Honeybee queen supersedure is a recurring and inexhaustible topic for discussion among beekeepers. It is something we will all experience at some point in our beekeeping adventures. At the same time, supersedure is something that we seem to know remarkable little about. In this article I will try to shed some light on queen supersedure and what causes it. Let us start by looking at what our beekeeping textbooks say about supersedure…

Literature about queen supersedure

The phenomenon of supersedure is always referenced in beekeeping textbooks. However, it seldom gets more attention than a short paragraph, a footnote, or a few brief token mentions. From them we learn that supersedure is the natural process of queen replacement in a honeybee colony without swarming. The emphasis, where one is given, is on supersedure as a means of replacing an old or spent queen. Or as a means of replacing a queen that is failing or defective.

In these books, we also come across the term supersedure in relation to different types of queen cells. We are encouraged to learn to tell the difference between swarm cells, emergency cells and supersedure cells. It is mentioned that supersedure cells are often few in numbers, about 1-3. And that they are built on the face of the comb, along the top or nestled in at the sides. We also learn that the supersedure queen cells are usually very similar in age. This means that the resulting queens will emerge at about the same time.

Some books will elaborate further and explain that queens can get as old as three to five years. They are then being superseded when their pheromones start to wane. Or they could be running out of sperm to fertilize their eggs. Yet other literature will describe that during supersedure, the old queen will often keep laying while the new queen is developing and mating. They may also state that it is sometimes possible to find both the old queen and the new queen in the colony for some time after the new queen has started laying. It is occasionally also added that supersedure queens often make excellent queens. And that is it as far as supersedure is concerned. Largely.

Information on the internet

If you roam the internet looking for more information, you will find much of the same. However, it is often a little more fleshed out. You will come across a lot of videos and photographs showing supersedure cells. And also, photos and videos of two queens, side by side, on a frame of brood. It does not take long to realise that there is remarkably little material available for anyone who wishes to explore this intriguing subject. But why is this?

Scarcity of scientific data about queen supersedure

The dearth of information is by and large a reflection of the scarcity of scientific data that exists about it. I hasten to add that it is not like this for the lack of trying. We can manipulate hives to induce both swarming and queenlessness. This, in turn, triggers the development of emergency queen cells. However, researchers find it difficult to induce supersedure. When you think about it, it makes perfect sense. Supersedure is a process that belongs to the bees. They set it in motion and they execute it, and neither beekeeper nor scientist can do much to start the natural process of supersedure.

If researchers cannot provoke supersedure in a colony, then measuring responses within the colony become difficult. It then also becomes difficult to repeat experiments and compare results. Hence, when we attempt to understand what is causing supersedure and what are the triggers and processes involved, we are forced to balance whatever scant scientific data, anecdotal evidence and experience available with a few measures of hearsay, opinions, qualified and unqualified guesses, and speculations.

Are queen failures on the rise?

Putting aside this lack of empirical evidence, supersedure is nonetheless an important issue. It is also an issue that affects many bees and beekeepers. According to numerous experienced beekeepers, even more so now than twenty or thirty years ago. Some are reporting a marked increase in queen failure or queen problems relating to young, newly mated queens that are superseded already in their first or second year. This can be both perplexing and frustrating for the breeders, and lead to a scarcity of quality mated queens available for beginners and other beekeepers.

Supersedure may be the natural response within a honeybee colony to deal with an old queen or a queen that is getting close to depleting her spermatheca and becoming a drone layer. However, many beekeepers feel that it is not natural or normal for a high number of young, seemingly healthy, laying queens, to be superseded (what we consider to be) prematurely. It is becoming so frequent that those of us who have taken up beekeeping in the last few years may be excused for getting the impression that this is indeed normal colony behaviour. I am afraid I do not hold the ultimate answer as to why this is happening. Although I suspect the reason is not one single issue, but a myriad of factors affecting the viability of our queens. None the less, queen failure is a real and growing concern for hobby beekeepers and bee breeders alike.

