Social Life in the Insect World Part 10

It is almost flat on the back, but suddenly folds over at the side, the turn being almost at right angles. This lateral fold encloses the flank of the abdomen and is covered with fine oblique and parallel nervures.

The powerful nervures of the dorsal portion of the wing-cover are of the deepest black, and their general effect is that of a complicated design, not unlike a tangle of Arabic caligraphy.

Seen by transmitted light the wing-cover is of a very pale reddish colour, excepting two large adjacent s.p.a.ces, one of which, the larger and anterior, is triangular in shape, while the other, the smaller and posterior, is oval. Each s.p.a.ce is surrounded by a strong nervure and goffered by slight wrinkles or depressions. These two s.p.a.ces represent the mirror of the locust tribe; they const.i.tute the sonorous area. The substance of the wing-cover is finer here than elsewhere, and shows traces of iridescent though somewhat smoky colour.

These are parts of an admirable instrument, greatly superior to that of the Decticus. The five hundred prisms of the bow biting upon the ridges of the wing-cover opposed to it set all four tympanums vibrating at once; the lower pair by direct friction, the upper pair by the vibration of the wing-cover itself. What a powerful sound results! The Decticus, endowed with only one indifferent "mirror," can be heard only at a few paces; the Cricket, the possessor of four vibratory areas, can be heard at a hundred yards.

The Cricket rivals the Cigale in loudness, but his note has not the displeasing, raucous quality of the latter. Better still: he has the gift of expression, for he can sing loud or soft. The wing-covers, as we have seen, are prolonged in a deep fold over each flank. These folds are the dampers, which, as they are pressed downwards or slightly raised, modify the intensity of the sound, and according to the extent of their contact with the soft abdomen now m.u.f.fle the song to a _mezza voce_ and now let it sound _fortissimo_.

Peace reigns in the cage until the warlike instinct of the mating period breaks out. These duels between rivals are frequent and lively, but not very serious. The two rivals rise up against one another, biting at one another's heads--these solid, fang-proof helmets--roll each other over, pick themselves up, and separate. The vanquished Cricket scuttles off as fast as he can; the victor insults him by a couple of triumphant and boastful chirps; then, moderating his tone, he tacks and veers about the desired one.

The lover proceeds to make himself smart. Hooking one of his antennae towards him with one of his free claws, he takes it between his mandibles in order to curl it and moisten it with saliva. With his long hind legs, spurred and laced with red, he stamps with impatience and kicks out at nothing. Emotion renders him silent. His wing-covers are nevertheless in rapid motion, but are no longer sounding, or at most emit but an unrhythmical rubbing sound.

Presumptuous declaration! The female Cricket does not run to hide herself in the folds of her lettuce leaves; but she lifts the curtain a little, and looks out, and wishes to be seen:--

_Et fugit ad salices, et se cupit ante videri._

She flies towards the brake, but hopes first to be perceived, said the poet of the delightful eclogue, two thousand years ago. Sacred provocations of lovers, are they not in all ages the same?

CHAPTER XI

THE ITALIAN CRICKET

My house shelters no specimens of the domestic Cricket, the guest of bakeries and rustic hearths. But although in my village the c.h.i.n.ks under the hearthstones are mute, the nights of summer are musical with a singer little known in the North. The sunny hours of spring have their singer, the Field-Cricket of which I have written; while in the summer, during the stillness of the night, we hear the note of the Italian Cricket, the _OEcanthus pellucens_, Scop. One diurnal and one nocturnal, between them they share the kindly half of the year. When the Field-Cricket ceases to sing it is not long before the other begins its serenade.

The Italian Cricket has not the black costume and heavy shape characteristic of the family. It is, on the contrary, a slender, weakly creature; its colour very pale, indeed almost white, as is natural in view of its nocturnal habits. In handling it one is afraid of crushing it between the fingers. It lives an aerial existence; on shrubs and bushes of all kinds, on tall herbage and gra.s.ses, and rarely descends to the earth. Its song, the pleasant voice of the calm, hot evenings from July to October, commences at sunset and continues for the greater part of the night.

This song is familiar to all Provencals; for the least patch of thicket or tuft of gra.s.ses has its group of instrumentalists. It resounds even in the granaries, into which the insect strays, attracted thither by the fodder. But no one, so mysterious are the manners of the pallid Cricket, knows exactly what is the source of the serenade, which is often, though quite erroneously, attributed to the common field-cricket, which at this period is silent and as yet quite young.

The song consists of a _Gri-i-i, Gri-i-i_, a slow, gentle note, rendered more expressive by a slight tremor. Hearing it, one divines the extreme tenuity and the amplitude of the vibrating membranes. If the insect is not in any way disturbed as it sits in the low foliage, the note does not vary, but at the least noise the performer becomes a ventriloquist.

First of all you hear it there, close by, in front of you, and the next moment you hear it over there, twenty yards away; the double note decreased in volume by the distance.

