It is said that anyone can keep bees for nine months of the year; it is the three swarming months, which define the true beekeeper. Swarm prevention is indeed one of the more demanding skills of the craft, and one, which most beekeepers feel they should be better at. Swarming can take place at any time from April to September, but the most common occurrence is in May, June and July. The emergence of a swarm means the loss of half the beekeeper’s work force, plus all the honey that the bees carry away with them, and a break in brood production, while the colony has to wait for the new queen to emerge, get mated and start laying. This inevitably affects honey production, and usually results in a greatly reduced crop, if any at all, so swarm prevention is clearly in the interest of the beekeeper.
So what can be done to prevent this natural phenomenon? In order to take preventative measures, one must first understand what makes the bees swarm. There is no single major reason, but rather a number of conditions, which lead the bees along the path to swarming. First of all, it is a natural impulse for the bees. It is their way of reproducing, where one colony splits into two or three or more. But not all colonies swarm, so there must be other factors involved. One of these, and probably the most important, is congestion in the brood area. The hive becomes overcrowded, and the bees find it difficult to carry out their respective duties. The space in which the queen can lay is being restricted by the influx of nectar and pollen. The young bees are secreting wax, and there is nowhere to build new comb. The seasonal increase in the queen’s laying capacity means that the ratio of young, house bound bees to older foragers is imbalanced, adding to the congestion. These are ideal conditions to spark off the swarming impulse.
Another contributing factor is the age of the queen. The queen produces a pheromone, which we know as “queen substance”, which is taken from her by the workers during the grooming and feeding process. This substance is passed around the hive to all occupants, and has the effect of inhibiting the construction of queen cells. A young queen will produce this pheromone in adequate quantities, but as she gets older and her glands become less productive, there may not be enough to go around. This results in queen cells being constructed, and the colony is on its way to swarming.
So the beekeeper has two major areas to consider, insufficient queen substance, and congestion. The first can be rectified by ensuring that a young queen heads the colony. This means replacing queens every second or third year. The congestion problem requires regular attention by the beekeeper. The swarming impulse usually starts early in the season, and once it takes hold it is often impossible to stop, so preventative measures must be taken well in advance. On the first warm day in early spring, when the weather is conducive to opening the hive and carrying out the first inspection of the new season, two of the outer combs should be removed from the brood chamber, and replaced with two new frames fitted with wax foundation. This will give the bees some comb to build when they require it. Overcrowding can then be prevented by putting on a queen excluder and adding the first honey super, which will increase the hive capacity by about fifty per cent. While this does not directly allow extra space for the queen, the incoming nectar, which would otherwise be stored in the brood chamber, can now be placed in the super, thereby allowing more room for the brood. This new super area will also require house bees to maintain it, so young bees will move up from the brood chamber to carry out these duties, further reducing congestion in the brood area.
Of course, a colony with a young queen will grow rapidly, and it will not be long before this super is overcrowded and a second one is needed. This is where regular attention is required. The need to keep ahead of the bees’ needs is paramount, and as soon as one super is occupied, another should be added. A further way to reduce the congestion in a populous colony is to take a nucleus or artificial swarm. (See “How to take a Nucleus” and “How to make an Artificial Swarm”).
It has to be said however, that in spite of all the beekeeper’s efforts, sometimes nature will not be thwarted, and the swarming impulse is too strong, so nine day inspections should be carried out throughout the swarming season, watching out for the construction of queen cells. If queen cells are found, then swarm prevention has failed, and consideration must be given to swarm control.