Works of Grant Allen

by Grant Allen

  It is a peculiarity of the wasps, however, that they are fairly omnivorous. Most of their cousins, like the bees, have mouths adapted to honey-sucking alone — mere tubes or suction-pumps, incapable of biting through any hard substance. But the wasp, with her hungry large family to keep, has to be less particular about the nature of her food; she cannot afford to depend upon honey only. Not only does she suck nectar; she bites holes in fruits, as we know to our cost in our gardens, to dig out the pulp; and she has a perfect genius for selecting the softest and sunniest side of an apricot or a nectarine. She is not a strict vegetarian, either; all is fish that comes to her net: she will help herself to meat or any other animal matter she can find, and will feed her uncomplaining grubs upon raw and bleeding tissue. Nay, more, she catches flies and other insects as they flit in the sunshine, saws off their wings with her sharp jaws, and carries them off alive, but incapable of struggling, to feed her own ever-increasing household.

  By-and-by the first grubs, which covered themselves in with silk in order to undergo their pupa or chrysalis stage, develop their wings under cover, and emerge from their cases as full-grown workers. These workers, whose portrait you will find on a previous page, are partially developed females, being unable to lay eggs. But in all other respects they inherit the habits or instincts of their estimable mother; and no sooner are they fairly hatched out of the pupa-case, where they underwent their rapid metamorphosis, than they set to work, like dutiful daughters, to assist mamma in the management of the city. Like the imagined world of Tennyson’s “Princess,” no male can enter. If ever there was a woman-ruled republic in the world, such as Aristophanes feigned, it is a wasp’s nest. The workers fall to at “tidying up” at once; they put the house in order; they go out and gather paper; they help their mother to build new cells; and they assist in feeding and tending the still-increasing nursery. The first comb formed, you will remember, was at the top of the foundation column or footstalk; the newer combs are built below this in rows, each opening downward, so that the compound house or series of flats is planned on the exactly opposite system from our own — the top storeys being erected first, and the lower ones afterward, each storey having its floor above and its entrance at the bottom. At the same time, the umbrella-shaped covering is continued downward as an outer wall to protect the combs, until finally the nest grows to be a roughly round or egg-shaped body, entirely enclosed in a shell or outer wall of paper, and with only a single gateway at the bottom, by which the busy workers go in and out of their city.

  The nest of the tree-wasp, which we have also been kindly permitted to photograph from the specimens at the Natural History Museum (Nos. 5 and 6), exhibits this final stage of the compound home.

  By the time the workers have become tolerably numerous in the growing nest, the busy mother and queen begins to relax her external efforts, and confines herself more and more to the performance of her internal and domestic duties. She no longer goes out to make paper and collect food; she gives herself up, like the queen-bee, exclusively to the maternal business of egg-laying. You must remember that she is still the only perfect female in the wasp hive, and that every worker wasp the home contains is her own daughter. She is foundress, queen, and mother to that whole busy community of 4000 or 5000 souls. The longer the nest goes on, the greater is the number of workers produced, and the faster does the queen lay eggs in the new cells now built for her use by her attentive daughters. These in turn fly abroad everywhere in search of nectar, fruits, and meat, or gather honey-dew from the green-flies, or catch and sting to death other insects, or swoop down upon and carry off fat, juicy spiders; all of which foodstuffs, save what they require for their own subsistence, they take home to the nest to feed the grubs, from which, in due time, will issue forth more workers. It is a wonderful world of women burghers.

  As long as summer lasts, our queen lays eggs which produce nothing else than such neuter workers. As autumn comes on, however, and the future of the race must be provided for, she lays eggs which hatch out a brood of perfect females or queens like herself. It is probable that the same egg may develop either into a queen or a worker, and that the difference of type is due to the nature of the food and training. A young grub fed on ordinary food in an ordinary cell becomes a neuter; but a similar grub, fed on royal food and cradled in a larger cell, develops into a queen. As with ourselves, in fact, royalty is merely a matter of the surroundings.

