§ IX. REPRODUCTIVE ECONOMY.
The fertilisation of the queen and the determination of the sexes of her progeny are two subjects of so much interest that we must make room for some exposition of the discoveries of the past thirty years in relation thereto. What has been already stated on the former of these under the section on "The Drone" consists of facts which were mainly established by Huber; but within the present generation the great German apiarians have returned to the question, and Dzierzon has set forth some most marvellous deductions, which Baron von Berlepsch has followed up with amplification and further proof. It was found that the queen while in a virgin condition was often capable of depositing eggs, and that these eggs, unlike those of poultry laid under somewhat similar conditions, would hatch equally with others, but they all produced drones. From this arose the question. Whence come the drones after the queen has been fertilised? A fact known from the days of Huber and Riem was by some supposed to settle the difficulty. In many hives there exist what are called "fertile workers"—bees having the female organs sufficiently developed to deposit eggs, but not sufficiently so to receive fecundation; and as it was found that the eggs of these fulfilled the conditions required, and invariably produced drone bees, the theory was erected that these fertile workers were the regular producers of that sex. But this plausible solution of the problem did not stand examination. Every fertile queen does habitually lay eggs in drone cells, and from those eggs drones are uniformly developed. Dissection and microscopic analysis had therefore to be resorted to, and the course of investigation commenced by Swammerdam and pursued by Mlle. Jurine was now pushed to a much further extent.
Proceeding from the two ovaries of the queen there are two canals, called oviducts, which presently unite, and immediately beyond their point of juncture is a small globular receptacle which is called the spermatheca. With fertile queens it was found that this appendage is permanently occupied by a fluid identical with that in the reproductive organs of the drones, and that as such it abounds in spermatozoa; while with a virgin queen the fluid is totally destitute of these, and is wholly different in appearance, being thin and transparent. From this discovery the conclusion followed that each egg, as it passes down the oviduct and over the mouth of the spermatheca, may either receive fecundation or not, according as the queen's own will or some other circumstance shall determine. Dzierzon accordingly propounded as the apparent, though still only hypothetical, solution of the enigma, what is known as the doctrine of parthenogenesis or virgin breeding—the law that life is imparted by the mother independently, and that every egg as originally developed in her ovaries is of the male sex, but that whenever fertilised with the male fluid it becomes transformed into a female!
To convert this hypothesis into a demonstration, Von Berlepsch invited to his apiary in succession the two great comparative anatomists Professors Leuckart and Von Siebold, and furnished each with a number of both drone and worker eggs for microscopic examination. Leuckart examined the surfaces of the eggs; Von Siebold, who followed him, tried the interiors, and the latter by this means was triumphantly successful, for, after the most careful preparation of his subjects, he detected in thirty out of forty worker eggs from one to four spermatozoa apiece, while in his twenty-four drone eggs he found not a single one. The exceptions were insufficient to invalidate the results, for the ten worker eggs in which no signs of impregnation were found were only the failures of observation to be naturally expected in so delicate a scrutiny. Thus the fact was established that eggs which produce male bees are descended from the female only—in other words, that drones have no fathers!
Most strikingly has this law been corroborated by a discovery which we owe to the introduction of the Italian bee—a discovery, too, which any bee-keeper can make for himself. If an Italian queen is crossed with an English drone, or vice versa, the workers only of her progeny will be mongrels—the drones will invariably retain the pure blood of the queen, thus proving to demonstration that they owe their origin to her alone. Should a mongrel drone be then observed, it will be a sure sign that a fertile worker is in the hive: the queen will not be its mother. Dr. Dönhoff, we are told, confirmed the same law by a converse method, having in 1855 obtained a worker bee from a drone egg which he had artificially impregnated with the male fluid.
The queen, as we have observed, is capable before fertilisation of becoming the mother of drones, but it is believed by some that if she has once commenced drone-laying it is impossible for her to become subsequently fertilised. Mr. Langstroth, however, mentions an instance to the contrary, where a queen of his, after persistently laying drone eggs for a week or two, became after that the happy mother of a thriving colony of workers. Von Berlepsch alludes to this case (with others like it), but is unconvinced, being suspicious that here again it was a fertile worker and not the queen who laid the drone eggs. But looking to the fact that many permanently unfertile queens lay drone eggs, while others lay no eggs at all, does it not seem reasonable that a similar difference may subsist previous to fecundation? Thus, while the Baron is on firm ground as to the general rule, we incline to a belief that as to the exception the American observer is quite correct.
Dzierzon thus writes: "In general, so long as the young queen continues her wedding flights—which in the warm summer she does at the very most for four weeks, but in the cool spring or autumn, when life and development are slower in the hive, she still pursues for even five or six weeks—she is capable of becoming properly fertile." But some queens continue to fly long after it is hopeless, cases being recorded in which they have gone on for ten or twelve weeks. The same observer speaks of having had several young queens which were either lame in their wings or born in a continued cold season, so that they were prevented from leaving the hive, and thus developed into confirmed drone-breeders. The queen leaves the hive every fine day till her purpose is accomplished, and this led Bevan and others to surmise that she met successively with several drones till one Of them lost his life in consequence; but we do not find in later authorities any confirmation nor even mention of this conjecture, and it may be set down as entirely improbable. In the case observed by Von Klipstein, and referred to above ([page 22]), as the queen met with her death shortly after, he sent her to Leuckart, who found that from this obviously first impregnation her organs were so completely filled as to imply no need for a second. Leuckart has elsewhere stated that a queen's spermatheca is capable of containing twenty-five millions of spermatozoa, so that there need be no wonder at the fact of a single fecundation being sufficient to answer for her entire term of existence.
The fertile workers, which by their course of adding to the drone stock may prove a terrible nuisance in a hive, were ascertained by Huber to be always hatched in close proximity to the queen cells, whence he conjectured that they obtained by accident a portion of the royal jelly designed for the rearing of princesses. Von Berlepsch and Langstroth prefer the theory that such jelly was purposely given them, and the conversion of their own cells into royal ones commenced, but that the intention was afterwards abandoned, as it is known that bees often, start more of such cells than they ultimately proceed with. They are of only exceptional occurrence in hives in a normal condition, but in a queenless stock they very often appear, sometimes even in considerable numbers, having been probably fostered with the jelly, but at too late a period to convert them into queens. They usually deposit their eggs correctly in drone cells, though drone-breeding queens lay in those of workers and even in royal cells—thus evincing a presence of the will though an absence of the power. To get rid of a fertile worker it has been recommended by Mr. Rorl to "drive" the bees ([Chap. V. § iv.]) to an empty hive, and place this in a near spot; all will return to their old home except the one to be got rid of, she having probably never flown before, and therefore not knowing her way.