Feeding the ant commune

Continuing our studies of the emmet modes of feeding the commune, our thoughts once more return to the great confederacy of mound-making ants among the Alleghany Mountains. We fix our attention upon a column of workers pressing along a well-worn path straight from a large mound to an oak-tree that stands by a boundary stone wall eight rods distant. There the column leaves the ground, mounts the trunk, and is lost among the branches.

But here several interesting things are noted. There is a descending as well as an ascending column. Moreover, there is something like the sentry service established at the gates. There is a tree-trail one to three inches wide, to which the ants steadily keep, and which is blackened by the continuous fumes of formic acid issuing from them. On either side of this are watchmen, who persistently challenge passers-by. There follow swift crossings of antennae and mutual recognitions - how one longs to know the countersign!-prompt withdrawals, and the pilgrims pass on and are soon distributed among the principal limbs. A goodly number lead off upon one of the lower boughs which overhangs the stone fence.

Mounting this, one has the key to the movements of the marchers on the avenue beneath. At various points

simply feeding, but collecting food supplies which they are taking home in their mandibles or stored in their capacious crops for the natural dependents and others of the formicary entitled thereto. Following with closer attention the trail of the repletes, you observe some of them suddenly disappear at the roots of the tree. Turn back the sod, clear away the leaves; what do you see ? Masses of insects are huddled together in the angles of roots at the foot of the tree and in sundry depressions in the soil. Some are repletes, some are ordinary workers; and the latter are stopping or trying to stop the former, who seek to avoid them and to push into certain openings that lead into galleries beneath the surface, which evidently communicate with the central mound. A few succeed in this, but many yield to the friendly force and halt.

And now what? See this replete. She has raised herself upon her two pairs of hind legs until her body slants in a wide angle toward the horizon. And one, two yes,three workers, assuming a like rampant position, have placed their mouths against the replete's mouth. Look closely now, and you will see a droplet of amber or - whitish, syrup-like liquid gather upon the delicate, thread-like maxillae beneath the replete's jaw. It is the honey-dew obtained from the aphides upon the oak. It has been forced up from the crop by pressure of the contracting muscular sac that encloses it in other words, by regurgitation. It is greedily lapped by the three "pensioners," and the replete breaks away and disappears within one of the gallery doors. All around the foot of the tree are like scenes wrought-visiting ants taking toll of the foragers.

Who are these visiting ants? Are they highway robbers? They are certainly not aliens, for the relations of all concerned are most friendly. There is, indeed, here and there a slight show of force in the detention of a replete who has more than usual reluctance to part with its stored sweets, but there is no element of real hostility therein. Plainly repletes and pensioners are citizens of one community, and their behavior must term apart of a natural social arrangement. What is it ?

Not all at once, but gradually, the facts dawned that repletes, acting as communal foragers, were carrying supplies to the formicary; that numbers of their fellows, engaged as builders, sentinels, and nurses, had left their several duties for a little while to feed, and instead of spending time and energy due to the commonwealth in gathering food afield, had come out to tap the garnered stores of their comrades, and, having relieved their hunger, would return to their labors. In short, they had been drawing rations from a sort of field commissary department. They are no devotees, these adventurers, of the theory that,

"To feed were best at home;
But thence, the sauce is ceremony;
Meeting were bare without it."

There certainly seemed to be scant ceremony in this method of banqueting abroad. In truth, it had the outward look of levying mail or highway robbery, although there was no real violence on the part of those who bade the repletes "stand and deliver." Indeed, upon due reflection, the affair resolved itself into a beneficent social function, of which the following appears to be the spirit and intent: The ants at work in or about the home premises leave the collecting of food to others of their fellow-citizens, not only for the public dependents but for themselves. Content with satisfying the simple wants of nature that they may have strength to toil, they leave their work and visit the feeding-grounds to get food from the repletes. The stations for this purpose are wisely chosen; for, as many of the foragers are overladen, their progress homeward is eased by yielding somewhat from their stores.

Besides, it seems probable that the instinct which urges repletes to gather supplies for home dependents might, after the formicary had been reached, prevent parting with them to others. Moreover, since ant nature in some degree is partaker of the weakness of human nature, it is supposable that the surplus honey-dew, after feeding dependents, would be kept for individual delectation, and the home worhing-force be compelled to leave their work and forage for themselves. The general movement, therefore, to arrest repletes at stations near the feeding-grounds is evidently for the public good.