  Last of all, as the really cold weather begins to set in, the queen wasp lays some other eggs from which a small brood of males is finally developed. Nobody in the nest sets much store by these males: they are necessary evils, no more, so the wasps put up with them. It is humiliating to my sex, but I cannot avoid mentioning the fact, that the production of males seems even to be a direct result of chill and unfavourable conditions. The best food and the biggest cells produce fertile queens; the second best food and smaller cells produce workers; finally, the enfeeblement due to approaching winter produces only drones or males. We cannot resist the inference that the male is here the inferior creature. These facts, I regret to say, are also not without parallels elsewhere. Among bees, for instance, the eggs laid by very old, decrepit queens, or by maimed and crippled queens, produce males only; while among tadpoles, if well fed, the majority become female frogs; but if starved, they become preponderantly male. So, too, starved caterpillars produce only male butterflies, while the well-fed produce females. I know this is the opposite of what most people imagine; but then, science not infrequently finds itself compelled to differ in opinion from most people.

  The drones, or males, are thus of as little account in the nest of wasps as in the hive of bees. In both, they only appear for a short time, and for the definite purpose of becoming fathers to the future generations. When they have fulfilled this their solitary function, the hive, or the nest, cares no more about them. The bees, as you know, have a prudent and economical habit of stinging them to death, so as not to waste good honey on useless mouths through the winter. The wasps act otherwise. They are not going to live through the winter themselves, so they don’t take the trouble to execute their brothers: they merely turn the young queens and males loose, and then leave the successful suitors to be killed by the first frost without further consideration.

  And now comes the most curious part of all this strange, eventful history. We do not love wasps; yet so sad a catastrophe as the end of the nest cannot fail to affect the imagination. As soon as the young queens and males have quitted the combs, the whole bustling city, till now so busy, seems to lose heart at once and to realise that it is doomed to speedy extinction. Winter is coming on, when no worker wasp can live. So the community proceeds with one accord to commit communal suicide. The workers, who till now have tended the young grubs with sisterly care, drag the remaining larvæ ruthlessly from their cells, as if conscious that they can never rear this last brood, and carry them in their mouths and legs outside the nest. There they take them to some distance from the door, and then drop them on the ground to die, as if to put them out of their misery. As for the workers themselves, they return to the nest and starve to death or die of cold; or else they crawl about aimlessly outside in a distracted way till the end overtakes them.

  There is something really pathetic in this sudden and meaningless downfall of a whole vast cityful; something strange and weird in this constantly repeated effort to build up and people a great community, only to see it fall to pieces hopelessly and helplessly at the first touch of winter. Yet how does it differ, after all, from our human empires, save in the matter of duration? We raise them with infinite pains only to see them fall apart, like Rome or Babylon.

  So, by the time the dead of winter comes, both males and workers are cleared off the stage; and universal waspdom is only represented by a few stray fertilised females, who carry the embodied hopes of so many dead and ruined cities.

  And now that I have traced the history of the commune from its rise to its fall, I must say a few words in brief de
tail about the individual wasps which make up its members.

  And first of all as to the wasp’s head. You will have gathered from what I have said that the head of the insect is practically by far its most important portion. All the work we do with our hands, the wasp does with its complicated mouth-organs. And the wasp’s head is such a wonderful mechanism, that some little study of the accompanying illustrations, though they may not at first sight look very attractive, will amply repay you. I will try to explain the uses of each part with as little as possible of scientific technicalities.

