The Wings
In the long-bodied, golden-hued Italian bee, the wings are not more than three-fourths the length of the abdomen. Clinging to the flowers with these small and dainty gossamers vibrating above its form, the little creature seems like some tiny sprite bearing wings for beauty rather than for use.
Yet the airy wings of our pretty bee are most effectual instruments of flight, carrying her many miles in the course of a summer day.
Butler quaintly tells us that "Nature hath furnished her with four wings: which, swifter than the East-wind, carry her into all the four coasts of the world; and thence with her precious lading bear her back again, until her incessant labor hath worn them out."
The thorax, that division of the body next back of the head, is specially devoted to the organs of progression, bearing as it does the wings and the legs. Isolate the thorax and its appendages, and we appear to have the principal part of the bee, certainly it is the most showy part.
The head possesses the organs of sense and the wonderful tongue; the abdomen, which is the last division of the body, carries the complex and respected sting; but the thorax controls the usefulness of all these, since it has attached to it the means of locomotion.
In dealing with the bee's power of movement, it is right that the wings have precedence of the legs, they being the more poetical, dainty, and as well uppermost in position of all the organs of progression.
The description of bees given by Moffett that "they have four wings, being of a bright and clear color, growing to their shoulder-blades, whereof the two hindermost are the lesser, because they might not hinder their flying," is not without its merits.
Certainly they have four wings of a bright and clear color. One could scarcely better describe the appearance of the shining transparent gauzes that adorn the bee's back, and if they are not attached to the shoulder-blades, at least they are attached to what doubtless would be shoulder-blades if the bee had shoulders.
They are where the shoulder-blades of the human being are located, and to speak of them in this way immediately and accurately places them, in the imaginative and unprejudiced mind of the non-scientific observer. It is true, too, that there are four of them, and that the hindermost are the lesser.
When flying, a bee appears to have but two wings, and practically this is true; but when it comes to rest, these two accommodatingly resolve themselves into four, in order that the hindermost and lesser pair may be tucked away beneath the foremost and greater pair.
The smaller and lighter the wings, the less do they hamper the movements of the bee, yet they must be strong and firm; and these wings have a stiff framework like that of a kite, and like that are also overlaid with a thin light membrane ١/٠ against which the air can find resistance. The lines of the framework though quite complex are very constant, so that The Wings the species of a bee is determined by slight variations in them.
On either side of the thorax, at the point of the suppositional shoulder-blades, two wings are attached. The points of attachment of the two are very close together, but when the wing is extended, the lesser and hindermost is seen to be placed a little behind the larger and foremost.
While the double wing, when closed, is a great convenience in exploring flowers and moving about the crowded hive, it would be extremely disastrous when set for flight if the lesser and the greater were then to separate. But this they never do, as they are locked together in a very ingenious manner.
The upper edge of the lower wing bears a row of hooks, the points of which are turned towards the inside. On the lower edge of the upper wing, opposite these hooks, is a fold forming a slender groove into which the hooks catch when the wings are raised. The mere act of raising the wings draws the hooks into the groove and locks them.
The greater the pressure brought to bear against the surface of these locked wings, the more firmly are they held together, so they are in no danger of coming apart in the most rapid or erratic flight.
Quickly and safely as the wings are locked into one, they can as easily be separated into two, when lowered against the back in a state of rest.
The wings do not necessarily come unlocked when lowered, however, and one often sees a captive bee with its locked wings spread over its back, as though it knew that were safe enough under the circumstances, and would not take the trouble to pack them away. But when it enters a flower or its hive, a slight motion of the upper wings separates them from the lower, when the latter slip away out of sight under the former.
Important as it is that the bee should have ample wing expanse when flying, it is equally important that it be not hampered by outreaching wings when about its work in flowers and in the hive, where large wings would not only be inconvenient, but would be liable to become torn and broken.
The speed with which the wings move is amazing, it having been calculated that during their swiftest motion they make over four hundred vibrations a second!
