Bible Encyclopedias
Bee

Structure

Details of the structure of bees are given in the article Hymenoptera. The feelers (fig. 2, a) are divided into "scape" and "flagellum" as in the ants, and the mandibles vary greatly in size and sharpness in different genera. The proboscis or "tongue" (fig. 2, 1) is a hollow organ enclosing an outgrowth of the body-cavity which is filled with fluid, and with its flexible under-surface capable of invagination or protrusion. Along this surface stretches a groove which is surrounded by thickened cuticle and practically formed into a tube by numerous fine hairs. Along this channel the nectar is drawn into the pharynx and passes, mixed with saliva, into the crop or "honey-bag"; the action of the saliva changes the saccharose into dextrose and levulose, and the nectar becomes honey, which the bee regurgitates for storage in the cells or for the feeding of the grubs. The sting (fig. 6, pg, st.) of female bees is usually highly specialized, but in a few genera it is reduced and useless.

Many modifications in details of structure may be observed within the family. The tongue is bifid at the tip in a few genera; usually it is pointed and varies greatly in length, being comparatively short in Andrena, long in the humble-bees(Bombus), and longest in Euglossa, a tropical American genus of solitary bees. The legs, which are so highly modified as pollen-carriers in the higher bees, are comparatively simple in certain primitive genera. The hairy covering, so notable in the hive-bee and especially in humble-bees, is greatly reduced among bees that follow a parasitic mode of life.

Early stages

As is usual where an abundant food supply is provided for the young insects, the larvae of bees (fig. 3, SL.) FIG. 3. - Larva and Pupa of Apis (magnified four times).

SL, Spinning larva. sp, Spiracles. w, Wing.

N, Pupa. t, " Tongue." ce, Compound Eye.

FL, Feeding larva. m, Mandible. e, Excrement.

co, Cocoon. an, Antenna. ex, Exuvium.

(From Cheshire's Bees and Bee-keeping.) are degraded maggots; they have no legs, but possess fairly well-developed heads. The successive cuticles that are cast as growth proceeds are delicate in texture and sometimes separate from the underlying cuticle without being stripped off. The maggots may pass no excrement from the intestine until they have eaten all their store of food. When fully grown the final larval cuticle is shed, and the "free" pupa (fig. 3, N) revealed. The larvae of some bees spin cocoons (fig. 3, co) before pupation.

Nests of Solitary Bees

Bees of different genera vary considerably in the site and arrangement of their nests. Many - like the common "solitary" bees Halictus and Andrena - burrow in the ground; the holes of species of Andrena are commonly seen in springtime opening on sandy banks, grassy lawns or gravel paths. Our knowledge of such bees is due to the observations of F. Smith, H. Friese, C. Verhoeff and others. The nest may be simple, or, more frequently, a complex excavation, cells opening off from the entrance or from a main passage. Sometimes the passage is the conjoint work of many bees whose cells are grouped along it at convenient distances apart. Other bees, the species of Osmia for example, choose the hollow stem of a bramble or other shrub, the female forming a linear series of cells in each of which an egg is laid and a supply of food stored up. J. H. Fabre has found that in the nests of some species of Osmia the young bee developed in the first-formed cell, if (as often happens) she emerges from her cocoon before the inmates of the later cells, will try to work her way round these or to bite a lateral hole through the bramble shoot; should she fail to do this, she will wait for the emergence of her sisters and not make her escape at the price of injury to them. But when Fabre substituted dead individuals of her own species or live larvae of another genus, the Osmia had no scruple in destroying them, so as to bite her way out to air and liberty.

The leaf-cutter bees (Megachile) - which differ from Andrena and Halictus and agree with Osmia, Apis and Bombus in having elongate tongues - cut neat circular disks from leaves, using them for lining the cells of their underground nests. The carpenter-bees (Xylocopa and allied genera), unrepresented in the British Islands, though widely distributed in warmer countries, make their nests in dry wood. The habits of X. violacea, the commonest European species, were minutely described in the 18th century in one of R. A. F. de Reaumur's memoirs. This bee excavates several parallel galleries to which access is gained by a cylindrical hole. In the galleries are situated the cells, separated from one another by transverse partitions, which are formed of chips of wood, cemented by the saliva of the bee.

