CHAPTER IX
THE AMAZONS AND THEIR SLAVES
Another type of slave-owning ants is represented by the genus Polyergus, found in both Europe and North America, and known as amazons. Slavery among the amazons is a very different thing from the casual master-servant relationship found in the various species of sanguinary ants. The sanguinea are quite able to build nests, gather food, and rear their young unaided by slave labor, and slaveless colonies are not at all uncommon, but the amazons are absolutely dependent upon their slaves, and no amazon colony could exist without them. As Wheeler says, the amazons “are even incapable of obtaining their own food, although they may lap up water or liquid food when this happens to come in contact with their short tongues. For the essentials of food, lodging and education they are wholly dependent on the slaves hatched from worker cocoons that they have pillaged from alien colonies. Apart from these slaves they are quite unable to live, and hence are always found in mixed colonies inhabiting nests whose architecture throughout is that of the slave species. Thus the amazons display two contrasting sets of instincts. While in the home they sit about in stolid idleness or pass the long hours begging the slaves for food or cleaning themselves and burnishing their ruddy armor, but when outside the nest on one of their predatory expeditions they display a dazzling courage and capacity for concerted action compared with which the raids of sanguinea resemble the clumsy efforts of a lot of untrained militia. The amazons may, therefore, be said to represent a more specialized and perfected stage of dulosis than that of the sanguinary ants. In attaining to this stage, however, they have become irrevocably dependent and parasitic.”
The same author describes a slave-hunting foray of the European species. “The ants leave the nest very suddenly and assemble about the entrance if they are not, as sometimes happens, pulled back and restrained by their slaves. Then they move out in a compact column with feverish haste, sometimes, according to Forel, at the rate of a meter in 33 seconds, or 3 cm. per second. On reaching the nest to be pillaged, they do not hesitate like sanguinea but pour into it at once in a body, seize the brood, rush out again and make for home. When attacked by the slave species they pierce the heads or thoraces of their opponents and often kill them in considerable numbers. The return to the nest with the booty is usually made more leisurely and in less serried ranks. The observer of one of these forays cannot fail to be impressed with the marvelous precision of its execution. Although the ants may occasionally lose their way and have to retrace their steps or start off in a different direction, they usually make straight for the nest to be plundered. They must, therefore, like sanguinea, possess a keen sense and memory of locality. There can be little doubt that they often leave the nest singly and make a careful reconnoissance of the slave colonies in the vicinity.”
One can hardly believe that as soon as the fighting is over these warriors relapse into their accustomed lethargy, and are fed and cared for by their slaves, who often prevent them from leaving the nest, and sometimes, when they have wandered away, pick them up bodily and carry them home by main strength. When a colony moves to a new home the whole enterprise is left to the slaves, who choose and prepare the new nesting site, and carry the warriors to it. In the case of the sanguinea it will be remembered that it is the masters who carry the slaves on these occasions.
An American amazon which has been the subject of considerable study is Polyergus breviceps, found in the mountainous regions of Colorado and New Mexico. This species is very striking in appearance, the worker and queen being of a rich purplish-red color, while the male is jet-black with white wings. A peculiar feature of the breviceps’ raiding parties is that there are no casualties on either side. The slave species offer no real resistance, and the amazons simply put them gently to one side, take their larvae and pupae, and go their way.
We do not know exactly how new amazon colonies are established. Forel, Wasmann and Viehmeyer have agreed that the queen lacks the domestic instinct, and therefore the new colony must be founded by the slave species, which cares for the amazon females. It has been shown that the adoption occurs readily enough in artificial nests. Some experiments by Wheeler gave rather conflicting results, and he closes his discussion of the matter by saying: “It will be necessary, therefore, to study this question further before making definite statements in regard to the method employed by our American amazons in establishing colonies.”