You go forward. Nothing is there. The sound proceeds again from its original point. But no--it is not there; it is to the left now--unless it is to the right--or behind.... Complete confusion! It is impossible to detect, by means of the ear, the direction from which the chirp really comes. Much patience and many precautions will be required before you can capture the insect by the light of the lantern. A few specimens caught under these conditions and placed in a cage have taught me the little I know concerning the musician who so perfectly deceives our ears.

The wing-covers are both formed of a dry, broad membrane, diaphanous and as fine as the white skin on the outside of an onion, which is capable of vibrating over its whole area. Their shape is that of the segment of a circle, cut away at the upper end. This segment is bent at a right angle along a strong longitudinal nervure, and descends on the outer side in a flap which encloses the insect's flank when in the att.i.tude of repose.

The right wing-cover overlaps the left. Its inner edge carries, on the under side, near the base, a callosity from which five radiating nervures proceed; two of them upwards and two downwards, while the fifth runs approximately at right angles to these. This last nervure, which is of a slightly reddish hue, is the fundamental element of the musical device; it is, in short, the bow, the fiddlestick, as is proved by the fine notches which run across it. The rest of the wing-cover shows a few more nervures of less importance, which hold the membrane stretched tight, but do not form part of the friction apparatus.

The left or lower wing-cover is of similar structure, with the difference that the bow, the callosity, and the nervures occupy the upper face. It will be found that the two bows--that is, the toothed or indented nervures--cross one another obliquely.

When the note has its full volume, the wing-covers are well raised above the body like a wide gauzy sail, only touching along the internal edges.

The two bows, the toothed nervures, engage obliquely one with the other, and their mutual friction causes the sonorous vibration of the two stretched membranes.

[Ill.u.s.tration: THE ITALIAN CRICKET.]

The sound can be modified accordingly as the strokes of each bow bear upon the callosity, which is itself serrated or wrinkled, or on one of the four smooth radiating nervures. Thus in part are explained the illusions produced by a sound which seems to come first from one point, then from another, when the timid insect is alarmed.

The production of loud or soft resounding or m.u.f.fled notes, which gives the illusion of distance, the princ.i.p.al element in the art of the ventriloquist, has another and easily discovered source. To produce the loud, open sounds the wing-covers are fully lifted; to produce the muted, m.u.f.fled notes they are lowered. When lowered their outer edges press more or less lightly on the soft flanks of the insect, thus diminishing the vibratory area and damping the sound.

The gentle touch of a finger-tip m.u.f.fles the sharp, loud ringing of a gla.s.s tumbler or "musical-gla.s.s" and changes it into a veiled, indefinite sound which seems to come from a distance. The White Cricket knows this secret of acoustics. It misleads those that seek it by pressing the edge of its vibrating membranes to the soft flesh of its abdomen. Our musical instruments have their dampers; that of the _OEcanthus pellucens_ rivals and surpa.s.ses them in simplicity of means and perfection of results.

The Field-Cricket and its relatives also vary the volume of their song by raising or lowering the elytra so as to enclose the abdomen in a varying degree, but none of them can obtain by this method results so deceptive as those produced by the Italian Cricket.

To this illusion of distance, which is a source of perpetually renewed surprise, evoked by the slightest sound of our footsteps, we must add the purity of the sound, and its soft tremolo. I know of no insect voice more gracious, more limpid, in the profound peace of the nights of August. How many times, _per amica silentia lunae_, have I lain upon the ground, in the shelter of a clump of rosemary, to listen to the delicious concert!

The nocturnal Cricket sings continually in the gardens. Each tuft of the red-flowered cistus has its band of musicians, and each bush of fragrant lavender. The shrubs and the terebinth-trees contain their orchestras.

With its clear, sweet voice, all this tiny world is questioning, replying, from bush to bush, from tree to tree; or rather, indifferent to the songs of others, each little being is singing his joys to himself alone.

Above my head the constellation of Cygnus stretches its great cross along the Milky Way; below, all around me, palpitates the insect symphony. The atom telling of its joys makes me forget the spectacle of the stars. We know nothing of these celestial eyes which gaze upon us, cold and calm, with scintillations like the blinking of eyelids.

Science tells us of their distance, their speeds, their ma.s.ses, their volumes; it burdens us with stupendous numbers and stupefies us with immensities; but it does not succeed in moving us. And why? Because it lacks the great secret: the secret of life. What is there, up there?

What do these suns warm? Worlds a.n.a.logous to ours, says reason; planets on which life is evolving in an endless variety of forms. A superb conception of the universe, but after all a pure conception, not based upon patent facts and infallible testimony at the disposal of one and all. The probable, even the extremely probable, is not the obvious, the evident, which forces itself irresistibly and leaves no room for doubt.

But in your company, O my Crickets, I feel the thrill of life, the soul of our native lump of earth; and for this reason, as I lean against the hedge of rosemary, I bestow only an absent glance upon the constellation of Cygnus, but give all my attention to your serenade. A little animated slime, capable of pleasure and pain, surpa.s.ses in interest the universe of dead matter.

