a white blossom spotted with black. Of the balm, again, Gerarde remarked, They are delighted with this herb above others.' And in colour this flower is white or spotted with rose. We need not pursue the colour question through the pinks, reds, purples, and other shades to which it is often difficult to give a name. It would, indeed, be difficult to name any colour which bees do not appreciate as much as blue. Not that the bee despises blue flowers. There are blue flowers much visited, but these are neither more numerous in species nor more frequently visited than green, yellow, or white. The bee, in fact, is indifferent to the colour of the flower it visits. It will even on occasions do without the flowers altogether. Thus Mr. Bates tells us of certain forest-bees in South America which ' are more frequently seen feeding on the sweet sap which exudes from the tree, or on the excrement of birds on leaves, than on flowers.' Whatever, then, may be the right interpretation of Lord Avebury's experiments, they do not prove that the bee selects blue flowers in And if it does not, it cannot have been the agent in their evolution. But if the bee is to play the part of florist-in-chief to the human race, and evolve for man the blue flower, another qualification is required. It must not only prefer blue flowers, and visit them rather than those of other colours, it must also be constant in its visits. That is to say, it must visit only one species of flower in a single journey. Otherwise it will carry pollen from one species to another, and so retard rather than promote the evolution of a new species. And Darwin has emphasised the need for guarding against crossing as regards the new varieties of the florist. As a result of his long series of experiments on cross-fertilisation, he warns gardeners against allowing a cross even between flowers of the same variety. If, then, the bee is to play the part of florist in nature, it must exhibit a high degree of constancy in its visits. And it has been gifted, by a number of writers who do not seem to have been very familiar with its habits, with a degree of constancy which has been considered by many sufficient for the purpose. Darwin quotes Aristotle : During each flight the bee does not settle upon flowers of different kinds, but flies, as it were, from violet to violet, and touches no other species till it returns to the hive. But why should a great naturalist and keen observer drag out of its obscurity a somewhat vague assertion of an old Greek writer when he might have made direct observations for himself? And why should he bolster it up with an obviously unscientific statement from an obscure writer named Dobbs, to the following effect: I have frequently followed a bee loading the farina, bee-bread, or crude wax on its legs through part of a great field in flower, and on whatever flower it first alighted and gathered the farina, it continued gathering from that kind of flower, and passed over many other species, though very numerous in the field, without alighting on or loading from them, though the flower it chose was much scarcer than the others; so that, if it began to load from a daisy, it continued loading from the same, neglecting clover, honeysuckle, and the violet ? As a matter of fact the inconstancy of the bee did not escape the keen observation of Darwin, as the following quotation shows: In a flower-garden containing some plants of cenothera, the pollen of which can easily be recognised, I found not only single grains, but masses of it within many flowers of mimulus, digitalis, antirrhinum, and linaria. Other kinds of pollen were likewise detected in these same flowers. A large number of the stigmas of a plant of thyme, in which the anthers were completely aborted, were examined; and these stigmas, though scarcely larger than a split needle, were covered, not only with pollen of thyme brought from other plants by the bees, but with several other kinds of pollen. And yet Darwin expresses his opinion on the bee's constancy thus: All kinds of bees, and certain other insects, usually visit the flowers of the same species as long as they can before going to another species. Other writers have expressed themselves in similar terms. Hermann Müller states that: The most specialised, and especially the gregarious bees, have produced great differentiations in colour, which enables them on their journeys to keep to a single species of flower. It is a remarkable fact [says Lord Avebury] that in most cases bees confine themselves in each journey to a single species. And Dr. A. R. Wallace writes: Now it has been ascertained by several observers that many insects, bees especially, keep to one kind of flower at a time, visiting hundreds of blossoms in succession and passing over other species that may be mixed with them. As a matter of fact it has not been ascertained by anybody, and the above writers in thus expressing their opinions seem to show that they have not been very familiar with the habits of the real bee. Take, for example, the following notes of what the bee really does in visiting flowers. Here is one gathering honey from the little white flowers of the chickweed, from which it goes to dandelion. It returns to chickweed, but presently leaves it for blue veronica. Back to chickweed it goes, and then to dandelion, returning to chickweed once more. Again we see it on veronica, and then it returns to chickweed, where we leave it. In this corner of the garden, again, is a rockery on which different species of wild geranium are growing together. On the adjacent wall are hanging great tufts of the ivy-leaved toad-flax. We choose a particular bee out of the many which are