I think swarm prevention is misleading and "Swarm Reduction" might be a more accurate term.

In my view swarm prevention should be a major part of all management methods and I include some below:-

The Bees.

• Some bees are much more prone to swarming than others. It is universally known that carniolans (Apis mellifera carnica) are heavy swarmers and this is accepted by beekeepers in countries where carniolans are the bee of choice. My own experience is it is often difficult to keep them in the hive. I haven't used any myself for a very long time, but I once helped a new beekeeper who bought a nucleus headed by a carniolan queen. The next year they swarmed and later in the season, both the parent colony and the swarm swarmed again. Four colonies for the price of one, but no honey! The message here is if you use carniolans, then expect heavy swarming.
• The higher the number of swarm cells that are built by a colony, the more swarmy it will be - see Peak Qeencell Number (PQN). When using swarm cells to raise queens, e.g. when artificial swarming, only use those from colonies that produce relatively small numbers, say no more than 10-12. This of course is at the point of swarming.

The above points are relevant to the types of bees that are kept. The good beekeeper will cull any colonies that show strong tendencies to swarm. In my opinion Bee Improvement should be a major part of all beekeeping management systems and selecting for lower swarming tentencies could be one characteristic.

Colony Management.

• Understand the life cycle of the queen and the swarming procedure.
• Inspect your colonies regularly and inderstand the swarming process.
• Congestion is often a problem. There are two issues you need to think about, firstly the amount of room there is for honey and secondly the room for the brood. In the wild a swarm has already chosen the cavity it uses and it is known they take size into account. There are usually no restrictions as they use the comb for storing honey and raising brood. They can't do that with managed colonies, where the beekeeper is constantly changing the capacity and confining the queen by the use of a queen excluder. It will reduce the chance of swarming if the brood box and queen are matched and supers are added in advance of requirements.
• Overheating is often said to cause swarming, but I'm not sure it is as important as is made out. When everyone used solid floors, bees would often cling to the outside of the hive when they were in full sun. Now we have open mesh floors this doesn't often happen, presumably because ventillation is easier, but in my experience swarming is still at the same level. Having said that I would still put hives in shade, as I think it will cause less stress to a colony.
• It is often said that colonies are less likely to swarm if they have a young queen. With prolific bees I will agree with that, but in my experience not with non-prolific bees, where queens will usually give good account of themselves throughout their lives and not show any inclination to swarm.

If you attend to the details above you have done as much as you can to reduce swarming. Regular inspections will still be needed and as soon as eggs appear in queen cells you will need to use some method of swarm control.

With the current queen problems it has become common for a colony to swarm on supersedure cells and there is no chance that swarm prevention will affect that. It is also common for colonies to swarm on emergency cells.

Roger Patterson.