Guy Anstruther Knox Marshall

“ Distant, that the Tiger has not yet learnt that in pursuit of game nothing can be done down wind. Considerations such as these must lend a certain measure of support to the mechanical conception of natural selection. Thus, in the matter of conscious resemblance, although many animals may show undoubted intelligence in other directions, it is highly probable that, in the great majority of cases, their reasoning powers would not be sufficient to enable them to decide whether, or no, their own colouring would have a protective value in any new or unusual environment. ”

“ But, as a matter of fact, this principle predicates no such complete immunity from attack; in truth, the very essence of the theory of natural selection negatives any such supposition; for, according to this theory, protective resemblance, as we now see it, has been arrived at by the gradual accumulation and improvement of colour variations which make for concealment, and the protective value of such variations must essentially be, or have been, of only a partial character. ”

“ If the process of natural selection was to be applied, according to a very frequent method, as universal, then birds arising from these white and prominent eggs would seem in course of time to be doomed to destruction. But we find nothing of the kind. Natural selection is here replaced by the evolution of intelligence or active mimicry. True, it may be argued that birds laying white eggs would become extinct without they had gradually acquired the intelligent or automatic powers of concealment through a process of natural selection. ”

“ In conclusion, I can only hope that sufficient has been said to show that there are good grounds for opposing the suggestion that active mimicry is of any general occurrence in the animal kingdom; and, further, that the attempt to minimise certain phenomena of ordinary protective resemblance, in order to bring them within the scope of that principle, is not justifiable upon the evidence adduced. ”

“ For example: if we break a piece off a termite-heap and see that the inmates at once run back into the nest or avail themselves of the nearest cover they can find, we cannot assume that this is due to their intelligent recognition that their colours are out of harmony with their then surroundings, but we should rather attribute it to the instinctive avoidance of light shown by all such nocturnal creatures, an instinct which is preferably explained by natural selection. ”

“ Their habits, however, vary in this respect, and among the dozen or more species which I have observed in various parts of South Africa, I have found it to be a very general rule that their wariness is inversely proportionate to their protective resemblance; those species which live on rough, knotted bark, or among dense foliage, permitting one to approach much nearer than do those that rest on bare, smooth trunks or small twigs. ”

“ Distant appears to have overestimated the danger, and the contention that this noise invalidates their admirably protective colouration appears to be an inverted way of looking at the question. It is more reasonable to suppose that the protective resemblance of these insects is so efficacious, that they have been able to develop these extraordinary cries through the process of sexual selection (or perhaps even natural selection, supposing aesthetic appreciation on the part of the female be denied) , without unduly endangering the safety of the species. ”

“ As a matter of fact, the most satisfactory style of evidence would probably consist in a careful and exact observation of the demeanour of protectively-coloured animals, which find themselves, by a natural accident or necessity, in an environment to which their colour is quite unsuited; or, conversely, of the behaviour of striking sports or variations of such species, when occurring in their normal surroundings. ”

“ It is improbable that any of the lower animals have any real conception of their own appearance, and it is likely that any consciousness they may exhibit in their protective actions consists rather in the general recognition that they are freer from attack in certain particular spots or types of country, than from any true appreciation of the optical phenomena to which they really owe their safety. ”

“ Rather must we continue the laborious search for further evidence, not by a study of the anatomy of extinct animals, but by seeking a deeper and more intimate knowledge of the real life-histories of living organisms; for we are still profoundly ignorant of the immensely complex factors which go to make up the conditions of life of the very commonest animal upon this earth. ”

“ A consideration of these facts has led him to offer the suggestion that "animals of their own volition, and in their efforts to avoid their enemies, place themselves where possible in such adaptation to their surroundings, that protective resemblance and some forms of mimicry are due to animal intelligence, and not so entirely to what is generally understood as the unconscious process of natural selection" (l.c. 1899, p. 465) . It is proposed to designate this conscious action by the somewhat unsatisfactory name of "active mimicry" ”

“ Distant's attitude towards the subject is somewhat as follows:—When we find that the colouring of any animal assimilates well with that of its environment, but, at the same time, that this animal is apt to render itself more or less noticeable by certain movements or noises, then we are not justified in regarding its colouration as an efficient protection, and the case must therefore be removed from the category of protective resemblance. Tempting as such a conclusion may be to the opponents of Darwinism, [7] it appears to me to be wholly erroneous. ”

“ Seeing that this attitude permeates the whole discussion, it is somewhat disconcerting to read in the concluding remarks that, "to fully understand mimicry, we must appreciate general animal intelligence, and then we shall probably comprehend how much activity has been displayed by animals seeking protection by adaptive and assimilative efforts. ”

“ Distant replies that "This is a cardinal doctrine in natural and apologetic theology, but is the very antithesis of science, natural or otherwise. The man who orders his whole life on probabilities will probably arrive at the conclusion that hope is a very good breakfast, but a most indifferent dinner." ”

“ This in no way contradicts, but supports, the doctrine of Natural Selection. The animal survives which can best hide from its enemies, and this implies that the variations which tend to adaptive and assimilative efforts, not only succeed in the battle of life, but by the selective process become dominant, and more and more accentuated with a greater need" (l.c., 1900, p. 124) . It is scarcely necessary to point out that the latter position, which is essentially that of those very selectionists (n2) whose views Mr. Distant is combatting, is quite at variance with the former. ”

