NATURE NOTES

Evening Post, Volume CIX, Issue 119, 23 May 1925, Page 13

NATURE NOTES

THE WAYS OF ANTS

DO THEY REASON ?

(By E. H. D. Stidolph, R.A.O.tT.)

The interesting and intelligent habits of ants have for many years created widespread interest in theso small inhabitants of the earth. On a recent occasion, when on an ornithological ramble in the Wairarapa, near Masterton, I rested for a few moments on a log on the Kuamahunga river-bed. Glancing at the ground at my feet I perceived large numbers of ants, seemingly bent on an industrious undertaking, as neverending streams emerged from several adjacent hole?, and after proceeding a short distance, perhaps three inches, stopped, aad then returned again to tha holes. Their actions denoted that they had no time to loss. Closer investigation- disclosed that each ant wa-s carrying, a grain of sand, and was dumping it away from ths holes. Excavating york was undoubtedly in progress. While watching these insects working so industrially, and 60 methodically,' and apparently so intelligently—for does not the depositing of the sand at a distance from the holes indicate intelligence!—the question arose in my mind a* to whether ants reason. This same question has been debated by naturalists for many years. Some contend that ants do reason; others hold that these insects have not that gift. Darwin said, with justice, indeed, that, considering its size, the brain of an ant was perhaps the most marvellous piece of matter in the whole universe; and its raw material of intelligence is apparently supplied it, most of all through the mysterious antennae. These antennae, or feelers as some people would call them, aTe large and fully developed appendages. They turn in a beautiful ball-and-socket joint, which enables them to move freely in every direction. Now, those antennae quite clearly serve several most important uses in ant life. They ar« the organs of speech in ants, as well as the organs of a special sense, just a«, with ourselves, the mouth is used equally for tasting and talking.

"How does a ne3t begin to bet Well," writes Grant Allen, a most distinguished naturalist, in one of his charming books on natural history, "it starts from a queen, or perfect female, who sots out with a few others to form a colony. This colony soon grows, but it is rather a republic than an Amazon kingdom, like the hives of bees or nests of wasps. It is composed of several perfect femalea (instead of one queen), numerous imperfect females or workers, and a few males, who, as is usual among social insects, are very unimportant and unconsidered creatures. The males and females are winged when they first emerge from their cocoons, and they use their wings for their marriage flight, which is" a- recognised institution among all insect Socialists. But as soon as ths perfect females have been safely wedded, their wings drop off; or, in cases where they do not fall off themselves, the insects themselves wriggle and pull them off with their legs in a most comic fashion. As for the males, they are ol no further use -to the community, so they die at once. But the mass of the larvae develop into imperfect females or workers, which are always wingless from ■the very first, and.it is these that form the ordinary ants of the everyday observer. The winged ants have large and compound eyes, to aid them in their flight abroad; and they have also single eyelets or ocelli, as in the case of the wasp, which seem to be useful to them in finding the way over large areas, as the compound eyes are probably designed for nearer and minute vision. But the workers have always the true eyea small, and often rudimentary, while the eyelets are mostly wanting. To put it plainly, they R re almost blind. There can be very little doubt that their principal organ of sense resides in the antennae, which are probably used in part for smelling. Whatever may be the perceptive function which thesi' curious appendages subserve, however, nobody who has watched ants closely ever doubts that they are also used as a means ol inter-communication, almost analagous to human language. Whenever two ants of the same nest meet, they stop and parley with one another by waving and crossing their antennae. So obvious is it, that the information thus conveyed makes one ant follow another towards a source of food, or other subject of interest. The performance is universally described by ant observers as 'talking.' " •*•**■•

Now, let us take a peep nt a nest, and allow Grant Allen to describe it in his vivid manner. "We here have an interior view, with one wall removed of a tunnel or gallery, which runs through the soft upper portion of the nest. An ant, which has been out foraging for food, approaches one of the mouths of the nest. Beneath are three successive floors or stages of the tunnel, with excavated chambers, each appropriated to its own particular purpose. In the upper floor of all, we see two groups of minute eggs awaiting their hatching. Four of the eggs have just arrived at hatching point,- therefore, one of the careful nurses who look after them 18 seen just in the act of bundling them over on to stage two, which it the floor they have reserved for the nursery of the hatched-out grubs- or larvae. In this second stage you see a chamber with a group of.such grubs,' all hungry and greedy, waiting for their nurses to bring them'food from outside the household.. Observe the obvious ex pectency of their attitude, with heads held up, like that of small birds clamouring eagerly for food when their mother approaches them with a worm or a caterpilar. After feeding for some time m this legless, grubbish condition the larva turns into a picker, and encloses itself in a cocoon. One larva has just completed this happy trans, formation, and a watchful nurse ant is therefore at this moment enjmtred in carrying it tenderly a stage lower down to the floor reserved for the chrysalis condition. On the third floor below you see a group of pupae lying by in the dark, and awaiting their development, ihe wall of .one cocoon has been removed, and within you may catch a glimpse of the imprisoned grub now recently transformed into the adult ant pattern Of course, the nest cohtaiiiß many hundreds of such tunnelled galleries all teeming with.life, and all made up of several distinct chambors."

"A certain nnt, very common in Brazil, has tho habit of .cutting large round pieces out of tho leaves of troea, which it then convoys to its nest for tho purpose of growing fungi upon them—in human language, making tiny mushroombeds. Now, this habit is naturally obnoxious to the trees, which produce tho leaves for their own advantage, not for the sake of leaf-cutting ants which back and rob them. To guard against tho burglarious leaf-cutters, accordingly, one clever South American acacia "has hit upon an excellent, plan oF defence. 11, produces curious hollow thorns, while each leaflet, has a- gland at its base 'which secretes honey". Into thew hollow tliomjj colonies of a email osd liartu.

less ant migrate, and' take up their abode there. They live off tha honey at the base of the leaflets. They thus acquire a nested interest in the acacia tree,, which iB their home and territory; and whenever_ the leaf-cutting ants attack the acacia, the little occupants of the thorns and owners of the- honeychambers pour out upon them in their thousands, and compel tha invaders to beat a hasty retreat with heavy losses. Thus, the running tree supplies its insect bodyguard with board and lodging in return for efficient protection against tho dreaded onslaught of the common enemy.