Secondly. When the larvæ hatched from the eggs laid by the queen, in the royal cells, are ready to transform to nymphs, this queen leaves the swarm conducting a swarm along with her; and the first swarm that proceeds from the hive is uniformly conducted by the old queen.[M] I think I can divine the reason of it.
That there may never be a plurality of females in a hive, nature has inspired queens with a natural horror against each other; they never meet without endeavouring to fight, and to accomplish their mutual destruction. Thus, the chance of combat is equal between them, and fortune will decide to which the empire shall pertain. But if one combatant is older than the rest, she is stronger, and the advantage will be with her. She will destroy her rivals successively as produced. Thus, if the old queen did not leave the hive, when the young ones undergo their last metamorphosis, it could produce no more swarms, and the species would perish. Therefore, to preserve the species, it is necessary that the old queen conduct the first swarm. But what is the secret means employed by nature to induce her departure? I am ignorant of it.
In this country it is very rare, though not without example, for the swarm, led forth by the old queen, in three weeks to produce a new colony, which is also conducted by the same old queen; and that may happen thus. Nature has not willed that the queen shall quit the first hive before her production of male eggs is finished. It is necessary for her to be freed of them, that she may become lighter. Besides, if her first occupation, on entering a new dwelling, was laying more male eggs, still she might perish either from age or accident before depositing those of workers. The bees in that case would have no means of replacing her, and the colony would go to ruin.
All these things have been with infinite wisdom foreseen. The first operation of the bees of a swarm is to construct the cells of workers. They labour at them with great ardour, and as the ovaries of the queen have been disposed with admirable foresight, the first eggs she has to lay in her new abode are those of workers. Commonly her laying continues ten or eleven days; and at this time portions of comb containing large cells are fabricated. It may be affirmed, that the bees know their queen will also lay the eggs of drones; she actually does begin to deposit some, though in much smaller number than at first; enough however to encourage the bees to construct royal cells. Now, if in these circumstances the weather is favourable, it is not impossible that a second colony may be formed, and that the queen may depart at the head of it within three weeks of conducting the first swarm. But I repeat, the fact is rare in our climate. Let me now return to the hives from which the queen has led the first colony.
Thirdly. After the old queen has conducted the first swarm from the hive, the remaining bees take particular care of the royal cells, and prevent the young queens successively hatched from leaving them, unless at an interval of several days between each.
In the preceding letter, I have given you the detail and proof of this fact, and I shall here add some reflexions. During the period of swarming, the conduct or instinct of bees seems to receive a particular modification. At all other times, when they have lost their queen, they appropriate workers worms to replace her; they prolong and enlarge the cells of these worms; they supply them with aliment more abundantly, and of a more pungent taste; and by this alteration, the worms that would have changed to common bees are transformed to queens. We have seen twenty-seven cells of this kind constructed at once; but when finished the bees no longer endeavour to preserve the young females from the attacks of their enemies. One may perhaps leave her cell, and attack all the other royal cells successively, which she will tear open to destroy her rivals, without the workers taking any part in their defence. Should several queens be hatched at once, they will pursue each other, and fight until the throne remain with her that is victorious. Far from opposing such duels, the other bees rather seem to excite the combatants.
Things are quite reversed during the period of swarming. The royal cells then constructed are of a different figure from the former. They resemble stalactites, and in the beginning are like the cup of an acorn. The bees assiduously guard the cells when the young queens are ready for their last metamorphosis. At length the female hatched from the first egg laid by the old queen leaves her cell; the workers at first treat her with indifference. But she, immediately yielding to the instinct which urges her to destroy her rivals, seeks the cells where they are enclosed; yet no sooner does she approach than the bees bite, pull, and drive her away, so that she is forced to remove; but the royal cells being numerous, scarce can she find a place of rest. Incessantly harassed with the desire of attacking the other queens, and incessantly repelled, she becomes agitated, and hastily traverses the different groupes of workers, to which she communicates her agitation. At this moment numbers of bees rush towards the aperture of the hive, and, with the young queen at their head, depart to seek another habitation.
After the departure of the colony, the remaining workers set another queen at liberty, and treat her with equal indifference as the first. They drive her from the royal cells; being perpetually harrassed, she becomes agitated; departs, and carries a new swarm along with her. In a populous hive this scene is repeated three or four times during spring. As the number of bees is so much reduced, that they are no longer capable of preserving a strict watch over the royal cells, several females then leave their confinement at once; they seek each other, fight, and the queen at last victorious reigns peaceably over the republic.
The longest intervals we have observed between the departure of each natural swarm have been from seven to nine days. This is the time that usually elapses after the first colony is led out by the old queen, until the next swarm is conducted by the first young queen set at liberty. The interval between the second and third is still shorter; and the fourth sometimes departs the day after the third. In hives left to themselves, fifteen or eighteen days are usually sufficient for the throwing of the four swarms, if the weather continues favourable, as I shall explain.
A swarm is never seen except in a fine day, or, to speak more correctly, at a time of the day when the sun shines, and the air is calm. Sometimes we have observed all the precursors of swarming, disorder and agitation, but a cloud passed before the sun, and tranquillity was restored; the bees thought no more of swarming. An hour afterwards, the sun having again appeared, the tumult was renewed; it rapidly augmented; and the swarm departed.