Bramble-Bees and Others

by Jean-Henri Fabre

I at first doubted the universal presence of this spermatic receptacle, having failed to find it under my scalpel in my former investigations into the anatomy of the Sphex-wasps and some other game-hunters. But this organ is so delicate and so small that it very easily escapes the eye, especially when our attention is not specially directed in search of it; and, even when we are looking for it and it only, we do not always succeed in discovering it. We have to find a globule attaining in many cases hardly as much as a millimetre (About one-fiftieth of an inch.—Translator's Note.) in diameter, a globule headed amidst a tangle of air-ducts and fatty patches, of which it shares the colour, a dull white. Then again, the merest slip of the forceps is enough to destroy it. My first investigations, therefore, which concerned the reproductive apparatus as a whole, might very well have allowed it to pass unperceived.

In order to know the rights of the matter once and for all, as the anatomical treatises taught me nothing, I once more fixed my microscope on its stand and rearranged my old dissecting-tank, an ordinary tumbler with a cork disk covered with black satin. This time, not without a certain strain on my eyes, which are already growing tired, I succeeded in finding the said organ in the Bembex-wasps, the Halicti (Cf. Chapters 12 to 14 of the present volume.—Translator's Note.), the Carpenter-bees, the Bumble-bees, the Andrenae (A species of Burrowing Bees.—Translator's Note.) and the Megachiles. (Or Leaf-cutting Bees. Cf. Chapter 8 of the present volume.—Translator's Note.) I failed in the case of the Osmiae, the Chalicodomae and the Anthophorae. Is the organ really absent? Or was there want of skill on my part? I lean towards want of skill and admit that all the game-hunting and honey-gathering Hymenoptera possess a seminal receptacle, which can be recognized by its contents, a quantity of spiral spermatozoids whirling and twisting on the slide of the microscope.

This organ once accepted, the German theory becomes applicable to all the Bees and all the Wasps. When copulating, the female receives the seminal fluid and holds it stored in her receptacle. From that moment, the two procreating elements are present in the mother at one and the same time: the female element, the ovule; and the male element, the spermatozoid. At the egg-layer's will, the receptacle bestows a tiny drop of its contents upon the matured ovule, when it reaches the oviduct, and you have a female egg; or else it withholds its spermatozoids and you have an egg that remains male, as it was at first. I readily admit it: the theory is very simple, lucid and seductive. But is it correct? That is another question.

One might begin by reproaching it with making a singular exception to one of the most general rules. Which of us, casting his eyes over the whole zoological progression, would dare to assert that the egg is originally male and that it becomes female by fertilization? Do not the two sexes both call for the assistance of the fertilizing element? If there be one undoubted truth, it is certainly that. We are, it is true, told very curious things about the Hive-bee. I will not discuss them: this Bee stands too far outside the ordinary limits; and then the facts asserted are far from being accepted by everybody. But the non-social Bees and the predatory insects have nothing special about their laying. Then why should they escape the common rule, which requires that every living creature, male as well as female, should come from a fertilized ovule? In its most solemn act, that of procreation, life is one and uniform; what it does here it does there and there and everywhere. What! The sporule of a scrap of moss requires an antherozoid before it is fit to germinate; and the ovule of a Scolia, that proud huntress, can dispense with the equivalent in order to hatch and produce a male? These new-fangled theories seem to me to have very little value.

One might also bring forward the case of the Three-pronged Osmia, who distributes the two sexes without any order in the hollow of her reed. What singular whim is the mother obeying when, without decisive motive, she opens her seminal phial at haphazard to anoint a female egg, or else keeps it closed, also at haphazard, to allow a male egg to pass unfertilized? I could imagine impregnation being given or withheld for periods of some duration; but I cannot understand impregnation and non-impregnation following upon each other anyhow, in any sort of order, or rather with no order it all. The mother has just fertilized an egg. Why should she refuse to fertilize the next, when neither the provisions nor the lodgings differ in the smallest respect from the previous provisions and lodgings? These capricious alternations, so unreasonable and so exceedingly erratic, are scarcely appropriate to an act of such importance.

But I promised not to argue and I find myself arguing. My reasoning is too fine for dull wits. I will pass on and come to the brutal fact, the real sledge-hammer blow.

Towards the end of the Bee's operations, in the first week of June, the last acts of the Three-horned Osmia become so exceptionally interesting that I made her the object of redoubled observation. The swarm at this time is greatly reduced in numbers. I have still some thirty laggards, who continue very busy, though their work is in vain. I see some very conscientiously stopping up the entrance to a tube or a Snail-shell in which they have laid nothing at all. Others are closing the home after only building a few partitions, or even mere attempts at partitions. Some are placing at the back of a new gallery a pinch of pollen which will benefit nobody and then shutting up the house with an earthen stopper as thick, as carefully made as though the safety of a family depended on it. Born a worker, the Osmia must die working. When her ovaries are exhausted, she spends the remainder of her strength on useless works: partitions, plugs, pollen-heaps, all destined to be left unemployed. The little animal machine cannot bring itself to be inactive even when there is nothing more to be done. It goes on working so that its last vibrations of energy may be used up in fruitless labour. I commend these aberrations to the staunch supporters of reasoning-powers in the animal.

Before coming to these useless tasks, my laggards have laid their last eggs, of which I know the exact cells, the exact dates. These eggs, as far as the microscopes can tell, differ in no respect from the others, the older ones. They have the same dimensions, the same shape, the same glossiness, the same look of freshness. Nor are their provisions in any way peculiar, being very well suited to the males, who conclude the laying. And yet these last eggs do not hatch: they wrinkle, fade and wither on the pile of food. In one case, I count three or four sterile eggs among the last lot laid; in another, I find two or only one. Elsewhere in the swarm, fertile eggs have been laid right up to the end.

Those sterile eggs, stricken with death at the moment of their birth, are too numerous to be ignored. Why do they not hatch like the other eggs, which outwardly they resemble in every respect? They have received the same attention from the mother and the same portion of food. The searching microscope shows me nothing in them to explain the fatal ending.

To the unprejudiced mind, the answer is obvious. Those eggs do not hatch because they have not been fertilized. Any animal or vegetable egg that had not received the life-giving impregnation would perish in the same way. No other answer is possible. It is no use talking of the distant period of the laying: eggs of the same period laid by other mothers, eggs of the same date and likewise the final ones of a laying, are perfectly fertile. Once more, they do not hatch because they were not fertilized.