Wasps, Social and Solitary

by George W. Peckham; E. G. Peckham

A suitable place for the nest being found, the spider is very prettily taken care of while the work is in progress. A plant, usually a bean or a sorrel, is chosen, and the strix is hung in the crotch of a branching stem, where it will be safe from the depredations of ants. This precaution is not always taken. We have many times seen the spider left on the ground, although there were plenty of plants at hand.

The next point is to decide upon the precise spot for the nest, and here our wasp shows herself very uncertain and hard to please. Never have we seen one settle down and complete her work in the spot first chosen. She dashes at a place and scratches and digs away with furious energy for a few minutes, and then, starting up, she darts wildly hither and thither until a new place, near by, is fixed upon and another beginning made. In one instance eight nests were started and some of them nearly finished, the little worker seeming to be beside herself with excitement. After the decision is finally made the tunneling is a rapid process. In one case it took the wasp a whole hour to complete the work, but out of the thirty nests that we saw made, nineteen were finished in from twenty to twenty-five minutes. Like Fabre’s Sphex the wasp interrupts herself three or four times to visit her spider and make sure that it is safe. When all is done she brings the strix to within a foot or two of the opening, runs to the nest to take a final look, and then, going backward herself, pulls it inside.

In two instances we saw the fidgety little creature go through a most comical performance, which again recalls the Sphex of Fabre. Leaving her treasure on the ground, she ran to the nest and kicked out a little more earth; hastening back she dragged it an inch nearer; then away she went to the nest again for more digging, and so on, dropping her spider half a dozen times before she at last brought it home. In two other cases in which there was no such anxiety about the size of the nest, there was, in reality, more reason for it. Indeed, in one instance the opening had to be enlarged before the spider could be taken in. There is a wide-winged parasitic fly that, having nothing else to do, lays prodigious numbers of eggs, not in any particular nest, but at the edge of holes wherever it may chance to see them. It hovers about over the ground until it comes to an opening, dips down twice or thrice, ovipositing each time, and then passes along. The habit of scratching out a little dirt at the threshold, just before the prey is brought in, seemingly from a desire to enlarge the nest, or in other cases from mere nervousness, is perhaps of use in destroying these eggs, which might otherwise adhere to the spider or caterpillar as it is dragged over them.

The laying of the egg takes only two or three minutes, and then the hole is filled up. In this part of her work quinquenotatus shows a great deal of variation, sometimes coming out of the hole and sweeping in the dirt with her first legs and sometimes standing in the tunnel while she draws the earth in with her mandibles and then jams it down with the end of her abdomen. The former plan was in vogue in the garden, while the latter was more common with the wasps on the island. After the hole is filled the spot is covered with pellets of earth and pebbles brought from a little distance, very much as is done by Ammophila.

When we found that quinquenotatus was a very common species, and that nearly every day brought us a fresh example, we thought that we had the question of its stinging habits in our own hands. What could be easier than to carry a strix about with us and to exchange it, when opportunity offered, for the paralyzed spider of the wasp? The good results obtained by Fabre and Marchal from this manœuvre made us confident of success. We did not doubt that when the wasp came for her spider and found it livelier than it ought to be, she would repeat the stinging operation before our eyes.

Accordingly, the next time that we saw quinquenotatus digging we made a diligent search for her spider, and soon found it on a bean plant five feet away. Just as we discovered it, however, the wasp swooped down and carried it to some purslain, close to the hole, where she hung it up again, while she went to make her final preparations at the nest. We seized our chance, and quickly substituted a fresh strix for the one that had been paralyzed. According to the habit of its species when danger threatens, it kept perfectly quiet, and when the wasp returned it was hanging there as motionless as a piece of dead matter. How she knew the difference was a mystery, but she would not touch it. She seemed to think that she had made a mistake in the locality and that her own spider must be hanging somewhere close by, for she hunted all over that plant and then over several others near to it, returning continually to look again in the right spot. After five minutes she gave it up, circled about three or four times, and flew off in the direction of the woods to catch another spider.

Why did she go to the woods? When she realized that the strix she had stung was gone and that she must have another, why did she not take the one that hung there in plain view? Our failure could not have been due to the fact that we had handled the spider, since, when on other occasions we took one that had been paralyzed, examined it and then returned it to the wasp, she accepted it without hesitation.

Disappointed though we were at the irrational conduct of our wasp, we resolved to await her return and to try again. In forty minutes she came back with another spider, but instead of taking it into the nest she hung it upon a bean plant near by and then proceeded to dig a new hole a few inches distant from the first. Foolish little wasp, what a waste of labor! Truly, if you are endowed with energy beyond your fellows you are but meagrely furnished with reason.

Again we availed ourselves of our opportunity, and substituted our spider for hers. This time it had grown weary of playing its motionless rôle, and frequent readjustments were necessary in order to keep it in position. At the moment that the wasp came back to take it, the spider scrambled from its place and began to make its way along the stem. The wasp evidently saw it, for she hovered over it a moment. She then flew to the next plant, where she hunted about over the leaves and branches in search of her lost treasure. After a time she returned. The spider had now come to a standstill, and the wasp examined it attentively, although without touching it. She then flew away without circling at all, which might, perhaps, be taken as an indication that she had no intention of returning to a place where she had fared so badly.

Just at this moment we chanced to see another paralyzed strix hanging near by. Again the exchange of our specimen was accomplished; but when the second wasp came to find her spider she gave us no more satisfaction than the first. The substitute hung there quietly enough. We ourselves could not have distinguished it from the original, but quinquenotatus took a good look at it, decided that something was wrong, hunted about a little for her own spider, and then flew away.