Part 34
The cells are of different sizes, corresponding to that of the three orders of individuals which compose the community; the largest for the grubs of females, the smallest for those of workers. The last always occupy an entire comb, while the cells of the males and females are often intermixed. Besides openings which are left between the walls of the combs to admit of access from one to the other, there are at the bottom of each nest two holes, by one of which the wasps uniformly enter, and through the other issue from the nest, and thus avoid all confusion or interruption of their common labours. As the nest is often a foot and a half under ground, it is requisite that a covered way should lead to its entrance. This is excavated by the wasps, who are excellent miners, and is often very long and tortuous, forming a beaten road to the subterranean city, well known to the inhabitants, though its entrance is concealed from curious eyes. The cavity itself, which contains the nest, is either the abandoned habitation of moles or field-mice, or a cavern purposely dug out by the wasps, which exert themselves with such industry as to accomplish the arduous undertaking in a few days.
When the cavity and entrance to it are completed, the next part of the process is to lay the foundations of the city to be included in it, which, contrary to the usual customs of builders, wasps begin at the top, continuing downwards. It has already been observed, that the coatings which compose the dome, are a sort of rough but thin paper, and that the rest of the nest is composed of the same substance variously applied. "Whence do the wasps derive it?" They are manufacturers of the article, and prepare it from a material even more singular than any of those which have of late been proposed for this purpose; namely, the fibres of wood. These they detach by means of their jaws from window-frames, posts, and rails, &c. and, when they have amassed a heap of the filaments, moisten the whole with a few drops of a viscid glue from their mouth, and, kneading it with their jaws into a sort of paste, or _papier mâché_, fly off with it to their nest. This ductile mass they attach to that part of the building upon which they are at work, walking backwards, and spreading it into laminæ of the requisite thinness by means of their jaws, tongue, and legs. This operation is repeated several times, until at length, by aid of fresh supplies of the material, and the combined exertions of so many workmen, the proper number of layers of paper, that are to compose the roof, is finished. This paper is as thin as the leaf you are reading; and you may form an idea of the labour which even the exterior of a wasp's nest requires, on being told that no fewer than fifteen or sixteen sheets of it are usually placed above each other, with slight intervening spaces, making the whole upwards of an inch and a half in thickness. When the dome is completed, the uppermost comb is next begun, in which, as well as all the other parts of the building, precisely the same material and the same process, with little variation, are employed. In the structure of the connecting pillars, there seems a greater quantity of glue made use of than in the rest of the work, doubtless with the view of giving them superior solidity. When the first comb is finished, the continuation of the roof or walls of the building is brought down lower; a new comb is erected; and thus the work successively proceeds until the whole is finished. As a comparatively small proportion of the society is engaged in constructing the nest, its entire completion is the work of several months: yet, though the fruit of such severe labour, it has scarcely been finished a few weeks before winter comes on, when it merely serves for the abode of a few benumbed females, and is entirely abandoned at the approach of spring, as wasps are never known to use the same nest for more than one season.
There is good reason for thinking, and the opinion had the sanction of the late Sir Joseph Banks, that wasps have sentinels placed at the entrances of their nests, which, if you can once seize and destroy, the remainder will not attack you. This is confirmed by an observation of Mr. Knight, in the Philosophical Transactions, (vol. 1. 2d Ed. p. 505;) that if a nest of wasps be approached without alarming the inhabitants, and all communication be suddenly cut off between those out of the nest and those within it, no provocation will induce the former to defend it and themselves. But if one escapes from within, it comes with a very different temper, and appears commissioned to avenge public wrongs, and prepared to sacrifice its life in the execution of its orders. He discovered this when quite a boy.
In October, wasps seem to become less savage and sanguinary; for even flies, of which, earlier in the summer, they are the pitiless destroyers, may be seen to enter their nests with impunity. It is then, probably, that they begin to be first affected by the approach of the cold season, when nature teaches them it is useless longer to attend to their young. They themselves all perish, except a few of the females, upon the first attack of frost.
Reaumur, from whom most of these observations are taken, put the nests of wasps under glass hives, and succeeded so effectually in reconciling these little restless creatures to them, that they carried on their various works under his eye.
CHAP. XXV.
CURIOSITIES RESPECTING INSECTS.--(_Continued._)
_Ants--White Ants--Green Ants--Visiting Ants--The Ant-Lion._
These emmets, how little they are in our eyes! We tread them to dust, and a troop of them dies Without our regard or concern: Yet, as wise as we are, if we went to their school, There's many a sluggard, and many a fool, A lesson of wisdom might learn. _Watts._
The societies of ANTS, as also of other _Hymenoptera_, differ from those of the Termites, in having inactive larvæ and pupæ, the neuter, or workers, combining in themselves both the military and civil functions. Besides the helpless larvæ and pupæ, which have no locomotive powers, these societies consist of females and workers. The office of the females, at their first exclusion distinguished by a pair of ample wings, (which however, they soon cast,) is the foundation of new colonies, and the furnishing of a constant supply of eggs, for the maintenance of the population in the old nests, as well as in the new. These are usually the least numerous part of the community.