Among the solitary bees none has more remarkable nesting habits than the mason bee (Chalicodoma) represented in the south of France and described at length by Fabre. The female constructs on a stone a series of cells, built of cement, which she compounds of particles of earth, minute stones and her own saliva. Each cell is provided with a store of honey and pollen beside which an egg is laid; and after eight or nine cells have been successively built and stored, the whole is covered by a dome-like mass of cement. Fabre found that a Chalicodoma removed to a distance of 4 kilometres from the nest that she was building, found her way back without difficulty to the exact spot. But if the nest were removed but a few yards from its former position, the bee seemed no longer able to recognize it, sometimes passing over it, or even into the unfinished cell, and then leaving it to visit again uselessly the place whence it had been moved. She would accept willingly, however, another nest placed in the exact spot where her own had been. If the unfinished cell in the old nest had been only just begun, while that in the substituted nest were nearly completed, the bee would add so much material as to make the cell much larger than the normal size, her instinct evidently being to do a certain amount of building work before filling the cell with food. The food, too, is always placed in the cell after a fixed routine - first honey disgorged from the mouth, then pollen brushed off the hairs beneath the body (fig. 7, c) after which the two substances are mixed into a paste.

Inquilines and Parasites

The working bees, such as have been mentioned, are victimized by bees of other genera, which throw upon the industrious the task of providing for the young of the idle. The nests of Andrena, for example, are haunted by the black and yellow species of Nomada, whose females lay their eggs in the food provided for the larva of the Andrena. According to H. Friese, the relations between the host and the inquiline are quite friendly, and the insects if they meet in the nestgalleries courteously get out of each other's way. D. Sharp, in commenting on this strange behaviour, points out that the host can have no idea why the inquiline haunts her nest. "Why then should the Andrena feel alarm? If the species of Nomada attack the species of Andrena too much, it brings about the destruction of its own species more certainly than that of the Andrena." More violent in its methods is the larva of a Stelis, whose operations in the nest of Osmia leucomelana have been studied by Verhoeff. The female Stelis lays her eggs earlier than the Osmia, and towards the bottom of the food-mass; the egg of the Osmia is laid later, and on the surface of the food. Hence the two eggs are at opposite ends of the food, and both larvae feed for a time without conflict, but the Stelis, being the older, is the larger of the two. Finally the parasitic larva attacks the Osmia, and digging its mandibles into its victim's head kills and eats it, taking from one to two days for the completion of the repast.

Social Bees

The bees hitherto described are "solitary," all the individuals being either males or unmodified females. The most highly developed of the long-tongued bees are "social" species, in which the females are differentiated into egg - laying queens and (usually) infertile "workers" (fig. 6). Verhoeff has discussed the rise of the "social" from the "solitary" condition, and points, out that for the formation of an insect community three conditions are necessary - a nest large enough for a number of individuals, a close grouping of the cells, and an association between mother and daughters in the winged state. For the fulfilment of this last condition, the older insects of the new generation must emerge from the cells while the mother is still occupied with the younger eggs or larvae. One species of Halictus nearly reaches the desired stage; but the first young bees to appear in the perfect state are males, and when the females emerge the mother dies.

Among the social bees the mother and daughter-insects co-operate, and they differ from the "solitary" groups in the nature of their nest, the cells (fig. 25) of which are formed of wax secreted by special glands (fig. 5) in the bee's abdomen, the wax being pressed out between the segmental sclerites in the form of plates (fig. 4), which are worked by the legs (fig. 7) and jaws into the requisite shape. In our well-known hive-bee (Apis) and humble-bees (Bombus) the wax glands are ventral FIG. 5. - Abdominal Plate (worker of Apis), under side, third segment (magnified twenty times). W, wax-yielding surface, covering true gland; s, septem, or carina; wh, webbed hairs.

(From Cheshire's Bees and Bee-keeping.) in position, but in the "stingless" bees of the tropics (Trigona and Melipona) they are dorsal. A colony of humble-bees is started in spring by a female queen "which has survived the winter. She starts her nest underground or in a surface depression, forming a number of waxen cells, roughly globular in shape and arranged irregularly. The young females (" workers ") that develop from the eggs laid in these early cells assist the queen by building fresh cells and gathering food for storage therein. The queen may be altogether relieved of the work of the nest as the season advances, so that she can devote all her energies to egg-laying, and the colony grows rapidly. The distinction between queen and worker is not always clear among humble-bees, the female insects varying in size and in the development of their ovaries. If any mishap befall the queen, the workers can sometimes keep the community from dying out. In autumn males are produced, as well as young queens. The community is broken up on the approach of winter, the males and workers perish, and the young queens after hibernation start fresh nests in the succeeding year.

