Although beekeepers aim to control the swarming that disrupts the normal activity of the hive and interrupts honey production, it is nonetheless the process by which a new colony of bees is created. Before the appearance of movable frame hives, the swarming of bees was expected and occupied the beekeeper for a good part of the year.
Why are bees swarming?
When the colony reaches a critical mass (approximately 2 to 3 bees per cubic cm of hive volume), new queens are raised in specific cells and fed with the famous royal jelly. Shortly before these larvae hatch, the old queen leaves the nest with around 10,000 to 20,000 workers (and a few drones) and creates a new nest elsewhere. Only honey bees swarm like this.
How do they prepare for swarming?
Workers prepare for swarming several days in advance. The most obvious clue is the construction of queen calyxes, large cells built around the edges of combs intended to rear queen larvae. The signal inducing this behavior surely comes from the emission of specific pheromones by the active queen.
If the queen is removed from the nest or physically isolated from the workers, then they immediately begin to urgently build queen cells by enlarging the worker cells.
It is recognized that the queen's pheromones are picked up by the many workers who constantly accompany, care for, nourish, and exchange bodily fluids with the queen. The exchanges of food and fluids between the members of the hive explain that this signal is quickly known to all the inhabitants of the hive.
The exchange of pheromones can be hampered when the bees are so numerous that they are clustered on the combs. The workers then end up receiving only part of the required daily dose. This is the main signal for swarming.
In addition, the queen also secretes chemical compounds by their legs which soak up the combs as they progress through them. When the colony has grown too large to visit any location, the absence of this chemical fingerprint is another signal to workers that the time has come to build new queen cells.
Here is a video of a live swarming
A few days before the departure of the swarm, the bees called "scouts" (often old bees who know the surroundings of the hive well) look for new sites likely to welcome the new nest. The swarm has two forms: a cloud of bees or a compact mass. Either way, it's a beautiful sight. The cloud of bees can fly for several hundred meters. Rest assured, when bees swarm, they are not aggressive.
The Scout bees lead the swarm to the place they discovered by guiding it from outside to inside. They cross the mass of bees, indicating the direction to follow. Some land at the chosen location and release a chemical signal, the Nasanov pheromone, to guide the swarm.
When the bees arrive at the new site, the workers rush to build a new honeycomb. They are capable of this because before leaving the old nest, they gorged themselves on honey, each taking 40% of their own weight. In a few days the honeycomb is usable and a new functional nest is established.
Swarming on a currant
What if the bees are swarming in my house?
Sometimes bees choose places that could not be more surprising and even embarrassing for humans such as chimneys, a corner of a house, under a roof ... You have to act quickly because it can be very difficult to dislodge them later. At this time, call a beekeeper around your home to come and collect the swarm to direct it to a new hive.
Here is an explanatory video of a beekeeper collecting a swarm and transferring it to a new hive:
What happens in the old hive?
Meanwhile, in the old hive, new queens begin to emerge from their cells. There will only be one who can live there. As soon as the first queen has emerged, she searches for all the queen cells on the comb, opens the wax seals with her mandibles and stings the other queens and their larvae to death. Merciless!
The new queen then leaves the nest for her nuptial flight. The queen trains a host of males (drones) which release attractive pheromones. As soon as these drones see the queen, they chase after her in a mating “swarm.” This lasts about 30 minutes and the swarm can travel several miles while one or more males mate.
The male approaches the queen from below. It grips it with its paws and inserts its endophallus into its sting cavity. He then releases his grip and flies back. This brutal movement compresses his abdominal organs causing an explosive ejaculation, his endophallus breaks in the bee. Mating lasts a few seconds and the castrated male immediately drops to the ground and dies. The queen returns to the nest by storing the sperm. The endophallus in place, emerging from her vagina, testifies that she is no longer a virgin. The broken phallus helps the queen retain the sperm she has stored for her entire existence. Once back to the hive, the queen will be rid of this phallus by the workers.