These facts explain the egg-layer’s tactics. What is her object when, before proceeding to bore the hole, she inspects her acorn, above, below, in front and behind, with fastidious care? She is making sure that the fruit is not already occupied. It is a rich larder, certainly; nevertheless, there is not enough for two. Never indeed have I found two larvæ in the same acorn. One only, always one only, digests the generous morsel and converts it into pale-green flour before leaving it and descending to the ground. Of the seed-lobe bread, at most an insignificant crumb remains. The rule is that each grub has its loaf, each consumer its ration consisting of one acorn.
Before trusting the egg to the acorn, therefore, it is important to examine it, to ascertain if it already has an occupant. Now this occupant, if any, is at the bottom of a crypt, at the base of the acorn, under the cover of a cup bristling with scales. Nothing could be more secret than this hiding-place. No eye would suspect the presence of a recluse if the surface of the acorn did not bear the mark of a tiny puncture.
This just visible mark is my guide. Its appearance tells me that the fruit is inhabited or that it [[82]]has at least been prepared for the reception of the egg; its absence assures me that the acorn has not been appropriated. The Weevil, beyond a doubt, obtains her information in the same manner.
I see things from a height, with a comprehensive glance, assisted if need be by the magnifying-glass. I turn the object for a moment in my fingers; and my inspection is over. The Weevil, investigating at close quarters, is obliged to point her microscope more or less everywhere before detecting the tell-tale speck with certainty. Moreover, the welfare of her family compels her to make a far more scrupulous search than that prompted by my curiosity. This is why her examination of the acorn is so excessively protracted.
It is done: the acorn is accepted as a good one. The drill is driven in and kept working for hours; then, very often, the insect goes away, despising her work. The laying of the egg does not follow on the boring. What is the object of so great and so long an effort? Can the Weevil simply be piercing the fruit to satisfy her appetite and obtain refreshment? Can the reed-like beak go down to the depths of the barrel to draw, from the likeliest spots, a few mouthfuls of sustaining drink? Can the enterprise be a matter of personal nourishment?
I thought so at first, though I was a little surprised at this display of perseverance in view of a sip. The males taught me to abandon the idea. [[83]]They too possess a long rostrum, capable of opening a well if necessary; nevertheless I never see one standing on an acorn and working at it with his drill. Why take so much trouble? A mere nothing satisfies these frugal eaters. A superficial digging with the tip of the proboscis into the tender leaf yields enough to maintain their strength.
If they, the idlers who have leisure to enjoy the delights of the table, want no more, how will it be with the mothers, busy with the laying? Have they the time to eat and drink? No, the pierced acorn is not a bar at which to lounge, sipping without end. That the beak, when driven into the fruit, levies a small mouthful is possible; but this scrap is certainly not the object in view.
I seem to catch a glimpse of the real object. The egg, as we said, is always at the base of the acorn, in the midst of a sort of wadding moistened by the sap that oozes from the stalk. At the hatching, the grub, incapable as yet of tackling the firm substance of the seed-lobes, chews the delicate felt at the bottom of the cup and feeds upon its juices.
But, as the fruit matures, this cake becomes more solid and changes in flavour and in the consistency of its pulp. What was soft hardens, what was moist dries up. There is a period during which the conditions necessary to the new-born grub’s welfare are fulfilled to perfection. At an earlier stage, [[84]]things would not have reached the requisite degree of preparation; later, they would be too ripe.
Outside, on the green rind of the acorn, there is nothing to show the progress of this inner cooking. In order not to serve her grub with noxious food, the mother, inadequately informed by the sight of the acorn, is therefore obliged first to taste with the tip of her proboscis what lies at the bottom of the store-room.