The Courtship of Animals

by W. P. Pycraft

The most familiar instances of Parthenogenesis are furnished by the Hymenoptera, and notably by the Bees and the Aphides.

There are certain cases among the Rotifers where no males have ever been found, and it is possible that they have become entirely suppressed, but in every other case the periodical advent of males is an absolute essential for the continuation of the race. Perhaps the least degenerate of these types are the Bees, wherein we meet with well-developed, highly-organized males and females, which, in their sexual relationships, are perfectly normal. But in the fulfilment of the mating instincts in these insects, a most amazing sequence of events is revealed such as are without parallel in the rest of the Animal Kingdom. The story has been charmingly told already by Maeterlinck, in his delightful “Life of the Bee,” and it has been told again by Tickner Edwardes, with less of poetry, perhaps, but still fascinatingly: and it must be told again now, but in a condensed fashion.

Briefly, a community of hive-bees harbours both male and female individuals only for a very short space. During the greater part of the year it consists only of a vast concourse of infertile females, the daughters of one mother; the “queen” of the hive. The males of that hive are the brothers, not the fathers, of the workers, as some have supposed, and their sojourn there is brief. To gain a clear idea of the facts in regard to the life-history of these insects it is necessary to trace some of the incidents which lead up to the manner in which the population of the hive is regulated, and its continuance ensured. These may well begin with the time when the number of the inhabitants consonant with the well-being of the hive has reached its limit. This occurs during the early part of June, when the queen leaves the hive, accompanied by several thousands of her daughters; they settle at some distance from their late abode in a “swarm” for the purpose of founding a new colony. Here we may leave them. The house just vacated is, however, not entirely deserted. A few of the inhabitants, the infertile sexless workers, degenerate females—degenerate so far as the power of reproduction is concerned at any rate—are left behind, and there remain also in their cradles a variable number of unhatched queens, and drones or males. One of these potential queens and the males now speedily emerge, and for a day or two remain within the seclusion of the hive, feeding upon the honey stored in the combs.

The males are the first to leave, making daily excursions abroad in the search for mates. They display in this a very leisurely behaviour, rising late and not venturing out till the day is well aired. Returning early in the afternoon with sharpened appetites, they feed to repletion and soon fall asleep.

In about three days, however, the young queen ventures abroad, timidly at first, to stretch her wings in the sunshine. She is preparing for the great moment of her life, the nuptial flight. So far, though drones may swarm on every side of her, no sign of recognition is given, nor do the males evince any consciousness of her presence. She behaves warily and demurely throughout. Her first excursions abroad are very brief; they are not so much trial flights, apparently, as efforts to locate the exact position of the hive in relation to the outer world. To this end the flights are rapidly extended in ever-widening circles, till at last, with lightning speed, she makes for the blue sky, to return to the gloom of the hive almost immediately after. During all this time the stimulus of sexual desire has been gathering force, and now, being no longer controllable, she darts off, and up into the sky; almost at once she is recognized by the swarms of males from neighbouring hives, some thousands in number, which for days have been seeking this event. Instantly they give eager chase, mounting after her higher and ever higher. But as they ascend so their numbers decrease. Some, the feeble, the ill-fed from impoverished hives, are speedily left behind; many endure to the end, but only one secures the prize, and this great moment of his life is also his last, for the fact of impregnation is no sooner completed than Death claims him. He falls earthwards, as if struck by lightning, and in his fall the intromittent organ is dragged from his body, to be removed by the survivor of this mad flight, on her descent.

She leaves a bride and returns a widow, filled with murderous intentions. There are captive queens in the hive, and she can tolerate no rivals. So soon as she has removed from her person the embarrassing souvenir of her nuptial flight she makes for the Royal cells. Accompanied by attendant workers she proceeds to tear off their waxen coverings and put their occupants to death with a thrust of her stiletto. No sooner is the work of execution over than the dead bodies are seized by the workers and borne out of the hive. This awful task is soon over, however, and henceforth for four or five long years she remains a prisoner within the walls of her own palace. Craving neither the air nor the light of the sun, she will die without once having sipped the nectar from a flower. And during all this time, save during the winter sleep, her sole duty is to produce sons and daughters. In the prime of her maternity she may lay as many as three thousand eggs a day. But strangely enough the number of eggs produced is determined for her by the workers, who are the real rulers in this constitutional state. By varying the amount and quality of the food they give her they can increase or check the number of eggs produced; while even the sex of the resultant larva is apparently also under their control.

