As the association of ideas by contiguity is the principle which forms the basis of all psychology, it is desirable to consider still more attentively this the earliest manifestation that we have of it in the memory of the Hymenoptera. That it is not exercised with exclusive reference to locality is proved by the following observation of Sir John Lubbock:—
I kept a specimen of Polistes Gallica for no less than nine months.[49] . . . . I had no difficulty in inducing her to feed on my hand; but at first she was shy and nervous. She kept her sting in constant readiness. . . . . Gradually she became quite used to me, and when I took her on my hand apparently expected to be fed. She even allowed me to stroke her without any appearance of fear, and for some months I never saw her sting.
One other observation which goes to prove that other things besides locality are noted and remembered by bees may here be quoted. Sir John placed a bee in a bell jar, the closed end of which he held towards a window. The bee buzzed about at that end trying to make for the open air. He then showed her the way out of the open end of the jar, and after having thus learnt it, she was able to find the way out herself. This seems to show that the bee, like the wasp on the closed window-pane, was able to appreciate and to remember the difference between the quality of glass as resisting and air as permeable, although to her sense of vision the difference must have been very slight. In other words, the bee must have remembered that by first flying away from the window, round the edge of the jar, and then towards the window, she could surmount the transparent obstacle; and this implies a somewhat different act of memory from that of associating a particular object—such as honey—with a particular locality. It is noteworthy that a fly under similar circumstances did not require to be taught to find its way out of the jar, but spontaneously found its own way out. This, however, may be explained by the fact that flies do not always direct their flight towards windows, and therefore the escape of this one was probably not due to any act of intelligence.
While upon the subject of memory in the Hymenoptera, it is indispensable that we should again refer to the observation of Messrs. Belt and Bates already alluded to on pages 150-51. For it is from that observation rendered evident that these sand-wasps took definite pains, as it were, to teach themselves the localities to which they desired to return. Mr. Bates further observed that after thus taking a careful mental note of the place, they would return to it without a moment's hesitation after an absence of an hour. The observation of Mr. Belt, already quoted in extenso, proves that these mental notes may be taken with the utmost minuteness, so that even in the most intricate places the insect, on its return, is perfectly confident that it has not made a mistake.
With regard to the duration of memory, Stickney relates a case in which some bees took possession of a hollow place beneath a roof, and having been then removed into a hive, continued for several years to return and occupy the same hole with their successive swarms.[50]
Similarly Huber relates an observation of his own showing the duration of memory in bees. One autumn he put some honey in a window, which the bees visited in large numbers. During the winter the honey was taken away and the shutters shut. When they were again opened in the spring the bees returned, although there was no honey in the window.
These two cases amply prove that the memory of bees is comparable with that of ants, which, as we have seen from analogous facts, also extends at least over a period of many months.
Emotions.
Sir John Lubbock's experiments on this head go to show that the social sympathies of bees are even less developed than he found them to be in certain species of ants. Thus he says:—