  In No. 7 you get the head of a queen wasp, seen full-face in front, with the mouth-organs open. The three little knobs in the centre up above are the simple eyes or eyelets (ocelli, if you prefer a Latin word, which sounds much more learned). The large kidney-shaped bodies on either side of the head (here seen as interrupted by the antennæ or feelers) are the compound eyes, each of which consists of innumerable tiny lenses, giving the wasp that possesses them a very acute sense of vision. We do not know exactly what is the difference in use between the simple eyes and the compound ones; but either sort has doubtless its own special part to play in this complex personality. The antennæ, or feelers, again, with their many joints and their ball-and-socket base, are beautiful and wonderful objects. The various parts of the mouth are here seen open; conspicuous among them are the great saw-like outer jaws, used for scraping wood and manufacturing paper; the long, narrow shield; the broad tongue; and the delicately jointed palps, or finger-like feeders. Notice how some of these organs are suitable for cutting and rasping, while others lend themselves to the most dainty and delicate manipulation.

  No. 8 shows us the same head, decapitated, and seen from behind. The shield-like space in the very middle represents the point of decapitation — the cut neck, if I may use frankly human language. Below is the hollow or receptacle into which all the organs can be withdrawn when not in use, and packed away like surgical knives and lancets in an instrument case. Observe in the sequel how neatly and completely this can be done: how each has its groove in the marvellous economy of nature.

  In No. 9 you see the organs closing (also a back view), the tongue having been now drawn in, while the saw-like jaws and the delicate feeling palps are still exposed and ready for working. No. 8, on the contrary, is the feeding attitude.

  In No. 10 (another back view), the palps have been turned back into their special groove, and the saw-like jaws are seen free for working. This is the attitude in which the wasp attacks a park paling, in order to scrape off wood-fibre for the manufacture of paper. Here, as you see, the jaws are open. In No. 11 they are closed, at the end of a scrape. These two last attitudes are, of course, alternate. One shows the jaws opened, the other closed, as they look at the beginning and end of each forward and backward movement. You will notice also that, as usual, the insect’s jaws work sideways, not up and down like those of man and other higher animals. If you examine closely this series of wasp’s heads in different postures, you will see how well the various parts are adapted, not only for rasping and manufacturing paper, but also for the more delicate work of wall and cell building.

  Almost as interesting as the head are the wings of wasps, of which there are four, as in most other insects. But they have this curious peculiarity: the two front wings have a crease down the middle, so that they can be folded up lengthwise, like two segments or rays of a fan, and thus occupy only half the space on the body that they would otherwise do. It is this odd device that makes the transparent and gauzy wings so relatively inconspicuous when the insect is at rest, and the same cause contributes also to the display of the handsome black-and-yellow-striped body. No. 12 shows us a queen with her wings folded: below is one upper or front wing, folded over on itself, and then laid across the under wing. No. 13 introduces us to a more characteristic feature, common to wasps with the whole bee family.

  All these cousins possess by common descent the usual four wings of well-regulated insects. But it so happens that the habits of the race make strong and certain flight more practically important for them than the mere power of aërial coquetting and pirouetting possessed by the far less business-like butterflies. Your wasp and your bee are women of business. They have therefore found it pay them to develop a mechanism by which the two wings on either side can be firmly locked together, so as to act like a single pinion. No. 13 very well illustrates this admirable plan for fastening the fore and hind wings together. On top you see the back portion of the front wing, with a curved groove on its inner edge. Below, you get the front portion of the hinder wing, with a series of little hooks, microscopic, yet exquisitely moulded, which catch into the groove on the opposite portion. When thus hooked together, the two wings on the right act exactly like one. So do the two on the left. But they can be unhooked and folded back on the body at the will of the insect. To either side of No. 13 you will notice sections of the two wings, which will help you to understand the nature of the mechanism. On the right, the wings are seen hooked together; on the left, they are caught just in the act of unhooking.

