Chapter XVIII. Insects and Mushrooms

Jean-Henri Fabre The Life of the Fly

Rove beetle

Rove beetle (Staphylinidae)

It were out of place to recall my long relations with the bolete and the agaric if the insect did not here enter into a question of grave interest. Several mushrooms are edible, some even enjoy a great reputation; others are formidable poisons. Short of botanical studies that are not within everybody's reach, how are we to distinguish the harmless from the venomous? There is a widespread belief which says that any mushroom which insects, or, more frequently, their larvae, their grubs, accept can be accepted without fear; any mushroom which they refuse must be refused. What is wholesome food for them cannot fail to be the same for us; what is poisonous to them is bound to be equally baneful to ourselves. This is how people argue, with apparent logic, but without reflecting upon the very different capabilities of stomachs in the matter of diet. After all, may there not be some justification for the belief? That is what I purpose examining.

The insect, especially in the larval stage, is the principal devourer of the mushroom. We must distinguish between two groups of consumers. The first really eat, that is to say, they break their food into little bits, chew it and reduce it to a mouthful which is swallowed just as it is; the second drink, after first turning their food into a broth, like the bluebottles. The first are the less numerous. Confining myself to the results of my observations in the neighborhood, I count, all told, in the group of chewers, four beetles and a moth caterpillar. To these may be added the mollusk, as represented by a slug, or, more specifically, an arion, of medium size, brown and adorned with a red edge to his mantle. A modest corporation, when all is said, but active and enterprising, especially the moth.

At the head of the mushroom loving beetles, I will place a Staphylinid (Oxyporus rufus, LIN.), prettily garbed in red, blue and black. Together with his larva, which walks with the aid of a crutch at its back, he haunts the fungus of the poplar (Pholiota aegerita, FRIES). He specializes in an exclusive diet. I often come across him, both in spring and autumn, and never any elsewhere than on this mushroom. For that matter, he had made a wise choice, the epicure! This popular fungus is one of our best mushrooms, despite its color of a doubtful white, its skin which is often wrinkled and its gills soiled with rusty brown at the spores. We must not judge people by appearances, nor mushrooms either. This one, magnificent in shape and color, is poisonous; that other, so poor to look at, is excellent.

Here are two more specialist beetles, both of small size. One is the Triplax (Triplax russica, LIN.), who has an orange head and corselet and black wing-cases. His grub tackles the hispid polyporus (Polyporus hispidus, BULL.), a coarse and substantial dish, bristling at its top with stiff hairs and clinging by its side to the old trunks of mulberry trees, sometimes also of walnut and elm trees. The other is the cinnamon-colored Anisotoma (Anisotoma cinnamomea, PANZ.). His larva lives exclusively in truffles.

The most interesting of the mushroom-eating beetles is the Bolboceras (Bolboceras gallicus, MUL.). I have described elsewhere his manner of living, his little song that sounds like the chirping of a bird, his perpendicular wells sunk in search of an underground mushroom (Hydnocystis orenaria, TUL.), which constitutes his regular nourishment. He is also an ardent lover of truffles. I have taken from between his legs, at the bottom of his manor house, a real truffle the size of a hazelnut (Tuber Requienii, TUL.). I tried to rear him in order to make the acquaintance of his grub; I housed him in a large earthen pan filled with fresh sand and enclosed in a bell cover. Possessing neither hydnocistes nor truffles, I served him up sundry mushrooms of a rather firm consistency, like those of his choice. He refused them all, helvellae and clavariae, chanterelles and pezizae alike.

With a rhizopogon, a sort of little fungoid potato, which is frequent in pine woods at a moderate depth and sometimes even on the surface, I achieved complete success. I had strewn a handful of them on the sand of my breeding pan. At nightfall, I often surprised the Bolboceras issuing from his well, exploring the stretch of sand, choosing a piece not too big for his strength and gently rolling it towards his abode. He would go in again, leaving the rhizopogon, which was too large to take inside, on the threshold, where it served the purpose of a door. Next day, I found the piece gnawed, but only on the under side.

