A still more extraordinary instance of a slave-holding species of ant than the one just mentioned is Anergates atratulus, for in this there are no workers at all, only kings and queens, who are waited on, and their eggs and larvæ fed and tended, by the slave species—Tetramorium, in this case also—just as though these latter were their true-born subjects. Here too the slave species is only represented by workers. These male and female Anergates—a worker of the species has never been known—are both few in number and weak in themselves. When a pair of them (or a fertilised queen) go off to found a new colony, how do they, or how do their few weak descendants, impress a strong fierce species into their service, by whom the nest is built, and every other service performed? The question remains unanswered. Nobody knows. Several theories have been advanced, one by Sir John Lubbock, who supposes that the king and queen of Anergates assassinate the queen of Tetramorium and reign in her stead,[[54]] and another, more recently, by Wasmann, whose idea is that fertile queens of Anergates are sometimes adopted by a colony of Tetramoriums who have lost their own queen. This last is the newest suggestion, and is considered just at present, perhaps for that reason, the most probable. To me Sir John Lubbock’s view seems likelier to be correct, since it is more usual in nature for the weak to prey, as parasites, upon the strong, than for the strong to seek assistance of the weak. True, I can form no idea as to how the assassination of the rightful queen takes place, but Nature is full of resources, and will do much to promote a really worthy end.
I will conclude this chapter by quoting some remarks of Sir John Lubbock as to the ill effects which the institution of slavery exercises, with ants as with men, upon the character of the slave-holder. “These four genera,” he says, “offer us every gradation from lawless violence to contemptible parasitism. Formica sanguinea, which may be assumed to have comparatively recently taken to slave-making, has not, as yet, been materially affected. Polyergus, on the contrary, already illustrates the lowering tendency of slavery. They have lost their knowledge of art and their natural affection for their young! They are, however, bold and powerful marauders. In Strongylognathus the enervating influence of slavery has gone further, and told even on the bodily strength. They are no longer able to capture their slaves in fair and open warfare. Still, they retain a semblance of authority, and, when roused, will fight bravely, though in vain. In Anergates, finally, we come to the last scene of this sad history. We may safely conclude that in distant times their ancestors lived, as so many ants do now, partly by hunting, partly on honey; that by degrees they became bold marauders, and gradually took to keeping slaves; that for a time they maintained their strength and agility, though losing, by degrees, their real independence, their arts, and even many of their instincts; that gradually even their bodily force dwindled away under the enervating influence to which they had subjected themselves, until they sank to their present degraded condition—weak in body and mind, few in numbers, and, apparently, nearly extinct, the miserable representatives of far superior ancestors, maintaining a precarious existence as contemptible parasites of their former slaves.”[[55]]
Since, however, in all these cases the masters are still truly served by their slaves, who make them comfortable, and have no more sense of their degradation than they themselves have, an answer might be made to these moralisings. However various the masks behind which true motives lie hid, happiness, diversely conceived of, is the one end and aim of all. Does it, then, really much matter by what means it is attained? Till we can show that these slave-holding ants have become less and less happy, we are only tilting at shadows, and an Anergates might very well say, in regard to the above view, “Tut, prut, drop your heroics. I am very comfortable; these strong fellows work for me. I like not working, and what I am I wish to be.”
CHAPTER XIV
Ant partnerships—How some ants feed—Persuasive methods—An imperium in imperio—Amusement by instinct—Begging the question—Nest within nest—Ant errors v. human perfection—Distorted arguments—How partnerships begin—Housing an enemy—Ant ogres.
