Insect Architecture

by James Rennie

[Different species of wasps use different materials for their nest. Vespa vulgaris always uses decayed wood, while V. germanica and other species use sound wood. Owing to the colour, the distinction between the nests of these insects is evident at a glance.

The bundles of ligneous fibres thus detached are moistened before being used, with a glutinous liquid, which causes them to adhere together, and are then kneaded into a sort of paste, or papier maché.

The method employed by the wasp in making its nest has been so admirably described by Mr. S. Stone, that we cannot do better than copy his description, which appeared in “Beeton’s Annual” of 1865.

"Having found a place suitable—the deserted burrows of the field-mice being perhaps more generally selected than any other by the underground species, the chamber formed by that animal for its nest being exactly the kind of place required by the insect—it proceeds to attach its web to the centre of the roof of the chamber. This consists, in the first instance, of a pedicle, or footstalk, about half an inch in length, at the extremity of which a single cell is formed, which is presently surrounded by others.

"Simultaneously with the formation of these cells, an umbrella-shaped covering is prepared above them. More cells are added, an egg being deposited in each of them as soon as formed, while constant additions are made to the covering until it has assumed a globular form, with only an aperture sufficiently large for the insect to pass in and out. Before the completion of the first covering, a second, just large enough to enclose it, is begun, and while this is in progress a third is commenced, and then a fourth, and so on. When young wasps have been produced in sufficient numbers to carry on the work without the assistance of the parent, an event which usually takes place in about six weeks from the commencement of the nest, she does not again leave home, but occupies herself solely in the task of depositing eggs as fast as cells can be formed by the workers for their reception.

"There are two methods by which the nests are enlarged by the workers after the queen has given up the task of building; some species choosing one, some adopting the other. One consists in forming a series of regular sheets or layers, which are made to overlap each other like the slates or tiles on the roof of a building, in the same way as is pursued by the queen of every species so long as she continues to be the architect. When a few of these sheets have been completed, that is, when they have been made to assume a spherical form, with only a small aperture for ingress and egress, each internal sheet is cut away, nearly but not quite, as fast as additional ones are formed externally, the shell or covering therefore slightly increasing in thickness as the nest increases in size. Thus architects among the human race are careful to proportion the thickness, and consequently the strength of the walls to the magnitude of the building designed to be erected.

"The other method consists in forming hollow pieces, or raising, as it were, blisters all over the plain surface which the queen has left; and upon these other blisters, and so on continually; cutting away, as in the former case, the under skin on the formation of the outer one. The latter method is adopted by the workers of V. crabro, V. vulgaris, and V. germanica; the former by V. Norvegica, V. sylvestris, V. rufa, and probably by V. arborea. Cutting away the inner portions of the coverings is a necessary process in order to make room for the increased size of the comb or combs. The material cut away is not thrown by as useless, but is worked up afresh; indeed this is effected in, and by, the very act of removing it; it is then either used in enlarging the combs or it is brought out and employed in making additions to the outside.

"As the nest increases in size, it is obvious that the cavity in which it is placed must be proportionably enlarged; accordingly, each wasp, as it emerges from the aperture, may be observed to bring out with it a small lump of earth which it has scraped from the walls of the chamber, care being taken to keep a clear space of about a quarter of an inch between the covering of the nest, and the walls of the chamber. About the same space also occurs between the combs, which are placed horizontally, with the mouth of the cells downwards; supporting columns or pillars being constructed at regular intervals so as to keep them at a proper distance apart, thus allowing the insects room to pass between them for the purpose of feeding the grubs. Supporting columns or pillars are also placed between the roof of the chamber and the crown of the nest, connecting the one with the other; and these supports are constantly strengthened as the increasing weight of the nest renders such a precaution necessary.

"The material of which the wasps’ nests are composed is a sort of paper manufactured chiefly from wood by the insects themselves; one species using sound wood for the purpose, another that which has become decayed. This they scrape by means of their jaws from posts, rails, gates, hurdles, &c., in which act it becomes mixed with some peculiar fluid with which they are provided; it then possesses nearly the same properties as the pulp from which paper is made, but is of firmer consistence. This is gathered in a small lump under the chest, to which it adheres, and in that way is carried to the nest.