It would be an odd speculation to consider the effect upon society were such a rule to prevail among men. Suppose the citizens of cities like New York, Philadelphia, and Chicago, or of such states as Georgia, Ohio, and Massachusetts, were to agree that one moiety of their number should take the duty of earning or collecting food supplies of every kind for the entire community, leaving all other duties to the rest? Further, suppose that these gatherings must be divided with equal hand among all sorts and conditions of people-young and old, active and dependent, high and lowly, rich and poor, with sole regard to their real natural needs?

Stop! Our phrasing is faulty; for in this ideal state of society, if fairly conformed to the type of an ant city, there would be no rank or grade, no rich or poor, no personal distinctions, no individual property. All things would be in common. There would be one and only one property holder - the State; nor would even the faintest desire for separate possessions ever cross the thought of the most fanciful. There would be no lust for riches or superior place or an easier lot in life. One purpose would dominate all with absolute sway: to serve the All-the whole community - with all one's powers, in any line of required duty, without hesitation, without stint, without reserve, and without pay.

This is truly a wild speculation! This is to conceive of the inconceivable - that human beings could attain the social standards of an ant-bill! One must first suppose a moral revolution which even the dreams of a Golden Age or a Millennium - such as idealists in every century have had - would dimly depict; a revolution more radical than that implied by a literal conformity to the precepts of the Sermon on the Mount and the Saviour's summary of the moral law. It would be a revolution not only in social characteristics, but in individual character, a veritable palengenesis of every member of the commonwealth. Would it be for the better or the worse? Would our race gain or lose by achieving the communistic - individualistic type of the government of ant cities?

It is evident that there must be a good deal of variation in the food supply even under favorable conditions. This would be felt at times when other labors of the commune, as extension and repair of the living quarters, interfere with the regular foraging. Moreover, there are periods when the reproduction of eggs by the queen is especially active, and the vast increase of larva,, all needing food and care, greatly multiplies the demand both for food and labor. The pinch of such conditions must fall inevitably upon the helpless young. Should they chance to come contemporaneously with a few days of scarcity, which may arise from various causes, the communal dependents must certainly fare ill, and the death-rate be enlarged among them.

And it befalls communes of ants, as it comes to nations of men, that great deviations from the ordinary course of nature bring about disasters, at times so great that the very life of the community is at stake. Famine follows in the wake of war and floods, and untimely frosts and droughts consume the sources of food in the world of ants even as of men. The plough turns up the fallow field, and multitudes of ant-nests are destroyed by agriculture. Thus some of our noblest species of native ants are vanishing before the advance of man, as are higher types of animals.

However, the vitality of some species under the strain of famine is remarkable. Miss Fielde has shown (Tenacity of Life in Ants) that the workers of Camponotus americanus may live nine months without food. They thus rival, in their ability to endure a prolonged fast, the queens that go solitary and draw upon their reserve tissue enough for self-sustenance and also to nourish the firstlings of their flock. The common mode of feeding the young, as heretofore described, is by transfer from the nurses' crops by regurgitation. But a wholly different manner has been observed that is more like our way of giving food to domestic fowl and animals. This grows out of the fact that the larvae of Pachycondyla and some other genera are able to feed themselves; perhaps have been educated thereto, though the natural aptitude must have underlain the habit.

While lying upon their backs the larvae suck the juices of particles of food given them. The nurses of Leptogenys dismember termite nymphs and scatter the pieces among their larvae, who thrust their beaks into the soft parts and feed thereon. So also workers of Odontomachus will tear off the heads and legs of house flies, cut the thorax and abdomen into pieces and feed them to their larvae. In the above cases the food was not first masticated, as is done by social wasps, but simply cut into pieces to expose the soft parts to the larval mandibles. Adlerz has made like observations of the larvae of Leptothorax, Stenamma, and Pheidole, who are fed with solid as well as liquid food. Such increase in the variety of food and feeding the young must add to the chances of their whole some survival by lessening the danger of a failure of food, since it greatly widens the field from which available supplies may be gathered.

An example of the strange exigencies that befall the inhabitants of an ant commune appears in the case of certain workers of Pheidole commutata that become infested with large internal parasites, and are therefore known as Mermithergates. This condition is accompanied with an enormous appetite, and they continually beset the nurses for food, which they get often at the expense of the hungry larvae.

The voracious creatures not only ply the nurses with mimetic entreaties, including the out-thrust tongue, but keep up a stridulating chant of solicitation. At times they resort to more vigorous measures, and seizing a replete, hold down its head with their large forefeet, and compel it to give up the contents of its crop. This greediness has its penalty in times when food is scarce; for in order to rid the commune of such voracious and non-productive mendicants, they are killed outright or starved to death by the workers.

