We can observe in bees, an impressive organization and a very evolved social life. The colony develops entirely through the laying of the queen, a sort of “laying mother”. One day, this colony splits in two: a large part of the hive leaves, leaving the other to take care of the new queen cells: this is the swarming.
Why does this phenomenon occur? Can it be avoided? If so, how? How to react to a swarm? This is what we are going to find out.
What is swarming?
Swarming is the natural model of colony reproduction: the queen, accompanied by the foragers (the swarm) leaves the hive to rebuild a new habitat elsewhere. This is a beneficial process that allows the regeneration and multiplication of their population.
After several successive swarmings, the beekeeper risks to find the population of his hive with only a very small quantity of bees, more occupied with taking care of his brood than with making honey…
How does this happen?
In bees, the laying mother emits two known kinds of pheromones:
- We find 9-keto-2-decenoic acidproduced by its mandibular glands, which attracts the drones during the nuptial flight but also ensures harmony within the colony: it is the signal that indicates to the workers the task to be carried out (cleaning, feeding…)
- The methyl-4-hydrobenzoateIt is secreted by its epidermal glands. It proves her presence and health in the hive, and also prevents the workers from raising another queen.
However, for various reasons that we will develop below, it happens that this last pheromone is absent or less well perceived by the worker bees. These are then taken by “swarm fever” : they assume that their laying mother is gone or failing.
In response, they begin to raise new queen cells to accommodate and raise new queens.
They can place these queen cells anywhere, but most often they are found at the edge of the frames, vertically for swarming.
There are two possibilities; either :
- The queen herself lays eggs directly inside the new queen cells,
- The workers deposit freshly laid queen’s eggs (less than 3 days old).
They then feed the larvae with royal jelly for a few days, and proceed to the capping of the cell: the larvae become pupae. A few days before the births, they stop feeding the “old” queen. This one being put on a diet, its abdomen is reduced: it can fly again.
About three or four days before hatching, the royal nymph emits vibrations from inside its cell. This vibration, perceived by the old queen, is the signal that she can (or must) leave the hive. So she will leave with about half of the bees, hence the impressive cloud of flying insects that can sometimes be seen landing in gardens! These swarms, which can measure up to twenty meters in the air, thus leave in search of the ideal place to start a new colony.
When does the swarming occur?
The strongest period is in spring between April and the end of JuneThis is the time of year when the breeding is most intense. From the summer solstice (June 21), this swarming fever calms down. In bees, weather conditions are decisive You must leave early enough to give the new colony time to settle in and build up provisions for the winter.
The old queen and her workers therefore choose a sunny day to leave the hive, usually between 11 am and 3 pm. They eat all the honey they can swallow in order to prepare themselves and accumulate reserves for their journey.
They can spend up to three days outside before finding the right place for their migrationThey are fixed in clusters on a support close to their former habitat. This phenomenon can occur as well in early summer, if the climate is favorable and sustenance is available. Indeed, the group must quickly find a place to settle and nectar to avoid starvation.
What causes a swarming?
It is a natural need in order to perpetuate the species, it is almost inevitable. However, several factors can speed up the process.
The lack of space encourages bees to divide. When resources are too abundant, the excess honey, nectar and pollen take up a lot of space in the hive. This is often the case for the spring honeyflow with rapeseed, especially in Normandy. The difference between an apiary that has access to rapeseed fields and others is obvious.
After several days of rain in a row: the battalions of foragers can’t get out, the bees feel cramped in their habitat.
If the beekeeper does not add supers to his hives, they quickly become too small: the bees are stuck together, pheromones do not circulate well and the bees lack space.
When it is very hot inside the hive, either because of excessive external heat or because of poor ventilation, the pheromones again are poorly distributed and the same phenomenon occurs.
The genetics of bees
Some bees produce more honey, others swarm more. This is the case of the Carnica bee, which is much more swarming than the Black or Italian bee.
