Numerous as are the instincts I have already enumerated, the list must yet include those connected with that mysterious principle which binds the working bees of a hive to their queen:—the singular imprisonment in which they retain the young queens that are to lead off a swarm, until their wings be sufficiently expanded to enable them to fly the moment they are at liberty, gradually paring away the waxen wall that confines them to their cell to an extreme thinness, and only suffering it to be broken down at the precise moment required;—the attention with which, in these circumstances, they feed the imprisoned queen by frequently putting honey upon her proboscis, protruded from a small orifice in the lid of her cell;—the watchfulness with which, when at the period of swarming more queens than one are required, they place a guard over the cells of those undisclosed, to preserve them from the jealous fury of their excluded rivals;—the exquisite calculation with which they invariably release the oldest queens the first from their confinement;—the singular love of monarchical dominion, by which, when two queens in other circumstances are produced, they are led to impel them to combat until one is destroyed;—the ardent devotion which binds them to the fate and fortunes of the survivor;—the distraction which they manifest at her loss, and their resolute determination not to accept of any stranger until an interval has elapsed sufficiently long to allow of no chance of the return of their rightful sovereign;—and (to omit a further enumeration) the obedience which in the utmost noise and confusion they show to her well-known hum.
I have now instanced at least thirty distinct instincts with which every individual of the nurses amongst the working-bees is endowed: and if to the account be added their care to carry from the hive the dead bodies of any of the community; their pertinacity in their battles, in directing their sting at those parts only of the bodies of their adversaries which are penetrable by it; their annual autumnal murder of the drones, &c. &c.—it is certain that this number might be very considerably increased, perhaps doubled.
At the first view you will be inclined to suspect some fallacy in this enumeration, and that this variety of actions ought to be referred rather to some general principle, capable of accommodating itself to different circumstances, than to so many different kinds of instinct. But to what principle? Not to reason, the faculty to which we assign this power of varying accommodation. All the actions above adduced come strictly under the description of instinctive actions, being all performed by every generation of bees since the creation of the world, and as perfectly a day or two after their birth as at any subsequent period. And as the very essence of instinct consists in the determinate character of the actions to which it gives birth, it is clear that every distinctly different action must be referred to a distinct instinct. Few will dispute that the instinct which leads a duck to resort to the water is a different instinct from that which leads her to sit upon her eggs; for the hen though endowed with one is not with the other. In fact, they are as distinct and unconnected as the senses of sight and smell; and it appears to me that it would be as contrary to philosophical accuracy of language, in the former case to call the two instincts modifications of each other, as in the latter so to designate the two senses; and as we say that a deaf and blind man has fewer senses than other men, so (strictly) we ought not to speak of instinct as one faculty (though to avoid circumlocution I have myself often employed this common mode of expression), or say that one insect has a greater or less share of instinct than another, but more or fewer instincts.—That it is not always easy to determine what actions are to be referred to a distinct instinct and what to a modification of an instinct, I am very ready to admit; but this is no solid ground for regarding all instincts as modifications of some one principle. It is often equally difficult to fix the limits between instinct and reason; but we are not on this account justified in deeming them the same.
This multitude of instincts in the same individual, becomes more wonderful when considered in another point of view. Were they constantly to follow each other in regular sequence, so that each bee necessarily first began to build cells, then to collect honey, next pollen, and so on, we might plausibly enough refer them to some change in the sensations of the animal, caused by alterations in the structure and gradual development of its organs, in the same way as on similar principles we explain the sexual instincts of the superior tribes. But it is certain that no such consecutive series prevails. The different instincts of the bee are called into action in an order regulated solely by the needs of the society. If combs be wanted, no bee collects honey for storing until they are provided[800]: and if, when constructed, any accident injure or destroy them, every labour is suspended until the mischief is repaired or new ones substituted[801]. When the crevices round the hive are effectually secured with propolis, the instinct directing the collection of this substance lies dormant: but transfer the bees to a new hive which shall require a new luting, and it is instantly re-excited. But these instances are superfluous. Every one knows that at the same moment of time the citizens of a hive are employed in the most varied and opposite operations. Some are collecting pollen; others are in search of honey; some busied at home in the first construction of the cells; others in giving them their last polish; others in ventilating the hive; others again in feeding the young brood and the like.