Why are queens superseded?

Supersedure queens are raised by a colony in order to replace the existing queen. This can be done for several different reasons:

Depleting or depleted spermatheca

The queen could be old and running out of sperm. If the queen runs out of sperm to fertilize her eggs, she becomes uncapable of laying female eggs. This means that there is no chance of any of her offspring turning into either queens or worker bees and she becomes a drone laying queen. Because drones, or male bees, are made from unfertilized eggs, she can still keep laying until she runs out of eggs, but the colony is doomed. Hence, the bees will try to supersede a queen with a depleting spermatheca while she still has sperm left to produce female eggs.

Running out of eggs

The queen could also become superseded if she is running out of eggs.

Disease or physical damage

The queen can also be affected by disease such as nosema or have physical damage to her body. Such as a missing leg or wing, which drives the bees to want to replace her. (Missing legs can cause a queen to not walk around the hive a lot. This leads to a smaller brood area and less footprint pheromone being spread around the hive. A missing or damaged front leg can negatively affect her ability to measure the cell size, which she does in advance of deciding to lay a fertilized or unfertilized egg in it. This in turn could lead to an imbalance of worker-drones within the hive.)

Poorly bred queen

If the bees are trying to supersede a queen, she could be a poorly bred queen that was allowed to develop from an older larva rather than a younger larva. This could be as a result of natural queen development within the colony or through the beekeeper grafting from older larvae or selecting a queen cell that the bees themselves made from an older larva.

Diminishing or poor dissemination of queen pheromone

If the queen is old, her pheromones could be starting to diminish causing the bees to want to replace her. She could be not very old, still carrying plenty of sperm but for some reason not producing or spreading enough pheromones to satisfy her workers. In a large colony, a perfectly well functioning queen, at least in the eyes of the beekeeper, could be superseded because her pheromones are not spread adequately throughout the hive due to the sheer size of the colony.

Slow egg laying

If the queen is young but newly introduced to the colony, her egg laying could be slow at the start. Especially if she was not laying for some time (i.e. if she was transported) or introduced from a small mating nuc. This could cause the bees to want to replace her in favour of a more productive queen. Older queens whose rate of laying in slowing down are also prone to supersedure.

What factors trigger the supersedure process?

There is not much known about what triggers the start of the supersedure process. Most believe it is a gradual change within the hive which culminates in the bees deciding to build supersedure cells. One thing is clear, and that is that the queen substance, or pheromones, play a vital role. A pheromone is a chemical substance that affects the behaviour or physiology of other animals belonging to the same species as the animal that produces it.

Queen pheromone

Honeybee queens produce a pheromone consisting mainly of 9 oxydecenoic acid and 9 hydroxydecenoic acid. This queen substance (or Queen Mandibular Pheromone to use the correct scientific term) is disseminated throughout the colony via trophallaxis. Here, a worker that has licked the queen will pass the pheromone on to another bee. This bee in turn will pass it on to another one, and so on. Eventually spreading the queen pheromone to all the bees in a colony. This will alert the bees to the fact that the colony is queen right and the bees will carry on with their usual duties. When there is no or insufficient queen pheromone disseminated within the hive, the bees will sense it and take action to remedy. In some instances, this means that they will initiate the process of supersedure.

The queen substance has several different functions. It influences social behaviour and mating behaviour. It also inhibits the building of queen cells and the maturation of the ovaries in worker bees. The queen also gives off what is called a footprint pheromone or trail pheromone. This pheromone is spread on the comb by the queen’s feet as she moves around the hive. It is believed that this pheromone also inhibits the construction of queen cells.

What happens in two-queen colonies?

A young queen will produce more queen substance than an old queen. When the queen’s production of pheromone decreases or ceases, or the distribution of pheromone throughout the hive is lessened due to for instance the colony being very large. The inhibitor is thereby removed, and the workers may create queen cells to start a process of supersedure.