The honey-ants as studied by the author in Colorado made their night expeditions into a scrub-oak copse, and the sweet liquid with which their crops were filled on their return was collected from oak-galls formed upon the twigs and branches. But, doubtless, like other ants, they know the value of aphides, and, as the seasons change, gather from them and from other sources the supplies for current sustenance, as well as for their peculiar mode of providing for future wants.

Among the honey-ants the workers, though varying III size, are structurally alike. Yet certain individuals, quite independent of caste, and following an impulse unknown, but apparently fixed in the germ and early manifest in the callows, begin to store up food in their crops, and thus develop into rotunds or honeybearers. It must be allowed to be a curious manifestation of communal philomyrmicry which causes one of the most active of creatures to become little more than an animated honey-pot, that the food supply of its fellow-formicans may not lapse. But so we find it; and, after all, it is little more than a development to its climax of an instinct that urges ants of other species to charge their crops with an excess of food in order to impart it to the commune dependents.

According to Dr. Hunter Corbett, in many parts of the province of Canton, where cereals cannot be cultivated profitably, the land is given up to orange-trees. These are subject to attack by a species of "worms" - the specific name is not given - which work serious injury in the orange orchards. A peculiar mode of protection from these enemies is adopted by the proprietors, apparently suggested by the fact that the injurious larvae are preyed upon by certain ants native to the orangeries. But these are not bred in sufficient numbers to be of much practical advantage. Resort was therefore had to the "hill-people" of the countries, who find the ant nests suspended from the branches of the bamboo and other trees.

There are two varieties, a red and a yellow, whose nests resemble small cotton bags. These are captured by the Chinese mountaineers by means of pig or goat bladders baited inside with lard. The mouths of the bladders are stretched across the gates of the ant-nests, and as the insects are fond of oils and greasy food, they enter in, are trapped in great numbers, and are sold at the orangeries. They are colonized upon the trees by turning them loose upon the branches. Once established, they begin their work as insecticides by capturing and killing the destructive larvae. To enable them to pass freely from tree to tree, all the trees of an orchard are connected by bamboo rods.

Whether such a method is practicable in the United States, at least to an extent to justify extensive use, may be doubted. If successful at all, it would probably need the painstaking patience of Chinese men with the Chinese ants. However, a, somewhat similar experiment has been tried upon a Ponerine ant (Ectatomma tuberculatum), popularly known as the "Kelep." This ant was imported into Texas by the United States Department of Agriculture as an insecticide, with the special purpose of directing its insect-destroying energies against the cotton boll-weevil. It had shown marked tendencies in that direction in its native Guatemala. Apart from the more or less complete success of such experirnents, the fact remains, which is here relevant, that it is one of a great army of ants that feed upon living insects.

That this habit is widely distributed among the native ants of our Southern States was shown in a report made by the author a number of years ago to the then entomologist of the Department of Agriculture, Prof. J. H. Comstock. Several species therein described were found to prey upon the eggs, the larvae, and the pupae of the cotton caterpillar over a wide section of our southern territory.

It is not difficult to suggest a theory as to how the taste for cereal foods may have arisen among ants. Whether it be the true one or not is another matter. Following their habit of general scouting for supplies, and of putting all promising objects to the test of antennal or gustatory approval, they would be sure to fall upon seeds in the milk stage. Being then soft and easily crushed, and to the ants a toothsome relish., all grain-like seeds would soon commend themselves, and easily pass into the accepted and fixed menu.

As the outer shell gradually hardened, the growing taste for such food would prompt to break it open, and so would come, little by little, the habit of removing the husk. Although the flavor of the seed would change with its ripening, one readily conceives that the taste for it might have a corresponding gradual change; and also the power of utilizing it for food by rasping off or breaking up the starchy substance instead of crushing and lapping it, as in the milk stage.

In quite the same way the use of nutty or oily seeds would gradually form, aided by the natural emmet appetite for animal and vegetable fats and oils of all sorts. The tendency to carry all these seeds to the common centre, the nest, would in due course be followed by, first, the taking off and deporting the useless husk or shell, and, next, the retaining for temporary, and so at last storing for more permanent use, the grain or nutty meat of the seed. The harvesting habit in ants since it was first scientifically confirmed by Moggridge has excited an exceptional degree of interest and surprise. But in truth, when one considers all the conditions, the wonder is that it is not more widely distributed. Here we may notice a peculiarity that appears in the communes of a Texas species, Pheidole instabilis.

