THE WHITE-FACED DECTICUS: HIS HABITS

The Life of the Grasshopper by Jean-Henri Fabre, is part of the HackerNoon Books Series. You can jump to any chapter in this book here. THE WHITE-FACED DECTICUS: HIS HABITS

CHAPTER XI. THE WHITE-FACED DECTICUS: HIS HABITS

The White-faced Decticus (D. albifrons, Fabr.) stands at the head of the Grasshopper clan in my district, both as a singer and as an insect of imposing presence. He has a grey costume, a pair of powerful mandibles and a broad ivory face. Without being plentiful, he does not let himself be sought in vain. In the height of summer we find him hopping in the long grass, especially at the foot of the sunny rocks where the turpentine-tree takes root.

At the end of July I start a Decticus-menagerie. As a vivarium I adopt a big wire-gauze cover standing on a bed of sifted earth. The population numbers a dozen; and both sexes are equally represented.

The question of victuals perplexes me for some time. It seems as though the regulation diet ought to be a vegetable one, to judge by the Locust, who consumes any [212]green thing. I therefore offer my captives the tastiest and tenderest garden-stuff that my enclosure holds: leaves of lettuce, chicory and corn-salad. The Dectici scarcely touch it with a contemptuous tooth. It is not the food for them.

Perhaps something tough would suit their strong mandibles better. I try various Graminaceæ, including the glaucous panic-grass, the miauco of the Provençal peasant, the Setaria glauca of the botanists, a weed that infests the fields after the harvest. The panic-grass is accepted by the hungry ones, but it is not the leaves that they devour: they attack only the ears, of which they crunch the still tender seeds with visible satisfaction. The food is found, at least for the time being. We shall see later.

In the morning, when the rays of the sun visit the cage placed in the window of my study, I serve out the day’s ration, a sheaf of green spikes of common grass picked outside my door. The Dectici come running up to the handful, gather round it and, very peaceably, without quarrelling among themselves, dig with their mandibles between the bristles of the spikes to extract and nibble the unripe seeds. Their costume makes one [213]think of a flock of Guinea-fowl pecking the grain scattered by the farmer’s wife. When the spikes are robbed of their tender seeds, the rest is scorned, however urgent the claims of hunger may be.

To break the monotony of the diet as much as is possible in these dog-days, when everything is burnt up, I gather a thick-leaved, fleshy plant which is not too sensitive to the summer heat. This is the common purslane, another invader of our garden-beds. The new green stuff meets with a good reception; and once again the Dectici dig their teeth not into the leaves and the juicy stalks, but only into the swollen capsules of half-formed grains.

This taste for tender seeds surprises me: δηκτικός, biting, fond of biting, the lexicon tells us. A name that expresses nothing, a mere identification-number, is able to satisfy the nomenclator; in my opinion, if the name possesses a characteristic meaning and at the same time sounds well, it is all the better for it. Such is the case here. The Decticus is eminently an insect given to biting. Mind your finger if the sturdy Grasshopper gets hold of it: he will rip it till the blood comes.

And can this powerful jaw, of which I [214]have to beware when I handle the creature, possess no other function than to chew soft grains? Can a mill like this have only to grind little unripe seeds? Something has escaped me. So well-armed with mandibular pincers, so well-endowed with masticatory muscles that swell out his cheeks, the Decticus must cut up some leathery prey.

This time I find the real diet, the fundamental if not the exclusive one. Some good-sized Locusts are let into the cage. I put in it the species mentioned in a note below,1 now one, now the other, as they happen to get caught in my net. A few Grasshoppers2 are also accepted, but not so readily. There is every reason to think that, if I had had the luck to capture them, the entire Locust and Grasshopper family would have met the same fate, provided that they were not too insignificant in size.

Any fresh meat tasting of Locust or Grasshopper suits my ogres. The most frequent victim is the Blue-winged Locust. [215]There is a deplorably large consumption of this species in the cage. This is how things happen: as soon as the game is introduced, an uproar ensues in the mess-room, especially if the Dectici have been fasting for some time. They stamp about and, hampered by their long shanks, dart forward clumsily; the Locusts make desperate bounds, rush to the top of the cage and there hang on, out of the reach of the Grasshopper, who is too stout to climb so high. Some are seized at once, as soon as they enter. The others, who have taken refuge up in the dome, are only postponing for a little while the fate that awaits them. Their turn will come; and that soon. Either because they are tired or because they are tempted by the green stuff below, they will come down; and the Dectici will be after them immediately.