Gould indeed says, that the males and females are nearly equal in number, p. 62; but from Huber's observations it seems to follow that the former are the most numerous, p. 96.
Upon the workers devolves, except in nascent colonies, all the work, as well as the defence of the community, of which they are the most numerous portion.
In the warm days that occur from the end of July to the beginning of September, and sometimes later, the habitations of the various species of ants may be seen to swarm with winged insects, which are the males and females, preparing to quit for ever the scene of their nativity and education. Every thing is in motion: and the silver wings, contrasted with the jet bodies which compose the animated mass, add a degree of splendour to the interesting scene. The bustle increases, till at length the males rise, as it were by a general impulse, into the air, and the females accompany them. The whole swarm alternately rises and falls with a slow movement to the height of about ten feet, the males flying obliquely with a rapid zigzag motion; and the females, though they follow the general movement of the column, appearing suspended in the air, like balloons, seemingly with no individual motion, and having their heads turned towards the wind.
Sometimes the swarms of a whole district unite their infinite myriads, and, seen at a distance, produce an effect resembling the flashing of an aurora borealis. Rising with incredible velocity in distinct columns, they soar above the clouds. Each column looks like a kind of slender net-work, and has a tremulous undulating motion, which has been observed to be produced by the regular alternate rising and falling just alluded to. The noise emitted by myriads and myriads of these creatures, does not exceed the hum of a single wasp. The slightest zephyr disperses them; and if in their progress they chance to be over your head, if you walk slowly on, they will accompany you, and regulate their motions by yours.
Captain Haverfield, R. N. gives an account of an extraordinary appearance of ants observed by him in the Medway, in the autumn of 1814, when he was first-lieutenant of the Clorinde; which is confirmed by the following letter, addressed by the surgeon of that ship, now Dr. Bromley, to Mr. Mac Leay.
"In September, 1814, being on the deck of the bulk to the Clorinde, my attention was drawn to the water by the first-lieutenant (Haverfield) observing there was something black floating down with the tide. On looking with a glass, I discovered they were insects. The boat was sent, and brought a bucket full of them on board; they proved to be a large species of ant, and extended from the upper part of Salt-pan Reach out towards the Great Nore, a distance of five or six miles. The column appeared to be in breadth eight or ten feet, and in height about six inches, which I suppose must have been from their resting one upon another." Purchas seems to have witnessed a similar phenomenon on shore. "Other sorts (of ants)," says he, "there are many, of which some become winged, and fill the air with swarms, which sometimes happens in England. On Bartholomew-day, 1613, I was in the island of Foulness, on our Essex shore, where were such clouds of these flying pismires, that we could no where flee from them, but they filled our clothes; yea, the floors of some houses where they fell were in a manner covered with a black carpet of creeping ants; which, they say, drown themselves about that time of the year in the sea."--_Pilgrimage_, 1090. These ants were winged; but whence this immense column came, was not ascertained. From the numbers here accumulated, one would think that all the ant-hills of the counties of Kent and Surrey could scarcely have furnished a sufficient number of males and females to form it.
When Colonel Sir Augustus Frazer, of the Horse Artillery, was surveying, on the 6th of October, 1813, the scene of the battle of the Pyrenees, from the summit of the mountain called Pena de Aya, or Les Quatre Couronnes, he and his friends were enveloped with a swarm of ants, so numerous as entirely to intercept their view, so that they were glad to remove to another station, in order to get rid of these troublesome little creatures.
The females that escape from the injury of the elements and their various enemies, become the founders of new colonies, doing all the work that is usually done by the neuters. M. P. Huber has found incipient colonies,[11] in which were only a few workers engaged with their mother in the care of a small number of larvæ; and M. Perrot, his friend, once discovered a small nest, occupied by a solitary female, who was attending upon four pupa only. Such is the foundation and first establishment of those populous nations of ants with which we every where meet.