A study of its feeding habits presents a striking example of a sharp distinction between the functions of the soldier and the worker caste. The workers are much the smaller but far more numerous, and the bulk of the commune's work is done by them. They collect and store seeds and dead insects. They dig rooms and galleries, care for the huge royal larva; and pupae, feed the brood, and aid the callows break out from the pupal sac.

The soldiers do none of this work. They are the communal trenchers. They crush and carve the tough insects and hard seeds stored by workers, a service for which their large muscular heads and jaws are well fitted. The same organs are efficient weapons for defence of the commune, a service which attaches to them as soldiers. As such they may be seen, as if on sentinel duty, surrounding the communal dependents. They are stolid in temperament. They decline, in Indian fashion, to take part in nursing the communal young. Their big heads, though of such value to the commune, may sometimes be a serious incumbrance to themselves; for when dropped upon their backs on a polished surface, they are not able to recover themselves, and may die literally standing on their heads.

It seems to be an odd characteristic that these megalacephalous creatures appear never to feed upon the oily seeds and insect juices which they make available by cracking the material brought in by the workers, but live on liquid food regurgitated by the workers. One must note in this a beneficent arrangement; for the soldiers, not being exposed to the temptation of feeding directly upon the food which they carve for the workers, and which must thus all pass through their "hands," make sure that the dependents are not stinted or starved and the community thereby imperilled. This characteristic seems all the more important in view of the philoprogenitive defects of these soldiers. A species of Pheidole is found in and around Philadelphia, and it too is characterized by a big-headed worker caste. I have made observations of its seed-storing habits, but it remains to be learned whether the soldiers have acquired so remarkable a role as that of communal trenchermen.

Some of the feeding habits of the Indian Leptogenys are interesting. Writing of Lobopolata dtistinguenda, Mr. Wroughton says D'Ur. that it is occasionally seen going about solitary, probably when acting as scout, but ordinarily is only met in the early morning or late in the afternoon travelling in an unbroken column four to six or eight abreast, by the straight or the easiest road to the scene of operations. This is usually a colony of termites, or white ants, whose galleries have been broken open by the hoof of a passing beast or some like accident. Apparently they do not have the initiative faculty of breaking into the termites' nest, but wait far an accidental opening. Arrived at their destination, every ant seizes her termite prey, swings it under her thorax in the usual way of these porters, and the attacking column then moves homeward. But the return formation is much less regular than the advance; it is, in fact, a "march at ease."

The same writer gives a note on the allied species Lobopelta chinensis. A populous community of this ant had settled in a cavity of the house foundations of Mr. Aitken, who reports the incident. From this nest there ran a well-marked ant road which crossed a broad gravel path and then branched out over the tennisground. After sunset the workers would conic out and march along one of these branches, or break up into parties and take different routes. Their point of approach was a termite's nest; and when they reached a place where these insects had thrown up new earthworks, and were busy eating dead grass underneath, they collected in dense masses, awaiting an opportunity to break in. This came when the termites sought to extend their works on any side. Then the waiting columns of ants were precipitated in mass upon the unprotected creatures, and the slaughter began. Sometimes the termites were killed faster than they could be carried off. After one raid, as late as 7 A.M., the ground was still heaped with the slain, and an unbroken stream of ants fifty-six yards long was taking them away, every porter having two or three of the dead in its jaws.

Sometimes the tables would be sharply turned upon the plunderers. If they chanced to cross the territory of a commune of harvesting ants after they had opened their gates and were abroad on morning duty, the Lobopelta hordes had to flee before their betters, often abandoning their booty. Yet, per contra, the observer once saw a Lobopelta, who had come to the aid of a comrade assaulted by a harvester, after vainly trying to tear off the aggressor, deliberately pick up both comrade and assailant, and carry them off together! Apparently both were so intent upon the personal combat that they gave no heed to the deportation.

Leptogenys elongata feeds largely upon the common wood slaters (Omiscus and Armadillidium), which abound under stones and logs in shady sites where the formicaries are placed. The workers have repeatedly been seen carrying dead slaters in their mandibles, and the space surrounding the gates is white with bleaching limbs and segments of the crustaceans, a proof that great numbers of these animals must be destroyed by the ants.

Their long, toothless mandibles resemble scissors, and are well adapted for piercing the intersegmental membranes of their prey and exposing edible parts. This ant appears to be the only one known to feed on crustaceans as a regular diet. Other species are insectivorous, granivorous, mycetophagous (fungus eating) feeders on the sweet, liquid excretions and secretions of insects, or the juices and sugary exudations of fruits, plants, and galls, and on animal fats and oils.