The Bolboceras does not like eating in public, in the open air; he needs the discreet retirement of his crypt. When he fails to find his food by burrowing under ground, he comes up to look for it on the surface. Meeting with a morsel to his taste, he takes it home when its size permits; if not, he leaves it on the threshold of his burrow and gnaws at it from below, without reappearing outside. Up to the present, hydnocistes, truffles and rhizopoga are the only food that I have known him to eat. These three instances tell us at any rate that the Bolboceras is not a specialist like the Oxyporus and the Triplax; he is able to vary his diet; perhaps he feeds on all the underground mushrooms indiscriminately.

The moth enlarges her domain yet further. Her caterpillar is a grub five or six millimeters long, white, with a black shiny head. Colonies of it abound in most mushrooms. It attacks by preference the top of the stem, for epicurean reasons that escape me; thence it spreads throughout the cap. It is the habitual boarder of the boletes, agarics, lactarii and russulie. Apart from certain species and certain groups, everything suits it. This puny grub, which will spin itself an infinitesimal cocoon of white silk under the piece attacked and will later become an insignificant moth, is the primordial ravager.

Let us next mention the arion, that voracious mollusk who also tackles most mushrooms of some size. He digs himself spacious niches inside them and there sits blissfully eating. Few in numbers, compared with the other devourers, he usually sets up house alone. He has, by way of a set of jaws, a powerful plane which creates great breaches in the object of his depredations. It is he whose havoc is most apparent.

Now all these gnawers can be recognized by their leavings, such as crumbs and worm holes. They dig clean passages, they slash and crumble without a slimy trail, they are the pinkers. The others, the liquefiers, are the chemists; they dissolve their food by means of reagents. All are the grubs of flies and belong to the commonalty of the Muscidae. Many are their species. To distinguish them from one another by rearing them in order to obtain the perfect stage would involve a great expenditure of time to little profit. We will describe them by the general name of maggots.

To see them at work, I select, as the field of exploitation, the satanic bolete (Boletus Satanas, LENZ.), one of the largest mushrooms that I can gather in my neighborhood. It has a dirty-white cap; the mouths of the tubes are a bright orange-red; the stem swells into a bulb with a delicate network of carmine veins. I divide a perfectly sound specimen into equal parts and place these in two deep plates, put side by side. One of the halves is left as it is: it will act as a control, a term of comparison. The other half receives on the pores of its undersurface a couple of dozen maggots taken from a second bolete in full process of decomposition.

The dissolving action of the grub asserts itself on the very day whereon these preparations are made. The undersurface, originally a bright red, turns brown and runs in every direction into a mass of dark stalactites. Soon, the flesh of the cap is attacked and, in a few days, becomes a gruel similar to liquid asphalt. It is almost as fluid as water. In this broth the maggots wallow, wriggling their bodies and, from time to time, sticking the breathing holes in their sterns above the water. It is an exact repetition of what the liquefiers of meat, the grubs of the grey flesh fly and the bluebottle, have lately shown us. As for the second half of the bolete, the half which I did not colonize with vermin, it remains compact, the same as it was at the start, except that its appearance is a little withered by evaporation. The fluidity, therefore, is really and truly the work of the grubs and of them alone.

Does this liquefaction imply an easy change? One would think so at first, on seeing how quickly it is performed by the action of the grubs. Moreover, certain mushrooms, the coprini, liquefy spontaneously and turn into a black fluid. One of them bears the expressive name of the inky mushroom (Coprinus atramentarius, BULL.) and dissolves into ink of its own accord. The conversion, in certain cases, is singularly rapid. One day, I was drawing one of our prettiest coprini (Coprinus sterquilinus, FRIES), which comes out of a little purse or volva. My work was barely done, a couple of hours after gathering the fresh mushroom, when the model had disappeared, leaving nothing but a pool of ink upon the table. Had I procrastinated ever so little, I should not have had time to finish and I should have lost a rare and interesting find.

