If we would make the Cockchafer squeak, all that we need do is to take him in our fingers and tease him a little. The sound box works at once and does not cease until we do. What we now hear is not a song but a complaint, a protest against misfortune. It is a singular world in which sorrow is translated by couplets and joy by silence.
The other scrapers of the abdomen or corselet behave in like fashion. When surprised upon her pills, at the bottom of her burrow, the mother Copris groans, for a moment bewailing her fate: the Bolboceras, held captive in the hand, protests with a gentle elegy; the Capricorn when caught sets up a desperate grating. All are mute as [[206]]soon as the danger is past; all likewise persist in their silence when absolutely at rest. I never knew any of the three to sound his instrument apart from the alarm to which I subjected them.
Others, supplied with highly improved instruments, sing to beguile their solitude, to summon each other to the wedding, to celebrate the joys of life and the festival of the sunshine. Most of these singers are mute in a moment of danger. At the least disturbance, the Decticus[8] shuts up his musical box and veils his dulcimer, on whose notes he was playing with his bow; the Cricket[9] furls the wings which were vibrating above his back.
On the other hand, the Cicada raises a desperate outcry in our fingers; and the Ephippiges[10] bemoans his fate in a minor key. Sorrows and joys are translated into the same tongue, so that it becomes difficult to say for what exact purpose the stridulating organ is intended. When left in peace, does the insect actually celebrate its happiness? When teased, does it bewail its misfortune? Does [[207]]it try to overawe its enemies with noise? Could the sound-apparatus, at the requisite moment be a means of defence or intimidation? If the Capricorn and the Cicada made a sound when in danger, then why are the Decticus and the Cricket silent?
After all, we know next to nothing of the determining causes of insect phonetics. We know very little more of the sounds perceived. Do the insect’s ears catch the same sounds as ours do? Is it sensible, in particular, to what we call musical sounds? Without, I may say, any hope of solving this obscure problem, I tried an experiment which is worth relating. One of my readers, filled with enthusiasm for what my animals taught him, sent me a musical box from Geneva, hoping that it might be useful to me in my acoustic researches. And it really was so. Let me tell the story. It will give me the opportunity of thanking the kind sender of the present.
The little musical-box has a fairly varied selection of pieces, all translated into notes of crystal clearness which should, to my thinking, attract the attention of an insect audience. One of the tunes best suited to my [[208]]plans is that from Les Cloches de Corneville. With this lure shall I secure the attention of a Cockchafer, a Capricorn or a Cricket?
I begin with a Capricorn, the little Cerambyx cerdo. I seize the moment when he is courting his mate at a distance. With his delicate antennæ extended motionless, he seems to be making enquiries. Now, melodiously, Les Cloches de Corneville ring out: ding-dong-ding-dong. The insect’s meditative posture is unchanged. There is not the least tremor, not the least inflexion of the antennæ, the organs of hearing. I renew the attempt, altering the hour and the degree of daylight. My experiments are useless: there is not a movement of the antennæ to denote that the insect pays the least attention to my music.
The same result, with the Pine-chafer, whose antennary leaves retain exactly the same position as when all was silent; the same result with the Cricket, whose tiny, out-stretched, thread-like antennæ should vibrate easily under the impact of the sound-waves. My three subjects are absolutely indifferent to my methods of exciting emotion: not one of them gives a hint of feeling any impression whatever. [[209]]
Years ago, a mortar thundering under the plane-tree in which the orchestra of the Cicadæ[11] was performing did not for a moment interrupt or otherwise affect their concert: at a later date, the hullabaloo of a holiday crowd and the crackling of fireworks let off close by failed to disturb the geometry of a Garden Spider working at her web,[12] to-day, the limpid tinkle of Les Cloches de Corneville leaves the insect profoundly indifferent, in so far as we are able to judge. Are we to infer deafness? That would be going a great deal too far.
These experiments merely justify our opinion that the insect’s acoustics are not ours, even as the optics of its faceted eyes are not to be compared with those of our own. A mechanical toy, the microphone, hears—if I be permitted to say so—that which to us is silence; it would not hear a mighty uproar; it would be thrown out of gear and work imperfectly if subjected to the din of thunder. What of the insect, another, even more delicate toy! It knows nothing of our sounds, [[210]]whether musical notes or noises. It has those of its own little world, apart from which other sound-waves possess no value.