Under the Maples

THERE is a lively interest among students of history and society in the uncovering of rubbish heaps, and the reconstruction of village communities out of institutional hints. I have found my pleasure in unearthing the villages and farms and pasture-lands and battle-fields which lie under my maple-trees. Every year the busy life goes on there, whether I watch it or not; it is a microcosm of that world which my daily newspaper reports ; for here among the ants are the builders of cities, the governors and leaders, the masters of slaves, the harvesters, the herdsmen, and the mechanics. No emancipation proclamation has yet been issued, but there are wars and rumors of wars.

Failing to discover the official records of these busy creatures — too busy, may be, to trouble themselves about history — I have kept a journal of my observations. I have had, moreover, the opportunity of comparing the observations which I have made under my Northern maple trees with what I have seen at the South, and I record with pleasure the fact that there is more common ground of pursuit between the two sections than some would have us believe. Naturalists have given us the impression that no harvesting ants are to be found at the North. They are mistaken. Familiar as I am with those of the South, I have never found a more interesting species than one at the North, Pheidole pennsylvanica, a large colony, whose subterranean city is beneath the spreading branches of a maple in near proximity to my house, affording an excellent opportunity to observe its habits.

The colony is composed of males and females and two sets of neuters, consisting of soldiers and workers, each set widely differing from the other in looks and occupation. The soldiers are at once recognized by their superior size and large heads, and they take no part in the ordinary work of the community. The workers are much smaller than the soldiers, and as their name indicates they are the architects, food providers, and nurses of the community. They gather various grains and seeds, which they store in underground rooms, usually below the frost line, which indicates that the grain is housed mostly for winter use ; this idea is further confirmed by the fact of the great quantity of shells and chaff of seeds which they bring out when their city is undergoing its first thorough spring cleaning.

In what way the seeds are prepared so that they may be made into available food is something of a mystery, as the ants take all nourishment in a liquid form. I have noticed that they are partial to those which yield an abundance of mucilage, such as plantain (Plantago lanceolata) ; but whether these seeds are gathered for the mucilage which they contain, or for the albumen, which is also abundant, is a question, for the ants are not confined to mucilaginous seeds, by any means, but harvest those of Oxalis stricta, Spergula arvensis, and grassseed, which are destitute of mucilage but abound in albumen. As the embryo swells it acts upon the albumen, dissolving and chemically changing its substance into a large quantity of sugar, which seems to point to the way in which they are used for food.

But the ants also gather a great many seeds of a cruciferous plant (Lepidium virginicum), which contains no albumen. So instead of devoting my time to finding out the properties of the various seeds which they collected, and speculating upon how and in what way they use them, I have closely observed their habits from early spring until late autumn.

In the first warm days of April, sometimes in the latter part of March, several gates of the city are opened, and the busy inhabitants are engaged in bringing out the refuse of grain and other rubbish which has accumulated during the winter, and which they deposit in a heap outside of the city limits. The laborers work continuously during pleasant weather, and are attended by sentinels, or perhaps street commissioners, who seem to be watching and directing their movements. When the spring cleaning is completed, all the gates are permanently closed except one, and this is shut and barricaded at all times save when the ants are actively engaged at harvest or other work.

Upon excavating a formicary in July, I found several nearly empty chambers ; some near the surface of the ground, others scattered irregularly about to the depth of three feet, where I came to several small rooms or granaries stored with seed. I noticed one chamber much larger than the rest, which from all appearances was the dining-room, as it contained some partly consumed insects. The ants were in great consternation over the loss of their city, running in every direction and carrying the larvae and pupæ, while many of them were buried beneath the ruins. It appears heartless and cruel to destroy one of these neatly built cities, doubtless the work of years and representing the labor of many thousand individuals. And in fact very little can be learned of the interior of such a formicary, even with the most careful handling, owing to the nature of the soil in which it is built. The most satisfactory way of obtaining knowledge of the interior of a formicary is to cut into one of some species that builds in wood, and take out sections that can be carried home ; and at the same time secure a colony of the ants, together with the larval and pupae. This I accomplished with a species of Aphœnogaster, nearly related to the harvesting ants. The blocks were cut through several chambers, but fitted together perfectly. The ants were soon domiciled, and came out and walked timidly about among their new surroundings. I now placed dry crumbs of cake and small lumps of dry, hard sugar near the blocks, which they soon found and carried within. Three days afterward I carefully separated the blocks, and found the dining-room, where the cake and sugar had been taken. The blocks were dry and placed where no moisture could reach them except what the ants might convey, and yet the cake and sugar were dissolved into a pulpy mass. The larvæ were in dry chambers, not far removed from the food. This indicates that the harvesting ants bring their stored seeds from the granaries to another room, as needed, and have some process unknown to us whereby they make the seed into available food.