  Last of all, and most important of all to ordinary humanity, we come to the sting, with its appendage the poison-bag. It is well represented in No. 14. The main object of the sting, and its original function by descent, is that of laying eggs; it is merely the ovipositor. But besides the grooved sheath or egg-layer (marked S in the illustration) and the two very sharp lances or darts (marked D) which pierce the flesh of the enemy, it is provided with a gland which secretes that most unpleasant body, formic acid; and when the wasp has cause to be annoyed, she throws the sting rapidly into the animal that annoys her, and injects the fluid with the formic acid in it. In No. 15 the darts are shown still more highly magnified. In the queen wasp, the sting is used both for laying eggs and as a weapon of offence; but in the workers, which cannot lay eggs, it is entirely devoted to the work of fighting.

  Two other little peculiarities of the wasp, however, deserve a final word of recognition. One of these is the elaborate brush-and-comb apparatus or antennæ-cleaner, drawn in a very enlarged view in No. 16. Whatever the sense may be which the antennæ serve, we may at least be certain that it is one of great importance to the insect; and both wasps and bees have therefore elaborate brushes for keeping these valuable organs clean and neat and in working order. They always remind me of the brushes I use myself for cleaning the type in my typewriting machine. The antennæ-brush of the wasp is fixed on one of her legs; its precise situation on the leg as a whole is shown in the little upper diagram; its detail and various parts are further enlarged below. To the left is the coarse or large-tooth comb; to the right is the brush; and above the brush, connected with the handle by an exceedingly thin and filmy membrane, is the fine-tooth comb, used for removing very small impurities. With this the wasp cleans her precious feelers much as you may have seen flies clean their wings when they have fallen in a jam-pot; only the wasp’s mechanism is much more beautiful and perfect.

  Almost equally interesting with the brush and comb are the series of tucks in the wasp’s body or abdomen, delineated in No. 17. By means of these extraordinarily flexible rings, each held in place or let loose by appropriate muscles, the wasp can twist her body round so conveniently that, no matter how carefully and gingerly you hold her, she will manage to sting you. They are models of plate-armour. They work upward, downward, and more or less sideways, so that they enable her to cock her body up or down, right or left, at will, with almost incredible flexibility.

  Adequately to tell you all about the wasp, however, would require a very stout volume. I have said enough, I hope, to suggest to you that the wasp’s history is quite as interesting as that of her over-lauded relation, the little busy bee. Indeed, I suspect it is only the utilitarian instinct of humanity that has caused so much attention to be paid to the domestic producer of honey, and so relatively little to that free and independent insect, the first paper-maker.

  VIII. ABIDING CITIES

  THE papery nests of wasps
are purely temporary empires: the vespine race has “no abiding city here”; each summer sees the populous homes built afresh from the ground; each winter sees them unpeopled and demolished. But with ants, which are builders for time, things are quite otherwise. The communities of those clever and intelligent little creatures are tolerably permanent; they go on from year to year, and generation to generation, often for very long periods together. Lest I weary you unnecessarily by a long preamble, however, I shall present you with views of one such nest at once, outside and inside, in Nos. 1 and 2, in order that you may see without delay the curious method of their detailed construction.

  The city whose external lineaments are shown you in the photograph reproduced in No. 1 is actually situated on St. George’s Hill, near Weybridge, just ten feet away from the large Scotch fir whose trunk appears on the right of the illustration. It is only one among many various types of ants’ nests built by different species. From outside, all you can see of it is a confused mass of dry pine-needles, arranged in a barrow-shaped hill or mound, some eight feet across at the base, and two feet high. But that is in reality only the outwork or top storey of the communal habitation. Beneath it lies a second layer, six inches thick, composed entirely of roots of heather and rootlets of fir-trees, all carefully stripped clean of bark, and making a dry foundation for the warm hillock of pine-needles. Below this woody layer, again, the ground is tunnelled to an unknown depth by long subterranean galleries, driven right through a stratum of solid sandstone. These inner galleries extend not only beneath the hillock, but also all round it, for wherever you step the soil treads soft, and gives beneath your foot to a depth of six or eight inches. This illustrative example is a city built by the common Wood Ant. I have had another just like it — an insect London — under observation for three or four years in a copse on a spur of Hind Head, not far from my cottage.