Aristotle says that in each journey from the hive, bees attend only one species of flower[222]; Reaumur, however, seems to think that they fly indiscriminately from one to another: but Mr. Dobbs in the Philosophical Transactions[223], and Butler before him, asserts that he has frequently followed a bee engaged in collecting pollen, &c. and invariably observed that it continued collecting from the same kind of flowers with which it first began: passing over other species, however numerous, even though the flower it first selected was scarcer than others. His observations, he thinks, are confirmed—and the idea seems not unreasonable—by the uniform colour of the pellets of pollen, and their different size. Reaumur himself tells us that the bees enter the hive, some with yellow pellets, others with red ones, others again with whitish ones, and that sometimes they are even green: upon which he observes, that this arises from their being collected from particular flowers, the pollen of whose anthers is of those colours[224]. Sprengel, as before intimated[225], has made an observation similar to that of Dobbs. It seems not improbable that the reason why the bee visits the same species of plants during one excursion may be this:—Her instinct teaches her that the grains of pollen which enter into the same mass should be homogeneous, in order perhaps for their more effectual cohesion; and thus Providence also secures two important ends,—the impregnation of those flowers that require such aid, by the bees passing from one to another; and the avoiding the production of hybrid plants, from the application of the pollen of one kind of plant to the stigma of another. When the anthers are not yet burst, the bee opens them with her mandibles, takes a parcel of pollen, which one of the first pair of legs receives and delivers to the middle pair, from which it passes to one of the hind legs.
If the contents of one of the little pellets be examined under a lens, it will be found that the grains have all retained their original shape. A botanist practised in the figure of the pollen of the different species of common plants might easily ascertain, by such an examination, whether a bee had collected its ambrosia from one or more, and also from what species of flowers.
In the months of April and May, as Reaumur tells us, the bees collect pollen from morning to evening; but in the warmer months the great gathering of it is from the time of their first leaving the hive (which is sometimes so early as four in the morning) to about 10 o'clock A.M. About that hour all that enter the hive may be seen with their pellets in their baskets; but during the rest of the day the number of those so furnished is small in comparison of those that are not. In a hive, however, in which a swarm is recently established, it is generally brought in at all parts of the day. He supposes, in order for its being formed into pellets, that it requires some moisture, which the heat evaporates after the above hour; but in the case of recently colonized hives, that the bees go a great way to seek it in moist and shady places[226].
When a bee has completed her lading, she returns to the hive to dispose of it. The honey is disgorged into the honey-pots or cells destined to receive it, and is discharged from the honey-bag by its alternate contraction and dilatation. A cell will contain the contents of many honey-bags. When a bee comes to disgorge the honey, with its fore legs it breaks the thick cream that is always on the top, and the honey which it yields passes under it. This cream is honey of a thicker consistence than the rest, which rises to the top in the cells like cream on milk: it is not level, but forms an oblique surface over the honey. The cells, as you know, are usually horizontal, yet the honey does not run out. The cream, aided probably by the general thickness of the honey and the attraction of the sides of the cell, prevents this. Bees, when they bring home the honey, do not always disgorge it; they sometimes give it to such of their companions as have been at work within the hive[227]. Some of the cells are filled with honey for daily use, and some with what is intended for a reserve, and stored up against bad weather or a bad season: these are covered with a waxen lid[228].
The pollen is employed as circumstances direct. When the bee laden with it arrives at the hive, she sometimes stops at the entrance, and very leisurely detaching it by piecemeal, devours one or both the pellets on her legs, chewing them with her jaws, and passing them then down the little orifice before noticed. Sometimes she enters the hive, and walks upon the combs; and whether she walks or stands, still keeps beating her wings. By the noise thus produced, which seems a call to some of her fellow-citizens, three or four go to her, and placing themselves around her, begin to lighten her of her load, each taking and devouring a small portion of her ambrosia: this they repeat, if more do not arrive to assist them, three or four times, till the whole is disposed of[229]. Wildman observed them on this occasion supporting themselves upon their two fore feet; and making several motions with their wings and body to the right and left, which produced the sound that summoned their assistants[230]. This bee-bread, as I said before, is generally found in the second stomach and intestines, but the honey never; which induced Reaumur to think (but he was mistaken) that the bees elaborated wax from it: and he observes, that the bees devour this when they are busily engaged in constructing combs[231]. When more pollen is collected than the bees have immediate occasion for, they store it up in some of the empty cells. The laden bee puts her two hind legs into the cell, and with the intermediate pair pushes off the pellets. When this is done, she, or another bee if she is too much fatigued with her day's labour, enters the cell with her head first, and remains there some time: she is engaged in diluting the pellets, kneading them, and packing them close; and so they proceed till the cell is filled[232]. A large portion of the cells of some combs are filled with this bread, which one while is found in insulated cells, at another in cells amongst those that are filled with honey or brood.—Thus it is everywhere at hand for use.