Speared by the hunter’s fore-legs, the game is first wounded in the neck. It is always there, behind the head, that the Locust’s shell cracks first of all; it is always there that the Decticus probes persistently before releasing his hold and taking his subsequent meals off whatever joint he chooses.

It is a very judicious bite. The Locust is hard to kill. Even when beheaded, he goes [216]on hopping. I have seen some who, though half-eaten, kick out desperately and succeed, with a supreme effort, in releasing themselves and jumping away. In the brushwood, that would be so much game lost.

The Decticus seems to know all about it. To overcome his prey, so prompt to escape by means of its two powerful levers, and to render it helpless as quickly as possible, he first munches and extirpates the cervical ganglia, the main seat of innervation. Is this an accident, in which the assassin’s choice plays no part? No, for I see the murder performed invariably in the same way when the prey is in possession of its full strength; and again no, because, when the Locust is offered in the form of a fresh corpse, or when he is weak, dying, incapable of defence, the attack is made anywhere, at the first spot that presents itself to the assailant’s jaws. In such cases the Decticus begins either with a haunch, the favourite morsel, or with the belly, back or chest. The preliminary bite in the neck is reserved for difficult occasions.

This Grasshopper, therefore, despite his dull intellect, possesses the art of killing scientifically of which we have seen so many [217]instances elsewhere;3 but with him it is a rude art, falling within the knacker’s rather than the anatomist’s domain.

Two or three Blue-winged Locusts are none too many for a Decticus’ daily ration. It all goes down, save the wings and wing-cases, which are disdained as too tough. In addition, there is a snack of tender millet-grains stolen every now and again to make a change from the banquet of game. They are big eaters, are my boarders; they surprise me with their gormandizing and even more with their easy change from an animal to a vegetable diet.

With their accommodating and anything but particular stomachs, they could render some slight service to agriculture, if there were more of them. They destroy the Locusts, many of whom, even in our fields, are of ill fame; and they nibble, amid the unripe corn, the seeds of a number of plants which are obnoxious to the husbandman.

But the Decticus’ claim to the honours of the vivarium rests upon something much better than his feeble assistance in preserving the fruits of the earth: in his song, his nuptials [218]and his habits we have a memorial of the remotest times.

How did the insect’s ancestors live, in the palæozoic age? They had their crude and uncouth side, banished from the better-proportioned fauna of to-day; we catch a vague glimpse of habits now almost out of use. It is unfortunate for our curiosity that the fossil remains are silent on this magnificent subject.

Luckily we have one resource left, that of consulting the successors of the prehistoric insects. There is reason to believe that the Locustids4 of our own period have retained an echo of the ancient customs and can tell us something of the manners of olden time. Let us begin by questioning the Decticus.

In the vivarium the sated herd are lying on their bellies in the sun and blissfully digesting their food, giving no other sign of life than a gentle swaying of the antennæ. It is the hour of the after-dinner nap, the hour of enervating heat. From time to time a male gets up, strolls solemnly about, raises his wing-cases slightly and utters an occasional [219]tick-tick. Then he becomes more animated, hurries the pace of his tune and ends by grinding out the finest piece in his repertoire.

Is he celebrating his wedding? Is his song an epithalamium? I will make no such statement, for his success is poor if he is really making an appeal to his fair neighbours. Not one of his group of hearers gives a sign of attention. Not a female stirs, not one moves from her comfortable place in the sun. Sometimes the solo becomes a concerted piece sung by two or three in chorus. The multiple invitation succeeds no better. True, their impassive ivory faces give no indication of their real feelings. If the suitors’ ditty indeed exercises any sort of seduction, no outward sign betrays the fact.

According to all appearances, the clicking is addressed to heedless ears. It rises in a passionate crescendo until it becomes a continuous rattle. It ceases when the sun vanishes behind a cloud and starts afresh when the sun shows itself again; but it leaves the ladies indifferent.

She who was lying with her shanks outstretched on the blazing sand does not change her position; her antennary threads [220]give not a quiver more and not a quiver less; she who was gnawing the remains of a Locust does not let go the morsel, does not lose a mouthful. To look at those heartless ones, you would really say that the singer was making a noise for the mere pleasure of feeling himself alive.

It is a very different matter when, towards the end of August, I witness the start of the wedding. The couple finds itself standing face to face quite casually, without any lyrical prelude whatever. Motionless, as though turned to stone, with their foreheads almost touching, the two exchange caresses with their long antennæ, fine as hairs. The male seems somewhat preoccupied. He washes his tarsi; with the tips of his mandibles he tickles the soles of his feet. From time to time he gives a stroke of the bow: tick; no more.