This does not mean that the other mushrooms, especially the boletes, are of ephemeral duration and lacking in consistency. I made the attempt with the edible bolete (Boletus edulis, BULL.), the famous cepe of our kitchens, so highly esteemed for its flavor. I was wondering whether it would not be possible to obtain from it a sort of Liebig's extract of fungus, which would be useful in cooking. With this purpose, I had some of these mushrooms cut into small pieces and boiled, on the one hand, in plain water and, on the other, in water with bicarbonate of soda added. The treatment lasted two whole days. The flesh of the bolete was indomitable. To attack it, I should have had to employ violent drugs, which were inadmissible in view of the result to be attained.

What prolonged boiling and the aid of bicarbonate of soda leave almost intact the fly's grubs quickly turn into fluid, even as the flesh worms fluidify hard-boiled white of egg. This is done in each instance without violence, probably by means of a special pepsin, which is not the same in both cases. The liquefier of meat has its own brand; the liquefier of the bolete has another sort. The plate, then, is filled with a dark, running gruel, not unlike tar in appearance. If we allow evaporation free course, the broth sets, into a hard, easily crumbled slab, something like toffee. Caught in this matrix, grubs and pupa perish, incapable of freeing themselves. Analytical chemistry has proved fatal to them. The conditions are quite different when the attack is delivered on the surface of the ground. Gradually absorbed by the soil, the excess of liquid disappears, leaving the colonists free. In my dishes, it collects indefinitely, killing the inhabitants when it dries up into a solid layer.

The purple bolete (Boletus purpureus, FRIES), when subjected to the action of the maggots, gives the same result as the Satanic bolete, namely, a black gruel. Note that both mushrooms turn blue if broken and especially if crushed. With the edible bolete, whose flesh invariably remains white when cut, the product of its liquefaction by the vermin is a very pale brown. With the oronge, or imperial mushroom, the result is a broth which the eye would take for a thin apricot jam. Tests made with sundry other mushrooms confirm the rule: all, when attacked by the maggot, turn into a more or less fluid mess, which varies in color.

Why do the two boletes with the red tubes, the purple bolete and the satanic bolete, change into a dark gruel? I have an inkling of the reason. Both of them turn blue, with an admixture of green. A third species, the bluish bolete (Boletus cyanescens, BULL., var. lacteus, LEVEILLE), possess remarkable color sensitiveness. Bruise it ever so lightly, no matter where, on the cap, the stem, the tubes of the undersurface: forthwith, the wounded part, originally a pure white, is tinted a beautiful blue. Place this bolete in an atmosphere of carbonic acid gas. We can now knock it, crush it, reduce it to pulp; and the blue no longer shows. But extract a fragment from the crushed mass: immediately, at the first contact with the air, the matter turns a most glorious blue. It reminds us of a process employed in dyeing. The indigo of commerce, steeped in water containing lime and sulfate of iron, or copperas, is deprived of a part of its oxygen; it loses its color and becomes soluble in water, as it was in the original indigo plant, before the treatment which the plant underwent. A colorless liquid results. Expose a drop of this liquid to the air. Straightway, oxidization works upon the product: the indigo is reformed, insoluble and blue.

This is exactly what we see in the boletes that turn blue so readily. Could they, in fact, contain soluble, colorless indigo? One would say so, if certain properties did not give grounds for doubt. When subjected to prolonged exposure to the air, the boletes that are apt to turn blue, particularly the most remarkable, Boletus cyanescens, lose their color, instead of retaining the deep blue which would be a sign of real indigo. Be this as it may, these mushrooms contain a coloring principle which is very liable to change under the influence of the air. Why should we not regard it as the cause of the black tint when the maggots have liquefied the boletes which turn blue? The others, those with the white flesh, the edible bolete, for instance, do not assume this asphalty appearance once they are liquefied by the grubs.