You have seen how the bees collect and employ two of the materials that I mentioned; I must now advert to the third—the Propolis. Huber was a long time uncertain from whence the bees procured this gummy resin; but it at last occurred to him to plant some cuttings of a species of poplar (before their leaves were developed, when their leaf-buds were swelling, and besmeared and filled with a viscid juice,) in some pots, which he placed in the way of the bees that went from his hives. Almost immediately a bee alighted upon a twig, and soon with its mandibles opened a bud, and drew from it a thread of the viscid matter which it contained; with one of its second pair of legs it took it from the mouth, and placed it in the basket: thus it proceeded till it had given them both their load[233]. I have myself seen bees very busy collecting it from the Tacamahaca (Populus balsamifera). But this is an old discovery, confirmed by recent observation; for Mouffet tells us from Cordus, that it is collected from the gems of trees, instancing the poplar and the birch[234]. Riem observes that it is also collected from the pine and fir. The propolis is soft, red, will pull out in a thread, is aromatic, and imparts a gold colour to white polished metals. It is employed in the hive not only in finishing the combs, as I related in my letter on Habitations[235]; but also in stopping every chink or orifice by which cold, wet, or any enemy, can enter. They cover likewise with it the sticks which support the combs, and often spread it over a considerable portion of the interior of the hive. Like the pellets of pollen, it is carried on the posterior tibiæ, but the masses are lenticular[236].
Mr. Knight mentions an instance of bees using an artificial kind of propolis. He had caused the decorticated part of some tree to be covered with a cement composed of bees-wax and turpentine: finding this to their purpose, they attacked it, detaching it from the tree by their mandibles, and then, as usual, passing it from the first leg to the second, and so to the third. When one bee had thus collected its load, another often came behind and despoiled it of all it had collected; a second and third load were frequently lost in the same manner; and yet the patient animal pursued its labours without showing any signs of anger[237].
Bees in their excursions do not confine themselves to the spot immediately contiguous to their dwelling, but, when led by the scent of honey, will go a mile from it. Huber even assigns to them a radius of half a league round their hive for their ordinary excursions; yet from this distance they will discover honey with as much certainty as if it was within their sight. To prove that it is by their scent that bees find it out, he put some behind a window-shutter, in a place where it could not be seen, leaving the shutter just open enough for insects, if they liked, to get at it. In less than a quarter of an hour four bees, a butterfly, and some house-flies had discovered it. At another time he put some into boxes, with little apertures in the lid, into which pieces of card were fitted, which he placed about two hundred paces from his hives. In about half an hour the bees discovered them, and traversing them very industriously, soon found the apertures, when, pushing in the pieces of card, they got to the honey. That contained in the blossom of many plants is quite as much concealed, yet the acuteness of their scent enables them to detect it.
These insects, especially when laden and returning to their nest, fly in a direct line, which saves both time and labour. How they are enabled to do this with such certainty as to make for their own abode without deviation, I must leave to others to explain. Connected with this circumstance, and the acuteness of their smell, is the following curious account, given in the Philosophical Transactions for 1721, of the method practised in New England for discovering where the wild hive-bees live in the woods, in order to get their honey. The honey-hunters set a plate containing honey or sugar upon the ground in a clear day. The bees soon discover and attack it: having secured two or three that have filled themselves, the hunter lets one go, which rising into the air, flies straight to the nest: he then strikes off at right angles with its course a few hundred yards, and letting a second fly, observes its course by his pocket-compass, and the point where the two courses intersect is that where the nest is situated[238].
The natural station of bees is in the cavities of decayed trees; such trees, Mr. Knight tells us, they will discover in the closest recesses, and at an extraordinary distance from the hive; in one instance it was a mile: and at swarming, they sometimes are inclined to settle in such cavities. After the discovery of one, from twenty to fifty, who are a kind of scouts, may be found examining and keeping possession of it. They seem to explore every part of it and of the tree with the greatest attention, even surveying the dead knots and the like[239]. When a hive stands unemployed, a swarm will also sometimes send scouts to take possession of it.