Part 25

While spiders most commonly mimic ants, we hear also of their imitating beetles, snail-shells, ichneumons and horseflies. There is also a curious Madagascar species which looks exactly like a little scorpion, the resemblance being heightened by its habit of curving its flexible tail up over its back when irritated.

Those that resemble beetles comprise nearly all the species of the genera Coccorchestes and Homalattus. These are small spiders with short, convex bodies. The abdomen fits closely over the cephalothorax, and the epidermis, which has usually a metallic lustre, is sometimes coriaceous. Striking examples are found in H. coccinelloides, which bears a strong resemblance to beetles of the family Coccinelloidae, and in C. cupreus, in which certain marks on the abdomen imitate the elytra of beetles.

The following account of a spider which mimics a snail-shell is given by Mr. G. F. Atkinson;--

"An undescribed species of _Cyrtarachne_ mimics a snail-shell, the inhabitant of which, during the summer and fall, is very abundant on the leaves of plants in this place. In the species of Cyrtarachne the abdomen partly covers the cephalothorax, is very broad at the base, in this species broader than the length of the spider, and rounds off at the apex. When it rests upon the under side of a leaf with its legs retracted it strongly resembles one of these snail-shells by the color and shape of its abdomen. The two specimens which I collected deceived me at first, but a few threads of silk led me to make the examination. The spider seemed so confident of its protection that it would not move when I jarred the plant, striking it several hard blows. I pulled the spider forcibly from the leaf, and it did not exhibit any signs of movement until transferred to the cyanide bottle." ...

Trimen gives an account of the imitation, by spiders, of horseflies, a case falling into Class 2, as follows:--

"Hunting spiders are in some cases very like their prey, as may everywhere be noticed in the case of the species of Salticus which catch horseflies on sunny walls and fences. The likeness is not in itself more than a general one of size, form and coloring; but its effect is greatly aided by the actions of the spider, which walks hurriedly for short distances, stopping abruptly, and rapidly moving its falces, in evident mimicry of the well-known movements so characteristic of flies."

Instances of spiders mimicking ants are very numerous, and in many cases the resemblance is so close as to, at first sight, deceive a trained naturalist. This resemblance is brought about by the spider's body being elongated and strongly constricted, so that it appears to be composed of three segments instead of two, by the color, by the way in which the spider moves about, zig-zagging from side to side like an ant, and by its habit of holding up one pair of its legs and moving them in such a way that they look exactly like the antennae of an ant.

Ants may be regarded as specially protected, by their sharp, acid flavor, and in some species by the possession of stings or of horny processes.

On the ground that there are birds which do eat ants, and eat them greedily, it has been thought by some naturalists that they cannot be considered specially protected creatures, and that, as spiders can therefore derive no protection from mimicking them, all cases of such mimicry depend upon the spider's increased ability to capture the ants as prey, but I am convinced that this is too hasty a conclusion. It is unquestionably true that some birds feed almost exclusively upon ants, but these are the exceptions. It is a common thing to find that specially protected groups, which are safe from the attacks of most creatures, have their special enemies. Thus, even the nauseous Heliconidae are preyed upon by certain spiders and wasps; and bees, in spite of their stings, are preferred to other insects by the bee-eaters. Moreover, the ant-devouring birds are found largely among the wood-peckers, which eat the ants that run on the trunks of trees, and are therefore not a source of danger to the ant-like spiders, the American species of which, so far as I can learn, live entirely upon the ground.

In the United States comparatively small numbers of either ants or spiders are eaten by birds, but in tropical America there are enormous numbers of humming-birds feeding almost exclusively upon spiders, and there the protective advantage of looking like ants must be of great importance to the smaller species.

Belt considers that the advantages gained by ant-mimicking Central American spiders lies entirely on the side of protection. In relation to this subject he says: "Ant-like spiders have been noticed throughout tropical America and also in Africa. The use that the deceptive resemblance is to them has been explained to be the facility it affords them for approaching ants on which they prey. I am convinced that this explanation is incorrect, so far as the Central American species are concerned. Ants, and especially the stinging species are, so far as my experience goes, not preyed upon by any other insects. No disguise need be adopted to approach them, as they are so bold that they are more likely to attack a spider than a spider them. Neither have they wings to escape by flying, and generally go in large bodies easily found and approached. The use is, I doubt not, the protection the disguise affords against small insectivorous birds. I have found the crops of some humming-birds full of small, soft-bodied spiders, and many other birds feed on them. Stinging-ants, like bees and wasps, are closely resembled by a host of other insects; indeed, whenever I found any insect provided with special means of defence I looked for imitative forms, and was never disappointed in finding them."

