The examples Mr. Allen quotes of bright insects being associated with bright flowers seem very forcible, but are really deceptive or erroneous; and quite as many cases could be quoted which prove the very opposite. For example, in the dense equatorial forests flowers are exceedingly scarce, and there is no comparison with the amount of floral colour to be met with in our temperate meadows, woods, and hillsides. The forests about Para in the lower Amazon are typical in this respect, yet they abound with the most gorgeously coloured butterflies, almost all of which frequent the forest depths, keeping near the ground, where there is the greatest deficiency of brilliant flowers. In contrast with this let us take the Cape of Good Hope—the most flowery region probably that exists upon the globe,—where the country is a complete flower-garden of heaths, pelargoniums, mesembryanthemus, exquisite iridaceous and other bulbs, and numerous flowering shrubs and trees; yet the Cape butterflies are hardly equal, either in number or variety, to those of any country in South Europe, and are utterly insignificant when compared with those of the comparatively flowerless forest-depths of the Amazon or of New Guinea. Neither is there any relation between the colours of other insects and their haunts. Few are more gorgeous than some of the tiger-beetles and the carabi, yet these are all carnivorous; while many of the most brilliant metallic buprestidae and longicorns are always found on the bark of fallen trees. So with the humming-birds; their brilliant metallic tints can only be compared with metals or gems, and are totally unlike the delicate pinks and purples, yellows and reds of the majority of flowers. Again, the Australian honey-suckers (Meliphagidae) are genuine flower-haunters, and the Australian flora is more brilliant in colour display than that of most tropical regions, yet these birds are, as a rule, of dull colours, not superior on the average to our grain-eating finches. Then, again, we have the grand pheasant family, including the gold and the silver pheasants, the gorgeous fire-backed and ocellated pheasants, and the resplendent peacock, all feeding on the ground on grain or seeds or insects, yet adorned with the most gorgeous colours.
There is, therefore, no adequate basis of facts for this theory to rest upon, even if there were the slightest reason to believe that not only birds, but butterflies and beetles, take any delight in colour for its own sake, apart from the food-supply of which it indicates the presence. All that has been proved or that appears to be probable is, that they are able to perceive differences of colour, and to associate each colour with the particular flowers or fruits which best satisfy their wants. Colour being in its nature diverse, it has been beneficial for them to be able to distinguish all its chief varieties, as manifested more particularly in the vegetable kingdom, and among the different species of their own group; and the fact that certain species of insects show some preference for a particular colour may be explained by their having found flowers of that colour to yield them a more abundant supply of nectar or of pollen. In those cases in which butterflies frequent flowers of their own colour, the habit may well have been acquired from the protection it affords them.
It appears to me that, in imputing to insects and birds the same love of colour for its own sake and the same aesthetic tastes as we ourselves possess, we may be as far from the truth as were those writers who held that the bee was a good mathematician, and that the honeycomb was constructed throughout to satisfy its refined mathematical instincts; whereas it is now generally admitted to be the result of the simple principle of economy of material applied to a primitive cylindrical cell.[162]
In studying the phenomena of colour in the organic world we have been led to realise the wonderful complexity of the adaptations which bring each species into harmonious relation with all those which surround it, and which thus link together the whole of nature in a network of relations of marvellous intricacy. Yet all this is but, as it were, the outward show and garment of nature, behind which lies the inner structure—the framework, the vessels, the cells, the circulating fluids, and the digestive and reproductive processes,—and behind these again those mysterious chemical, electrical, and vital forces which constitute what we term Life. These forces appear to be fundamentally the same for all organisms, as is the material of which all are constructed; and we thus find behind the outer diversities an inner relationship which binds together the myriad forms of life.
Each species of animal or plant thus forms part of one harmonious whole, carrying in all the details of its complex structure the record of the long story of organic development; and it was with a truly inspired insight that our great philosophical poet apostrophised the humble weed—
Flower in the crannied wall,
I pluck you out of the crannies,
I hold you here, root and all, in my hand,
Little flower—but if I could understand
What you are, root and all, and all in all,
I should know what God and man is.
FOOTNOTES:
[136] Burchell's Travels, vol. i. p. 10.
[137] Nature, vol. iii. p. 507.
[138] Flowers, Fruits, and Leaves, p. 128 (Fig. 79).