A number of ants are known that construct extensive underground dwellings, in which they store seeds of various kinds. Some of the American species (Pogonomyrmex) may be even said to winnow their grain, for they carefully strip off the husks and deposit these on rubbish-heaps outside the nest.
Some of the seed-storing ants almost deserve the name of maltsters on account of the way they deal with their harvest. The human method of making malt is to allow the barley grains to germinate to a certain extent until the contained starch is converted into malt-sugar, when the process is arrested by scalding. In similar fashion ants permit germination to go on to a certain point, and then kill the seedlings by biting away the little shoots and roots. In this way a supply of the sweet food they love is secured.
Among the most interesting of ants are leaf-cutting forms (Atta) native to tropical America. They are associated in huge communities occupying complex underground dwellings, the sides of which are marked by mounds that may measure as much as forty yards round. The chief food consists of a kind of fungus (Rozites gongylophora), cultivated on bits of leaf, and treated in such a way that little white elevations are produced. It is these that the ants desire.
The chief duty of one set of workers is to collect the pieces of leaf required. To facilitate their operations, roads, largely underground, are constructed, which lead to suitable trees, and may be as much as twenty yards long, or more. Curved pieces of leaf are bitten out and carried back to the nest, where they are handed over to [239] another set of workers, by them to be reduced to smaller fragments and made into mushroom beds.
WHERE AND HOW THE HOMES OF
ANTS ARE BUILT
Ants live in dwellings of the most varied kind, many being underground. In a large number of species ant-hills are constructed of various loose materials, our common native wood-ant (Formica rufa) being a good example of this. An Asiatic ant (Oecophylla) constructs a summer-house of leaves in a curious fashion. The larva possesses silk-glands from which a sticky fluid exudes, hardening quickly on exposure to the air. Advantage of this is taken by the workers, for they hold larvæ in their jaws, and employ them as living gum-bottles, while the leaf-edges to be cemented are held in position by other workers.
Some South American ants construct hanging nests in trees, by which protection against floods is secured. Other ants in the same part of the world make curious homes which well deserve the name of “hanging gardens,” for they are mainly constructed of living plants, some of which have never been found in any other situation. The plants are cultivated and tended by the ants with which they are associated. The soldiers of certain ants (Colobopsis), which tunnel out homes in the wood of trees, play the part of living front doors. Every entrance to the nest is guarded by one of these hall-porters, its huge head not only exactly filling the aperture, but closely resembling the adjacent bark in appearance. If this curious door be touched by a bit of stick or a feather, it remains shut, but is immediately opened when stroked by the antennæ of a worker.
CURIOUS ANT GUESTS
AND ASSOCIATES
Not only may ants of two or more kinds be associated together in the same dwelling, but a nest may also be tenanted by peculiar species of beetles (and other insects), spiders, mites, or other creatures. Many of these, especially the beetles, are fed and cared for by the ants, some of them for the sake of a substance which exudes from their bodies; others, perhaps, to serve as pets. The beetle-grubs are looked after as well as the adults; at least in the case of certain blind species.
On the other hand, certain ant-beetles not only steal food from the ants, but also devour their young. There can be no doubt that these curious associations are very ancient ones, for many species of beetles are found nowhere else. A kind of bristle-tail that lives in ants’ nests is a thief pure and simple. It has been seen to steal the drops of honey being passed from the mouth of one worker to another, afterwards retreating at full speed.