Yet one would think that this was the very moment at which to make the most of his strong points. Why not declare his flame in a fond couplet, instead of standing there, scratching his feet? Not a bit of it. He remains silent in front of the coveted bride, herself impassive.

The interview, a mere exchange of greetings [221]between friends of different sexes, does not last long. What do they say to each other, forehead to forehead? Not much, apparently, for soon they separate with nothing further; and each goes his way where he pleases.

Next day, the same two meet again. This time, the song, though still very brief, is in a louder key than on the day before, while being still very far from the burst of sound to which the Decticus will give utterance long before the pairing. For the rest, it is a repetition of what I saw yesterday: mutual caresses with the antennæ, which limply pat the well-rounded sides.

The male does not seem greatly enraptured. He again nibbles his foot and seems to be reflecting. Alluring though the enterprise may be, it is perhaps not unattended with danger. Can there be a nuptial tragedy here, similar to that which the Praying Mantis has shown us? Can the business be exceptionally grave? Have patience and you shall see. For the moment, nothing more happens.

A few days later, a little light is thrown upon the subject. The male is underneath, lying flat on the sand and towered over by [222]his powerful spouse, who, with her sabre exposed, standing high on her hind-legs, overwhelms him with her embrace. No, indeed: in this posture the poor Decticus has nothing of the victor about him! The other, brutally, without respecting the musical-box, is forcing open his wing-cases and nibbling his flesh just where the belly begins.

Which of the two takes the initiative here? Have not the parts been reversed? She who is usually provoked is now the provoker, employing rude caresses capable of carrying off the morsel touched. She has not yielded to him; she has thrust herself upon him, disturbingly, imperiously. He, lying flat on the ground, quivers and starts, seems trying to resist. What outrageous thing is about to happen? I shall not know to-day. The floored male releases himself and runs away.

But this time, at last, we have it. Master Decticus is on the ground, tumbled over on his back. Hoisted to the full height of her shanks, the other, holding her sabre almost perpendicular, covers her prostrate mate from a distance. The two ventral extremities curve into a hook, seek each other, meet; and soon from the male’s convulsive loins there [223]is seen to issue, in painful labour, something monstrous and unheard-of, as though the creature were expelling its entrails in a lump.

It is an opalescent bag, similar in size and colour to a mistletoe-berry, a bag with four pockets marked off by faint grooves, two larger ones above and two smaller ones below. In certain cases the number of cells increases and the whole assumes the appearance of a packet of eggs such as Helix aspersa, the Common Snail, lays in the ground.

The strange concern remains hanging from the lower end of the sabre of the future mother, who solemnly retires with the extraordinary wallet, the spermatophore, as the physiologists call it, the source of life for the ovules, in other words the cruet which will now in due course transmit to the proper place the necessary complement for the evolution of the germs.

A capsule of this kind is a rare, an infinitely rare thing in the world of to-day. So far as I know, the Cephalopods5 and the Scolopendras6 are, in our time, the only [224]other animals that make use of the queer apparatus. Now Octopuses and Millepedes date back to the earliest ages. The Decticus, another representative of the old world, seems to tell us that what is a curious exception now might well have been a more or less general rule originally, all the more so as we shall come upon similar incidents in the case of the other Grasshoppers.

When the male has recovered from his shock, he shakes the dust off himself and once more begins his merry click-clack. For the present let us leave him to his joys and follow the mother that is to be, pacing along solemnly with her burden, which is fastened with a plug of jelly as transparent as glass.

At intervals she draws herself up on her shanks, curls into a ring and seizes her opalescent load in her mandibles, nibbling it calmly and squeezing it, but without tearing the wrapper or shedding any of the contents. Each time, she removes from the surface a particle which she chews and then chews again slowly, ending by swallowing it.

This process is continued for twenty minutes or so. Then the capsule, now drained, is torn off in a single piece, all but the jelly plug at the end. The huge, sticky [225]mass is not let go for a moment, but is munched, ground and kneaded by the insect’s mandibles and at last gulped down whole.

At first I looked upon the horrible banquet as no more than an individual aberration, an accident: the Decticus’ behaviour was so extraordinary; no other instance of it was known to me. But I have had to yield to the evidence of the facts. Four times in succession I surprised my captives dragging their wallet and four times I saw them soon tear it, work at it solemnly with their mandibles for hours on end and finally gulp it down. It is therefore the rule: when its contents have reached their destination, the fertilizing capsule, possibly a powerful stimulant, an unparalleled dainty, is chewed, enjoyed and swallowed.

