|C.D. Warner, et al., comp. The Library of the Worlds Best Literature.|
An Anthology in Thirty Volumes. 1917.
|Among the Heather|
|By Grant Allen (18481899)|
From The Evolutionist at Large
|I SUPPOSE even that apocryphal person, the general reader, would be insulted at being told at this hour of the day that all bright-colored flowers are fertilized by the visits of insects, whose attentions they are specially designed to solicit. Everybody has heard over and over again that roses, orchids, and columbines have acquired their honey to allure the friendly bee, their gaudy petals to advertise the honey, and their divers shapes to insure the proper fertilization by the correct type of insect. But everybody does not know how specifically certain blossoms have laid themselves out for a particular species of fly, beetle, or tiny moth. Here on the higher downs, for instance, most flowers are exceptionally large and brilliant; while all Alpine climbers must have noticed that the most gorgeous masses of bloom in Switzerland occur just below the snow-line. The reason is, that such blossoms must be fertilized by butterflies alone. Bees, their great rivals in honey-sucking, frequent only the lower meadows and slopes, where flowers are many and small: they seldom venture far from the hive or the nest among the high peaks and chilly nooks where we find those great patches of blue gentian or purple anemone, which hang like monstrous breadths of tapestry upon the mountain sides. This heather here, now fully opening in the warmer sun of the southern countiesit is still but in the bud among the Scotch hills, I doubt notspecially lays itself out for the humble-bee, and its masses form almost his highest pasture-grounds; but the butterfliesinsect vagrants that they arehave no fixed home, and they therefore stray far above the level at which bee-blossoms altogether cease to grow. Now, the butterfly differs greatly from the bee in his mode of honey-hunting: he does not bustle about in a business-like manner from one buttercup or dead-nettle to its nearest fellow; but he flits joyously, like a sauntering straggler that he is, from a great patch of color here to another great patch at a distance, whose gleam happens to strike his roving eye by its size and brilliancy. Hence, as that indefatigable observer, Dr. Hermann Müller, has noticed, all Alpine or hill-top flowers have very large and conspicuous blossoms, generally grouped together in big clusters so as to catch a passing glance of the butterflys eye. As soon as the insect spies such a cluster, the color seems to act as a stimulant to his broad wings, just as the candle-light does to those of his cousin the moth. Off he sails at once, as if by automatic action, towards the distant patch, and there both robs the plant of its honey, and at the same time carries to it on his legs and head fertilizing pollen from the last of its congeners which he favored with a call. For of course both bees and butterflies stick on the whole to a single species at a time; or else the flowers would only get uselessly hybridized, instead of being impregnated with pollen from other plants of their own kind. For this purpose it is that most plants lay themselves out to secure the attention of only two or three varieties among their insect allies, while they make their nectaries either too deep or too shallow for the convenience of all other kinds.|| 1|
| Insects, however, differ much from one another in their æsthetic tastes, and flowers are adapted accordingly to the varying fancies of the different kinds. Here, for example, is a spray of common white galium, which attracts and is fertilized by small flies, who generally frequent white blossoms. But here again, not far off, I find a luxuriant mass of the yellow species, known by the quaint name of ladys-bedstraw,a legacy from the old legend which represents it as having formed Our Ladys bed in the manger at Bethlehem. Now why has this kind of galium yellow flowers, while its near kinsman yonder has them snowy white? The reason is that ladys-bedstraw is fertilized by small beetles; and beetles are known to be one among the most color-loving races of insects. You may often find one of their number, the lovely bronze and golden-mailed rose-chafer, buried deeply in the very centre of a red garden rose, and reeling about when touched as if drunk with pollen and honey. Almost all the flowers which beetles frequent are consequently brightly decked in scarlet or yellow. On the other hand, the whole family of the umbellates, those tall plants with level bunches of tiny blossoms, like the fools-parsley, have all but universally white petals; and Müller, the most statistical of naturalists, took the trouble to count the number of insects which paid them a visit. He found that only fourteen per cent. were bees, while the remainder consisted mainly of miscellaneous small flies and other arthropodous riff-raff, whereas, in the brilliant class of composites, including the asters, sunflowers, daisies, dandelions, and thistles, nearly seventy-five per cent. of the visitors were steady, industrious bees. Certain dingy blossoms which lay themselves out to attract wasps, are obviously adapted, as Müller quaintly remarks, to a less æsthetically cultivated circle of visitors. But the most brilliant among all insect-fertilized flowers are those which specially affect the society of butterflies; and they are only surpassed in this respect throughout all nature by the still larger and more magnificent tropical species which owe their fertilization to humming-birds and brush-tongued lories.|| 2|
| Is it not a curious, yet a comprehensible circumstance, that the tastes which thus show themselves in the development, by natural selection, of lovely flowers, should also show themselves in the marked preference for beautiful mates? Poised on yonder sprig of harebell stands a little purple-winged butterfly, one of the most exquisite among our British kinds. That little butterfly owes its own rich and delicately shaded tints to the long selective action of a million generations among its ancestors. So we find throughout that the most beautifully colored birds and insects are always those which have had most to do with the production of bright-colored fruits and flowers. The butterflies and rose-beetles are the most gorgeous among insects; the humming-birds and parrots are the most gorgeous among birds. Nay, more, exactly like effects have been produced in two hemispheres on different tribes by the same causes. The plain brown swifts of the North have developed among tropical West Indian and South American orchids the metallic gorgets and crimson crests of the humming-bird; while a totally unlike group of Asiatic birds have developed among the rich flora of India and the Malay Archipelago the exactly similar plumage of the exquisite sun-birds. Just as bees depend upon flowers, and flowers upon bees, so the color-sense of animals has created the bright petals of blossoms; and the bright petals have reacted upon the tastes of the animals themselves, and through their tastes upon their own appearance.|| 3|