Part 5
Today I split open a dead twig of sumac in which the little upholsterer-bee had laid her eggs. From the summit a well or shaft was sunk some ten inches through the central pith. This I cautiously descended by means of a jack-knife and found it partitioned into a dozen cells, in each of which lay a pupa, the pallid sleepers like mummies in their royal tombs awaiting a resurrection.
The cells were lined--upholstered--in silk and partitioned from each other by walls of chips cemented together. In some cases the pupa was being devoured by the minute larvæ of a chalcid fly, and in one cell only the dried skin remained. For that pupa there was to be no resurrection into the life of the bee, but as the cell was opened, out stepped a tiny chalcid into the light of day, its dapper little person shining blue-black and its minute wings of an iridescent green.
You may see many broken twigs of sumac, elder and blackberry, perforated at the end in evidence that in the cells below are the larvæ of a bee, or perhaps the pupæ wrapped in their transforming slumbers. This sepulcher is sign to the chalcid fly as well. In one such that I opened were several perfect bees, beautiful little green creatures. Immediately they stepped out upon my hand and began dusting and cleaning themselves, but appeared to be troubled by the brightness, and eager to hide. When offered the open end of a tube, such as they had recently come from, they seemed glad to enter. They were not yet fitted for contact with the world of light and preferred to return to the darkness and security of their cells. A spider had concealed herself in a silken room at the mouth of one tube, perhaps seeking this privacy in which to change her skin. When their time had come to emerge, the inmates would naturally have walked into the spider's den, while the light of day appeared beyond, but for a single instant, as a faint glimmer which they were destined never to reach.
However, there is a Theseus for every monster. A spider was one day spinning her web in an outer angle of the veranda, laying the first strands, the scaffolding. Attaching one point she swung out on her line and fixed a second, aided by the breeze. Without the wind she perhaps could not have erected her scaffolding in that place. The morning sunlight caught these first threads, stretched from post to beam, and they gleamed like silver or spun glass. At length a wide space was to be bridged and she swung free at the end of a long strand. The breeze carried her to and fro, far out from under the roof, so that she remained suspended in mid-air.
But other eyes were watching her at her work. As she swung thus, self-possessed and at ease, suddenly a mud-dauber pounced upon her. The silver strand parted in the sunlight, and the spider was carried to the beam above, where the wasp apparently stung her several times. A moment after she rose in air holding the large globular spider, now paralyzed and inert, and sailed away over the treetops in the direction of her nest. The victim was to be immured in a sarcophagus of mud together with the egg of the wasp. When the egg hatched, the larva in this tomb with the body of the spider would find such gruesome state congenial enough--being of the wasps. In this case a spider the less means a wasp the more.
Late one afternoon a spider was constructing her web. She already had her first line stretched between two small shrubs. On this she crossed and recrossed several times, each trip reeling out a new strand from her spinnerets, until she had a stout cable from which the gossamer structure was to depend. From an end of this she dropped to the ground and fastened a thread, then ascended, traversed the cable and dropped lines from the other end to the twigs beneath. All were remarkably taut and firm. By crossing two she now established the center of the web--not the geometric center--and from the overhead cable spun some radii to this point and from this to the lower strand. In an incredibly short time she had lines radiating in all directions from the center like the spokes of a wheel.
She now fairly ran over these spokes paying out the strand as she laid the spiral web upon the gleaming radii. Starting at the center she traveled from left to right, passing the thread through the claw of one of the last pair of legs. By this means it was held from her as far as possible and quickly attached to each of the radii. A very short time sufficed for her to complete this spiral of perhaps a foot in diameter, and she had only to return over the ground with the final thread, on which are strung the viscid drops.
She paused as if resting, and in that moment a Social wasp descended like a fury and bore her to the ground. The wasp quickly rose holding the spider in her embrace, and returning to the bush suspended herself by one hind claw. Here she held the body of the spider with two pair of legs, and turning it about, as though it were on a spit, bit off some of the head parts with her strong jaws which worked like a pair of shears. So near was I that I could see these jaws meet and sever the thorax, which fell and glanced from a leaf a few inches below with the faintest imaginable sound. The wasp then proceeded to tear open the abdomen. The builder of gossamer bridges, who overcame space and flung her nets to the breeze, was no more. I looked again at the unfinished web and in it struggled a small fly.
In stretching the first strand the spider avails herself of the wind to some extent. When crossing from one point to another it is by no means necessary she should drop from a height equal to the distance to be crossed; for if the wind is strong enough she has but to descend a little way, and then, as it holds her out at right angles, she pays out the line and so continues moving in mid-air. As soon as she comes in contact with some object she at once attaches her thread. I have more than once observed a spider drop a short distance when there was no breeze to carry her, but by the movement of her body she imparted a slight motion to the line and thus set herself to gyrating until she finally swung across the intervening space.