When some reconnoitering member of the community has found an abundant harvest, the news is soon imparted, and the workers form in line and march to the spot. Here the line is broken, and the numerous individuals scatter about and collect the seeds, when they again form in line and return over the same road. Day after day this road is traversed, until the grain is exhausted, or until some enterprising member has found better harvesting-grounds, when the old field is forsaken for the new. I have never seen the soldiers in line with the laborers carrying seeds, but they are always at the front, where strength and courage are required, and they will work in case of an emergency.

In common with other ants, the harvesters are very partial to animal food, upon which, no doubt, they greatly subsist during the summer. A dead fly, several times larger than one of the ants, was placed a short distance from the gate of the city. A wandering individual from the tribe of Lasius discovered it at the same moment with one of the Pheidoles. (As our little harvester has a name and place in the scientific world, I will hereafter call it by its generic name, Pheidole.) The two are about equally matched in size and strength, and now a struggle ensues for the coveted prize. First one and then the other seems to have the advantage. Lasius succeeds in getting it a short distance from the place of discovery in the direction of her camp, but is obliged to drop it to make sure of her bearings, when Pheidole hurries with it in the opposite direction, eager to place it within her gate before the other again seizes it. But Lasius is not to be beaten in this manner, and again struggles for the mastery, and it begins to look as if she might be successful. At this point Pheidole seems to be discouraged, gives up the contest, and starts for home. She enters the gate for a moment, and hastily returns, closely followed by a soldier. During this short interval Lasius has moved well forward in the direction of her camp. Pheidole reaches the spot where she left the prize only to find it gone, and now she rushes in frantic haste round and round, widening the circle as she advances, until she finds Lasius, and again lays hold of the fly. The soldier, meanwhile, moves more slowly, but makes the same circuit until she reaches the contending parties, and takes hold of the fly by the side of her comrade ; and now the burden is easily carried, with Lasius clinging to the opposite side, and holding on with untiring pertinacity, occasionally preventing the rapid transit by bracing herself against some object in the path. This seems to provoke the soldier, who drops the fly, lays hold of Lasius, and tears her in pieces, while the smaller Pheidole carries the prize to the city and disappears within the gate.

I placed six freshly killed horse-flies near the city, any one of which was many times larger than one of the Pheidoles. Two workers soon made the discovery, and walked over and around this huge pile, as if taking its dimensions. Satisfied that it was beyond their power to do anything alone, they simultaneously started for the city, as if each were anxious to be the first to impart the news. Not a soldier was visible, but several must have been just within the gate, for they immediately came pouring out in large numbers, and at once proceeded to this supply of food. The flies were soon carried to the city, but were too large to drag through the gate (the streets, or galleries, were much broader than the gate from which they diverged) ; so they were removed a short distance, and a company of laborers was employed in enlarging the gate, while the soldiers were engaged in cutting off the wings and legs from the flies. Soon one was brought back to the gate, two legs and a wing still adhering to the body. They tried to take it in head first, but it would not go ; they lifted it out and turned it round, but succeeded no better until the remaining legs and wing were severed. All of the flies were managed in the same way. The legs and wings, as fast as the soldiers severed them, were borne within by the workers. Sometimes the wings were at first rejected and thrown among the débris, but other more provident individuals were sure to find them, and bearing them aloft like banners carried them into the city. In less than an hour all of the flies were housed, the gate closed, and not an inhabitant was to be seen.

Each tribe has its own peculiarities. Lasius flavus is a thieving, vagabond race, widely differing from the Pheidoles, who have regular settled homes, while the camps of the Lasius are scattered everywhere, and often changed. Sometimes several camps are near the city, and prove to be a great annoyance to the citizens; the strolling tribes hinder them in their work, and interfere with their funeral rites. Several workers are employed among the Pheidoles to keep the dining-room in order: they bring out the chaff of grain and shells of seeds and remains of insects after the feast, and deposit them in a heap some distance beyond the gateway. While they are thus engaged a sentinel is always patrolling around the gate to warn them of approaching danger. The Lasius are the most dreaded enemy. They are sure to be on the alert when the gate of the city is open, ready to snatch prey from the returning hunters; or they rush up to the workers, to see if they are carrying out anything desirable. So the sentinel, when she meets any of this tribe, hurries to the entrance and stations herself there, and seems to whisper to each advancing worker, who hastily retreats with her burden. As long as the sentinel remains at the gate not one of the laborers passes out; but she no sooner returns to her rounds than they begin to emerge, at first slowly and cautiously, deposit their burdens, and return for more.

