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Ants — Part 2

Many stories have been told of the supposed intelligence of ants, but perhaps it will not be out of place to tell one more which has not been published. In one of the greenhouses of the Department of Agriculture at Washington, a medium-sized black ant occurred in considerable numbers, attracted by the presence of plant lice and mealy bugs upon the hothouse plants. As is well known, ants are especially fond of the nectar secreted by these insects. A number of years ago some Liberian coffee-trees were started in the greenhouse. On the under side of the leaves of these coffee-trees, there exist at the bases of certain of the leaf ribs some very minute, nectar-secreting glands. The ants soon found this out and sipped the nectar. Then the idea occurred to some clever ant that these nectar glands would be the best places in the world for mealy bugs to live and grow fat and they would in consequence secrete a great deal more nectar then they would if they lived on other parts of the leaf. But the nectar glands were too small to accommodate even one good-sized mealy bug. So, the word was passed around and the ants gnawed the edges of the gland and enlarged it so that it would accommodate a good-sized mealy bug, which was carried to it. Doubtless to the delight of the ants, the result was as we may imagine it to have been anticipated. The mealy bug thrived exceedingly. The gland was enlarged still further and a whole family of mealy bugs was raised in the same hole. Thus a custom grew up and many such greatly enlarged glands were found after a few months. Here was an ant, then, apparently taking advantage of an opportunity which was new not only to the experience of the individual, but new to the experience of the race, and if we adopt the most reasonable of the definitions of instinct here seems to have been displayed positive intelligence of a high order.

In all of these stories of the seeming intelligence of ants and of bees, and of other insects as well, it must be remembered that we are running a great risk in our interpretations for the reason that we make them from a human standpoint, that is to say, that we consider these insects as though they had human personalities. The observer and the narrator inject their own personalities into the subjects investigated and in fact they use words which carry with them meanings which may not be warranted by the facts. This fact is brought out strongly by the German writer Bethe, who wrote, in 1898, on the psychological qualities of ants and bees. He shows, for example, that while we see, all we know about bees and other insects is that they are influenced by the light and that it would be most unscientific to say that they do anything as highly psychical as seeing until it is proved. Some of the peculiar and apparently highly intelligent things which ants do, such as recognizing the enormous number of members of the same colony and fighting instantly members of other colonies, and such as finding their way to their own nests and to food supplies and communicating intelligence of the location of food supplies from one to the other, have been carefully tested by this author who concludes that he can find nothing in the phenomena exhibited by bees or ants to prove the existence of any psychical quality. "They learn nothing, but act mechanically in whatever they do, their complicated reflexes being set off by simple physiological stimuli."(Albrecht Bethe, Archiv. f. d. Ges. Phys. LXX. 15.# 100. January, 1898. A Review by Caswell Grave, American Naturalist, Vol. XXXII, pp. 437-439.)

It is interesting to note in passing that Bethe's conclusions were anticipated for a number of years by the famous American naturalist, Samuel L. Clemens (Mark Twain). If any reader does not believe this let him consult Chapter XXII of a "Tramp Abroad".