We were walking through the woods one hot day in the middle of August when our attention was attracted by a stream of yellow-jackets issuing from the ground. They came in such surprising numbers and looked so full of energy that we stopped to watch them, and this was our introduction to the study of these “bold sons of air and heat,” although a perusal of Fabre’s fascinating “Souvenirs Entomologiques” had prepared us to feel a lively interest in them. We were at our summer home near Milwaukee, where meadow and garden, with the wooded island in the lake close by, offered themselves as hunting grounds, while wasps of every kind, the socialistic tribes as well as the extreme individualists of the solitary species, were waiting to be studied.
The Vespas that had aroused our interest received our first attention, and a nest in the ground proved to be a most convenient arrangement. Experiments that would have been dangerous to life and limb had we tried them with a paper nest hanging in the open, were easy here so long as we kept calm and unflurried. Intent upon their own affairs, and unsuspicious of evil, perhaps because they knew themselves to be armed against aggression, they accepted our presence, at first with indifference; but as we sat there day after day we must have become landmarks to them, and perhaps before the summer was over they considered us really a part of home.
WASP EATING
While poor humanity takes comfort in a mid-day siesta, wasps love the heat of noontide, and with every rise in temperature they fly faster, hum louder, and rejoice more and more in the fullness of life. The entrance to the Vespa nest was but an inch across; and once when they were going in and out in a hurrying throng, jostling each other in their eagerness, we counted the number that passed, one taking the entrances and one the exits. In ten minutes five hundred and ninety-two left the nest and two hundred and forty-seven went in, so that we saw eight hundred and thirty-nine or about eighty to the minute. This must be a strong swarm, wonderful indeed when we thought that it had all come from a single queen mother. We imagined how she had made an early start, digging a hole in the ground, building within it a paper comb with five or six cells around a central column, and laying therein some neuter eggs; how she had then spent a month in attending carefully to the beginnings of things, feeding the young larvæ as they hatched, and watching over them through their childhood and youth; and then how her solicitude was rewarded by the filial devotion with which this first set of workers took upon themselves the labor of excavating, building, and feeding the young, everything indeed except the egg-laying. These queens, surrounded though they are by respectful and attentive subjects, have much the worst of it in our estimation, never going out, and passing their lives in a dull routine. Through the early summer only neuters are produced, but when fall approaches the future generation is provided for by the development of males and females. The activity of the little colony is limited by the season, for as the days grow colder the males and females leave the nest and mate, and a little later both males and workers lose ambition, become inactive and finally die, while the queens hide away in protected corners to reappear in the spring. The eggs and larvæ, left unfed and uncared for, become a prey to moulds and to hordes of insects, and thus the swarm comes to an end.
We had once made some not very successful attempts to find out whether spiders had a sense of color; and seeing that the conditions were much more favorable with our present subjects, we thought it would be a good plan to test their knowledge of the spectrum. Providing six sheets of stiff paper two feet square, colored respectively red, blue, green, pink, and two shades of yellow, and cutting a circular hole four and one half inches in diameter in the centre of each, we began our experiments by placing the red paper over the nest so that the entrance was clearly exposed. The outgoing wasps dashed upward without noticing it, but great was the confusion among the homecomers. Thrown out of their reckoning, they clamored about us in ever increasing swarms. Like Homer’s wasps,
“All rise in arms and with a general cry
Assert their domes and buzzing progeny,”
and a crisis (for us) was approaching, when one, a pioneer of thought, determined to go into the hole, which did not look like the right hole, although it was where the right hole ought to be; and so potent is example that one by one the others followed. Three hours later they had become accustomed to the change, and went in and out as usual.