The Lasius are not only cannibals, but they will snatch the dead body of a Pheidole from its relatives when on the way to the place of interment. I was sitting near the closed gate of the city, and observed that the sticks and pebbles with which it was barricaded were being moved to make room for an individual to go through. The ants came out one at a time to the number of seven, and removed the stones and sticks to one side, leaving a free opening. And now one of their comrades came bearing the dead body of a young female. She had died while still clothed in the white filmy material in which the young are swathed, — a fitting shroud, through which her plump body was plainly visible. Her limbs were neatly folded across her breast. The bearer started alone to conceal the body in some distant place, while her comrades reclosed the gate and retired within the city. I followed the bearer, and saw, from the direction she was taking, that she would soon be in the midst of several camps of Lasius, of which she seemed to be unaware. No sooner had she reached the border of the camps than her footsteps were dogged by one of the tribe, who soon overtook her, seized the body and tried to wrest it from her; but finding that her strength was not sufficient she let go her hold, and hastened to the nearest camp to tell of this desirable prize. Soon a dozen or more of the Lasius were on the track. She now became thoroughly alarmed, and impetuously rushed forward until she came to a deep pit. She did not drop the body, but clung frantically to the edge of the pit, until the little fragment of earth gave way, and she was precipitated with her burden to the bottom. The Lasius lingered a while, waiting for her reappearance ; but she did not come, and they returned to their quarters.

The Pheidole’s mode of defense when attacked by a large army is unlike that of any other species with which I am acquainted. A great troop of Lasius from surrounding camps came down upon the city, with the determination to take it. They scaled the fortified gate and hastily threw aside the barricade, but were met by a solid phalanx of large-headed soldiers which completely filled the gap. Defeated here, their next move was to mine into a street a short distance from the gate. But their labor was of no avail ; here, too, was a phalanx of soldiers, and not a Lasius was allowed to pass within. But they had their revenge in another way. Every little while one of the workers, who had been away from home, returned, and tried to reach the entrance, but was invariably seized by the enemy, when one or two soldiers would come to the rescue, and the little worker would make her escape and promptly pass into the city, while the soldier was immediately surrounded by a horde of the invading foe. She fought valiantly, and killed many, but sometimes succumbed to the overpowering numbers ; more frequently she freed herself and escaped, not back to the city, but by climbing the nearest object, — a stem of clover or grass, — where the enemy never followed. Several soldiers escaped in this manner, and remained concealed until the defeated army returned to its quarters.

A good illustration of the care and sympathy which the members of a colony of Pheidoles have for each other was manifested in an artificial formicary, arranged by the Rev. Mr. Morris, and placed upon his study table. The formicary was in a glass jar, about two thirds full of earth. The outside of the jar, as far as the earth extended, was encircled with paper, to exclude the light, in order that the ants might build their galleries and rooms next to the glass.

The colony soon became reconciled to their strange home, learning to come out of the jar and pass down the legs of the table to visit any part of the study and return. The workers had no difficulty in ascending the glass, but the large-headed soldiers could not get up without assistance. They would go as far as the paper extended, and fall back with every attempt to scale the smooth glass. Their large heads were a detriment rather than a help in such a novel emergency as this. And now the little workers, who had always looked to the Amazon soldiers for help in all trying circumstances, came to the rescue, and assisted them over the slippery place. One would come to the edge of the paper and meet a soldier, and gently take hold of her antennæ, and walk backward up the glass, steadying and supporting her until they both passed into the formicary. This soon became a fixed habit. After a while the soldiers did not try to walk up the glass alone, but would wait at the top of the paper for the workers to conduct them over it.

Several other species of ants in the North occasionally collect seeds and flowers and foliage. I have observed a tiny black ant, a species of Tetramorium, gathering honey from flowers, after the manner of bees. I first observed this species in New Hampshire, in the month of August, 1880, collected in great numbers on the golden-rod (Solidago nemoralis). They ascend the long stalks and enter the flowers, where they are almost entirely concealed, only the tips of their abdomens showing like black specks on the bright yellow florets. When they are satisfied they come slowly down, with their honey-sacks rounded out almost to bursting, and all follow the same path until they reach their subterranean formicary.

The harvesting ants and their allies have nothing to do with aphides or other sweet-secreting insects. They seem to have some way of elaborating or obtaining sugar directly from plants. But many other species depend in a great degree upon their flocks and herds for subsistence. Notable among this latter class are the Crematogasters, —an interesting race, divided into many clans or tribes. They often keep large herds of aphides, — cows the immortal Linnæus called them, — upon which they are greatly dependent; so the prosperity of a colony may be known by its herds. The droves are jealously guarded from marauding tribes who are less fortunate in their possessions, and who frequently try to get the control of the cows of their more wealthy neighbors.