The spinners of flat webs in the grass are associated with dog-days and with foggy weather, as if they spread their tents only at such times to fold them again and steal away with the appearance of the sun. As a matter of fact these spiders work in clear weather and at different hours of the day, but the web is so fine as to be next to invisible unless covered with moisture, when it at once attracts the eye, like a writing in invisible ink which becomes manifest only under the right conditions.
There are other spiders which become evident only at the approach of winter. It is something to the credit of these small spiders that, being without wings, they should still aspire to fly; whereas the ants, born with wings, are in haste to tear them off. The past year they were so in evidence on the 11th of November that I shall henceforth associate that day with the flight of the Erigone. The weather was cool, but with a suggestion of Indian summer in the air. I first noticed the spiders on top of a hill, for the bare twigs of sumacs were streaming with gossamer threads which shone like silver. From time to time little spiders descended from the upper regions and ran about over my coat. One, which was spinning threads on my sleeve, finally ran out upon my hand and, elevating its spinnerets, began paying out a line, which I could see as I held it against the sun. When this had reached a length of several feet the little spider was whisked off by the breeze and carried away.
Toward sunset a delicate network of gossamer threads covered the open pastures like a silver mesh in which the earth lay captive. These minute spiders have a way at this time of allowing the strands to be drawn from their spinnerets by the wind, until they carry sail enough to be lifted off their feet. They fly away thus on the wings of the winds, perhaps carried high above the earth by ascending currents. Lo, the hegira of the spiders!
It would appear that the Solitary wasps are more ingenious and self-reliant, and less governed by tradition, than the Social bees and wasps; for I have seen a small black one which was unable to rise on the wing with the large spider it was carrying, finally drag it up the trunk of an oak to the height of seven feet and from that vantage fly away. Such an one pulled a spider much larger than herself up on my knee and left it there, paralyzed but alive, while she made explorations, after which she returned and took it away. As I was making some notes at the time with reference to wasps, the incident made a pleasant impression, quite as though she had taken me into her confidence and had gone out of her way to reveal some facts of her life.
One day I encountered a sand-wasp which had just stung a wireworm and was dragging it over the ground. The worm, which resembled a brown twig, was three inches long and as large around as a slate-pencil, while the wasp was not over an inch and a quarter in length and very slender. Seizing the victim in her jaws and straddling it, the wasp walked along in this uncomfortable fashion, over ground strewn with pebbles and partly covered with brush. Difficulties were many, and she was kept constantly pulling, tugging and boosting to get the worm along.
At length she penetrated the brush and came out bearing the worm into an open gravelly space. Here she turned off sharply for a distance of two yards, and, after running nervously to and fro, stopped in front of a small hole. She had been over an hour dragging the worm. During that time one main direction had been followed, though never had she to my knowledge left her burden and risen above the brush and trees to get her bearings; yet she found her way unerringly, and only turned aside because of the boulders and clumps of white birch stumps. The whole distance was about forty feet in a straight line, but further as the wasp had gone.
Backing into the hole, she seized the worm and attempted to drag it in after her, but the entrance proved too small. She therefore came out and began rapidly enlarging it by seizing bits of gravel with her jaws and fore legs, rising in the air and carrying them off six or eight inches. Again she entered, and this time was able to pull the worm in after her. She remained three or four minutes in the hole, during which time she was depositing her eggs, then her head reappeared at the opening.
She now began filling in. Dropping two or more bits of gravel, she would then turn her back and rapidly scratch in dirt with her fore legs, evidently to fill up the interstices. Twice she took out a bit of gravel and carried it away, precisely as a mason might throw aside a stone that was not the right shape or size. As her head was thus inserted in the hole a black ant approached and peered into the depths. Suddenly the wasp turned and gave one look, whereupon the ant fled in haste.
When the hole was filled to the brim she tamped it down with her head. This occupied her some minutes and she appeared to take the utmost care. Gravel was then brought and piled upon the spot until it exactly resembled its surroundings. The stones carried varied in size from those as large as a buckshot to some the size of a marrowfat pea. They were lifted and carried seemingly without effort, and dropped almost before one could see what she was about. Twenty minutes were consumed in filling up the hole and restoring the surface.
On a sudden she vanished, and with her vanished the place itself where she had been at work. It was as if a trap-door had closed, and no sign was left. So carefully had she done her work and so closely imitated the surroundings, like a miser burying his gold, it was only after careful search I could again locate the spot.
