Honey bee hives swarm to duplicate their hive. A means of survival. One would think the Queen’s egg laying was the colonies means of replication, but it only builds and maintains colony strength for the nectar flow season.
To ensure the survivability of the bee race it must create a swarm for duplicity. Many in the beekeeping world struggle to prevent swarms. They would prefer to keep their hive intact. It is an interference of nature!
There are swarm signals one may read to know when a hive is about to take flight. Knowing these signs may allow the management of the hive pre-swarm.
Overcrowding
No matter the hive style the bees are residing within it becomes important to stay ahead of the growth. The bee box or space should not be beyond their means to manage. Homeostatis of the hive is cricital for many reasons, but most important to maintaining the temperature of the brood at 92 degrees. Therefore in a Langstroth Hive, add an additional box when the upper box is eighty percent involved with bees (built comb, brood, nectar, pollen). Different hive styles would have the same sort of management necessity.
Not staying ahead of hive space could encourage the girls to mount an exit.
Lack of egg laying space
Hive inspections should take into consideration sufficient cells for the queen to lay new brood. The term “honey bound” signifies a hive that has no room for brood rearing left. The non-brood cells are filled with nector/honey preventing the queen from accomplishing her duties.
Reducing Queen Pheromone
Queens lifespan used to be up to five years. We are fortunate to see one or two years for our current queens. As the queens ages her Queen Mandibular Pheromone (QMP) diminishes in strength signaling the workers to develop their ovaries and of course the hive to consider swarming. The hive volume may exceed the queens ability to spread her QMP sufficiently throughout which results in worker development and potentially swarm action.
Reducing Brood Pheromone
Amazingly pheromones are a significant communication for the bees. Uncapped brood emits a pheromone which partly suppresses worker ovary development and swarming. If the queen slows her egg laying due to age or other causes, this would set in motion a swarm.
Increasing day length
As the days light increase it may set in motion a swarm.
Swarmy strain of bee
The swarminess of some strains or the propensity to swarm “at the drop of a hat” may also tip the balance in conjunction with other factors. Largely attributed to the practices involved in skep beekeeping it is certainly noticeable and should be avoided, simply by non selection or re-queening with progeny of less swarmy stock. Carniolan (Apis mellifera carnica) bees are known to swarm heavily.
Overheating
This is often put forward as a swarm trigger and I used to believe it, but my mind has been changed. Before we used open mesh floors in the U.K. we had solid floors. On hot days, especially if the hive was in full sun, the bees would cluster on the front of the hive, presumably to protect it from the full sun. This doesn’t happen much now we have OMFs, as presumably the bees can ventilate through the floor. In my experience there is no less swarming than there was. If you visit a Mediterranean country, you often see hives in full sun all day and if overheating was a swarm trigger they would shade them.
Beekeepers
Yes, beekeepers! I believe there are more swarms caused by something a beekeeper has or hasn’t done than anything else.
Other reasons.
A colony will often swarm on queen cells that aren’t swarm cells, i.e. emergency or supersedure. There may not have been an intention by the colony to swarm, but they have used the opportunity given to them. This needs to be understood by beekeepers as many seem to think that because they aren’t swarm cells the colony won’t swarm. The “modern” advice of leaving two queen cells instead of one often leads to a swarm.
An overcrowded hive can be reason enough many times for bees to swarm; or a combination of a very mild winter and a bad queen can create swarm conditions for a hive. Prime swarm season is generally in late spring and early summer and can contain anywhere from several hundred bees and be the size of a grapefruit, too much, much larger swarms having upwards of 30,000 bees and easily more than half the hive.
When the old queen leaves the hive she has a following so to speak, of bees that also abscond with her. They fly around for a period of time and settle somewhere temporarily. A nearby tree branch, fence, a car mirror, or maybe even a low lying bush a foot or so above the hive. One never knows, but usually it is a convenient spot not too far from the hive and only for a few hours to a day or two. Once the scouting bees find a new nest the bees will move there, unless of course they are removed first by a helpful beekeeper. Swarms of bees are usually docile as they not protecting food or young bees. This is because no young bees participate in swarming and the bees are not protecting any food stores. Just refrain from provoking them.
To catch a swarm, calling a local beekeeper is always an option, but if you want to try to remove it yourself you can do so by placing an empty container, for example a hive, cardboard box or a nuc, on the ground below the swarm. Dislodge the bees into the container by shaking them. Other methods include using a ‘bee vac’ or even placing swarm traps in your apiary during swarm season. If the queen goes into the ‘new home’ the bees will follow her within the half hour and the swarm will have been ‘caught.’
Swarms are honey bees’ way of naturally reproducing themselves. If you catch a swarm, you have essentially acquired a new hive. If you want to keep your hive from swarming and notice overcrowding and swarm cells hanging off the bottom of frames, simply take a frame with a capped queen cell, or cells, along with a few more frames of open brood and place it into a nuc. This will slow the bees down and may eliminate the possibility of swarming for a good period of time. Also, keep in mind to have enough supers on during the nectar flow in the event that the bees may also fill up the brood box with honey, greatly reducing the area for the queen to lay and causing extra congestion in the hive. A situation such as this will only accelerate swarming. Sometimes however, no matter the precautions that are taken, the bees are still determined to swarm, so it is always a good idea to keep a close eye on your hives during prime swarm season and inspect them regularly.