields until both plants and pods, shrivelled by the sun, are completely desiccated. The process of beating the pods to loosen and separate the beans is thus greatly facilitated. It is then that the weevil, finding matters to suit her, commences to lay her eggs. By storing his crop a little late the peasant stores the pest as well.

But the weevil more especially attacks the haricot when warehoused. Like the Calander-beetle, which nibbles the wheat in our granaries but despises the cereal while still on the stalk, it abhors the bean while tender, and prefers to establish itself in the peace and darkness of the storehouse. It is a formidable enemy to the merchant rather than to the peasant.

What a fury of destruction once the ravager is installed in the vegetable treasure-house! My bottles give abundant evidence of this. One single haricot bean shelters a numerous family; often as many as twenty members. And not one generation only exploits the bean, but three or four in the year. So long as the skin of the bean contains any edible matter, so long do new consumers establish themselves within it, so that the haricot finally becomes a mere shell stuffed with excreta. The skin, despised by the grubs, is a mere sac, pierced with holes as many as the inhabitants that have deserted it; the ruin is complete.

The Bruchus pisi, a solitary hermit, consumes only so much of the pea as will leave a cell for the nymph; the rest remains intact, so that the pea may be sown, or it will even serve as food, if we can overcome our repugnance. The American insect knows nothing of these limitations; it empties the haricot completely and leaves a skinful of filth that I have seen the pigs refuse. America is anything but considerate when she sends us her entomological pests. We owe the Phylloxera to America; the Phylloxera, that calamitous insect against which our vine-growers wage incessant war: and to-day she is sending us the haricot-weevil, which threatens to be a plague of the future. A few experiments gave me some idea of the peril of such an invasion.

For nearly three years there have stood, on my laboratory table, some dozens of jars and bottles covered with pieces of gauze which prevent escape while permitting of a constant ventilation. These are the cages of my menagerie. In them I rear the haricot-weevil, varying the system of education at will. Amongst other things I have learned that this insect, far from being exclusive in its choice, will accommodate itself to most of our leguminous foods.

All the haricots suit it, black and white, red and variegated, large and small; those of the latest crop and those which have been many years in stock and are almost completely refractory to boiling water. The loose beans are attacked by preference, as being easier to invade, but when the loose beans are not available those in the natural shelter of their pods are attacked with equal zest. However dry and parchment-like the pods, the grubs have no difficulty in attaining the seeds. When attacked in the field or garden, the bean is attacked in this way through the pod. The bean known in Provence as the blind haricot—lou faioù borgné—a bean with a long pod, which is marked with a black spot at the navel, which has the look of a closed and blackened eye, is also greatly appreciated; indeed, I fancy my little guests show an obvious preference for this particular bean.

So far, nothing abnormal; the Bruchus does not wander beyond the limits of the botanical family Phaseolus. But here is a characteristic that increases the peril, and shows us this lover of beans in an unexpected light. Without the slightest hesitation it accepts the dry pea, the bean, the vetch, the tare, and the chick-pea; it goes from one to the other, always satisfied; its offspring live and prosper in all these seeds as well as in the haricot. Only the lentil is refused, perhaps on account of its insufficient volume. The American weevil is a formidable experimentalist.

The peril would be much greater did the insect pass from leguminous seeds to cereals, as at first I feared it might. But it does not do so; imprisoned in my bottles together with a handful of wheat, barley, rice, or maize, the Bruchus invariably perished and left no offspring. The result was the same with oleaginous seeds: such as castor-oil and sunflower. Nothing outside the bean family is of any use to the Bruchus. Thus limited, its portion is none the less considerable, and it uses and abuses it with the utmost energy. The eggs are white, slender, and cylindrical. There is no method in their distribution, no choice in their deposition. The mother lays them singly or in little groups, on the walls of the jar as well as on the haricots. In her negligence she will even lay them on maize, coffee, castor-oil seeds, and other seeds, on which the newly born grubs will promptly perish, not finding them to their taste. What place has maternal foresight here? Abandoned no matter where in the heap of seeds, the eggs are always in place, as it is left to the grub to search and to find the points of invasion.

In five days at most the egg is hatched. A little white creature with a red-brown head emerges. It is a mere speck of a creature, just visible to the naked eye. Its body is thickened forward, to give more strength to its implements—its mandibles—which have to perforate the hard substance of the dry bean, which is as tough as wood. The larvæ of the Buprestis and the Capricornis, which burrow in the trunks of trees, are similarly shaped. Directly it issues from the egg the wriggling creature makes off at random with an activity we should hardly expect in one so young. It wanders hither and thither, eager to find food and shelter as soon as possible.

Within twenty-four hours it has usually attained both. I see the tiny grub perforate the horny skin that covers the cotyledons; I watch its efforts; I surprise it sunk half-way in the commencement of a burrow, at the mouth of which is a white floury powder, the waste from the mandibles. It works its way inward and buries itself in the heart of the seed. It will emerge in the adult form in the course of about five weeks, so rapid is its evolution.

This hasty development allows of several generations in the year. I have recorded four. On the other hand, one isolated couple has furnished me with a family of eighty. Consider only the half of this number—supposing the sexes to be equal in number—and at the end of a year the couples issued from this original pair would be represented by the fortieth power of forty; in larvæ they would represent the frightful total of more than five millions. What a mountain of haricots would be ravaged by such a legion!

The industry of the larvæ reminds us at every point what we have learned from the Bruchus pisi. Each grub excavates a lodging in the mass of the bean, respecting the epidermis, and preparing a circular trap-door which the adult can easily open with a push at the moment of emergence. At the termination of the larval phase the lodgements are betrayed on the surface of the bean by so many shadowy circles. Finally the lid falls, the insect leaves its cell, and the haricot remains pierced by as many holes as it has nourished grubs.

Extremely frugal, satisfied with a little farinaceous powder, the adults seem by no means anxious to abandon the native heap or bin so long as there are beans untouched. They mate in the interstices of the heap; the mothers sow their eggs at random; the young larvæ establish themselves some in beans that are so far intact, some in beans which are perforated but not yet exhausted; and all through the summer the operations of breeding are repeated once in every five weeks. The last generation of the year—that of September or October—sleeps in its cells until the warm weather returns.

If the haricot pest were ever to threaten us seriously it would not be very difficult to wage a war of extermination against it. Its habits teach us what tactics we ought to follow. It exploits the dried and gathered crop in the granary or the storehouse. If it is difficult to attack it in the open it would also be useless. The greater part of its affairs are managed elsewhere, in our storehouses. The enemy establishes itself under our roof and is ready to our hand. By means of insecticides defence should be relatively easy

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