Thus in the economy of Nature every insect appears to be food for some other. On the leaves of the Virginia creeper you may usually find, in early autumn, some caterpillars which have received the eggs of a small chalcid fly. These caterpillars, otherwise so large and green and awesome to the beholder, have become limp and lean and have an aged and decrepit look. They hold feebly to the vine but no longer eat anything. I brought home one of them and in a short time there emerged from its body a great number of small white grubs, fifty or more by actual count. Upon the back of their emaciated host they proceeded to spin for themselves marvelous little cocoons of white silk which they did in a very brief time. Moving their heads this way and that they spun the fine threads about themselves until they were completely enveloped. Here were a great number of little spinners, making for themselves garments of silk, and at last spinning themselves out of sight. The caterpillar now bristled with the small white cocoons which stood upon end on its back, where they were attached, and almost hid it from view.
The wary caterpillar has many foes. If it escapes the hungry warblers and vireos, there is still the army of goggle-eyed wasps and nervous ichneumons to circumvent. Yet a prodigious number survive. Were it not for their enemies they would overrun the earth. The butterflies sporting in the sunshine, and the small moths flitting about the lamp, have come through many perils, and may almost be said to have lived by their wits, so astonishing are the ruses they have devised to deceive their pursuers.
THE WAYS OF THE ANT
If you would see the ants to advantage--to your own, that is--you must turn over a pasture stone under which one of the species of small yellow ants has its nest. By thus gently removing the roof, if it is a good-sized stone, the whole colony will be in view at once. The red-ant hill presents difficulties. To dig into it or to pull it apart is quite useless, as the earth falls in and nothing is to be seen but a struggling heap of dusty and indignant ants. It rarely happens that such a hill may be built around a small boulder. If this boulder is suddenly and deftly removed, not dragged or rolled aside, but lifted clear of the hill so that the sides of the nest may not be broken in, a remarkable scene is disclosed.
I have found such an ant hill, and by removing the stone the household was placed on exhibition--but not all its secrets revealed by any means. From several large chambers, now roofless, galleries and corridors radiated in all directions. The instant the stone was lifted the ants swarmed from the galleries into these chambers, which were packed with the large cocoons. There were thousands of pupæ, of a delicate brown tint, looking wonderfully clean and fresh, but with such celerity did the ants work that inside of ten minutes all were carried from view.
Among the rest were perhaps a dozen young ants, the head and thorax being white and the abdomen a pale mauve. These creatures moved feebly about, taking no interest in the proceedings, and were for the most part seized by the workers and conveyed into the galleries. Apparently they were individuals that had just emerged from their pupa-cases.
Under another large stone were two very numerous colonies living side by side, of different species. The nests were, of course, entirely separate and under opposite ends of the stone. The smaller of the two appeared to be stinging ants, for they clustered in great numbers over their small pupæ, elevating their abdomens in a threatening manner like so many diminutive scorpions. The other species were large and active ants of a polished bronze hue. Their pupæ were naked, which gave the nest the appearance of being filled with grains of rice.
These large ants set to work with frenzied activity and removed all of their own pupæ. Then, and not until then, they swarmed over into the adjoining nest and began carrying the cocoons of the small ants back into their own nest. Now and then some small ant bolder than the rest would resist, and an individual combat ensued which ended by the large ant carrying off her small antagonist. There was, however, very little resistance of this sort, and the pillage, if such it were, continued until the remaining cocoons had all been carried over into the nest of the large ants. So few of the small ants made any resistance that it gave one the agreeable impression the larger ants were only offering assistance. But I failed to find on subsequent visits that they had returned the pupæ. And although they daily brought their own pupæ out of the galleries, the smaller cocoons never more came to view, and the small ants subsequently abandoned their nest. Thereafter I felt some compunction in thus disturbing a whole community for mere curiosity.
It is noticeable above all how the ants at such times take no thought for their own safety, but for that of their charge solely. Whether their interest is in any sense maternal or merely a property interest does not appear. Another feature evident in disturbing a formicary is the general harmony in which the individuals of any one colony work together. Here is no less than a catastrophe, as if the roof of one's house were suddenly to be removed and everything upset. And yet not one runs away or apparently conflicts with any other. There are no cross purposes; no two get in each other's way; but animated by a common motive, and by one only, the community proceeds with despatch to the work in hand.
Is this socialism among ants something preordained for them as the condition of their life, or is it in part an acquired tendency of the ants themselves? That they _do_ acquire tendencies would seem clear enough. If it should be proven that this social state is in fact the result of an evolution among them, it would be one of the most significant facts of natural history.
