Fig. 20.Tongue of a Worker-Bee, much magnified.a—Ligula.b, b—Labial palpi.c, c—Maxillæ.d—Paraglossæ.[The average length of a black worker's tongue, as comparedwith this from an Italian, would be from base toa.]
Fig. 20.
The workers, as might be surmised by the importance and variety of their functions, are structurally very peculiar Their tongues (Fig, 20,a), labial palpi (Fig. 20,b, b), and maxillæ (Fig. 20,c, c), are very much elongated, while the former is very hairy, and doubles under the throat when not in use. The length of the ligula enables them to reach into flowers with long tubes, and by aid of the hairs they lap up the nectar. When the tongue is big with its adhering load of sweet, it is doubled back, enclosed by the labial palpi and maxillæ, and then extended, thus losing its load of nectar, which at the same time is sucked into the large honey-stomach. The bees, at will, can force the honey back from the honey-stomach, when it is stored in the honey-cells or given to the other bees.
Fig. 21.
The jaws (Fig, 21,c) are very strong, without the rudimentary tooth, while the cutting edge is semi-conical, so that when the jaws are closed they form an imperfect cone. Thus these are well formed to cut comb, knead wax, and perform their various functions. Their eyes (Fig, 5) are like those of the queen, while their wings, like those of the drones, attainthe end of the body. These organs (Fig, 3), as in all insects with rapid flight, are slim and strong, and, by their more or less rapid vibrations, give the variety of tone which characterizes their hum. Thus we have the rapid movements and high pitch of anger, and the slow motion and mellow note of content and joy.
Fig. 22.Part of Posterior Leg of Worker, outside,much magnified.t—Tibia.b—Rim of hairs.p—Pollen basket.t s—Joint of tarsi,c—Claws.
Fig. 22.
On the outside of the posterior tibia and basal tarsus is a cavity, made more deep by its rim of hairs, known as the pollen basket (Fig, 22,p). In these pollen baskets is compacted the pollen, which is gathered by the mouth organs, and carried back by the four anterior legs. Opposite the pollen baskets are regular rows of golden hairs (Fig. 23,e), which probably aid in storing and compacting the pollen balls.
On the anterior legs of the workers, between the femur and tibia, is a curious notch (Fig. 24,C), covered by a spur (Fig. 24,B).For several years this has caused speculation among my students, and has attracted the attention of observing apiarists. Some have supposed that it aided bees in reaching deeper down into tubular flowers, others that it was used in scraping off pollen, and still others that it enabled bees to hold on when clustering. The first two functions may belong to this, though other honey and pollen-gathering bees do not possess it. The latter function is performed by the claws at the end of the tarsi.
Fig. 23.Part of Worker's Posterior Leg, inside,much magnified.e—Rows of hairs.t—Tibia.c—Claws.
Fig. 23.
Fig. 24.Anterior Leg of Worker, magnified.
Fig. 24.
Fig. 25.Worker's Sting, magnified.a—Tube.b b—Barbed spears drawn out of tube and turned back,c—Poison sack.d—Muscles.
Fig. 25.
The workers, too, possess an organ of defense (Fig, 25), which they are quick to use if occasion requires. This is not curved as in the queen, but straight. The gland which secretes the poison is double, and the sack (Fig, 25,c), in which it is stored, is as large as a flax-seed. The sting proper, is a triple organ, consisting of three sharp spears, very smooth and of exquisite polish. The most highly-wroughtsteel instruments, under a high magnifier, look rough and unfinished, while the parts of the sting show no such inequalities. One of these spears (Fig, 25,a) is canaliculate—that is, it forms an imperfect tube—and in this canal work the other two (Fig. 25,b, b), which fill the vacant space, and thus the three make a complete tube, and through this tube, which connects with the poison sack, passes the poison. The slender spears which work in the tube are marvelously sharp, and project beyond it when used, and are worked alternately by small but powerful muscles (Fig. 25,d), so they may pass through buckskin, or even the thick scarf-skin of the hand. These are also barbed at the end with teeth, seven of which are prominent, which extend out and back like the barb of a fish-hook. Hence the sting cannot be withdrawn, if it penetrates any firm substance, and so when used, it is drawn from the bee, and carries with it a portion of the alimentary canal, thus costing the poor bee its life. Darwin suggests that bees and wasps were developed from the saw-flies, and that the barbs on the sting are the old-time saws, transformed into the spear-like barbs. He does not explain why these are so much shorter and more obscure in the queen, and in other bees and wasps. The honey-stomach or crop in the workers (Fig, 9,o) is well developed, though no larger than those in the drones. Whether it is more complex in structure, I do not know.
The workers hatch from an impregnated egg, which can only come from a queen that has met a drone, and is always laid in the small, horizontal cell. These eggs are in no wise different, so far as we can see, from those which are laid in the drone or queen-cells. All are cylindrical and slightly curved (Fig, 26,b, c) and are fastened by one end to the bottom of the cell, and a little to one side of the centre. As already shown, these are voluntarily fertilized by the queen as she extrudes them, preparatory to fastening them in the cells. These eggs, though so small—one-sixteenth of an inch long—may be easily seen by holding the comb so that the light will shine into the cells. With experience, they are detected almost at once, but I have often found it quite difficult to make the novice see them, though very plainly visible to my experienced eye.