The ant-like species are probably protected by their appearance from the attacks of many of the larger spiders. We have kept great numbers of Attidae in captivity, and, although they devoured flies, gnats, larvae, and other spiders, they would never touch ants. Among spiders, however, as among birds, we find that certain groups subsist almost entirely upon ants.

The class of spiders whose mimicry protects them from their enemies, whether they are birds or other spiders, probably includes at least two of our own ant-like species, Synageles picata and Synemosyna formica, which, in confinement, are always hungry for gnats, but will not touch ants, even of small size.

The existence of a class of spiders which mimic the particular species of ants upon which they prey is not to be questioned, but it is doubtful whether the benefit to the spider is increased facility in capturing the ant, or whether it is merely protective. It may be that the spider, by virtue of its resemblance to the ant, not only gets an abundant supply of food, but also escapes being eaten itself, and thus enjoys a double advantage. Both Bates and Wallace take the ground that the advantage derived by the spider consists in greater ease in the capture of prey, but both of these writers refer to spiders only incidentally to illustrate a general proposition, without special consideration of their peculiar conditions.

Mr. Herbert Smith, who has paid a good deal of attention to this subject, is inclined to believe that the mimicry in question is entirely protective. He writes as follows:--

"In the United States there are a few rare spiders that mimic ants. Here at Taperinha we find a good score of species of these spiders aping the various kinds of ants very closely; even the odd, spiny wood-ant, _cryptocerus_, furnishes a pattern, and there are spiders that mimic the wingless ichneumons. We find, after a while, that the spiders prey upon ants just as our spiders catch flies; indeed, this fact has already been noted by other observers. But we go a step beyond the books when we discover not only that the spiders eat the ants, but that they eat the particular ants which they mimic. At all events, we verify this fact in a great number of cases, and we never find the spiders eating any but the mimicked species.... I do not like to hazard a theory on this case of mimicry. It is difficult to suppose that the quick-witted ants would be deceived even by so close a resemblance; and, in any case, it would seem that the spiders do not require such a disguise in order to capture slow-moving ants. Most birds will not eat ants; it seems likely, therefore, that this is simply another example of protection; the spider deceives its enemies, not its prey; it mimics the particular species that it feeds on, because it is seen in that company when it is hunting, and among a host of similar forms is likely to pass unnoticed."

At first sight, and especially in view of the fact that such cases are not uncommon among insects, it would be naturally supposed that the object of the mimicry was to enable the spider to approach its victim without exciting suspicion; and it is difficult to account, on any other supposition, for the very close resemblance between certain species of spiders and the particular species of ants which they prey upon. It seems as though the highest point of _protective_ benefit would have been reached long before the resemblance of the spider to the ant had become so close as it really is. On the other hand, it is difficult to believe that ants are deceived, even by those spiders which mimic them most closely, when we remember that their perceptions are so keen that they discriminate not only between ants of their own and different species, but even between ants of their own species living in two different communities.

The mimicry of ichneumon flies by spiders was noted some years ago by Mr. Herbert Smith. This case comes under Class 3, in which one species mimics another which preys upon it. Great destruction is caused by ichneumons which lay their eggs on the bodies of the live spiders, and the disguise probably protects the spider by leading the fly to mistake it for one of its own species.

We have no proof that spiders ever mimic ants as a method of escaping from them, but it is possible that this sometimes happens. We know that some ants prey upon them. The foraging ants of South America destroy spiders as well as many kinds of insects, and Wallace mentions a small, wood-boring ant which fills its nest with small spiders.

If the spiders that feed upon ants deceive them by their mimicry those which are preyed upon by ants would gain an advantage by a similar disguise. I once placed a little ant-like spider of the genus Herpyllus in a bottle with three ants no larger than itself, which I had caught with it in the sweep-net. In a very few minutes the ants had killed and begun to devour the spider. It may be that the resemblance was sufficiently close to deceive them in the open, but failed when spider and ants were confined together in close quarters.