But though the majority of females produced in a nest probably thus desert it, all are not allowed this liberty. The prudent workers are taught by their instinct, that the existence of their community depends upon the presence of a sufficient number of females. Some, therefore, that are fecundated in or near the spot, they forcibly detain, pulling off their wings, and keeping them prisoners till they are ready to lay their eggs, or are reconciled to their fate. De Geer, in a nest of _F. rufa_, observed that the workers compelled some females that were come out of the nest to re-enter it; (vol. ii. 1071,)--and from M. P. Huber we learn, that, being seized at the moment of fecundation, they are conducted into the interior of the formicary, when they become entirely dependent upon the neuters, who, hanging pertinaciously to each leg, prevent their going out, but at the same time attend upon them with the greatest care, feeding them regularly, and conducting them where the temperature is suitable to them, but never quitting them a single moment. By degrees these females become reconciled to their condition, and lose all desire of making their escape; their abdomen enlarges, and they are no longer detained as prisoners, yet each is still attended by a body-guard, a single ant, which always accompanies her, and prevents her wants. Its station is remarkable, being mounted upon her abdomen, with its posterior legs upon the ground. These sentinels are constantly relieved; and to watch the moment when the female begins the important work of oviposition, and carry off the eggs, of which she lays four or five thousand or more in the course of the year, seems to be their principal office.
When the female is acknowledged as a mother, the workers begin to pay her a homage very similar to that which the bees render to their queen. All press round her, offer her food, conduct her by her mandibles through the difficult or steep passages of the formicary; nay, they sometimes even carry her about their city: she is then suspended upon their jaws, the ends of which are crossed; and, being coiled up like the tongue of a butterfly, she is packed so close as to incommode the carrier but little. When these set her down, others surround and caress her, one after another tapping her on the head with their antennæ.
"In whatever apartment (says Gould) a queen condescends to be present, she commands obedience and respect. A universal gladness spreads itself through the whole cell, which is expressed by particular acts of joy and exultation. They have a particular way of skipping, leaping, and standing upon their hind-legs, and prancing with the others. These frolics they make use of, both to congratulate each other when they meet, and to shew their regard for the queen: some of them walk gently over her, others dance round her; she is generally encircled with a cluster of attendants, who, if you separate them from her, soon collect themselves into a body, and inclose her in the midst." Nay, even if she dies, as if they were unwilling to believe it, they continue sometimes for months the same attentions to her, and treat her with the same courtly formality as if she were alive, and they will brush her and lick her incessantly.
That the ants, though they are mute animals, have the means of communicating to each other information of various occurrences, and use a kind of language which is mutually understood, will appear evident from the following facts.
If those at the surface of a nest are alarmed, it is wonderful in how short a time the alarm spreads through the whole nest. It runs from quarter to quarter; the greatest inquietude seems to possess the community; and they carry with all possible dispatch their treasures, the larvæ and pupæ, down to the lowest apartments. Amongst those species of ants that do not go much from home, sentinels seem to be stationed at the avenues of their city. "Disturbing once the little heaps of earth thrown up at the entrances into the nest of _F. flava_, which is of this description, (says Huber,) I was struck by observing a single ant immediately come out, as if to see what was the matter, and this three separate times."
The _F. herculanea, L._ inhabits the trunks of hollow trees on the Continent, for it has not yet been found in England, upon which they are often passing to and fro. M. Huber observed, that when he disturbed those that were at the greatest distance from the rest, they ran towards them, and, striking their head against them, communicated their cause of fear or anger that these, in their turn, conveyed in the same way the intelligence to others, till the whole colony was in a ferment, those neuters which were within the tree running out in crowds to join their companions in the defence of their habitation. The same signals that excited the courage of the neuters, produced fear in the males and females, which, as soon as the news of the danger was thus communicated to them, retreated into the tree as to an asylum.
The legs of one of this gentleman's artificial formicaries were plunged into pans of water, to prevent the escape of the ants; this proved a source of great enjoyment to these little beings, for they are a very thirsty race, and lap water like dogs.--(_Gould_, 92. _De Geer_, ii. 1087. _Huber_, 5, 132.) One day, when he observed many of them tippling very merrily, he was so cruel as to disturb them, which sent most of the ants in a fright to the nest; but some, more thirsty than the rest, continued their potations: upon this, one of those that had retreated, returns to inform his thoughtless companions of their danger; one he pushes with his jaws; another he strikes first upon the belly, and then upon the breast; and so obliges three of them to leave off their carousing, and march homewards; but the fourth, more resolute to drink it out, is not to be discomfited, and pays not the least regard to the kind blows with which his compeer, solicitous for his safety, repeatedly belabours him; at length, determined to have his way, he seizes him by one of his hind-legs, and gives him a violent pull: upon this, leaving his liquor, the loiterer turns round, and opening his threatening jaws with every appearance of anger, goes very coolly to drinking again; but his monitor, without further ceremony, rushing before him, seizes him by his jaws, and at last drags him off in triumph to the formicary.--_Huber_, 133.