CHAPTER XII

THE SISYPHUS BEETLE.--THE INSTINCT OF PATERNITY

The duties of paternity are seldom imposed on any but the higher animals. They are most notable in the bird; and the furry peoples acquit themselves honourably. Lower in the scale we find in the father a general indifference as to the fate of the family. Very few insects form exceptions to this rule. Although all are imbued with a mating instinct that is almost frenzied, nearly all, when the pa.s.sion of the moment is appeased, terminate then and there their domestic relations, and withdraw, indifferent to the brood, which has to look after itself as best it may.

This paternal coldness, which would be odious in the higher walks of animal life, where the weakness of the young demands prolonged a.s.sistance, has in the insect world the excuse that the new-born young are comparatively robust, and are able, without help, to fill their mouths and stomachs, provided they find themselves in propitious surroundings. All that the prosperity of the race demands of the Pierides, or Cabbage b.u.t.terflies, is that they should deposit their eggs on the leaves of the cabbage; what purpose would be served by the instincts of a father? The botanical instinct of the mother needs no a.s.sistance. At the period of laying the father would be in the way. Let him pursue his flirtations elsewhere; the laying of eggs is a serious business.

In the case of the majority of insects the process of education is unknown, or summary in the extreme. The insect has only to select a grazing-ground upon which its family will establish itself the moment it is hatched; or a site which will allow the young to find their proper sustenance for themselves. There is no need of a father in these various cases. After mating, the discarded male, who is henceforth useless, drags out a lingering existence of a few days, and finally perishes without having given the slightest a.s.sistance in the work of installing his offspring.

But matters are not everywhere so primitive as this. There are tribes in which an inheritance is prepared for the family which will a.s.sure it both of food and of shelter in advance. The Hymenoptera in particular are past-masters in the provision of cellars, jars, and other utensils in which the honey-paste destined for the young is stored; they are perfect in the art of excavating storehouses of food for their grubs.

This stupendous labour of construction and provisioning, this labour that absorbs the insect's whole life, is the work of the mother only, who wears herself out at her task. The father, intoxicated with sunlight, lies idle on the threshold of the workshop, watching the heroic female at her work, and regards himself as excused from all labour when he has plagued his neighbours a little.

Does he never perform useful work? Why does he not follow the example of the swallows, each of whom brings a fair share of the straw and mortar for the building of the nest and the midges for the young brood?

No, he does nothing; perhaps alleging the excuse of his relative weakness. But this is a poor excuse; for to cut out little circles from a leaf, to rake a little cotton from a downy plant, or to gather a little mortar from a muddy spot, would hardly be a task beyond his powers. He might very well collaborate, at least as labourer; he could at least gather together the materials for the more intelligent mother to place in position. The true motive of his idleness is inept.i.tude.

It is a curious thing that the Hymenoptera, the most skilful of all industrial insects, know nothing of paternal labour. The male of the genus, in whom we should expect the requirements of the young to develop the highest apt.i.tudes, is as useless as a b.u.t.terfly, whose family costs so little to establish. The actual distribution of instinct upsets our most reasonable previsions.

It upsets our expectations so completely that we are surprised to find in the dung-beetle the n.o.ble prerogative which is lacking in the bee tribe. The mates of several species of dung-beetle keep house together and know the worth of mutual labour. Consider the male and female Geotrupes, which prepare together the patrimony of their larvae; in their case the father a.s.sists his companion with the pressure of his robust body in the manufacture of their b.a.l.l.s of compressed nutriment. These domestic habits are astonishing amidst the general isolation.

To this example, hitherto unique, my continual researches in this direction permit me to-day to add three others which are fully as interesting. All three are members of the corporation of dung-beetles. I will relate their habits, but briefly, as in many respects their history is the same as that of the Sacred Scarabaeus, the Spanish Copris, and others.

The first example is the Sisyphus beetle (_Sisyphus Schaefferi_, Lin.), the smallest and most industrious of our pill-makers. It has no equal in lively agility, grotesque somersaults, and sudden tumbles down the impossible paths or over the impracticable obstacles to which its obstinacy is perpetually leading it. In allusion to these frantic gymnastics Latreille has given the insect the name of Sisyphus, after the celebrated inmate of the cla.s.sic Hades. This unhappy spirit underwent terrible exertions in his efforts to heave to the top of a mountain an enormous rock, which always escaped him at the moment of attaining the summit, and rolled back to the foot of the slope. Begin again, poor Sisyphus, begin again, begin again always! Your torments will never cease until the rock is firmly placed upon the summit of the mountain.

I like this myth. It is, in a way, the history of many of us; not odious scoundrels worthy of eternal torments, but worthy and laborious folk, useful to their neighbours. One crime alone is theirs to expiate: the crime of poverty. Half a century or more ago, for my own part, I left many blood-stained tatters on the crags of the inhospitable mountain; I sweated, strained every nerve, exhausted my veins, spent without reckoning my reserves of energy, in order to carry upward and lodge in a place of security that crushing burden, my daily bread; and hardly was the load balanced but it once more slipped downwards, fell, and was engulfed. Begin again, poor Sisyphus; begin again, until your burden, falling for the last time, shall crush your head and set you free at length.