THE BATH OF THE BIRDS

BY RICHARD JEFFERIES.

[Illustration]

One morning Sir Bevis went down to the brook. Standing on the brink, he said: "Brook, Brook! what are you singing? You promised to tell me what you were saying."

The brook did not answer, but went on singing. Bevis listened a minute, and then he picked a willow leaf and threw it into the bubbles and watched it go whirling round and round in the eddies and back up under the fall, where it dived down and presently came up again, and the stream took it and carried it away past the flags. "Brook, Brook!" said Bevis, stamping his foot; "tell me what you are singing."

And the brook, having now finished that part of his song, said: "Bevis, dear; sit down in the shadow of the willow, for it is very hot to-day, and the reapers are at work; sit down under the willow and I will tell you as much as I can remember."

"But the reed said you could not remember anything," said Bevis, leaning back against the willow.

"The reed did not tell you the truth, dear; indeed, he does not know all; the fact is, the reeds are so fond of talking that I scarcely ever answer them now or they would keep on all day long, and I should never hear the sound of my own voice, which I like best. So I do not encourage them, and that is why the reeds think I do not recollect."

"And what is that you sing about?" said Bevis impatiently.

"My darling," said the brook, "I do not know myself always what I am singing about. I am so happy I sing, sing, and never think about what it means; it does not matter what you mean as long as you sing. Sometimes I sing about the sun, who loves me dearly, and tries all day to get at me through the leaves and the green flags that hide me; he sparkles on me everywhere he can, and does not like me to be in the shadow. Sometimes I sing to the wind, who loves me next most dearly, and will come to me everywhere in places where the sun cannot get. He plays with me whenever he can, and strokes me softly and tells me the things he has heard in the woods and on the hills, and sends down the leaves to float along; for he knows I like something to carry. Fling me in some leaves, Bevis, dear.

"Sometimes I sing to the earth and the grass; they are fond of me, too, and listen the best of all. I sing loudest at night to the stars; for they are so far away they would not otherwise hear me."

"But what do you say?" said Bevis; but the brook was too occupied now to heed him and went on.

"Sometimes I sing to the trees; they, too, are fond of me and come as near as they can; they would all come down close to me if they could. They love me like the rest, because I am so happy and never cease my chanting. If I am broken to pieces against a stone, I do not mind in the least; I laugh just the same and even louder. When I come over the hatch, I dash myself to fragments; and sometimes a rainbow comes and stays a little while with me. The trees drink me, and the grass drinks me; the birds come down and drink me; they splash me and are happy. The fishes swim about, and some of them hide in deep corners. Round the bend I go; and the osiers say they never have enough of me. The long grass waves and welcomes me; the moor-hens float with me; the kingfisher is always with me somewhere, and sits on the bough to see his ruddy breast in the water. And you come too, Bevis, now and then to listen to me; and it is all because I am so happy."

"Why are you so happy?" said Bevis.

"I do not know," said the brook. "Perhaps it is because all I think of is this minute; I do not know anything about the minute just gone by, and I do not care one bit about the minute that is just coming; all I care about is this minute, this very minute now. Fling me in some more leaves, Bevis. Why do you go about asking questions, dear? Why don't you sing and do nothing else?"

"Oh, but I want to know all about everything," said Bevis. "Where did you come from, and where are you going, and why don't you go on and let the ground be dry--why don't you run on, and run all away? why are you always here?"

The brook laughed and said: "My dear, I do not know where I came from, and I do not care at all where I am going. What does it matter, my love? All I know is I shall come back again; yes, I shall come back again." The brook sang very low and rather sadly now: "I shall go into the sea and shall be lost; and even you would not know me; ask your father, love; he has sailed over the sea in ships that come to Southampton, and I was close to him, but he did not know me. But by and by, when I am in the sea, the sun will lift me up, and the clouds will float along--look towards the hills, Bevis, dear, every morning and you will see the clouds coming and bringing me with them; and the rain and the dew, and sometimes the thunder and the lightning, will put me down again; and I shall run along here and sing to you, my sweet, if you will come and listen. Fling in some little twigs, my dear, and some bits of bark from the tree."