The old queen will often stay in the hive for some time after the new queen has started laying. This is of course useful for the colony in case the new queen fails to mate successfully. After the supersedure has taken place, the old queen dies (it is uncertain how). Prolific queens will often empty their spermatheca quicker than non-prolific queens such as the European dark bee, Apis mellifera mellifera, and thus be superseded earlier than their non-prolific counterparts.

Timing of supersedure

Supersedure can take place any time in the active season. However, it will often occur after the main flow in late summer or early autumn. The queen has been busy laying all summer and may be running low on sperm. The bees will want a new queen in place to head up the colony for the following season. Hence, they initiate supersedure. Supersedure at this point of the year is usually not problematic. There will still be plenty of drones for the new queen to mate with. The only thing the beekeeper needs to be aware of is that if conditions are right and the colony is strong, the bees can decide to swarm on supersedure cells.

It is well worth the trouble to, in late summer and autumn, keep checking colonies that have not attempted to swarm during the summer. If you find supersedure cells, you can either leave them all in place or select one, depending on your inclination and colony status.

Late autumn supersedure

Attempts at supersedure sometimes also take place later in autumn where mating conditions are more precarious. Late in the season, there may not be many drones available for a new queen to mate with. The weather may also not be conducive to mating. This means that new queens may be either poorly mated (low amount of sperm, low number of drones or inbreeding) or not mated at all. It should be stated of course, that not all late supersedures are unsuccessful. Some, in fact turn out very well indeed.

Early spring supersedure

Early spring supersedure is also relatively common and faces the same problems in relation to drones and weather, but the success rates are probably not as high. In the case of spring supersedure, the bees will try to replace a queen that has come through the winter. However, she may be failing to get her egg laying rate up to the speed required of her, which triggers the supersedure. The supersedure will fail if it happens too early, and queen fails to mate. They may make several attempts at supersedure. The old queen will be running out of eggs, and the colony appears to be dwindling. The best way to deal with colonies like this can be to remove the queen and unite with another queen right colony. Early signs that there may be a supersedure afoot is earlier than usual production of drones in a small or dwindling colony.

Problematic supersedures

Queen supersedure can be plain sailing. But sometimes it is not. The more problematic supersedures are those that we struggle either to understand, or to deal with. First is the supersedure of a newly introduced queen, perhaps bought for good money and intended as a breeder. Second is the sudden supersedure within a newly captured swarm. And third is the supersedure of a queen that only recently started laying.

Maybe the most frustrating of all problematic supersedures, is the one that does not happen! Where a queen keeps occupying the same few frames all summer long. The colony does not seem to thrive, it does not grow and does not produce honey. It just seems to plod along without any notion of attempting to replace the old queen. The question as to why the bees do not replace a queen that ought to be replaced may be just as important as the one asking why they are replacing a queen that does not need to be replaced. 

The supersedure of newly introduced queens

The supersedure of newly introduced queens is an occurrence that is quite common. It is very frustrating, and also quite easy to remedy. It is believed that supersedure in these cases is linked to the queen’s inability to quickly lay a lot of eggs. Mated queens that are introduced have often been caged for several days. Hence, they have not been laying eggs for that time. It will take some time after she is accepted into the colony to get her egg laying up to speed. During this time, and especially in a large colony, supersedure may commence.

There would be a number of factors at play here. These include unsatisfactory rate of laying, poor dissemination of queen substance and also reduced footprint pheromone as the queen may not travel around the hive as much looking for space to lay. Open brood as well as queen pheromones all serve to suppress the building of queen cells. When all or any of these factors are missing, the bees may well attempt to replace the new queen, regardless of her potential. This scenario can also be true for queens introduced from smaller mating nucs straight into large colonies.

To prevent this from happening, it is advised to introduce the queen to a nuc first and let her establish her egg laying. You can then either introduce her into the colony or join the nuc and colony together for a hassle-free introduction. It is a bit more work than letting the queen walk in the front door, but it is worth it if it means that the new queen can remain in place for longer.