It serves the community admirably at any rate. But with them the individual does not count. Ants are ahead of us in one respect in that they have order without coercion. There is such harmony, such co-operation among them, they have evolved no ruling class, the queens being such only in name and more properly the mother ants. The life of the community is all, and every one looks out for it.
On warm afternoons early in September you may look for the swarming of the queens, when myriads of ants sail into the air in their desultory marriage flight. In apparently endless succession they pass, every now and then one alighting, whereupon begins the curious part of the performance, for they run rapidly about, throwing themselves upon their backs to squirm from side to side after the manner of a dog scratching. They then get upon all sixes and continue running to and fro. After these contortions the wings wear a most disheveled appearance, and, as the process continues, become more and more crumpled, until at length one or more are missing.
Sometimes in sheer desperation an ant will lie on her back and revolve rapidly in this position. In some cases the wings seem to resist all attempts to remove them and the ants redouble their efforts. Their frenzy appears to know no bounds; they fairly stand on their heads and repeatedly fall over miniature precipices and into Lilliputian crevices in their blind determination to tear off the wings. Again they seem to use their legs as though trying to twist off a wing. It is the most fanatical performance to be witnessed among insects.
Such dogged persistence must sooner or later attain its end, and presently the ant is seen running about wingless or perhaps with only a torn stub left. The behavior is no longer frantic as before, but she now moves about as if enjoying great relief. During one such flight great numbers came down into a gravelly path through a huckleberry patch. They apparently avoided the bushes on either hand, and chose to alight in the path, for it was alive with ants twisting and turning and wriggling upon their backs in the gravel. Others, having gotten rid of their wings, were attempting to go head foremost into the ground, possibly with a view of laying their eggs, or merely because the soil was their natural element.
Around the formicary itself the workers were grouped _en masse_, endeavoring either to restrain the new brood of queens in the old colony or to coerce them into leaving. They appeared to drive them as a squad of police might force back a crowd. But it is manifestly difficult to interpret their motives with any assurance, and it is more likely they were provoking them to flight. At such times they ascend the branches of a bush and collect in excited little groups on the buds and flowers around the females, as if determined they should go. No doubt it is an exciting day with them, a sort of Labor Day demonstration. In this case it is the womenfolk who are thus bent on asserting their rights and doing as they will. But why, having once ascended into the larger world and the liberty of winged creatures, must they insist on tearing off this means of freedom to become crawling, laborious insects? They appear to hear two calls, one from above and the other of the earth, earthy, and to obey the latter. But it is with them the race and the future--always the future.
To an ant a tree is a forest in itself. Ascending its mammoth trunk to the upper regions, she follows the great highways of the branches, out into the unknown and trackless wilderness of leaves in pursuit of her game--the aphid. She knows well in what wild and solitary uplands to look for this mountain-goat.
The under side of maple leaves affords good pasturage to numerous green aphids which there browse contentedly in the pleasant shade and under the watchful eyes of the small brown ants that herd them. The aphids are all sizes and ages, though as to age the difference is probably but a few days. With a glass, the process of "milking" may be observed, the ants merely stroking the aphids with their antennæ. Two small tubes, like sap quills, protrude from the back of the aphid, and from time to time minute glistening drops are seen to exude from these tubes and are removed by the ants in attendance. Surely, to the ant here is the land of milk and honey. They move constantly to and fro among the aphids, now and then stopping to stroke one. Apparently they detect by some signs which are ready to yield the sweet fluid. Their presence appears to be agreeable to the aphids and is never in the least resented. After long watching with the glass, I have never seen anything akin to insubordination. Pluck the leaf ever so gently and hold it in a proper position, the difference is at once apparent to the aphids, for there begins an exodus, and large and small troop up the stem of the leaf and so on to whatsoever it may be attached; nor does it cease until they have deserted to the last one.
But the life of ants is by no means given over to these bucolic pursuits. While the meadow-ants seem to be in the pastoral stage, the red species and the large black ones are hunters and warriors. The most sanguinary conflict I have witnessed was a battle of the ants. Two armies of the same black species met on the floor of a neighbor's barn. The battle lasted throughout several days, and both sides fought with indescribable ferocity. Where they came from was a mystery, as no such colonies of ants had ever been seen thereabouts.
They appeared to be of the species _Formica pennsylvanica_ which nests in trees, but these do not occur in very large colonies, whereas the contending hosts upon the barn floor were as the Tartar hordes. The floor was strewn with struggling pairs and with the dead and injured, and always fresh forces were arriving.