THE relation of slave and slave-master—to use the received terminology—is not the only one of a social and friendly nature in which ants of different species stand towards one another; for as will have been gathered in the previous chapter, slavery amongst ants is a quite friendly institution, conducted, in fact, upon the “liberty-equality-fraternity” principle. Some species of ants, however, inhabit the nests of other species, or build their own amidst theirs in such a way as almost to make them one, and thus they live as perpetual guests, not only without paying for such accommodation by rendering their hosts any services, but often forcing these latter to be of service to them in other ways also. Thus, a small species of Texan ant whose first or Christian name is Leptothorax, but whose surname has not yet been fixed upon, lives on these terms in the nests of a larger one, the celebrated Myrmica brevinodis. Whether Professor Wheeler was the discoverer of the little ant I am not quite sure, but he was the first, I think, to observe its relations with the big one and those of the big one with it, and his account of them is excessively interesting. “A small dish,” he says, “containing a syrup of sugar and water was placed near the nest (an artificial one under close observation). This was soon found by two of the Myrmica workers, which at once gorged themselves with the liquid and returned into the nest.”[[56]] Soon afterwards a Leptothorax worker entered it also, and having run or tracked down one of the two honey-gorged creatures, forthwith got up on to its back, and, seated there, began to lick its head, an attention which it supplemented with a soft, persuasive titillation with its antennæ, whilst at the same time communicating a motion to its abdomen, which Professor Wheeler is so convinced must have been accompanied with certain sounds—known to the learned as stridulations—that he does not hesitate to affirm that it was thrown “into stridulatory oscillation.” Nor was the Myrmica deaf to such an appeal. It slackened its pace, hesitated, then paused, and as though unable longer to resist the influence, folded its antennæ and appeared to give itself up to the full pleasure of the thing. The tempter, now, still making soft play with the antennæ, lowered its own head, and began to lick the Myrmica first on one cheek and then the other, including also the mandibles and parts adjoining. Thus fostered, a dewy moisture, drawn evidently from the reservoir of lately swallowed nectar, began to glisten on the lips of the large ant, and, increasing rapidly to a droplet, was re-imbibed by the expectant little one. “The latter,” says Professor Wheeler, “then dismounted, ran to another Myrmica, climbed on its back, and repeated the very same performance. Again it took toll, and passed on to still another Myrmica.”[[56]] Up to the present the attention of Professor Wheeler had been concentrated on the doings of this one individual, but now, turning his attention to other parts of the nest, he “observed that nearly all the Leptothorax workers were similarly employed. In one corner a number of Myrmica workers had formed a circle about a few of their small larvæ, which they were cleansing and feeding. A Leptothorax soon found its way to this cluster, and stepped from the back of one ant to that of another, lavishing a shampoo on each in turn, and apparently filling its crop with the liquid contributions thus solicited.”
The above method of obtaining food appears to be peculiar to these ant parasites. Beetles, for example, solicit it either by taps or touches with the antennæ—which is a similar one indeed, but does not go so far nor involve a ride—or else by stroking the face of their host with their fore-feet. Other species of ants, when soliciting food from one another or demanding it from their slaves, employ a more or less similar method, whilst the Lepismid that we have before spoken of is a thief pure and simple. Licking seems to be the personal discovery of Leptothorax, and being licked the peculiar privilege of Myrmica brevinodis. That it is a valued one is clear, but the price asked for it is not always forthcoming, possibly because there is not always anything to forthcome. On such barren occasions Leptothorax makes the best of a bad job, and dismounting from its first love, runs about looking for another.
Sometimes, after having licked the head and face of its patron, the poor petitioner turns round and proceeds to do the same by its abdomen. This, perhaps, is a last effort of persuasion, but Professor Wheeler rather supposes the surface of Myrmica’s body to be “covered with some agreeable secretion.” Queen Myrmicas, however, seem to be very rarely treated to any sort of licking, and males apparently never. The reason of this, probably, is that both queens and males are themselves accustomed to receive their food from the workers by a similar process of regurgitation, and are probably therefore not in the habit of regurgitating it. They are therefore neglected by the little parasites, who console themselves by being all the more insistent with those who have something to give. These—that is to say, the workers—are waylaid whenever they enter the nest, as having presumably found something to eat outside it, and, in order to be on the spot, at once their importunate lickers, who seem to live in a perpetual state of crying, “Give! give!” keep in the more or less immediate proximity of the entrance, or entrances, should there be more than one. Professor Wheeler, indeed, doubts if the Leptos ever feed themselves in the ordinary way, but inasmuch as they were on one occasion seen by him to do so, such doubt appears to me to be uncalled for.