Swarm Basics, Part 2: Can We Control Swarming?
The behavior of swarming is probably one of the most dramatic occurrences in the life of a bee colony. And also, for the beekeeper. Wally Shaw, 34-year Welsh beekeeper in Anglesey, Wales, a retired research ecologist and author of numerous BeeCraft articles and a 200-page paperback “Swarming-Biology and Control,” echoes the sentiment of many: “There is no doubt that swarm control is simultaneously the most important and most difficult aspect of colony management.”
Swarming is the natural method of colony reproduction. Sometimes it is a means of beekeeper colony expansion and for individuals starting in beekeeping. Swarming becomes a greater management challenge the farther north you go. Bee colonies in temperate climates swarm every year or every other year, and more than once on average, if left unmanaged.
Factors that are connected with the behavior of swarming include the brood and adult population relative to the amount of room within the nest, and the amount and distribution of available queen substance. The third major factor, the environmental influence, is beyond control of the beekeeper. Management involves comb, box and queen management.
The spring hive environment
Spring hive management activities are multi-purpose. Generally, if interested in maximizing honey production, the major effort is to allow the bees to develop a large colony. The concept of swarm management is to avoid having the bees develop queen cells as the colony brood nest is expanding. Individuals less interested in honey harvest will not necessarily seek to develop a large populous colony but swarm control may still be a high priority during the spring.
Swarm management basically seeks to delay queen replacement by the bees. We can do this by requeening ourselves as colony stewards or delaying queen cell development so swarming does not occur. We delay queen replacement so bees do it later in the year via supersedure.
Arbitrarily we can divide our swarm management into two phases — preventive and reactive. Once a colony starts rearing replacement queens in the spring, beekeepers must assume that the bees have begun swarm preparations.
The first management is a relatively easy activity — checking expanding colonies for developing queen cells. This can be done quickly in removable-comb hives managed in two boxes by examining the bottoms of the frames of the top box, assuming the brood area extends between the two boxes. If bees are in a single brood box, the frames need to be removed to check for developing queen cells.
The earlier in the queen rearing cycle we discover that a bee colony is rearing replacement queens, the greater the chance for changing the behavior (i.e., halting swarming). When the queen cells are not discovered until well-advanced in their development and number, more drastic reactive action will be necessary to try to halt a colony from swarming.
Preventing bee swarms
The measures listed below are all aimed at ensuring that bees do not start queen cells, a critical first step in swarming. In most years, attention to each factor will keep the incidence of swarming at a low, tolerable level:
- Provision of plenty of room for egg laying in the brood nest. This usually means two full-depth hive bodies for brood rearing in strong colonies; one hive body is more difficult but can be managed with removal of brood combs or allowing the bees to temporarily expand into a second box. Alternately a second box is used to allow for storage of early nectar sources.
- If the colony in spring still has heavy stores left over from wintering and lots of bee bread stores on frames adjacent to brood, you might have to “open up” the box. Remove honey-filled frames (use to bolster weaker colonies or store in freezer for fall feeding) or move them to the center of the brood nest after scoring the capped honey with your hive tool. As the bees clean the mess you want the emptied cells to become available for the queen to lay eggs.
Brood comb management
- All brood nest combs should be in good condition for egg laying, contain a minimum of drone comb and should not possess large amounts of stored honey or pollen after late March. The beekeeper may move existing frames of mostly capped brood within the brood area or remove such frames from large, populous colonies to bolster weaker colonies in order to provide space for the queen to lay eggs. Culling of old or defective frames should be done early.
- Getting the bees to draw 2-4 new frames of foundation will be useful. Early in the season, in order to maintain brood nest integrity, foundation frames should be added at the edge of the brood nest — so that it becomes the next frame to be drawn as the brood nest expands. Later, when the colony has a large and expanding population, foundation frames can be alternated with drawn comb (checkerboarding) or 2-3 foundation frames put together in the middle of the upper box. Only do this if a super has been added, to avoid the bees filling newly drawn cells with nectar or bee bread.
- There is some disagreement but contrary to common opinion the best place to create space for the queen to lay is below the existing brood nest. A box of drawn comb placed on top of the brood nest will often be treated like a super and substantially filled with honey. So single box systems often add drawn comb below populous colonies, especially if early nectar income is substantial.
- Provision of sufficient nectar storage space is critical. Some super space should be available for nectar from March to mid-August. You want to move the cap of honey/ripening nectar from brood nest to super. It is OK to have some nectar stored in the brood nest — that is the food that will be fed to the larvae.
- When supers are added, it is sometimes necessary to entice bees into working in them immediately. You do not want ripening honey to be backfilled into the brood nest as that will reduce egg-laying space for the queen. When adding supers on top of the brood area, bait the supers (by raising a frame or two of ripening honey into the super added, if it’s the same size as frames of brood combs). If only capped honey is available, score some of it to make a “mess” — the bees will not tolerate dripping honey so they will enter to clean the mess. Frames can be added in the center of the super. An alternative is to drip sugar syrup on the comb face. Full supers of foundation should not be added until the honey flow has begun.
- Colonies should receive maximum sunlight early in the season. Afternoon-shaded apiary sites are acceptable. Colony entrances facing the morning sun or south are preferable. Painting hives white will help the bees regulate the temperature in the colony but may lead to excessive drifting if not distinctly marked. Provide each hive a “distinctive address.”
