The next day, when sunshine recalled the scattered workers, I again counted the bees with white dots on their thorax. My success surpassed all my hopes; I counted fifteen—fifteen of the deported bees storing or building as if nothing had happened! Then the storm, which had threatened more and more, burst, and a succession of rainy days stopped all further observations.
Such as it was, the experiment sufficed. Out of twenty bees which seemed fit for the journey when released, fifteen at least had come back—two in the first hour, and three in the course of the evening, and the rest next morning. They had come back in spite of having the wind against them, and—a yet greater difficulty—in spite of their unfamiliarity with the place whither I had transported them. There could be no question that it was for the first time that they saw the osier beds of the Aygues which I had chosen as the starting-place. Never on their own account had they gone so far afield, for they find all they want by way of building material and food close to my shed. The road at the foot of the wall furnishes mortar; the meadows round my house offer nectar and pollen. Economical of time as they are, they would not fly four kilometres to procure what abounds close to the nests. I see [[305]]them daily taking material from the road, and making a harvest on the meadow flowers, especially on Salvia. According to all appearance they do not fly beyond a circle of a hundred metres. How then did my exiles return? What guided them? Not memory, certainly, but some special faculty, which we can only recognise by its astonishing effects without pretending to explain it, so far outside our own psychology is it. [[306]]
XXII
AN EXCHANGE OF NESTS
Let us continue our series of experiments on Chalicodoma muraria. From its position on a stone which one can move at will, its nest lends itself to very interesting trials. This is the first of them. I change the place of a nest by carrying the pebble it is placed on some couple of yards away. Edifice and base forming but one, the move was made without at all disturbing the cells. I set the pebble in an open place well in sight, as it was before. When the bee returned, she could not fail to see it.
After a few minutes the owner arrived and went straight where the nest used to be. She hovered gently just above the vacant spot, looked, and alighted just where the stone used to lie. There she walked about, searching pertinaciously, then soared up and flew away. Her absence was short; she came back speedily and resumed her search on foot or on the wing—always on the spot formerly occupied by the nest. A new fit of irritation expressed by a sudden flight through the osier bed, then as sudden a return and resumption of the vain search—always [[307]]over the impression left by the pebble which I had carried away. These sudden flights, prompt returns, and obstinate examinations of the empty place, were repeated very many times before the mason bee could believe her nest was gone. She certainly must have seen it in its new position, for sometimes she flew only a few inches above it, but she did not care about it. For her it only represented the nest of another bee.
Often the experiment ends without so much as a visit to the stone carried three or four yards away; the bee departs and does not return. If the distance be less—say a yard—sooner or later she alights on the pebble on which her nest is built. She will visit the cell which she was making or storing a little while earlier, plunge in her head several times, examine the surface of the stone narrowly, and after much hesitation return to search over the original spot. The nest, which is no longer in its right place, is altogether abandoned, though it be but a yard away. Vainly does the bee alight on it; she cannot recognise it as hers. I convinced myself of this by finding it several days later in just the same state as when I moved it. The cell, half filled with honey, was still open, allowing the ants to pillage it; the cell in process of construction was unfinished, without a single new course of mortar. Of course the bee may have returned, but she had not resumed her work. The displaced abode was abandoned for ever.
I shall not deduce the strange paradox that a bee, capable of returning home from a great distance, is yet incapable of finding it a yard off; the interpretation [[308]]of the facts does not involve this. The conclusion appears to be that she retains a tenacious impression of the spot occupied by the nest, returning there with an indefatigable obstinacy when the nest is gone. But of the nest itself she has a very vague notion—does not recognise her own masonry kneaded with her own saliva, nor the honey paste she had collected. Vainly does she visit her work, the cell; she abandons it, not acknowledging it any more, since the place where lies the pebble is no longer the same.
We must own that insect memory is a strange one, so lucid in general knowledge of locality, so limited as to its home. I should be disposed to name it topographical instinct; the creature knows the localities, but not the dear nest—the dwelling. The Bembex led us to a like conclusion. The nest being laid open, she cared nothing for the family—for the larva writhing distressfully in the sun unrecognised. What they do recognise, what they seek, and find with marvellous precision, is the place where no longer exists anything of the entrance door—not even a threshold.