The language of ants, however, is not confined merely to giving intelligence of the approach or presence of danger; it is also co-extensive with all their other occasions for communicating their ideas to each other, or holding any intercourse. Some engage in military expeditions, and often previously send out spies, to collect information. These, as soon as they return from exploring the vicinity, enter the nest; upon which, as if they had communicated their intelligence, the army immediately assembles in the suburbs of their city, and begins its march towards that quarter whence the spies had arrived. Upon the march, communications are perpetually making between the van and the rear; and when arrived at the camp of the enemy, and the battle begins, if necessary, couriers are dispatched to the formicary for reinforcements.--_Huber_, 167, 217, 237.
If you scatter the ruins of an ant's nest in your apartment, you will be furnished with another proof of their language. The ants will take a thousand different paths, each going by itself, to increase the chance of discovery; they will meet and cross each other in all directions, and perhaps will wander long before they can find a spot convenient for their re-union. No sooner does any one discover a little chink in the floor, through which it can pass below, than it returns to its companions, and, by means of certain motions of its antennæ, makes some of them comprehend what route they are to pursue to find it, sometimes even accompanying them to the spot; these, in their turn, become the guides of others, till all know which way to direct their steps.--_Huber_, 137.
It is well known also, that ants give each other information when they have discovered any store of provision. Bradley relates a striking instance of this. A nest of ants in a nobleman's garden discovered a closet, many yards within the house, in which conserves were kept, which they constantly attended till the nest was destroyed. Some in their rambles must have first discovered this depôt of sweets, and informed the rest of it. It is remarkable that they always went to it by the same track, scarcely varying an inch from it, though they had to pass through two apartments; nor could the sweeping and cleaning of the rooms discomfit them, or cause them to pursue a different route.--_Bradley_, 134.
Here may be related a very amusing experiment of Gould's. Having deposited several colonies of ants (_F. fusca_) in flowerpots, he placed them in some earthen pans of water, which prevented them from making excursions from their nest. When they had been accustomed some days to this imprisonment, he fastened small threads to the upper part of the pots, and extending them over the water-pans, fixed them in the ground. The sagacious ants soon found out that by these bridges they could escape from their moated castle. The discovery was communicated to the whole society, and in a short time the threads were filled with trains of busy workers passing to and fro.--_Gould_, 85.
Legion's account of the ants in Barbadoes, affords another most convincing proof of this: as he has told his tale in a very lively and interesting manner, it shall be given nearly in his own words.
"The next of these moving little animals are ants, or pismires: these are but of a small size, but great in industry; and that which gives them means to attain to this end is, they have all one soul. If I should say they are here or there, I should do them wrong, for they are every where:--under ground, where any hollow or loose earth is; amongst the roots of trees; upon the bodies, branches, leaves, and fruit of all trees; in all places without the houses and within; upon the sides, walls, windows, and roofs, without; and on the floors, side-walls, ceilings, and windows, within; tables, cupboards, beds, stools, all are covered with them, so that they are a kind of ubiquitaries. We sometimes kill a cockroach, and throw him on the ground; and mark what they will do with him: his body is bigger than a hundred of them, and yet they will find the means to take hold of him, and lift him up; and having him above ground, away they carry him, and some go by as ready assistants, if any be weary; and some are the officers that lead and shew the way to the hole into which he must pass; and if the vancouriers perceive that the body of the cockroach lies across, and will not pass through the hole or arch through which they mean to carry him, order is given, and the body turned endwise, and this is done a foot before they come to the hole, and that without any stop or stay; and it is observable, that they never pull contrary ways. A table being cleared with great care, (by way of experiment,) of all the ants that are upon it, and sugar being put upon it, some, after a circuitous route, will be observed to arrive at it; and again departing, without tasting the treasure, will hasten away to inform their friends of the discovery, who, upon this, will come by myriads: you may then, while they are thickest upon the table, clap a large book, or any thing fit for that purpose, upon them, so hard as to kill all that are under it; and when you have done so, take away the book, and leave them to themselves but a quarter of an hour, and when you come again, you shall find all these bodies carried away.--Other trials we make of their ingenuity, as thus: Take a pewter dish, and fill it half full of water, into which put a little gallipot filled with sugar, and the ants will presently find it, and come upon the table, but when they perceive it environed with water, they try about the brims of the dish where the gallipot is nearest; and there the most venturous amongst them commits himself to the water, though he be conscious how bad a swimmer he is, and is drowned in the adventure; the next is not warned by his example, but ventures too, and is alike drowned; and many more, so that there is a small foundation of their bodies to venture; and then they come faster than ever, and so make a bridge of their own bodies."--_Hist. of Barbadoes_, p. 63.