The Western World / Picturesque Sketches of Nature and Natural History in North / and South America

by William Henry Giles Kingston

Of the numerous true ants which exist in all parts of Tropical America, the sauba is one of the most remarkable. In all parts of the country—as well near the abodes of man as in the distant wilds—large mounds are seen, two feet in length, and often upwards of forty yards in circumference, and distinguished from the surrounding soil by the difference of colour. Yet these mounds are merely the domes or upper works of the vast subterranean galleries which run for enormous distances and to great depths below the surface. Unlike the termites, the armies go forth in open daylight in vast hordes, to obtain food or materials for the construction of their wonderful habitations. Sometimes, many hundred yards away from these mounds, the whole ground seems covered with animated leaves, each of the size of a sixpence, moving at a steady pace over the ground. Each leaf is held vertically in the mandibles of an ant, which is conveying it for the purpose of thatching the domes which cover the entrance to its subterranean abode; the roof thus formed protecting the cells beneath, rilled with young, from the heavy rains. Going in the direction whence the army is seen coming, we may find a tree covered by innumerable multitudes employed in cutting off leaves. Here the labourers are protected by the warrior class, who appear also to perform the duties of overlookers, and keep them to their tasks. Each ant, on gaining a leaf, commences with its scissor-like jaws to make a semicircular incision on the upper side. It then takes it into its jaws, and detaches it by a sharp jerk. Having done this, it descends to the ground, and joining its comrades, who have been similarly employed, they return with their loads to the colony. Frequently, however, while an ant is up the tree, the piece of leaf falls to the ground, when it sets to work to cut off another; while fresh labourers appear, to carry away the pieces which have thus accumulated.

The sauba ants are greatly dreaded by the inhabitants, as they frequently attack their coffee and orange-trees, and utterly destroy them. Sometimes, indeed, plantations have to be abandoned in consequence of the inroads of these persevering insects.

The body of the sauba ant is of a pale reddish-brown colour, and of a solid consistency. The head is armed with a pair of sharp spines, while the thorax has three pairs of the same character.

There appear to be three orders of workers among them, greatly differing in size. One order has an enormously large head; the head of another is very highly polished; while that of a third is opaque—to enable it, apparently, to perform the duties of a subterranean labourer. The earth of which the domes of the sauba ants are composed is brought up from a considerable depth below. There are numerous entrances leading to the galleries, but, under ordinary circumstances, they are kept closed. The smaller galleries lead, at a depth of several feet, to a broad, elaborately-worked tunnel of four or five inches in diameter, which conducts downwards to the centre chamber; the abode of the royal pair, on whom devolves—as is the case with the termites—the duty of propagating the species. Here they are guarded much in the same way by the labourers, who deposit the eggs in the cells, and finally assist in the exit of the winged males and females—which fly forth to be destroyed in vast numbers, the few who remain becoming the parents of other families.

The female winged ants are of considerable size, measuring fully two and a quarter inches across the wings. The male is very much smaller.

The royal chamber is curiously constructed. As soon as the newly-wedded pair are conducted within, the workers, who are themselves much smaller, so diminish the size of the entrance that it is impossible for the king and queen to escape. Round it are numerous exits and entrances, through which the workers convey the eggs when laid. The queen, after the death of her consort, lives for two or three years, employed during the whole of the time in laying eggs, at the rate of fifty in a minute. This will give some idea of the rapid increase of the population.

The workers vary somewhat in size and appearance. While a large number are employed in bringing in leaves and granules of earth for thatching their domes, as well as various sorts of provision, others are engaged in tending the royal chamber—carrying the eggs to the cells, and watching over the young. There is another class, whose heads are covered with hairs, and who appear to be employed entirely below ground, probably as excavators or tunnellers.

Like the Cyclops, they have in the centre of their forehead a single eye, very different in structure to the compound eyes on the sides of their head. The other workers do not possess this peculiar frontal eye, nor is it found in any other species of ant.

It is wonderful what extensive tunnels these ants will form. Near Rio de Janeiro a tunnel was discovered, excavated by the creatures under the River Parahiba, as broad as the Thames at London Bridge. Near Para they, on one occasion, pierced the embankment of a large reservoir to such an extent as to allow the escape of a vast body of water before the damage could be repaired. In the same neighbourhood an attempt was made to destroy their colonies, by blowing fumes of sulphur down the galleries by means of bellows. Mr Bates relates, that he saw smoke issuing from a vast number of outlets, one of which was seventy yards distant from the place where the bellows were used.