All the boletes that change to blue when broken have a bad reputation; the books treat them as dangerous, or at least open to suspicion. The name of Satanic awarded to one of them is an ample proof of our fears. The caterpillar and the maggot are of another opinion: they greedily devour what we hold in dread. Now here is a strange thing: those passionate devotees of Boletus Satanas absolutely refuse certain mushrooms which we find delightful eating, including the most celebrated of all, the oronge, the imperial mushroom, which the Romans of the empire, past masters in gluttony, called the food of the gods, cibus deorum, the agaric of the Caesars, Agaricus caesareus. It is the most elegant of all our mushrooms. When it prepares to make its appearance by lifting the fissured earth, it is a handsome ovoid formed by the outer wrapper, the volva. Then this purse gently tears and the jagged opening partly reveals a globular object of a magnificent orange. Take a hen's egg, boil it, remove the shell: what remains will be the imperial mushroom in its purse. Remove a part of the white at the top, uncovering a little of the yolk. Then you have the nascent imperial. The likeness is perfect. And so the people of my part, struck by the resemblance, call this mushroom lou rousset d'iou, or, in other words, yolk of egg. Soon, the cap emerges entirely and spreads into a disk softer than satin to the touch and richer to the eye than all the fruit of the Hesperides. Appearing amid the pink heather, it is an entrancing object.

Well, this gorgeous agaric (Amanita caesarea, SCOP.), this food of the gods the maggot absolutely refuses. My frequent examinations have never shown me an imperial attacked by the grubs in the field. It needs imprisonment in a jar and the absence of other victuals to provoke the attempt; and even then the treacle hardly seems to suit them. After the liquefaction, the grubs try to make off, showing that the fare is not to their liking. The Mollusk also, the Arion, is anything but an ardent consumer. Passing close to an imperial mushroom and finding nothing better, he stops and takes a bite, without lingering. If, therefore, we required the evidence of the insect, or even of the Slug, to know which mushrooms are good to eat, we should refuse the best of them all. Though respected by the vermin, the glorious imperial is nevertheless ruined not by larvae, but by a parasitic fungus, the Mycogone rosea, which spreads in a purply stain and turns it into a putrid mass. This is the only despoiler that I know it to possess.

A second amanita, the sheathed amanita (Amanita vaginata, BULL.), prettily streaked on the edges of the cap, is of an exquisite flavor, almost equal to the imperial. It is called lou pichot gris, the grayling, in these parts, because of its coloring, which is usually an ashen gray. Neither the maggot nor the even more enterprising Moth ever touches it. They likewise refuse the mottled amanita (Amanita pantherina, D. C.), the vernal amanita (Amanita verna, FRIES) and the lemon-yellow amanita (Amanita citrina, SCHAEFF.), all three of which are poisonous. In short, whether it be to us a delicious dish or a deadly poison, no amanita is accepted by the grubs. The arion alone sometimes bites at it. The cause of the refusal escapes us. It were vain, speaking of the mottled amanita, for instance, to allege as a reason the presence of an alkaloid fatal to the grubs, for we should have to ask ourselves why the imperial, the amanita of the Caesars, which is wholly free from poison, is rejected no less uncompromisingly than the venomous species. Could it perhaps be lack of relish, a deficiency of seasoning for stimulating the appetite? In point of fact, when eaten raw, the amanitas have no particular flavor.

What shall we learn from the sharper-flavored mushrooms? Here, in the pinewoods, is the woolly milk mushroom (Lactarius torminosus, SCHAEFF.), turned in at the edges and wrapped in a curly fleece. Its taste is biting, worse than Cayenne pepper. Torminosus means colic producing. The name is very suitable. Unless he possessed a stomach built for the purpose, the man who touched such food as this would have a singularly bad time before him. Well, that stomach the vermin possess: they revel in the pungency of the woolly milk mushroom even as the spurge caterpillar browses with delight on the loathsome leaves of the euphorbiae. As for us, we might as well, in either case, eat live coals.