"That I will," said Bevis; and he picked up a stone and flung it into the water with such a splash that the kingfisher flew away; but the brook only laughed and told him to throw another and to make haste and grow bigger and jump over him.

"S--s, we shall meet by the drinking place," said the grasshopper; and was just hopping off, when Bevis asked him what the birds went down to bathe for.

"I'm sure I do not know," said the grasshopper, speaking fast, for he was rather in a hurry to be gone; he never could stand still long together. "All I can tell you is, that on Midsummer Day every one of the birds has to go down to the brook and walk in and bathe; and it has been the law for so many, many years that no one can remember when it began. They like it very much, because they can show off their fine feathers which are just now in full color; and if you like to go with me, you will be sure to enjoy it."

"So I will," said Bevis; and he followed the grasshopper, who hopped so far at every step that he had to walk fast to keep up with him.

They went on in silence a good way, except that the grasshopper cried "S--s" to his friends in the grass as he passed, and said good-morning also to a mole, who peeped out for a moment.

"Why don't you hop straight?" said Bevis presently. "It seems to me that you hop first one side and then the other, and go in such a zigzag fashion it will take us hours to reach the brook."

"How very stupid you are!" said the grasshopper. "If you go straight, of course you can only see just what is under your feet; but if you go first this way and then that, then you see everything. You are nearly as silly as the ants, who never see anything beautiful all their lives. Be sure you have nothing to do with the ants, Bevis; they are a mean, wretched, miserly set, quite contemptible and beneath notice. Now, I go everywhere, all round the field, and spend my time searching for lovely things; sometimes I find flowers, and sometimes the butterflies come down into the grass and tell me the news; and I am so fond of the sunshine, I sing to it all day long. Tell me, now, is there anything so beautiful as the sunshine and the blue sky, and the green grass, and the velvet and blue and spotted butterflies, and the trees which cast such a pleasant shadow and talk so sweetly, and the brook which is always running? I should like to listen to it for a thousand years."

"I like you," said Bevis; "jump into my hand and I will carry you." He held his hand out flat, and in a second up sprang the grasshopper and alighted on his palm and told him the way to go, and thus they went together merrily.

"Bevis, dear, I do not sing at night; but I always go where I can see a star. I slept under a mushroom last night, and he told me he was pushing up as fast as he could before some one came and picked him to put on a gridiron. I do not lay up any store, because I know I shall die when the summer ends; and what is the use of wealth then? My store and my wealth is the sunshine, dear, and the blue sky, and the green grass, and the delicious brook who never ceases sing, sing, singing all day and night. And all the things are fond of me; the grass and the flowers, and the birds and the animals--all of them love me."

"I think I shall take you home and put you under a glass case on the mantelpiece," said Bevis.

Off jumped the grasshopper in a moment, and fell so lightly on the grass it did not hurt him in the least, though it was as far as if Bevis had tumbled down out of the clouds. Bevis tried to catch him, but he jumped so nimbly this way and that, and hopped to and fro, and lay down in the grass, that his green coat could not be seen. Bevis now went down to the brook and stood on the bank, where it was high, near a bush at the side of the drinking place. "Ah, dear little Sir Bevis!" whispered a reed, bending towards him as the wind blew, "please do not come any nearer; the bank is steep and treacherous, and hollow underneath where the water-rats run. So do not lean over after the forget-me-nots--they are too far for you. Sit down where you are, behind that little bush, and I will tell you all about the bathing. The birds come down to bathe every Midsummer Day, and the goldfinches, and the sparrows, and the blackbirds, and the thrushes, and the swallows, and the wrens, and the robins, and almost every one of them, except two or three, whose great-grandfathers got into disgrace a long while ago. The rooks do not come because they are thieves, and steal the mussels, nor the crows, who are a very bad lot; the swan does not come either, unless the brook is muddy after a storm. The swan is so tired of seeing himself in the water that he quite hates it, and that is the reason he holds his neck so high, that he may not see more of himself than he can help."

Soon the birds came. They were all in their very best and brightest feathers, and as the sun shone on them and they splashed the water and strutted about, Bevis thought he had never seen anything so beautiful.