Most new beekeepers quickly learn how to work out when a colony is making preparations to swarm. That’s because, an unchecked swarm will result in a diminished population within the hive, a loss of bees for the beekeeper and can be a nuisance to neighbours.
A swarm will certainly reduce the foraging force at a key time of year and it will be several weeks before the bees lost in the swarm are replaced. That’s because a new queen must emerge, go out on a mating flight, then come into lay.
However, not all queen cells mean the colony has swarmed or is preparing to swarm. There are two other types of queen cell. In addition to swarm cells, there are what’s called supersedure and emergency cells. Knowing how to tell the difference and what to do in each case will greatly enhance your beekeeping and will help your bees.
The development of a colony, including its reproduction is cyclical and follows the seasons. In our temperate climate, the queen accelerates her egg laying in spring in order to have the maximum number of foragers available at the time of abundant nectar. This abundance of nectar is converted into honey to sustain the colony through winter.
Foraging workers live for only a few weeks while winter bees live for up to six months. Drones are allowed to live for a season. The queen is quite different. She may live for up to five years but usually, she’ll live for two or three years and may be replaced by swarming or supersedure.
Swarm cells are ‘planned’ by the bees and are built down from queen cups usually found at the bottom of the frames or in little nooks and crannies between the side edges of the comb and the frame. That doesn’t mean you won’t find them in other places; you know what we always say, the bees don’t read the same books as us! Swarming is the bees’ natural method of reproduction and involves the queen leaving her colony which means she must be replaced hence the need for swarm cells.
Queen cell types
Swarm cells are numerous, mostly hanging from the bottom edges of the combs. They contain larvae of different ages meaning the cell sizes can also be different.
When a colony reproduces itself by swarming, the established queen leaves the colony with a proportion of its existing population. This leaves the colony queenless but with the ability to raise a new queen in the form of these multiple (between ten and forty) queen cells.
At the time swarm cells are present, a careful inspection by the beekeeper will reveal numerous frames of capped brood with a reduced number of uncapped brood cells reflecting the recent reduction in laying of the established queen as she prepares to swarm.
When the time comes to swarm, larvae within the queen cells will be at different stages of development. Some cells will be fully sealed, other cells may be drawn down but not yet capped and some will be little more than queen cups. In stronger colonies, this variation in the developmental stages of the queens may give rise to the colony issuing secondary (or cast) swarms as the queens emerge over time.
Supersedure cells are also planned. They too will start out as queen cups (which look a bit like the cap of an acorn). The presence of queen cups in a colony does not necessarily mean the bees are planning to swarm or supersede; colonies build a number of queen cups as a matter of course and the cups don’t become cells until they contain an egg and royal jelly.
Supersedure cells are fewer in number than swarm cells and usually contain larvae of a similar age therefore the cells tend to be approximately the same size. However, visual examination of the cells is not enough to determine whether they are swarm or supersedure cells; the time of year and the state of the colony may be a better indication of whether the bees intend to swarm or supersede. *
• Are you looking at a very strong colony in spring? Then, more likely the bees are preparing to swarm. Is it a weaker colony, perhaps with patchy brood later in the year? More likely, it’s a supersedure situation.
In a supersedure situation, the colony is not usually as crowded as it would be prior to swarming. An injured queen or one suffering from disease or failing in some other way will present a scattered or sparse brood pattern or drone larvae may appear in worker cells.
Supersedure cells appear outside the normal swarm season, usually in autumn and drones are retained in the colony longer than they would normally be permitted. When the first queen of the small batch of cells emerges, she immediately destroys the remaining queen cells and perhaps the old queen. However, mother and daughter queen may live together for sometime until the the old queen dies naturally. We call this perfect supersedure.
Supersedure does not usually trigger swarming because conditions in the colony are not suitable however long periods of bad weather in swarm season may cause the colony to re queen by supersedure.
There are many reasons why an old or inferior queen may be superseded. She may have been poorly mated or her egg-laying is defective, possibly from poor nutrition. She may have been injured by wing clipping or when transferred from a queen cage or by fighting between virgins. Often a colony infected with nosema supersedes it queen. Age or physiological problems may cause her to produce insufficient queen pheromone. Sometimes an introduced queen (bought or raised at home) is quickly superseded; this is more likely to happen when the introduced queen is a different race or strain.
Emergency cells are not planned. As their name suggests, they are built in response to an emergency such as the loss of the queen through accident or disease. By ‘accident’ we usually mean being squashed or dropped by the beekeeper but it’s not always that!
Emergency cells are developed from an egg already laid in a worker cell or very early-stage female larvae and are therefore found on the face of the comb within a patch of worker brood. There will usually be between one and three emergency cells which will have been raised from very young larvae (no more than two to three days old). The drawn cell often protrudes slightly at the top where it has been adapted from a horizontal worker cell into one which is vertical.
Due to the emergency nature of these queens, there is a delay in the feeding of royal jelly which often results in the queen being developmentally, somewhere between a queen and a worker. These so called ‘scrub’ queens are themselves rapidly superseded.
A queen emerging from a swarm cell replaces a queen which has departed with a swarm. A queen emerging from a supersedure cell replaces an old or failing queen and a queen emerging from an emergency cell replaces a queen which has been lost.
Swarm and supersedure cells are developed from queen cups and tend to be found at the bottom edge of the comb. Swarm cells are found in the spring/early summer and are usually numerous and of varying sizes whereas supersedure cells are found later in the season and are fewer in number and tend to be more uniform in size.
Emergency cells are constructed on the face of the comb from adapted worker cells. There will usually be one to three of them angled out from the comb face.
When identifying the type of cell you are looking at, you must also take into account factors such as the time of year and colony conditions. If you discover supersedure or emergency cells, close the hive and leave well alone for at least four weeks. Swarm cells can be used to make splits or you can thin down the numbers to preserve the existing colony.