Supersedure of laying swarm queens

Supersedure of laying swarm queens is another one of those disappointing events that many of us will have experienced. It is not unusual to capture a swarm that arrives seemingly complete with a laying queen. Our hope is that the queen may be one of last year’s queens. Full of sperm and pheromones left to last another season at least. But this is not always the case. The queen in question could be a laying queen (unclipped or poorly clipped) that left in a prime swarm. She may have what it takes to motor on for another year or two before being superseded. But she may also be an ageing queen that left the hive when her workers decided to supersede her.

The queen now has a smaller colony to head. Hence, it is possible that she will produce enough pheromones to suppress the development of new supersedure cells for some time. However, as the colony grows and her pheromones diminish, she may soon be superseded. There is not much that can be done about this. Just to check in on your newly captured swarms and keep track of their development. If there is a supersedure afoot, you may want to leave the bees replace the old queen. You can then keep the stock as a way of increasing the genetic diversity of your bees. The colony may, however, get a little light on bees because of the break in brood rearing. If this happens, you can help them along by adding frames of capped brood from another colony.

Premature supersedure of a young queen

The most problematic of all problematic supersedures is the supersedure of a newly mated queen. Perhaps this is so, because we simply cannot understand what is happening, or why. For those of you who have not experienced it, here is what typically happens. A late spring or early summer queen, seemingly well mated and laying a good brood pattern in a healthy colony is superseded within a few weeks or months of starting to lay. This happens without any indication of anything being wrong with the queen or the colony. It is something that is experienced in many countries and both beekeeping experts and scientists are looking at this and trying to figure out what is going on. It is largely accepted that the reasons may be multifactorial, resulting in an array of different queen problems.

Possible reasons for early supersedure

Here are some of the issues that are thought to result in queen problems which may trigger early supersedure:

• Low quality queens. Queens made from larvae that is too old make inferior queens that are more worker like in their physiology. Younger larvae make better queens and are given the right food at the early stages, which will provide for better development and lead to better queens.
• Low quality queens mate with significantly fewer drones.
• Inbreeding, or lack of genetic diversity.
• The effects of hard chemicals being used as varroacides. Their residue causing a build-up of chemicals in the wax leading to reproductive defects in both queens and drones.
• Low sperm viability.
• Disease, viruses, and pesticides
• Nosema causing high levels of supersedure.
• The application of fungicides, pesticides, herbicides, and other chemicals outside the hives. How they may affect the colony as a whole and their potential of interfering with the many pheromones found in honeybee colonies that regulate all that happens in the colony.

The effects of broodless periods due to supersedure

The effects on a colony of having two brood less periods in one season cannot be understated. One brood less period is beneficial for the bees as a way of dealing with varroa. This is because it provides a break in the reproductive cycle of the mite itself. If the broodless period occurs during a flow, it can also mean that the bees bring in more honey. This is a result of the out of work nurse bees turning into foragers prematurely.

However, a second brood less period at the end of the summer or autumn can be detrimental for the development of winter bees. As a result, it could negatively affect the colony’s chances of surviving the winter. The beekeeper needs to be vigilant and check the development of newly mated queens. It may also be a good idea to produce a few extra queens each year. These can be used to replace the ones that are being superseded, or those that fail to mate.

Until we know what the causes of premature supersedure are and how to prevent it, all we can do is practice good husbandry.

• Replace the wax in the brood nest frequently.
• Test regularly for disease.
• Make sure not to cull drones unnecessarily
• Endeavour to keep good records so that you may be able to discern any patterns that you may otherwise not see.

Further reading

For anyone interested in exploring the literature about supersedure and the thoughts of many expert beekeepers, you will find a nice introduction to the subject in a piece by Mary Montaut, former editor of An Beachaire, The Irish Beekeeper, Supersedure and its Controversies, available from www.dublinbees.com/supersedure-and-its-controversies/

Thank you for reading, I hope you found the article interesting and informative. Please share any views and comments below and don’t forget to check out my other beekeeping blogs! / Hanna

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Hanna Bäckmo

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