Is a condiment of this kind necessary to the grubs? Not at all. Here, in the same pinewoods, is the „delicious“ milk mushroom (Lactarius deliciosus, LIN.), a glorious orange-red crater, adorned with concentric zones. If bruised, it assumes a verdigris hue, possibly a variant of the indigo tint peculiar to the blue-turning boletes. From its flesh laid bare by being broken or cut ooze blood-red? drops, a well-defined characteristic peculiar to this milk mushroom. Here the violent spices of the woolly milk mushroom disappear; the flesh has a pleasant taste when eaten raw. No matter: the vermin devour the mild milk mushroom with the same zest with which they devour the horribly peppered one. To them the delicate and the strong, the insipid and the peppery are all alike.

The epithet ‚delicious‘ applied to the mushroom whose wound weeps tears of blood is highly exaggerated. It is edible, no doubt, but it is coarse eating and difficult to digest. My household refuses it for cooking purposes. We prefer to put it to soak in vinegar and afterwards to use it as we might use pickled gherkins. The real value of this mushroom is largely overrated thanks to a too laudatory epithet.

Is a certain degree of consistency required, to suit the grubs: something midway between the softness of the amanitas and the firmness of the milk mushrooms? Let us begin by questioning the olive tree agaric or luminous mushroom (Pleurotus phosphoreus, BATT.), a magnificent mushroom colored jujube red. Its popular name is not particularly appropriate. True, it frequently grows at the base of old olive trees, but I also pick it at the foot of the box, the holm oak, the plum tree, the cypress, the almond tree, the Guelder rose and other trees and shrubs. It seems fairly indifferent to the nature of the support. A more remarkable feature distinguishes it from all the other European mushrooms: it is phosphorescent. On the lower surface and there only, it sheds a soft, white gleam, similar to that of the glowworm. It lights up to celebrate its nuptials and the emission of its spores. There is no question of chemist's phos­phorus here. This is a slow combustion, a sort of more active respiration than usual. The luminous emission is extinguished in the unbreathable gases, nitrogen and carbonic acid; it continues in aerated water; it ceases in water deprived of its air by boiling. It is exceedingly faint, however, so much so that it is not perceptible except in the deepest darkness. At night and even by day, if the eyes have been prepared for it by a preliminary wait in the darkness of a cellar, this agaric is a wonderful sight, looking indeed like a piece of the full moon.

Now what do the vermin do? Are they drawn by this beacon? In no wise: maggots, caterpillars and slugs never touch the resplendent mushroom. Let us not be too quick to explain this refusal by the noxious properties of the olive tree agaric, which is said to be extremely poisonous. Here, in fact, on the pebbly ground of the wastelands, is the eryngo agaric (Pleurotus eryngii, D. C.), which has the same consistency as the other. It is the berigoulo of the Provencaux, one of the most highly esteemed mushrooms. Well, the vermin will have none of it: what is a treat to us is detestable to them.

It is superfluous to continue this method of investigation: the reply would be everywhere the same. The insect, which feeds on one sort of mushroom and refuses others, cannot tell us anything about the kinds that are good or bad for us. Its stomach is not ours. It pronounces excellent what we find poisonous; it pronounces poisonous what we think excellent. That being so, when we are lacking in the botanical knowledge which most of us have neither time nor inclination to acquire, what course are we to take? The course is extremely simple.

During the thirty years and more that I have lived at S?rignan, I have never heard of one case of mushroom poisoning, even the mildest, in the village; and yet there are plenty of mushrooms eaten here, especially in autumn. Not a family but, when on a walk in the mountains, gathers a precious addition to its modest alimentary resources. What do these people gather? A little of everything. Often, when rambling in the neighboring woods, I inspect the baskets of the mushroom pickers, who are delighted for me to look. I see things fit to make mycological experts stand aghast. I often find the purple bolete, which is classed among the dangerous varieties. I made the remark one day. The man carrying the basket stared at me in astonishment: ‚That a poison! The wolf‘s bread!' he said, patting the plump bolete with his hand. ‚What an idea! It‘s beef marrow, sir, regular beef marrow!' (1).

He smiled at my apprehensions and went away with a poor opinion of my knowledge in the matter of mushrooms.

