Beekeepers must manage colonies so they do not swarm. If colonies do swarm, beekeepers may not only lose the swarming colony, but the parent hive is much smaller as summer progresses. This may inhibit honey production and overwintering success. Anyhow, swarming is bad beekeeping practice, and should be avoided at all costs. I have outline preventative and remedial techniques to avoid swarming, which should help you as swarm season pushes on!
Early prevention of swarms
Adequate space for brood and resources
Beekeepers should provide extra space during the spring as colony population drastically increases. If colonies are large entering the spring honey flow, then colonies may need 2 brood boxes and supers to inhibit swarming, but this depends upon the state of the colony. A good rule of thumb is colonies need at least 2 empty frames, but if you check the colonies 2 weeks later, this is often too late. It is often best to provide space extra space to prevent disaster later. Too much space can spread resources, such as nurse bees, but if you cannot check the colonies often, then do provide extra space.
Older queens are more likely to swarm than younger queens. However, this does not necessarily mean all old queens will swarm! I have seen colonies headed by 2 year old queens that have not swarmed, so do not worry too much unless signs of swarming exist. But annual requeening may be a great option to lessen that chance. Many beekeepers requeen their colonies annually because colonies with young queens often produce more honey, have a better brood pattern, and are more likely to live through the winter. This does not mean older cannot queens perform as well as younger queens, but it is less likely. If you plan to requeen to prevent swarm, purchase queens bred not to swarm. Obviously swarming is an embedded behavioral trait, but many queen breeders select colonies that do not swarm. Because of this, bees can be selected for their low propensity to swarm.
Removal of queen cells
Queen cells are a blatant sign of swarming. If these swarm cells have eggs or late-staged larvae, then swarming is far advanced and action must be taken. If the queen cell is open, then the queen has hatched, and the colony might have swarmed already. But if a colony contains swarm queen cells with eggs or late staged larvae, then these cells need to be removed immediately. The colony will swarm if a new queen is available to the colony. If a new queen is not available, then the colony will not swarm. Once queen cells are removed, then other steps need to be followed, such as brood removal or checkerboarding.
Checkerboarding is a useful practice that encourages colony build-up while preventing swarms. Essentially, checkerboarding tricks bees that the brood next is smaller than it actually is. Checkerboarding is the alternation of brood frames with empty frames, which creates a checkerboard pattern (brood, empty, brood, empty). This breaks the brood into multiple brood boxes, and tricks colonies to continue colony build-up. If the colony is packed wall-to-wall with brood, then add an additional brood box or super, and rotate frames between the two boxes. While this may seem like a lot of extra, unnecessary work, checkerboarding does prevent swarms while encouraging colony build-up.
Many beekeepers reverse the top and bottom boxes during the first spring inspection. In theory, this method prevents swarms by lessening congestion. Despite the lack of evidence on reversing, this is a common practice. Many beekeepers believe this practice lessens swarming because the majoring of the bees are located in the upper box. Because of heat, the bees stay in the upper box without migrating to the lower brood box, and this increases congestion. By reversing, the queen and ~ 1/2 the bees move to the empty box as they migrate up. Both boxes will now contain half the bees, which evenly spreads the bees between the two brood boxes. While not backed by scientific evidence, this is a common swarm management practice.
Many beekeepers use exchanging as their main method of swarm management, especially if the beekeepers as several colonies. Exchanging is the practice of switching the locations of a weak and strong colony during mid-day. Once foragers come back, they populate the weak colony, thus alleviating congestion of the stronger one. Many commercial beekeepers exchange colonies because it is a quick swarm management technique. Moreover, it provides a boost for weaker colonies. The colonies may lose queens, so be wary of this.
Late-stage prevention of swarms
Prevention is the best swarm management practice, but life does happen! Most beekeepers have a swarming colony at some point. In many cases, colonies are in the late stages of swarming and beekeepers must take immediate action. Unlike the previous section, more drastic measures must be taken to prevent swarming
Removal of queen
If the colony is about to swarm, than queen removal is prudent option. Remove the queen for 7-9 days, and requeen once again after all queen cells are removed. The beekeeper may choose to either requeen the colony with the original queen or with a new queen, but this is personal preference. While this technique does impact honey production and population increase, it does inhibit late-staged swarming.
Removal of brood
Beekeepers can remove brood to inhibit swarming. Either the beekeeper use the brood to produce a new colony or place the brood into a weaker colony, but this is a useful swarm management technique. If the beekeeper plans to produce a new colony (nuc), then place 3-5 frame of brood, bees, and a queen in a new brood box. Move the colony to a new location, and whala! A new colony without the swarm.
Separation of queen from the brood
This technique is called Dameering, and is a very common for swarm management among beekeeping circles. Essentially, the beekeeper separates the queen from the brood by rearranging the colony. With this technique, beekeepers place the queen and 1-2 frames of brood in an otherwise empty foundation box. The box is placed in the original location of the colony, and a queen excluder is placed on top. Beekeepers then place a 1-2 supers on top of the queen excluder, followed by the original brood box. This should be repeated 9-10 days later. There are several modifications, such as shaking all the colonies on the ground next to an empty foundation box with a queen excluder, so the bees and the enter the intended box. While many different techniques exist, the basic premise is to separate the queen from the brood.