The appearance of the heavy-bodied hairy Bombi is well known. They are closely" mimicked "by bees of the genus Psithyrus, which often share their nests. These Psithyri have no pollen-carrying structures on the legs and their grubs are dependent for their ' food - supply on the labours of the Bombi, though, according to E. Hoffer's observations, it seems that the femalePsithyrus builds her own cells. The colonies of Bombus illustrate the rise of the inquiline habit. Many of the species are very variable and have been differentiated into races or varieties. F. W. L. Sladen states that a queen belonging to the virginalis form of Bombus terrestris often invades a nest belonging to the lucorum form, kills the rightful queen, andtakespossession of the nest, getting the lucorum workers to rear her young. In the nests of Bombi are found various beetle larvae that live as inquilines or parasites, and also maggots of drone-flies (V olucella) , which act as scavengers; the Volucella-fly is usually a" mimic ' vades.

The "stingless" bees (Trigona) of the tropics have the parts of the sting reduced and useless for piercing. As though to compensate for the loss of this means of defence, the mandibles are very powerful, and some of the bees construct tubular entrances to the nest with a series of constrictions easy to hold against an enemy. The habits of the Brazilian species of these bees have been described in detail by H. von Jhering, who points out that their wax glands are dorsal in position, not ventral as in Bombus and Apis. With Apis, the genus of the hive-bee, we come to the most highly-specialized members of the family - better known,perhaps, than any other insects, on account of the long domestication of many of the species or races. In A pis the workers differ structurally from the queen, who neither builds cells, gathers food, nor tends brood, and is therefore without the special organs adapted FIG. 4. - Under Side of Worker, carrying Wax Scales (magnified three times).

(From Cheshire's Bees and Bee-keeping.) FIG. 6. - Ovaries of Queen and Workers (Apis). A, Abdomen of queen, under side (magnified eight times).

P, Petiole.

o, o, Ovaries.

hs, Position filled by honey-sack. ds, Position through which digestive system passes. od, Oviduct.

co.d, Vagina.

E, Egg-passing oviduct.

s, Spermatheca.

i, Intestine.

(From Cheshire's Bees and Bee-keeping.) Poison bag. Poison gland. Sting.

"Palps" or "feelers" of sting.

B, Rudimentary ovaries of ordinary worker.

sp, Rudimentary spermatheca.

C, Partiallydeveloped ovaries of fertile worker.

sp, Rudimentary spermatheca.

pb, pg, st, P, ' of the Bombus, whose nest she in for those functions which are possessed in perfection by the workers. The differentiation of queen and workers is correlated with the habit of storing food supplies, and the consequent permanence of the community, which finds relief for its surplus population by sending off a swarm, consisting of a queen and a number of workers, so that the new community is already specialized both for reproduction and for labour.

The workers of Apis may be capable (fig. 6, C) of laying eggs - necessarily unfertilized - which always give rise to males ("drones"), and, since the researches of J. Dzierzon (181119(36) in 1848, it has been believed that the queen bee lays fertilized eggs in cells appropriate for the rearing of queens or FIG. 7. - Modifications in the Legs of Bees.

A. a-d, Hive-bee (Apis). notch in tarsal segment for B. f-g, Stingless bee (Melipona). cleaning feeler.

C. h-i, Humble-bee (Bombus). e, Tip of intermediate shin with a, f, h, Outer view of hind-leg. spur.

b, g, i, Inner view. c, Feathered hairs with pollen d, Fore-leg of Apis showing grains, magnified.

(After Riley, Insect Life (U.S. Dept. Agr.), vol. 6.) workers, and unfertilized eggs in "drone-cells," virgin reproduction or parthenogenesis being therefore a normal factor in the life of these insects. F. Dickel and others have lately claimed that fertilized eggs can give rise to either queens, workers or males, according to the food supplied to the larvae and the influence of supposed "sex-producing glands" possessed by the nurse-workers. Dickel states that a German male bee mated with a female of the Italian race transmits distinct paternal characters to hybrid male offspring. A. Weismann, however, doubts these conclusions, and having found a spermaster in every one of the eggs that he examined from workercells, and in only one out of 272 eggs taken from drone-cells, he supports Dzierzon's view, explaining the single exception mentioned above as a mistake of the queen, she having laid inadvertently this single fertilized egg in a drone instead of in a worker cell.