During that brief, weird honeymoon in the clouds she received a store of spermatozoa, the fertilizing male germs, sufficient for all the eggs she can ever lay, and they may amount to nigh on a million. Incredible as this may seem, their purpose is yet more so; for they are destined to be expended solely in the production of female offspring doomed for the most part to perpetual spinsterhood. One youngster in ten thousand may attain to a higher state, may, if Fate wills, become a queen and mother. And because of this need for mothers to carry on the race, this extraordinary state of affairs has been brought about. All is under the control of her daughters—the spinster-workers. As she proceeds on her rounds of egg-laying an attendant crowd waits upon her, controlling her actions by gentle caresses. As she passes from cell to cell, the cradles of the young that are to be, she thrusts down her abdomen and lays an egg in each. The cells destined to produce the workers are the smallest, those for drones are larger, and those for queens are largest of all, and the walls are formed of pure pollen, not of wax as are those of the workers and drones. But it would seem that she never lays an egg in any of the last named. The sight of a queen-cell rouses her to fury. These cells, then, are filled by the workers, who remove the requisite number of worker—eggs from the cells in which they were laid and deposit them in the queen-cradles. The larvæ at hatching, and for the first three days of life, differ in no wise from their sisters around them. Their Royal state is determined solely by the food which is administered to them. This consists of “bee-jelly,” which is furnished in abundance: a white, shining liquid, regurgitated by the ever-zealous nurse-bees. These superfed babies cease feeding at about the fifth day, and each spins for herself a silken vestment in which to undergo the pupal state. This done, the door of each cell is sealed up with pollen. During the following sixteen days strange transformations take place: the queen that is to be is taking shape. But the cradle now becomes a prison, for at the end of the sixteenth day each of the four or five young queens begins to clamour for release. But this cannot be, for such as succeeded in emerging would immediately be slain by the reigning queen. A small hole is bored through the roof of the cell, and through this each is fed, and a close guard is kept night and day to ensure that they shall not emerge till the moment is ripe. Soon each captive begins to gnaw away the roof of her prison chamber, and as rapidly more material is placed by her guards on the outer surface. Not until the old queen leaves the hive with thousands of her daughters to “swarm” and found a new colony will freedom be allowed; and then only to one. The rest must remain till the new queen either also “swarms,” or returns from her nuptial flight, and in this case all will be slaughtered in their cramped quarters, unable to resist.

But what of the drone? He, as has already been mentioned, is reared in a larger cradle than that of his sisters—save such as are destined to be queens—and for the first three days of his life is fed on “bee-milk” of a special kind and more generous quality than that of his worker—sisters, the Cinderellas of the hive; but this generous diet is diminished at the end of three days, when a mixture of honey and pollen is given him. In about three weeks or rather more he emerges, a great, lazy drone, and for a fortnight more he wanders about the hive alternately soliciting bee-milk from his sisters and helping himself to honey from the comb, and when full to repletion he seeks some snug corner in which to sleep off his surfeit. In due time, however, he ventures abroad, his hour is at hand. He takes his daily flights abroad in search of a mate, returning home early in the afternoon for his rations, being too indolent or too stupid to draw nectar from the flowers for himself. Thus for many days he and his brothers disport themselves in riotous living, till one or other of them attains the end for which he was born; and after a few delirious moments drops earthwards a mutilated corpse.

But so far only a part of the story of the drone’s life-history has been told. Though the son of a queen, he has never had a father; and should he ever attain to the dignity of fatherhood his posthumous children are all daughters, most of whom die spinsters within six or seven weeks of their birth, worn out by a life of ceaseless toil and drudgery!

The queen, it will be remembered, cohabits with the male but once in her life. The sperm-cells then received are stored in a special receptacle and are released during the passage of the egg down the oviduct. In this act of releasing the fertilizing germs a singular economy is practised. In the case of most other creatures myriads of sperm-cells are released for the fertilization of a single egg, and of these but one can possibly attain its goal, the minute aperture or “micropyle” which is the doorway to the germ liberated, in the form of an egg, by the female. The rest die. In the case of the queen bee but one of these precious sperm-cells is liberated at a time. Hence her prolonged ability to produce fertilized eggs. But eggs destined to produce males, or drones, are never thus fertilized: they are born without the intervention of a father. A queen which has never mated will lay only male-producing eggs. This is an astounding thing, but it is true. No less remarkable is the fact that the sperm-cells should survive in their encapsuled state for periods extending over several years: it seems almost incredible, but it is nevertheless true.