resorting here for nectar, and follow its movements as long as we can. There, that one has visited forty-four flowers, and changed the species of flower ten times. Again, we catch sight of a bee leaving the flower of a balsam. It flies down, and alights on the purple blossoms of the meadow crane'sbill, from which it goes to wild marjoram. It could scarcely have chosen three more dissimilar and widely separated flowers for consecutive visits. In this early spring day, again, we find bees busy on the flowers of the chickweed (white), veronica (blue), scilla (blue), and little celandine (yellow). One goes from veronica to chickweed; another from celandine to scilla and back to celandine; a third goes from veronica to chickweed and back to veronica; a fourth goes from celandine to scilla. And these are not isolated cases: Examples I could cite you more, And anyone can obtain more for himself with a little care. A famous botanist, Kerner von Marilaun, writes on the subject thus: Insects certainly show a preference for a single species for considerable periods, particularly when this species is flowering in quantity on a confined space; still, anyone who closely observes insects visiting flowers can easily convince himself that the flowers visited are changed from time to time. A bee which has just dusted itself with pollen in the flower of a winter aconite will fly across to a bush of Salix daphnoides, and as it passes a plant of Daphne Mezereum it will suck its honey; a moment later it will swoop down to the flowers of crocus in the meadow near by, and then fly on to the sweet violet. On the stigma of the last-mentioned plant will be found the pollen of all or several of the just visited flowers; on the crocus that of the willow, and so on. But even if such cases are explained away as solitary instances— which they are not the bee would still be an utterly incompetent florist. For all species were ex hypothesi once mere varieties, and to raise these to the rank of species the bee must be constant to varieties: it must visit only one variety on a single journey. This is of even more importance than constancy as regards species. But not even the most extreme supporters of the theory have suggested that the bee does so. It is admitted, in fact, that bees pass freely from one variety to another of the same species. Darwin recorded his observation of this fact when, as we have seen, he called bees' good botanists.' And anyone can see it taking place daily in any garden where differently coloured varieties are growing together. Bees are also supposed to have selected the shape of flower best suited to them, and so to have evolved the spurs, hoods, tubes, and lips which occur in so many blossoms. No Lord Avebury has come forward to show that a bee prefers to take its honey out of a spur, or a hood, rather than from a flower of another shape. It is only supposed to do so because the theory requires it. And the flowers, according to the theory, have responded marvellously to the bees' exertions, and given them every convenience of shape. And yet the unconscionable bee is not satisfied. The flower offers it every facility for alighting and getting the nectar easily and quickly. Yet there are some 300 species of flowers in the European flora in which humble bees will bite through the calyx or corolla to get the honey. And then, if we take any particular species of bee, we find that it visits a number of flowers of widely different shapes. Even on a single journey a bee may visit such widely varying types of flower as the balsam, wild geranium, and marjoram. In their visits to flowers, indeed, bees offer some curious, one might almost say derisive, comments on the 'beautiful theory' in which they are supposed to have played so important a part. When there is any variation in the size of the flowers, the smaller and less showy ones would be the last to be visited by the insects,' says Müller. And this is what the bee must have done if it has evolved the blue flower. We are not sure, indeed, that it should not have gone further, and refused altogether to visit the smaller and less showy ones.' But we note in passing that Müller does not say are the last to be visited, but only would be. He does not give it, that is to say, as the result of his own observation-as indeed he could not-but it is what ought to happen if the theory is true. Lord Avebury says insects fertilise the largest and most brilliant flowers,' an assertion equally devoid of foundation. Here are some of the bees' comments. Some of the flowers of a wild geranium have lost their petals, leaving only the green calyx to attract the bee. While we watch, several bees visit such petal-less flowers. The same thing happens on a patch of cistus, and also on a flowering bramble bush. And Darwin himself has noted the visits of bees to flowers which have lost their petals. Here, again, is a flower of white clematis of which snails have eaten. the greater part of the petals. Yet it receives as many bee visits as the perfect flowers on the same plant. There, again, is a flower in that bed of harpaliums of which a caterpillar has neatly eaten off the ray florets. Nevertheless, there is a bee on it gathering nectar, although there are scores of perfect flowers around it! Such are the strange ways of the bee, which in the imagination of certain theorists selects the most showy flowers for its visits! With Aristotle's bee, constant in its visits, and Lord Avebury's bee, preferring blue, you may, theoretically, produce a blue flower. You put your penny of faith in the slot, and it is evolved while you wait. With the bee of nature, the real visitor of the flowers, this is impossible. |