Powerful muscles are necessary to sustain the bee's flight, and its thorax is a mass of muscles, perhaps the most remarkable of any in the world.
Tiny threads they are, yet when one considers the work they do, the massive muscles that move the elephant or the ox are as nothing compared to them.
The rapidity with which the bee is borne through the air is not very well known, as it is not an easy point to determine. Cheshire says, 66 - My own observations lead me to suppose that the pace ranges between two and sixteen or eighteen miles per hour, depending upon the load and the nature of the errand a bee, bearing the body of the deceased sister from the hive, taking the funereal pace, while those issuing forth on business bent go express." If the bee moved its small wings with the deliberation of the butterfly, they could not hold it suspended for a moment. But it has an engine that the butterfly dreams not of. At the moment of flight its thoracic muscles start the wings to moving with a rapidity that makes one think of a pair of buzz saws, and away goes the bee, merrily speeding through the air, its cheery hum an involuntary song of triumph to its own wonderful structure.
The Wings With its marvellous engine run by vital force in opera-- tion, it can go where it listeth; and while the more helpless butterfly is often blown about at the mercy of the wind, its gorgeous wings even serving as sails to catch the breeze and carry it far out to sea, the bee, like a trim little steam launch, heads up against the wind, and goes where it pleases.
The exact manner in which the wings are used as organs of progression, raising the bee from the earth, speeding it in any direction, with or against the wind, taking it high in the air, or dropping it with lightness and accuracy upon a selected flower, is still a problem for philosophers to puzzle over.
There is no doubt that the flight of the bee is aided, perhaps rendered possible, by a very wonderful system of air-sacs and air-tubes.
There are large air-sacs in the upper end of the abdomen, almost filling it when distended with air, and there are air-sacs at the bases of the wings. These air-sacs open to the surface by minute orifices called spiracles, one at the base of each of the four wings, and several others open on the sides of the abdominal walls.
The bee, like the bird, is supplied with air-cavities to sustain it in its flight, and these air-cavities are also its "lungs." It pumps the air into them by a continuous motion of the abdomen when at rest, and has the power to close the spiracles, and thus shut in a large amount of air when it desires to fly.
Packard tells us that the insect can change its specific gravity by filling or emptying its air-sacs, and that increased exertion causes increased activity in, breathing, while decreased exertion has of course the opposite effect, so that in hibernating insects respiration is almost entirely suspended. He also says that the air rushes into the thoracic spiracles when the wings are raised, filling the air-sacs in the body, lessening the specific gravity of the insect and enabling it to rise in the air and remain there with but slight muscular exertion. At the first stroke of the wings the spiracles are closed and the air retained.
Girard says that inside each spiracle is a muscular valve that by opening or closing can let in or shut out the air, and that this is under the control of the insect, who can thus at will fill the air-sacs and decrease the specific gravity. Thus we find the breathing apparatus of the bee complex in structure and varied in function. It serves to aërate the blood and at the same time to make effective the action of the wings.
Rapidity of respiration affects the temperature of the insect. The bumble-bee, according to Newport, raises its temperature by quickened respiration, and does this voluntarily in order to generate heat for purposes of incubation. Doubtless the enclosed air, which is shut at the will of the bee into the air-sacs during flight, is heated by its body, thus becoming lighter, and acting as the gas in a balloon to increase the buoyancy.
The bee cannot fly until its air-sacs are filled; consequently when one which has been sleeping is suddenly roused, it cannot at once fly away, but makes a series of "hops," or little jumps, fanning its wings rapidly the while until the air-sacs are expanded with air and its body is in a condition for flight.
The pitch of the bee's wing music depends upon the rapidity with which the wings vibrate, and it was this pitch from the wings of an excited bee that gave foundation to the declaration that the wings sometimes move at the rate of more than four hundred times a second. As a rule, however, they move considerably slower than this, the maximum rate of vibrations soon inducing exhaustion. The Wings By listening to the tone of the bee's wings, one can soon learn the state of its mind, for the low hum of happy industry is very readily distinguishable from the high-keyed note of fear or anger.