Now, how are we to account for this regularity of procedure—this undeviating accuracy with which the precise instinct wanted is excited—this total absence of all confusion in the employment by each inhabitant of the hive, of that particular instinct out of so many which the good of the community requires? No thinking man ever witnesses the complexness and yet regularity and efficiency of a great establishment, such as the Bank of England, or the Post-office, without marvelling that even human reason can put together with so little friction and such slight deviations from correctness, machines whose wheels are composed not of wood and iron, but of fickle mortals of a thousand different inclinations, powers, and capacities. But if such establishments be surprising even with reason for their prime mover, how much more so is a hive of bees whose proceedings are guided by their instincts alone! We can conceive that the sensations of hunger experienced on awaking in the morning should excite into action their instinct of gathering honey. But all are hungry: yet all do not rush out in search of flowers. What sensation is it that detains a portion of the hive at home, unmindful of the gnawings of an empty stomach, busied in domestic arrangements, until the return of their roving companions? Of those that fly abroad, what conception can we form of the cause which, while one set is gathering honey or pollen, leads another company to load their legs with pellets of propolis? Are we to say that the instinct of the former is excited by one sensation, that of the latter by another? But why should one sensation predominate in one set of bees, while another takes the lead in a second?—or how is it that these different instincts are called up precisely in the degree which the actual and changing state of things in the hive requires?—Of those which remain at home, what is it that determines in one party the instinct of building cells to prevail; in another that of ventilating the hive; in a third that of feeding the young brood? For my own part, I confess that the more I reflect on this subject, and contrast the diversity of the means with the regularity and uniformity of the end, the more I am lost in astonishment. The effects of instinct seem even more wonderful than those of reason, in the same manner as the consentaneous movements of a mighty and divided army, which, though under the command of twenty generals and from the most distant quarters, should meet at the assigned spot at the very hour fixed upon, would be more surprising than the steam-moved operations, however complex, of one of Boulton's mints.
For the sake of distinctness and compression, I have confined myself in considering the number of the instincts of individual insects to a single species, the bee; but if the history of other societies of these animals—wasps, ants, &c. detailed in my former letters, be duly weighed, it will be seen that they furnish examples of the variety in question fully as striking. These corroborating proofs I shall leave to your own inference, and proceed to the third head, under which I proposed to consider the instincts of insects—that of their extraordinary development.
The development of some of the instincts of the larger animals, such as those of sex, is well known to depend upon their age and the peculiar state of the bodily organs; and to this, as before observed, the succession of different instincts in the same insect, in its larva and perfect state, is closely analogous. But what I have now in view is that extraordinary development of instinct, which is dependent not upon the age or any change in the organization of the animal, but upon external events—which in individuals of the same species, age, and structure, in some circumstances slumbers unmoved, but may in others be excited to the most singular and unlooked-for action. In illustrating this property of instinct, which, as far as I am aware, is not known to occur in any of the larger animals, I shall confine myself as before to the hive-bee; the only insect, indeed, in which its existence has been satisfactorily ascertained, though it is highly probable that other species living in societies may exhibit the same phenomenon.
Several of the facts occurring in the history of bees might be referred to this head; but I shall here advert only to the treatment of the drones by the workers under different circumstances, and to the operations of the latter consequent upon the irretrievable loss of the queen—facts which have been before stated to you, but to the principal features of which my present argument makes it necessary that I should again direct your attention.
If a hive of bees be this year in possession of a queen duly fertilized, and consequently sure the next season of a succession of males, all the drones, as I have before stated[802], towards the approach of winter are massacred by the workers with the most unrelenting ferocity. To this seemingly cruel course they are doubtless impelled by an imperious instinct; and as it is regularly followed in every hive thus circumstanced, it would seem at the first view to be an impulse as intimately connected with the organization and very existence of the workers, and as incapable of change, as that which leads them to build cells or to store up honey. But this is far from being the case. However certain the doom of the drones this autumn, if the hive be furnished with a duly-fertilized queen, their undisturbed existence over the winter is equally sure if the hive have lost its sovereign, or her impregnation have been so retarded as to make a succession of males in the spring doubtful. In such a hive the workers do not destroy a single drone, though the hottest persecution rages in all the hives around them.