- Sufficient ventilation should be present in the developing colonies. Winter entrance blocks (for mice) should be removed by mid-spring. Some apiaries with poor air circulation could benefit if colonies are supplied with a screened bottom board and a top screen in place of the inner cover to improve ventilation. Breaking the propolis seal at the hive top increases upward ventilation within the colony.
Queen replacement management
- Ensure that young queens head all colonies. This is the most important thing that can be done to aid in reducing the possibilities of colonies raising queen cells. We seek to delay replacement via swarming to have bees replace their queen via supersedure. Swarm prevention 101. All requeening should be done from stock with low swarming tendencies. Queens that have not been through a spring tend to swarm much less than older queens, although most new queens swarm when in congested nests.
It is normal for bee colonies to build queen cups, especially during spring expansion. However, if there are occupied queen cells we need to assume the bees have started swarm preparations. If nothing is done the colony may swarm. There is abortion of queen cells so it is not inevitable.
To halt the preparations, two management steps are necessary. First, eliminate all the queen cells, both capped and uncapped, and second, manipulate the brood area so the colony does not resume queen rearing. Once initially done, colonies should be rechecked every seven to ten days and the control technique, or a new one, repeated if developing queen cells are once again observed.
Be cautious with this first step — queen cell elimination. You do not want to eliminate queen cells if the colony has already swarmed. You can determine that most reliably by seeing the queen or the colony actually swarming. Neither of these are infallible since it is easy to miss seeing a queen that has been preparing to swarm for nearly two weeks and swarm emergence is over within 10 minutes. Lacking that, determine if eggs are in the colony and look at the colony population. Once again this is very difficult as there may be few eggs present and looking at the population to determine which colony (if there are multiple present in the apiary) is reduced in adult population, particularly with heavy forager activity, is not much more than a guessing game.
The queen greatly reduces her rate of egg laying before she leaves in a swarm. Her most recently laid eggs will not change to larvae for three days, so just seeing eggs does not mean she is present (nor that she has left). Although more bees depart with a swarm than stay, emergence of new adults after swarming may quickly replace the absent swarming bees. Even seeing a swarm, it is hard to tell which colony might have swarmed.
If you eliminate queen cells, and the colony has already swarmed, the colony still has the possibility of raising a replacement if eggs are present. (After a week that opportunity has passed.) However, the replacement cells will be emergency cells. Thus, cell removal requires careful inspection and determination that cells are most likely swarm cells and definitely not emergency cells. The difference will be the base of the developing queen cells. Emergency cells develop from horizontal worker cells, not queen cups. But you have to look carefully.
It is critically important to eliminate, by killing or removing, all developing queen cells in the colony. Once all queen cells are destroyed, one of several management variations, as described next, should be performed. Select a method that suits your situation. There are numerous variations of these techniques. Consult a favorite reference or the leaflet from the Welsh beekeepers by Wally Shaw for some of these variations.
Swarm control is a lot of work and unless done skillfully and at the right time, might not successfully halt swarming. Remember, if nothing is done, a swarm may emerge from the colony once the colony has developing queen cells. When bees swarm, the bees are managing the beekeeper.
Option 1: Queen Management
De-queening a colony rearing queen cells can be effective swarm control. At time of locating and removing the queen, you must destroy all queen cells — not just cells visible between boxes but also those that may be “hidden.” A disadvantage is that it often takes considerable time to search for and find the queen.
After finding the queen you have option of killing her or placing her in a holding cage. Then the colony is left queenless for seven to ten days. The workers will build emergency queen cells, sometimes even if you confine the queen to a holding cage that is held within the colony itself.
The most effective holding cage is a queen excluder cage that encompass an entire frame along with the queen. After 3-5 days, remove the frame and use it to bolster a weaker colony — you can transfer the worker bees along with the frame to the weaker unit — but not the queen. Replace the removed frame with a drawn brood comb. Following this, requeen the colony by releasing the old queen from her cage (once again transfer the frame and adult nurse-age bees out of your colony as you release the queen you have been holding in a cage) or with a new queen. You must destroy all developing queen cells present in the colony.
By removing the queen, you create a break in the brood cycle which should weaken the colony enough to halt swarm preparations. The developing brood present at time of queen sequestration continues to emerge and the adult population continues to expand for another three weeks. If the target nectar flow begins within this time, there will be a large population of workers available for foraging as there will be less brood to tend.
Requeening seven to ten days later restores an expanding brood nest and the colony returns to a “normal” condition. Obviously timing is critical to success. One downside to this dequeening is the bees may begin to backfill nectar into cells that could serve as brood cells. These frames can be moved up into the super and drawn comb used to replace them so the new (or newly released) queen has plenty of empty cells for her eggs at time of queen restoration/requeening.
A good variation of this technique includes killing the original queen and introduction of a new purchased mated queen reared in another colony, or the addition of a capped queen cell, seven to nine days later. Instead of introducing a capped queen cell (produced in another colony), cut out all queen cells except one after you have removed the colony queen. This will create the desired brood break as the virgin will need 7-10 days to emerge and mate. There is a small risk the colony may swarm with this virgin once she emerges. This risk increases if you leave more than one capped queen cell.
Dequeening and then requeening creates a brood cycle break, which can be combined with introduction of a hygienic or locally selected ….