In the summer of 1881 I witnessed an exciting contest between two colonies of the same species, over a fine herd. The pasture on which the cows were feeding consisted of tender green herbage, and they were in good condition and yielded an abundance of the saccharine fluid. Around this pasture was a space of bare ground, where the troops were marshaled to keep the neighboring colony from trespassing among the drove. Tier upon tier, a solid phalanx extended around the entire pasture, making it impossible for the invaders to break through the ranks. The assaulting army was lean and hungry-looking, but fully as large and strong as the one attacked. There was no general engagement, but every little while two of the opposing forces would clinch and tumble about over the ground like two dogs, but on relaxing their hold neither party seemed to be hurt. The cows were not neglected during this skirmishing. A host of kind and gentle milkers were constantly employed in obtaining the fluid, patting and stroking the cows with their antennae until they gave down the milk. I noticed that the soldiers often changed places, those at the front going to the rear. The cause was soon apparent. All along the rear the milkers were feeding the troops. Other milkers were constantly going to and from the subterranean city, which was situated not far from the pasture-lands. They were no doubt supplying the queens and other members of the colony who were unable to be in the ranks.

After witnessing this skirmishing for several days, I established a drove of aphides near the city of the hostile colony. Some of the invaders were always on the road between the two colonies, slowly walking back and forth, like sentinels, to watch over their city, that it might not be taken by surprise while the protectors were absent. And now one of the sentinels came upon the cows, and ran around among them in an evident state of excitement, but did not stop to obtain any milk. Apparently satisfied with the fine condition of the herd, she ran with all haste to impart the good news to the army stationed around the neighboring colony. I followed her closely, never losing sight of her amid the throng. On her way she frequently met a returning comrade, whom she stopped for a moment and touched with her antennæ. The speed of the comrade after obtaining the news was greatly accelerated in the direction of home. The sentinel reached the outer ranks of the army, and communicated with every one with whom she came in contact, and somehow imparted the same excitement with which her own body was quivering, until the whole army was aroused and on the homeward road. Very soon there was a host of eager milkers among the drove. But a large part of the army retired within the city, where they were fed by the milkers. Now that the invading force was withdrawn, the troops of the threatened colony also disappeared, only a few sentinels remaining to watch over the milkers and herd.

A tribe of Formica (F. gagates) also makes stock-raising its principal means of support, but the herds are entirely different from those of the Crematogasters: they do not graze in open fields, but are stabled, and feed on the roots of various plants. Underground stables are made expressly for them. The earth is removed from around the tender roots, and the dun-colored cattle are clustered in small groups around the roots upon which they are feeding. The groups are arranged so as to enable the milkers to pass easily and freely among them.

I have often carefully opened the stables, but the owners always resented it, and carried the cows away to subterranean galleries beyond my sight. When the stables were reclosed, in due time they were brought back and disposed in the same regular order.

There are two distinct races of slavemakers among these humble creatures, who capture and hold slaves to carry on their domestic affairs. Polyergus lucidus is the more remarkable of the two, and it would require many pages to do it justice; but I can devote only a short space to this singular species, which is wholly dependent upon its slaves for its continued existence. These ants are very powerful warriors, and are furnished with sickle-shaped, pointed mandibles, sharp as spears, with which they can impale an enemy with great facility. Their wonderful prowess and skill in war seems to be recognized by all of the various tribes of the country. They are a ruddy race, about half an inch in length, with bright, shining coats ; a nervous haste characterizes their movements. They make slaves of but one tribe of blacks (Formica schaufussii), whereas the other slave makers (F. sanguinea) attack any and all tribes which they can overpower.¹

From the indolent habits of Polyergus, and from the fact that they are never seen except on the war-path, it has been supposed that they are of rare occurrence. But in New Jersey they are quite as numerous as Sanguineas. By carefully observing the movements of the latter I have been enabled to detect several colonies of the former of whose existence I was before unaware. If the Sanguineas pass a colony of blacks without attacking it, it is good evidence that the blacks are the slaves of the Polyergus. This can soon be ascertained by keeping watch over the colony.

The raids of Polyergus are made in the months of July and August, and always in the afternoon, usually between the hours of two and four. Their march is unlike that of any other tribe in this country. A dozen or more of the advance wheel and fall back in the ranks ; those coming after make the same move; and so they continue, constantly changing places, until they reach the black colony, upon which they make war and rob them of their young. When they return with their plunder they march in a direct line, — no turning back in the ranks. The slaves always remain at home during these raids; but they receive the young blacks from their masters, feed and nurse them, and rear them as slaves to wait on and serve their owners. As no slaves are born in the homes of Polyergus, it is needful each year to renew the stock from surrounding colonies.

In order to study the character of Polyergus more thoroughly, I captured several and made them prisoners. I gave them every necessary accommodation, and placed an abundance of food before them. But they seemed to scorn the idea of labor, and would not even feed themselves. I kept them in this condition three days, until I was satisfied they would all die without their slaves, so I put a few in the prison with them. These faithful creatures manifested joy on meeting their halffamished masters. They stroked and licked them, removing all dust from their bodies, and prepared food and fed them ; finally they excavated a room for them, and took them from my sight.

Mary Treat.