Fig. 26.Egg and Brood.bandc—Eggs.d, e, fandg—Various sizes of larvæ.h—Pupa.i—Pupa of queen, in queen-cell.k, k—Caps.
Fig. 26.
The egg hatches in three days. The larva (Fig, 26,d, e, f, g), incorrectly called grub, maggot—and even caterpillar, by Hunter—is white, footless, and lies coiled up in the cell till near maturity. It is fed a whitish fluid, though this seems to be given grudgingly, as it never seems to have more than it wishes to eat, so it is fed quite frequently by the mature workers. It would seem that the workers fear an excessive development, which, as we have seen, is most mischievous and ruinous, and work to prevent the same, by a mean and meager diet. The food is composed of pollen and honey. Certainly of pollen, for, as I have repeatedly proved, without pollen, no brood will be reared. Probably some honey is incorporated, as sugar is an essential in the nutrition of all animals, and we could hardly account for the excessive amount of honey consumed, while breeding, by the extra amount consumed by the bees, consequent upon the added exercise required incaring for the brood. M. Quinby, Doolittle, and others, say water is also an element of this food. But bees often breed very rapidly when they do not leave the hive at all, and so water, other than that contained in the honey, etc., cannot be added. This makes it a question if water is ever added. The time when bees seem to need water, and so repair to the rill and the pond, is during the heat of summer, when they are most busy. May this not be quaffed to slake their own thirst?
In six days the cell is capped over by the worker-bees. This cap is composed of pollen and wax, so it is darker, more porous, and more easily broken than the caps of the honey-cells; it is also more convex (Fig, 26,k). The larva, now full grown, having lapped up all the food placed before it, surrounds itself with a silken cocoon, so excessively thin that it requires a great number to appreciably reduce the size of the cells. These always remain in the cell, after the bees, escape, and give to old comb its dark color and great strength. Yet they are so thin, that cells used even for a dozen years, seem to serve as well for brood as when first used. In three days the insect assumes the pupa state (Fig, 26,h). In all insects the spinning of the cocoon seems an exhaustive process, for so far as I have observed, and that is quite at length, this act is succeeded by a variable period of repose. The pupa is also called a nymph. By cutting open cells it is easy to determine just the date of forming the cocoon, and of changing to the pupa state. The pupa looks like the mature bee with all its appendages bound close about it, though the color is still whitish:
In twenty-one days the bee emerges from the cell. The old writers were quite mistaken in thinking that the advent of these was an occasion of joy and excitement among the bees. All apiarists have noticed how utterly unmoved the bees are, as they push over and crowd by these new-comers in the most heedless and discourteous manner imaginable. Wildman tells of seeing the workers gathering pollen and honey the same day that they came forth from the cells. This idea is quickly disproved if we Italianize black-bees. We know that for some days these young bees do not leave the hive at all, except in case of swarming, when bees even too young to flywill essay to go with the crowd. These young bees, like the young drones and queens, are much lighter for the first few days.
The worker-bees never attain a great age. Those reared in autumn may live for eight or nine months, and if in queenless stocks, where little labor is performed, even longer; while those reared in spring will wear out in three, and when most busy, will often die in from thirty to forty-five days. None of these bees survive the year through, so there is a limit to the number which may exist in a colony. As a good queen will lay, when in her best estate, three thousand eggs daily, and as the workers live from one to three months, it might seem that forty thousand was too small a figure for the number of workers. Without doubt a greater number is possible. That it is rare is not surprising, when we remember the numerous accidents and vicissitudes that must ever attend the individuals of these populous communities.
The function of the worker-bees is to do all the manual labor of the hives. They secrete the wax, which forms in small pellets (Fig, 27,a, a) under the over-lapping rings under the abdomen. I have found these wax-scales on both old and young. According to Fritz Müller, the admirable German observer, so long a traveler in South America, the bees of the genus melipona secrete the wax on the back.
The young bees build the comb, ventilate the hive, feed the larvæ and cap the cells. The older bees—for, as readily seen in Italianizing, the young bees do not go forth for the first one or two weeks—gather the honey, collect the pollen, or bee-bread, as it is generally called, bring in the propolis or bee glue, which is used to close openings, and as a cement, supply the hive with water(?), defend the hive from all improper intrusion, destroy drones when their day of grace is past, kill and arrange for replacing worthless queens, destroy inchoate queens, drones, or even workers, if circumstances demand it, and lead forth a portion of the bees when the conditions impel them to swarm.
When there are no young bees, the old bees will act as house-keepers and nurses, which they otherwise refuse to do. The young bees, on the other hand, will not go forth to glean, even though there be no old bees to do this necessary part ofbee-duties. An indirect function of all the bees is to supply animal heat, as the very life of the bees require that the temperature inside the hive be maintained at a rate considerably above freezing. In the chemical processes attendant upon nutrition, much heat is generated, which, as first shown by Newport, may be considerably augmented at the pleasure of the bees, by forced respiration. The bees, too, by a rapid vibration of their wings, have the power to ventilate their hives, and thus reduce the temperature, when the weather is hot. Thus they moderate the heat of summer, and temper the cold of winter.
Under Surface of Bee, showing Wax between Segments.
Under Surface of Bee, showing Wax between Segments.