Page:Encyclopædia Britannica, Ninth Edition, v. 3.djvu/509

This page needs to be proofread.
BEE
493

when they rise from the midst of other cells, they are placed against the mouths of those cells, and project beyond the common surface of the comb. They are perfectly smooth on the inner surface, while their outer side is covered with a kind of hexagonal fret-work, as if intended for the founda

tion of regular cells.

The impregnation of the queen-bee was formerly in volved in the deepest obscurity, and has given rise to a multitude of very fanciful opinions. Some have denied that any intercourse with the male was necessary for the fecundation of the eggs. Swammerdam supposed that the mere effluvia proceeding from the males where they were collected in clusters was sufficiently active to produce this effect by penetrating the body of the female. Huber proved by decisive experiment that no such consequence resulted from these effluvia. Maraldi imagined that the eggs were fecundated by the drones after being deposited in the cells in the same way that the spawn of fishes is rendered prolific by the milt. Mr Deb raw of Cambridge gave an account, in a paper published in the Philoso phical Transactions, of a milk-like fluid he had seen in the cells. But this appearance Huber showed to be a mere optical illusion arising from the reflection of light at the bottom of the cells. When the males are excluded from the hive the queen is as fertile and the eggs as prolific as when they are present. Hattorff supposed that the queen is capable of impregnating herself, an opinion which was supported by Schirach and Wilhelrni, and was even favourably received by Bonnet, as it in some measure accorded with his discoveries respecting the aphis. Linnaeus was of opinion that an actual union between the sexes took place, and Reaumur fancied he had seen this happen within the hive. There is, however, great reason to think he was mistaken. It has since been clearly proved that copulation takes place in the air during flight, and if the queen is confined to the hive either by bad weather, or malformation or mutilation of her wings, although she may be surrounded by drones, she never becomes impregnated ; and if she does not find a mate within three weeks of her birth, the power of sexual intercourse seems to become lost. If a hive containing a virgin queen be attentively watched on fine days the queen will be observed preparing for her matrimonial flight, and after having attentively surveyed her home so as to be able to recognize it again she flies to a considerable height in the air ; and if her errand is successful, in half an hour she returns to the hive with unequivocal proofs of the intercourse that has taken place, for she has in fact robbed the drone of the organs concerned in this operation ; and the drone, thus mutilated, is left to perish on the ground. From its being necessary that the queen should fly to a distance in order to be impregnated, Huber infers the necessity of a great number of drones being attached to the hive, that there may be a sufficient chance of her meeting one of them during her aerial excursion.

The phenomenon that sometimes occurred in a bee-hive, of the queen laying eggs that produced males only, had for ages puzzled philosophers without any satisfactory solution, and it was reserved for Dzierzon to promulgate a new and startling theory of reproduction, which, in the words of its distinguished author, is said to have " explained all the phenomena of the bee-hive as perfectly as the Copernican hypothesis the phenomena of the heavens." Dzierzon first expressed his views upon the reproduction of bees in the year 1845. The principal points of this theory may be shortly expressed thus : 1st, That the queen (female bee), to become good for anything (i.e., to breed workers), must be fertilized by a drone (the male), and that the copulation takes place only in the air ; that drone eggs do not require fecundation, but that the co-operation of the drone is abso lutely necessary when worker bees are to be produced; that in copulation the ovaries are not fecundated, but the seminal receptacle (or spermatheca), a little vesicle or sac opening into the oviduct, which in the young queen is filled with a limpid fluid, is saturated with semen, after which it is more clearly distinguishable from its white colour; and that the supply of semen received during copulation is sufficient for her whole lifetime. The copulation takes place once for all, and (as already stated) only in the open air ; therefore no queen which has been lame in her wings from birth can ever be perfectly fertile, that is, capable of pro ducing both sexes, as copulation never takes place in the interior of the hive. 2d, All eggs which come to maturity in the ovaries of a queen-bee are only of one and the same kind, and when they are laid without coming in contact with the male semen, become developed into male bees. This theory of Dzierzou s has since been amply confirmed by numberless experiments, although what power the queen possesses (or how she exercises it) of determining what eggs shall receive fecundation and what not, is yet a mystery. Certain it is that when the queen lays an egg in a drone cell, a drone is produced ; and Von Siebold, who made many most skilful microscopical examinations of eggs, affirms that among fifty-two eggs taken from worker cells, examined by him with the greatest care and conscientiousness, thirty-four furnished a positive result, namely, the existence of seminal filaments, in which movements could even be detected in three eggs ; and among twenty-seven eggs from drone cells, examined with the same care and by the same method, he did not find one seminal filament in any single egg either exter nally or internally. On the passage of the eggs from the ovary through the oviduct they pass the opening of the spermatheca, from which some eggs receive a portion of the seminal fluid, these produce workers ; other eggs pass without receiving the fluid, these produce drones. What it is that governs the deposition or non-deposition of the seminal fluid on the egg is unknown. It has been sug gested that the smaller diameter of the worker cells exerts some mechanical pressure on the queen s organs, which may cause the seminal fluid to be extruded as the egg passes, while the drone cells being larger this pressure is not by them exerted, and the egg passes unfecundated. If the spermatheca of an impregnated queen be examined under the microscope its contents will be found to contain many thousands of spermatozoa, the characteristic move ments of which are very visible. The contents of the spermatheca of a virgin or drone-breeding queen, similarly examined, will be found a limpid fluid only without a trace of spermatozoa.

The fact that the eggs of an unimpregnated queen will hatch and produce drones may be easily verified, and is now undisputed. By depriving a colony of its queen late in the year, a young queen will be reared ; and the drones having been killed long before, no impregnation can take place, yet the queen will infallibly lay eggs which hatch into drones ; these eggs are laid indiscriminately in drone and worker cells, the bees bred in the latter being stunted in their growth. If now the spermatheca be examined, r>o spermatozoa will be found present. The same result wil be found if, in the summer, the virgin queen be deprived of her wings and so made unable to fly.

If the impregnation of the queen be delayed beyond, as

elsewhere stated, the twenty-first day of her life, she becomes incapable of receiving impregnation, and begins soon after to lay the eggs of drones, and produces no other kind of eggs during her life. This very curious and unexpected fact was discovered by Huber; and has been satisfactorily established by his very numerous

and varied experiments, although its explanation is perhaps