As the queen ages, she may emit much less powerful pheromones. This deficiency of hormonal secretions prompts the workers to raise new queens.
But it is also a desire that can simply come from the queen. As it ages, it naturally wants to swarm, as a biological need.
How to anticipate and avoid swarming?
Here are some beekeeping practices to delay or control the swarming of bees so dreaded by beekeepers
Giving space to the bees
The more space the bees have, the more the queen can move around and disperse her pheromones in the hive. The beekeeper can avoid a departure in :
– by expanding the hives early enough and by putting a top on the hives.
– giving new wax frames to build, in the bodies and in the first fittings.
One interesting method of managing swarming in a spring hive is to divide your hive into 6/7 frames after the summer honey flow to anticipate swarming at the beginning of the season. This division makes it possible to increase the space of the hive horizontally by adding frames of embossed wax and vertically by adding a top. Not to mention that the frames of brood taken after the summer honeyflow will be used to create a new swarm in a hive.
Having young queens
The queen naturally wants to swarm at least once in her life, especially as she ages. In the first year only 2 to 3 % of the plants swarm, in contrast to the second year (20 %) or the third year (50 %). By having a young queen, the beekeeper has statistically less chance of encountering a swarm.
In beekeeping, anticipation is essential to keep a colony in top shape. Requeening when you notice a queen deficiency is an appropriate beekeeping method.
Create an artificial swarm
Colony splitting is a widely practiced beekeeping method to slow down and control natural swarming. This process consists of preventively divide a “strong” hive into two or even three parts. There are different variants that we will see in a next more technical article to create a artificial swarm.
Simply remove from your hive:
- A frame of fresh brood with an egg laying of less than 3 days
- A capped brood frame and
- A third frame filled with pollen and honey.
And to place the whole in a hive which you will install at more than 3 kilometers from your apiary (by taking care not to take the queen).
After more or less 24 hours, they will understand that they are “orphans” and will set up the succession by feeding new eggs with royal jelly.
To speed up the process and save time, you can introduce into your new swarm a fertilized queen, a cell or a virgin queen.
Destroy the royal cells!
In bees, the development of the larva occurs in successive mutations. Once the long white egg is laid, it hatches 3 days later. It then becomes a larva for another three days. After five or six days, this larva is closed in the alveolus by a wax seal: is the capping. We must act before this stage. If the beekeeper chooses this method, he will have to . check the hives at least once a week and inspect them thoroughly to ensure that no queen cells are left available.
The clipping of the queens
Clipping is a controversial practice in beekeeping which consists in cutting a wing of the queen (“clipped queen”). Some beekeepers still use this practice, thinking that they can avoid the departure of the queen in case of swarming. In reality, due to the queen’s inability to leave, the swarm will remain just outside the original hive waiting for a young queen to be born to accompany it. It will not necessarily prevent the departure but, during this wait, it will be easy to recover the swarm.
What should I do if I have a swarm in my garden?
In the spring, swarms multiply and can settle in a tree, under a roof or in a chimney: this can seem very frightening to people who are not initiated in beekeeping. Don’t worry: very often, it will be gone before the evening. This temporary stop allows the Girl Scouts to search for the shelter where the new colony will settle permanently.
However, if the swarm begins to build up comb, action must be taken. The bees will not appreciate being disturbed and will appear more aggressive to defend their facility.
The best solution is to call a beekeeper. As bees are threatened by pollution and all the pesticides that surround them, we must not destroy them. There is no need to call a specialized company or the fire department. Do not use insecticides or fire extinguishers.
Many amateur beekeepers will be happy to come and get this swarm in order to enlarge their own breeding and to preserve the life of the new colony.
In Eure, you can contact the departmental coordinator of the Eure beekeeping union at 07 68 94 21 00 who will redirect you to a beekeeper near you who is interested in picking up your stray swarms. However, for the most delicate cases, swarms in a chimney, a wall, a roof, wasp nests or Asian hornet, it is preferable to contact a specialized company for the good of all.