When in the fields, one can soon learn to know the species of a bee by its hum, before the bee itself has been found by the eye. The low drowsy note of the bumble-bee can be recognized at once, and the sharp, short tone of the small wild bee is easily distinguishable from the pleasant, intermittent note of the honey-bee going from flower to flower, the most agreeable of all bee-voices.
A sharp listener can even tell whether the sound proceeds from the large or the small bumble-bee, and very likely one with gifted ears could tell, without seeing, just what species of the many wild bees that inhabit our land had crossed his path.
The voices of the bees are as significant to those who love and listen as are the voices of the birds to the birdlovers. These voices are only in part dependent upon the wings, however, as it has been ascertained that there is an apparatus in the tubes or tracheæ leading from the spiracles to the air-sacs, which, in a way, simulates our own vocal chords; and that by forcing the air past these organs the bee can at will produce a humming sound.
When a bee has lost its wings, or when they have been stuck together so as to be immovable, it can still "speak its mind" in a very shrill outcry. It is probable that the "crying" of bumble-bees caught in a net is due to the action of these vocal organs. Whoever has caught bumble-bees has been amused and even touched at the many-toned outcry they make, as though they were indeed calling for help, or imploring the mercy of their captor. The sound is very distinct from the buzzing made by the wings as the bee flies from flower to flower.
There is yet another bee-voice, as the French naturalist Girard tells us, - "The humming is not produced solely by the vibrating of the wings, as is generally admitted. Chabrier, Burmeister, Landois, have discovered in the humming three different sounds: the first, caused by the vibrating of the wings; the second, sharper, by the vibration of the rings of the abdomen; the third, the most intense and acute, produced by a true vocal mechanism placed at the orifices of the aerial tubes."
The ancients often came curiously near the truth in their observations, and Aristotle, speaking of the sounds made by insects, including bees, says, "Insects have neither voice nor speech, but make a sound with the air within them, not with that which is external."
He then speaks of the buzzing of bees with their wings, and of the singing of grasshoppers, - "All these make a noise with the membrane which is beneath the division of their body, in those which have a division."
With such power of making various noises it would indeed be strange if the bee were deaf, at least to the sounds made by its own kind, and there is every reason to believe it does hear and understand them. "When something seems to irritate the bees, who are in front of a hive on the alighting board," says a believer in the language of bees, "they emit a short sound, z-z-z, jumping at the same time towards the hive. This is a warning, then they fly and examine the object of their fears, remaining sustained by their wings near the suspected object, and emitting at the same time a distinct and prolonged sound. This is a sign of great suspicion. If the object moves quickly, or otherwise shows hostile intent, The Wings the song is changed into a piercing cry for help, in a voice whistling with anger. They dash forward violently and blindly, and try to sting. "When they are quiet and satisfied, their voice is the humming of a grave tune, or, if they do not move their wings, an allegro murmur. If they are suddenly caught or compressed, the sound is one of distress. If a hive is jarred at a time when all the bees are quiet, the mass speedily raise a hum, which ceases as suddenly. In a queenless hive, the sound is doleful, lasts longer, and at times increases in force. When bees swarm, the tune is clear and gay, showing manifest happiness."
Langstroth adds, - "The German pastor Stahala has published a very complete study on the language of bees, which has appeared in some of the bee-papers of Italy, France, and America. We do not consider it as altogether accurate; but there are some sounds described that all bee-keepers ought to study, especially the doleful wail of colonies which have lost their queen, and have no means of rearing another."
The voice of the bee humming about the flowers has always found favor with the poets, as in Virgil's "Bucolics," "Happy old man ! here, among well-known streams and sacred fountains, you will enjoy the cool shade. On this side, a hedge planted at the adjoining boundary, whose willow blossoms are ever fed on by Hyblæan bees, shall often court you by its gentle hummings to indulge repose. On the other side, the pruner beneath a lofty rock shall sing to the breezes: nor meanwhile shall either the hoarse wood-pigeons, thy delight, or the turtle from his lofty elm, cease to coo."