In the baskets aforesaid, I find the ringed agaric (Armillaria mellea, FRIES), which is stigmatized as valde venenatus by Persoon, an expert on the subject. It is even the mushroom most frequently made use of, because of its being so plentiful, especially at the foot of the mulberry trees. I find the Satanic bolete, that dangerous tempter; the belted milk mushroom (Lactarius zonarius, BULL.), whose burning flavor rivals the pepper of its woolly kinsman; the smooth-headed amanita (Amanita leiocophala, D. C.), a magnificent white dome rising out of an ample volva and fringed at the edges with floury relics resembling flakes of casein. Its poisonous smell and soapy aftertaste should lead to suspicion of this ivory dome; but nobody seems to mind them.

How, with such careless picking, are accidents avoided? In my village and for a long way around, the rule is to blanch the mushrooms, that is to say, to bring them to the boil in water with a little salt in it. A few rinsings in cold water conclude the treatment. They are then prepared in whatever manner one pleases. In this way, what might at first be dangerous becomes harmless, because the preliminary boiling and rinsing have removed the noxious elements.

My personal experience confirms the efficacy of this rustic method. At home, we very often make use of the ringed agaric, which is reputed extremely dangerous. When rendered wholesome by the ordeal of boiling water, it becomes a dish of which I have naught but good to say. Then again the smooth-headed amanita frequently appears upon my table, after being duly boiled: if it were not first treated in this fashion, it would be hardly safe. I have tried the blue-turning boletes, especially the purple bolete and the Satanic. They answered very well to the eulogistic term of beef marrow applied to them by the mushroom picker who scouted my prudent counsels. I have sometimes employed the mottled amanita, so ill famed in the books, without disastrous result. One of my friends, a doctor, to whom I communicated my ideas about the boiling water treatment, thought that he would make the experiment on his own account. He chose the lemon-yellow amanita, which has as bad a reputation as the mottled variety, and ate it at supper. Everything went off without the slightest inconvenience. Another, a blind friend, in whose company I was one day to taste the Cossus of the Roman epicures, treated himself to the olive tree agaric, said to he so formidable. The dish was, if not excellent, at least harmless.

It results from these facts that a good preliminary boiling is the best safeguard against accidents arising from mushrooms. If the insect, devouring one species and refusing another, cannot guide us in any way, at least rustic wisdom, the fruit of long experience, prescribes a rule of conduct which is both simple and efficacious. You are tempted by a basketful of mushrooms, but you do not feel very sure as to their good or evil properties. Then have them blanched, well and thoroughly blanched. When it leaves the purgatory of the stewpan, the doubtful mushroom can be eaten without fear.

But this, you will tell me, is a system of cookery fit for savages: the treatment with boiling water will reduce the mushrooms to a mash; it will take away all their flavor and all their succulence. That is a complete mistake. The mushroom stands the ordeal exceedingly well. I have described my failure to subdue the cepes when I was trying to obtain an extract from them. Prolonged boiling, with the aid of bicarbonate of soda, so far from reducing them to a mess, left them very nearly intact. The other mushrooms whose size entitles them to culinary consideration offer the same degree of resistance. In the second place, there is no loss of succulence and hardly any of flavor. Moreover, they become much more digestible, which is a most important condition in a dish generally so heavy for the stomach. For this reason, it is the custom, in my family, to treat them one and all with boiling water, including even the glorious imperial.

I am a Philistine, it is true, a barbarian caring little for the refinements of cookery. I am not thinking of the epicure, but of the frugal man, the husbandman especially. I should consider myself amply repaid for my persistent observations if I succeeded in popularizing, however little, the wise Provencal recipe for mushrooms, an excellent food that makes a pleasant change from the dish of beans or potatoes, when we can overcome the difficulty of distinguishing between the harmless and the dangerous.

Recorder's note:

1. Modern mycologists warn against Fabre's claim that boiling neutralizes all mushroom poisons.

Author's note:

1. People use them indiscriminately for cooking purposes, after removing the tubes on the under side, which are easily separated from the rest of the mushroom.

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