The cells of the honeycomb of Apis are usually hexagonal in form, and arranged in two series back to back (figs. 3, 25). Some of these cells are used for storage, others for the rearing of brood. The cells in which workers are reared are smaller than those appropriate for the rearing of drones, while the "royal cells," in which the young queens are developed, are large in size and of an irregular oval in form (fig. 25). It is believed that from the nature of the cell in which she is ovipositing, the queen derives a reflex impulse to lay the appropriate egg - fertilized in the queen or worker cell, unfertilized in the drone cell, as previously mentioned. Whether the fertilized egg shall develop into a queen or a worker depends upon the nature of the food. All young grubs are at first fed with a specially nutritious food, discharged from the worker's stomach, to which is added a digestive secretion derived from special salivary glands in the worker's head. If this "royal jelly" continue to be given to the grub throughout its life, it will grow into a queen; if the ordinary mixture of honey and digested pollen be substituted, as is usually the case from the fourth day, the grub will become a worker. The workers, who control the polity of the hive (the "queen" being exceedingly "limited" in her monarchy), arrange if possible that young queens shall develop only when the population of the hive has become so congested that it is desirable to send off a swarm. When a young queen has emerged, she stings her royal sisters (still in the pupal stage) to death. Previous to the emergence of the young queen, the old queen, prevented by the workers from attacking her daughters, has led off a swarm to find a new home elsewhere. The young queen, left in the old home, mounts high into the air for her nuptial flight, and then returns to the hive and her duties of egg-laying. The number of workers increases largely during the summer, and so hard do the insects work that the life of an individual may last only a few weeks. On the approach of winter the males, having no further function to perform for the community, are refused food-supplies by the workers, and are either excluded or banished from the hive to perish. Such ruthless habits of the bee-commonwealth, no less than the altruistic labours of the workers, are adapted for the survival and dominance of the species. The struggle for life may deal hardly with the individual, but it results - to quote Darwin's well-known title - in "the preservation of favoured races." BIBLIOGRAPHY. - More has been written on bees, and especially on the genus Apis, than on any other group of insects. The classical observations of Reaumur Memoires pour servir a l'histoire des insectes, vols. v., vi. (Paris, 1740-1742) and F. Huber's Nouvelles observations sur les abeilles (Geneve, 1792) will never be forgotten; they have been matched in recent times by J. H. Fabre's Souvenirs entomologiques (Paris, 1879-1891); and M. Maeterlinck's poetic yet scientific La vie des abeilles (Paris, 1901). Among writers on the solitary and parasitic species may be specially mentioned F. Smith, Hymenoptera in the British Museum (London, 1853-1859); H. Friese, Zool. Jahrb. Syst., iv. (1891) J. Perez, Actes Soc. Bordeaux, xlviii. (1895); and C. Verhoeff, Zool. Jahrb. Syst., vi. (1892). For the social species we have valuable papers by E. Hoffer, Mitt. Naturwissen. Ver. Steiermark, xxxi. (1881); H. von Jhering, Zool. Jahrb. Syst., xix. (1903); and others. For recent controversy on parthenogenesis in the hive bee, see J. Perez, Ann. Sci. Nat. Zool. (6), vii. (1878); F. Dickel, Zool. Anz., xxv. (1901), and Anatom. Anzeiger, xix. (1902); A. Petrunkevich, Zoolog. Jahrb. Anat., xiv. (1901); and A. Weismann, Anatom. Anzeiger, xviii. (1901). F. R. Cheshire's Bees and Bee-keeping (London, 1885-1888), and T. W. Cowan's Honey Bee (2nd ed., 1904), are invaluable to the naturalist, and contain extensive bibliographies of Apis. D. Sharp's summary in the Cambridge Natural History, vol. vi., should be consulted for further information on bees generally. British bees are described in the catalogues of Smith, mentioned above, and by E. Saunders, The Hymenoptera of the British Islands (London, 1896). (G. H. C.)