If this, as we are entitled to believe, is a relic of ancient manners, we must admit that the insect of old had singular customs. Réaumur tells us of the startling operations of the Dragon-flies when pairing. This again is a nuptial eccentricity of primeval times.

When the Decticus has finished her strange feast, the end of the apparatus still remains in its place, the end whose most visible [226]part consists of two crystalline nipples the size of pepper-corns. To rid itself of this plug, the insect assumes a curious attitude. The ovipositor is driven half-way into the earth, perpendicularly. That will be the prop. The long hind-legs straighten out, raise the creature as high as possible and form a tripod with the sabre.

Then the insect again curves itself into a complete circle and, with its mandibles, crumbles to atoms the end of the apparatus, consisting of a plug of clearest jelly. All these remnants are scrupulously swallowed. Not a scrap must be lost. Lastly, the ovipositor is washed, wiped, smoothed with the tips of the palpi. Everything is put in order again; nothing remains of the cumbrous load. The normal pose is resumed and the Decticus goes back to pilfering the ears of millet.

To return to the male. Limp and exhausted, as though shattered by his exploit, he remains where he is, all shrivelled and shrunk. He is so motionless that I believe him dead. Not a bit of it! The gallant fellow recovers his spirits, picks himself up, polishes himself and goes off. A quarter of an hour later, when he has taken a few mouthfuls, [227]behold him stridulating once more. The tune is certainly lacking in spirit. It is far from being as brilliant or prolonged as it was before the wedding; but, after all, the poor old crock is doing his best.

Can he have any further amorous pretensions? It is hardly likely. Affairs of that kind, calling for ruinous expenditure, are not to be repeated: it would be too much for the works of the organism. Nevertheless, next day and every day after, when a diet of Locusts has duly renewed his strength, the Decticus scrapes his bow as noisily as ever. He might be a novice, instead of a glutted veteran. His persistence surprises me.

If he be really singing to attract the attention of his fair neighbours, what would he do with a second wife, he who has just extracted from his paunch a monstrous wallet in which all life’s savings were accumulated? He is thoroughly used up. No, once more, in the big Grasshopper these things are too costly to be done all over again. To-day’s song, despite its gladness, is certainly no epithalamium.

And, if you watch him closely, you will see that the singer no longer responds to the [228]teasing of the passers’ antennæ. The ditties become fainter from day to day and occur less frequently. In a fortnight the insect is dumb. The dulcimer no longer sounds, for lack of vigour in the player.

At last the decrepit Decticus, who now scarcely touches food, seeks a peaceful retreat, sinks to the ground exhausted, stretches out his shanks in a last throe and dies. As it happens, the widow passes that way, sees the deceased and, breathing eternal remembrance, gnaws off one of his thighs.

The Green Grasshopper behaves similarly. A couple isolated in a cage are subjected to a special watch. I am present at the end of the pairing, when the future mother is carrying, fixed to the point of her sword, the pretty raspberry which will occupy our attention later.7 Debilitated by recent happenings, the male at this moment is mute. Next day, his strength returns; and you hear him singing as ardently as ever. He stridulates while the mother is scattering her eggs over the ground; he goes on making a noise long after the laying is done and when nothing more is wanted to perpetuate the race.[229]

It is quite clear that this persistent singing has not an amorous appeal for its object: by this time, all of that is over, quite over. Lastly, one day or another, life fails and the instrument is dumb. The eager singer is no more. The survivor gives him a funeral copied from that of the Decticus: she devours the best bits of him. She loved him so much that she had to eat him up.

These cannibal habits recur in most of the Grasshopper tribe, without however equalling the atrocities of the Praying Mantis, who treats her lovers as dead game while they are still full of life. The Decticus mother, the Green Grasshopper and the rest at least wait until the poor wretches are dead.

I will except the Ephippiger, who is so meek in appearance. In my cage, when laying-time is at hand, she has no scruples about taking a bite at her companions, without possessing the excuse of hunger. Most of the males end in this lamentable fashion, half-devoured. The mutilated victim protests; he would rather, he could indeed go on living. Having no other means of defence, he produces with his bow a few grating sounds which this time decidedly are not a nuptial song. Dying with a great hole in his belly, he utters his [230]plaint in a like manner as though he were rejoicing in the sun. His instrument strikes the same note whether it express sorrow or gladness.

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