“ It is true that at this period their food supply almost comes to a standstill, for during the winter months Coleoptera cease almost entirely to venture out on the wing; but this would affect the young ones equally, if not more. Even if this supposition be correct, it is difficult to understand how the young subsist through the winter, for, so far as I have seen, they do not emerge at all from the nest, and they certainly construct no snares during that season for the capture of insects. ”

“ At one time I had thought these Spiders never entirely nocturnal in their habits, and so far as the construction of their snares is concerned they are no doubt crepuscular, like most Spiders of procryptic colouring. But I find they are by no means loth to emerge in broad daylight to capture their prey; and when a luckless Beetle becomes enmeshed, two or three rapidly rush out and tackle it, keeping as much beneath it as possible, apparently to prevent any attack from above. ”

“ The former process would be a true instance of "active mimicry," as defined by Mr. Distant, but the latter cannot be included under that term; indeed, in such cases, experience in the individual is the equivalent of natural selection in the species.
In the preliminary portion of his paper, Mr. Distant has given us many excellent examples and arguments to show that mimicry and protective resemblance probably existed in very remote antiquity; (n10) and he has done well in drawing attention to the matter, which is apt to be overlooked. ”

“ Distant's point of view, but the fox is notoriously one of the most sagacious and cunning of animals, and, even if we believe that many of its actions are due to conscious intelligence, this does not in any way prove the occurrence of such intelligence in insects, fishes, or even other mammals, each of which cases would require independent proof. ”

“ I may here refer to one or two examples of this kind which tend to show that many cases of protective actions on the part of the higher vertebrates must be attributed to unreasoning instinct rather than to conscious volition.
The late Mr. Romanes very truly remarked, that "Every sportsman must have noticed that the somewhat rare melanic variety of the common Rabbit will crouch as steadily as the normal brownish-grey type, notwithstanding that, owing to its normal colour, a 'nigger rabbit' thus renders itself the most conspicuous object in the landscape. ”

“ Distant that these insects are easily captured owing to their shrill cries. All high-pitched, vibrating sounds of this kind are very difficult to localise exactly, and with Cicadas I have noticed very frequently, both with myself and others, that the distance of the insect is invariably much underestimated. (n14) But even when the tree on which the Cicada is sitting has been ascertained, it must be very cautiously approached, for many species are able to detect one's presence at a distance of fifteen to twenty yards in open country, and, on so doing, they will at once cease their call ”

“ If, therefore, we find that certain cases appear difficult of exact explanation in the present state of our knowledge, we are by no means justified in disposing of the difficulty by referring them to causes operating only in the dim past, which we can neither prove nor disprove. ”

“ Should the insect be too large for them, other Spiders come out to assist, and it is hauled off with all speed under shelter, no attempt being made to bind it up in any way as the geometric Spiders do. Judging by the position of the dead bodies of their prey, it is probable that at night many are devoured in situ, but even then the majority must be carried inside the nest. ”

“ We should be foolish indeed not to follow the only guide we have through life. But, for all that, our highest and surest generalizations remain on the level of justifiable expectations, that is, very high probabilities. ”

“ The food of the Social Spiders consists principally of Coleoptera, for the capture of which their strong glutinous snares are admirably adapted. Their chief victims are the Melolonthidse, such as Anomala, Trochalus, Adoretus, &c, which positively swarm round trees and bushes on the warm spring evenings after the early rains. Among the larger diurnal beetles, the handsome Buprestids of the genus Psiloptera fall a frequent prey to their wiles, and it seems strange how such securely armour-plated insects can afford sustenance to the weak little Spiders ”

“ The foundations of this were made by forming a dome-shaped canopy some eighteen inches in diameter over the top of the bush, the Spiders running backwards and forwards in all directions laying down the silk. I presume that eventually the edges of this canopy would be drawn together to form the outer shell of the nest, but unfortunately I was unable to remain longer to watch the process, and as I never found an opportunity to revisit the spot, I never learnt the sequel of this interesting chapter in the life-history of Stegodyphus. ”

“ It must be reeollected that our conception of mind, even in our fellow men, is based entirely on analogy, and thus the further we depart from the human type, the lower we go in the organic scale, the weaker and weaker must that analogy become, and the more careful must we be to avoid the conception that any apparently purposive actions we may observe in these lower organisms must be due to trains of reasoning such as we find in ourselves. ”

“ Although in many cases I have actually tracked down individuals by their cry, in order to learn the calls of the different species, yet such a method is far too laborious for ordinary collecting purposes. ”

“ The young Spiders are much more rotund in appearance than their parents, and of a yellow colour. In the early winter the nests may be noticed to fall considerably into disrepair, and the damaged snares are no longer mended, and eventually disappear. On investigation I found this to be due to the fact that about this time the older generation dies off entirely, the nests then being found to contain only young Spiders. ”

“ It is far more reasonable to suppose that such knowledge as they may have in this respect would be acquired through their experience of their liability to, or immunity from, attack under such conditions, quite apart from any colour considerations. ”

“ But it would take quite a long list to enumerate all the species of Coleoptera which I have found dead in the nests of these rapacious creatures, for in truth "all is fish that comes to their net," even though it be the evil-smelling Lycus or the caustic Mylabris. To illustrate the strength of the silk, I might mention the capture of such powerful Beetles as Copris, Catharsius, and the large Bolboceras panza, Pér. ”

“ I expect the primary attraction will be found to be the Beetles caught in the Spiders' web, the Dormice having gradually learnt to utilise these snares for their own purposes, and finally evicting the inhabitants. Whether they usually occupy deserted nests, or themselves oust the lawful proprietors, cannot yet be decided for certain ”