257 CHAPTER IX. EXPERIMENTAL INQUIRIES. RESULTS OF THE DESTRUCTION OF THE NEST. OF THE REMOVAL OF THE QUEEN, EXPLAINED BY PARTHENOGENESIS. THERE remains yet another phase of the History of Wasps, as interesting in a physiological point of view as any which may have preceded it, though commencing at a period when many might suppose that the misfortunes of the swarm which had been so unlucky as to become the subject of scientific experiments had been finally consummated by the capture of their nest and the death of the queen. Every little boy however knows that the mere destruction of the nest is not always followed by the extermination of the swarm. Indeed at first it might often seem that nothing is gained to the neighbours by the operation; for the nest is soon replaced, and the wasps are crosser than before. Even the additional calamity of the loss of the queen may at first produce no sensible difference. The swarm does not go wandering in search of their lost mistress, they do not hang mournfully on the hedge. On the contrary, they eat, and work, and sting, to all appearance, the same as ever; just as if nothing whatever had happened. But, if we watch a little more S closely, we shall find reason to change the opinion which we had hastily taken up. And the double calamity, the loss of the nest and the loss of the queen, opens two distinct branches of inquiry. First, we find that the nest, as rebuilt, resembles the former nest only externally. And next, the swarm without its queen, however strong, and fierce, and industrious it may be, contains within itself no bond of permanent union. And first with regard to the nest :— As soon as the irritation and confusion consequent on the removal of the nest have subsided, the instinct of the surviving wasps resumes its sway, and they set about making a new nest, either on the site of the old one, or in its immediate neighbourhood. This process may be repeated as many as three or four times, according to the strength of the swarm and the habit of the particular species. As fast as one nest is removed or destroyed it is replaced by another nest. Each of these successive nests bears more than a mere generic resemblance to the original structure; the peculiarities of the preceding nest being in some sort reproduced. They do not however pass through all the same stages as the original fabric in their development. For they are built up at once, on the scale, and outside plan, of that which has been removed. And this fact necessarily involves some important differences in the details of their construction. For instance, the upper part or crown of the nest is not made of the remains of older structures worked into each other, but of distinct sheets of paper, closely applied one over the other. I have seen a secondary nest of V. britannica, the species on which these observations were chiefly made, with as many as eleven successive layers thus disposed. Again, the new comb differs from the original structure. The formation of the cells is less regular, and the stages are arranged differently. Instead of the case being filled with these, closely packed one below the other, the stages which it contains, one, or at most two, have a large unoccupied space below them. In fact, the usual order has been reversed, the comb was made to go inside the case, as the work went on hurriedly and irregularly, and not the case to cover the comb. And the resemblance, which appears on the surface, does not enter very deeply into the construction of the nest. Each time that the nest is replaced it differs more and more from the original type. It becomes smaller, less shapely, and has less pretensions to anything like a regular comb within. After it has been destroyed three or four times, the survivors make no further attempts to replace it. Perhaps some little scraps of paper, forming a hood over half-a-dozen cells, represent the last efforts of the diminished swarm. Some few wasps will haunt round this, day after day, till, as their numbers decrease, only three or four workers are left as the guardians of as many abortive larvæ, or a heavy shower puts an end at once to the struggles of the colony. I have in my cabinet a series of nests,* made by one swarm of V. britannica, the successive specimens indicating the failing strength of the survivors of the successive operations. The second is made of the * Plate XIII. same size and to nearly the same pattern as the first nest, corresponding to the energies of so many papermakers suddenly thrown out of employment. This is succeeded by a much smaller one, which still however reproduces some of the chief features of the original structure; and it is still obviously a wasp's nest. But the last in the series consists merely of a few scraps of paper gathered on a neighbouring twig, looking just like an old grey rag which had been caught in the bushes. While the wasps which have been left in possession of the site are thus occupied, those which have been removed to another situation, along with the original nest, may have also established themselves, so that the swarm is possibly divided into two active colonies. Whether from the shaking they have undergone, or from whatever cause, the wasps which have been thus transplanted seem to have a feeling of insecurity, perhaps not wholly unnatural under the circumstances, and often attach the comb to the outer case of the nest to strengthen the fabric. But they will continue their labours in their new situation, if they are only prevented from straggling away in search of food, during the first few days, while their numbers are few and the neighbourhood is strange. Sometimes a swarm will divide into two, as the result of an accident. Thus, in one case, where the sticks in a hedgebank prevented my taking a secondary nest of V. sylvestris, which had got entangled among them, the unsuccessful attack caused the division of the nest into two portions, which became henceforth separate establishments. Conversely, two swarms will sometimes combine together, either, as we have seen,* from the fellowship of a common misfortune, or as the result of experiments such as Professor Edgeworth† has so ingeniously contrived. And this, whether the wasps be of the same or of different species.‡ The courage and endurance of V. britannica are conspicuous under these trying circumstances, while V. rufa is said § to be singularly wanting in energy under this calamity, and to make no attempt to repair the injury. The workers, in such case, are unworthy of their queen, who seems to be quite an Amazon among wasps. For, whenever a female of this species has been sent me in a box with other live females, V. rufa has generally contrived to murder and mutilate her travelling companions. . These experiments may be varied to any extent; and, by directing their labours, by means of threads and wires, wasps may be made to build in the most grotesque forms. But I need not dwell on these; for whoever has seen the results of Mr. Stone's || curious experiments in wasp architecture in the British Museum, will scarcely need any further illustrations of the various shapes which their nests may be made to assume. And we may go on at once to the second part of this inquiry, namely, as to the effect of the loss of the queen on the swarm. * Page 203. + On Irish Vespidæ. 'Annals and Magazine of Natural History,' 3rd Series, Vol. XIII, p. 470. Mr. Stone. Wood. Homes without Hands,' p. 361. See also Wood. Homes without Hands,' p. 358, and Plate. |