Swarm Prevention Techniques

Swarm control (swarm prevention) covers all the measures taken to delay or reduce the division of a honey bee colony, in which part of the bees leave the hive with the old queen, or to turn it into a split under the beekeeper's control. Swarming is the colony's natural reproductive urge and cannot be eliminated entirely; but it can be largely managed by giving space at the right time, keeping young queens and inspecting regularly.

Why do colonies swarm?

Swarming is how a honey bee colony reproduces. Swarm preparations begin when the colony has become strong and crowded, young bees have nothing to do and the queen's pheromone no longer reaches every part of the hive in sufficient amounts. The main triggers are:

• Lack of space: The queen can't find empty cells to lay in and the hive is congested.
• Old queen: Queen pheromone declines with age; the swarming tendency rises markedly in colonies with queens more than two years old.
• Too many young bees: Large numbers of young nurse bees with no brood to tend.
• Hot, stuffy hive: Hives in full sun with poor ventilation.
• Genetics: Some bee strains and races are more inclined to swarm than others.

How can you tell a colony is preparing to swarm?

The most reliable sign is queen cells. It is normal to see empty queen cups (play cups) in colonies in spring; what matters is whether they contain an egg or a larva.

• Swarm cells: Usually numerous and lined up along the bottom and side edges of the comb.
• Supersedure cells: Few in number (usually one to three) and found on the face of the comb, towards the middle. The colony is replacing its queen; these are not a sign of swarming.
• Other signs: The queen laying less, fresh nectar building up in the brood area, bees hanging idly about the front of the hive.

Swarm prevention methods (before preparations start)

Giving space in time

Lack of space is the strongest trigger. Space should be given before congestion sets in; adding a new box when the existing one is about three-quarters full is the usual rule. The details are on the Adding Boxes and Space Management page.

Getting foundation drawn

Giving young bees work reduces swarming pressure. During a flow, giving single sheets of foundation at the edge of the brood nest both keeps young bees busy and opens new laying space for the queen.

Removing capped brood

Taking one or two frames of capped brood from a strong colony and replacing them with empty drawn comb or foundation reduces crowding in the hive. The removed frames are given to weak colonies to strengthen them. One operation brings two benefits.

Young queens

Colonies with young queens show a markedly lower swarming tendency. Regularly replacing the queen every one or two years is the most lasting tool of swarm management.

Ventilation and shade

A hot, stuffy hive triggers swarming. Opening the entrance fully during the flow, providing top ventilation and offering shade from the midday sun are simple but effective measures.

What should you do if swarm preparations have begun?

If the colony has made cells with eggs or larvae, giving space alone is usually not enough. At this point, rather than trying to stop the colony, it is far more reliable for the beekeeper to carry out the division.

Artificial swarm

1. The old hive is moved a little to one side of its position.
2. A new hive with foundation is put on the old site; the queen and one frame of brood (without queen cells) are placed in it.
3. Because the foragers return to the old site, the new hive soon becomes as strong as a swarm.
4. The queen cells and young bees remain in the old hive; a single good cell is left there to raise a new queen.

The colony's urge to swarm is satisfied. In addition, a natural broodless period occurs in the old hive, opening a favourable window for varroa control.

Splitting

The colony is divided into a queenright part and a queenless part (with queen cells), or a small split is made from a strong colony with a few frames of bees and brood. For a beekeeper who wants to increase colony numbers, swarming pressure becomes an opportunity.

The Demaree method

The queen is left below in a brood box of foundation or empty comb; the brood frames are moved above a queen excluder to the top box. The crowding is relieved without splitting the colony, and it goes into the flow as a single strong colony. Any queen cells built in the top box are checked and destroyed a few days later. The method requires experience.

Swarm timing and inspection interval

About eight days pass from the egg in a queen cell to a capped cell, and the prime swarm usually leaves as the first cell is capped. The new queen emerges about 16 days after the egg was laid.

That is why, during the swarming season, the inspection interval should not exceed seven days. A beekeeper who checks every ten days may miss both the preparations, from egg to capped cell, and the swarm itself between two inspections.

Methods that don't work, or aren't enough on their own

Just destroying queen cells

If the colony has decided to swarm, it will build new cells to replace those destroyed. Removing the symptom without removing the cause only increases the inspection workload, and very often a single missed cell produces the swarm. What's more, if the colony has already swarmed and all cells are destroyed, it may be left queenless. Destroying cells only makes sense together with an intervention such as giving space, removing brood or splitting.

Clipping the queen's wings

Clipping does not prevent swarming; it only stops the old queen flying off with the swarm. The swarm still leaves, the queen falls to the ground because she can't fly and is usually lost; the bees return to the hive and may swarm again when the first new queen emerges, this time with her. Clipping is only a measure that buys time, combined with regular inspections.