Fabre, Poet of Science

by Georges Victor Legros

This marvellous prerogative the Osmia shares with a host of apiaries, in which the unequal development of the males and females requires an unequal provision of space and of nourishment for the future larvae. For the females, who exceed in point of size, huge cells and abundant provision; for the more puny males, narrow cells and a smaller ration of pollen and honey.

Now the circumstances which are encountered by the Osmia, when, pressed by the necessities of spawning, she searches for a dwelling, are often fortuitous and incapable of modification; and in order to give each set of larvae the necessary space "she lays at will a male or a female egg, according to the conditions of space."

In this marvellous study, which constitutes, with the history of the Cerceris, the finest masterpiece of experimental entomology, Fabre brilliantly establishes all the details of that curious law which in the Hymenoptera rules both the distribution and the succession of the sexes. In his artificial hives, in glass cylinders, he forces the Osmia to commence her spawning with the males, instead of beginning with the females as nature requires, since the insect is primarily preoccupied with the more important sex, that which ensures par excellence the perpetuation of the species. He even forces the whole swarm which buzzes about his work-tables, his books, his bottles, and apparatus, completely to change the order of its spawning. He shows finally that in the heart of the ovaries the egg of the Osmia has as yet no determined sex, and that it is only at the precise moment when the egg is on the point of emerging from the oviduct that it receives, at the will of the mother, the mysterious, final, and inevitable imprint.

But whence does the Osmia derive this, "distinct idea of the invisible"? Here again is one of those riddles of nature which Fabre declares himself quite incapable of solving. [(8/17.)]

Is this all? No; we are far from having made the tour of this miraculous and incommensurable kingdom through which this admirable master leads us, and I should never be done were I to attempt to exhaust all the spectacles which he offers us. Let us descend yet another step, among creatures yet smaller and humbler. We shall find tendencies, impulses, preferences, efforts, intentions, "Machiavellic ruses and unheard-of stratagems."

Certain miserable black mites, living specks, the larvae of a beetle, one of the Meloidae, the Sitaris, are parasites of the solitary bee, the Anthophora. They wait patiently all the winter at the entrance of her tunnel, on the slope of a sunny bank, for the springtime emergence of the young bees, as yet imprisoned in their cells of clay. A male Anthophora, hatched a little earlier than the females, appears in the entrance of the tunnel; these mites, which are armed with robust talons, rouse themselves, hasten to and fro, hook themselves to his fleece, and accompany him in all his peregrinations; but they quickly recognize their error; for these animated specks are well aware that the males, occupied all day long in scouring the country and pillaging the flowers, live exclusively out of doors, and would in no wise serve their end. But the moment comes when the Anthophora pays court to the fair sex, and the imperceptible creature immediately profits by the amorous encounter to change its winged courser. "These pigmies therefore have a memory, an experience of facts" (and how one is tempted to add, a glimmering of intelligence!). Grappled now to the female bee, the grub of the Sitaris "conceals itself, and allows itself to be carried by her" to the end of the gallery in which she is now contriving her cradle, "watches the precise moment when the egg is laid, installs itself upon it, and allows itself to fall therewith upon the surface of the honey, in order to substitute itself for the future offspring of the Anthophora, and possess itself of house and victuals." [(8/18.)]

Another "little gelatinous speck," "a shadow of a creature," the larva of a Chalcidian, the Leucopsis, one of the parasites of the Mason-bee, knows that in the cell of the mason there is food for one only. Scarcely has it entered the tiny dwelling but we see this "nameless shape" for several days "anxiously wandering; it visits the top and bottom, the back, the front, the sides"; it makes the tour of its domain; "it searches in the darkness, palpitating, seemingly with an object in view." What does this "animated globule" want? why is this atom so excited? It is searching to discover if there is not in some corner hitherto unexplored another larva, a rival, that it may exterminate it! [(8/19.)]

What then intrinsically is instinct? And what intrinsically is intelligence?

How can we propose to draw up the inexhaustible inventory of all the manifestations of life, and why attempt to include all its species and their unknown varieties in narrow classes? Why say that there are only two modes of life, instinct on the one hand and intelligence on the other, "when we know how subtle and illusive is this Proteus, and that there are not two things only, but a thousand dissimilar things" [(8/20.)]: or rather is it not always the same thing, everywhere present and acting in living matter, and susceptible of infinite degrees, under forms and disguises innumerable?

This is why it escapes the "scalpel of the masters" and the apparatus of the chemists. We may dissect, we may scrutinize organs under the magnifying glass, examine wing-cases, count the nervures of the wings, the number of articulations in the limbs; we may reckon every point, like Réaumur forgetting not a line, not a hair; we may compare and measure every portion of the mouth, and define the class; and we shall not find a single point in all this physical architecture which will positively inform us of the habits of the insect. Of what account are a few slight differences? It is in the physical far more than in the anatomical differences that the inviolable demarcation between two species exists. Instincts dominate forms; the tool does not make the artisan; "and none of these various structures, however well adapted they may appear to us, bears within it its reason or its finality."