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George Imirie's PINK PAGES
March 2003

How Much Do You Really Know About Swarming?

Note: The following article about Swarming was written by me for the American Beekeeping Federation Newsletter to appear soon, but we have so many new beeHAVER members and some forgetful beeKEEPER members in the Montgomery County Beekeepers Association, I thought it would be valuable to all members to read it, STUDY it, and ABSORB it!

How Much Do You Really Know About Swarming?
George W. Imirie - Certified EAS Master Beekeeper

During my 70 years of beekeeping, I have heard hundreds of reasons given for WHY bees swarm, the conditions causing swarms, systems to prevent swarming, how to catch a swarm; and the GREAT MAJORITY of these statements are just plain WRONG! As a scientist, I fail to understand how many of these stories ever got started, much less believed. There is little question that swarming can dramatically negate your honey crop, so I think it is vital that you know a GREAT DEAL of the true facts about swarming.

Swarming is a perfectly natural act for honey bees, and is done for two distinctly different reasons: 1) to increase the population of honey bees all over the livable space on the globe, and 2) for bees to spread out away from home to new territory and hence, find a new source of drones for the mating of any futuristic new queen which will help prevent "in breeding" and "open the door" to diverse genetic characteristics. Prior to the 20th century, the lack of sound knowledge by beekeepers about swarming forced them to keep 3 or 4 colonies of bees in order to get some quantity of honey from the 1 or 2 colonies that did NOT swarm that season; and this resulted in the average yield of a colony was only 15-30 pounds of honey each year. One of the main goals of 20th century bee scientists and professional apiculturists was to determine the primary reasons for swarming, and formulate colony management techniques to either prevent or greatly diminish the tendency of bees to swarm, resulting in increased honey production

Changing the established procedures of the times concerning swarming and scientifically researching the possible reasons for swarming as well as the management techniques to prevent or retard swarming moved forward slowly, but continually, during the past 100 years so that it is now possible for to prevent a colony from swarming so that it can produce 100 pounds, or more, of honey each year. The following points have been scientifically proven, and are firmly established: (You should know and thoroughly understand all 6 points!)

  1. There is a definite SWARM SEASON for all apis mellifera; which is defined as that period in the spring when brood rearing is at its peak and the brood area of the colony is a hubbub of congestion, confusion, and crowding. In most geographic areas, the swarm season occurs just before a major nectar flow.
  2. Some races of honey bees, notably the Carniolan race, have a higher propensity to swarm than other races; and the SAME can be said regarding the different stocks or strains of a race dependent upon the genetic selection of the queen breeder of that stock. This higher propensity to swarm may not be a problem for a skilled beekeeper, but can be a major problem for an UNINFORMED or novice apiarist.
  3. The NUMBER ONE reason for swarming is over crowding or congestion in the BROOD CHAMBER. Note that I did NOT say anything about the supers which is a totally different problem! Congestion in the supers is explained in Point #5.
  4. The Number Two reason for swarming is the presence of a queen bee that is over 9 months old! In addition to the queen's task of laying eggs, it is her job to produce the queen pheromone (queen substance, also called 'queen odor') which acts as a "glue" to seal all of her 40,000-60,000 progeny together as one single functioning unit. One of the many functions of the queen pheromone is that it inhibits the construction of queen cells by the worker bees, thereby removing any desire to swarm. Research has clearly proven that the queen's production of this queen pheromone DIMINISHES a little bit every day from the day she was mated, and hence, the older she becomes results in the lesser number of bees that she can control. Bees rarely swarm when headed by a queen that is less than a year old, primarily because she is capable of producing enough queen pheromone to distribute it widely so it contacts every bee in her colony.
  5. It is NOT natural for bees to swarm during a nectar flow, because they would leave the very thing, nectar that makes honey, that they are working so hard to collect to provide for colony survival in the coming winter! However, there must be enough super space on the colony to store this thin watery nectar until the bees can evaporate its water content and ripen it into thick honey. Although the water content of nectar is highly variable, it can be as high as 80% water, whereas honey is only 16%-18% water, so theoretically, 2, 3, or even 4 supers might be required to store the nectar that will only make one super of honey! Hence, if adequate super space is not available when the bees need it and since idleness or loafing are unknown in the genetic makeup of the honey bee, they will swarm during a nectar flow. This is totally 100% BEEKEEPER'S FAULT!
  6. Many beekeepers (really beeHAVERS) have concluded that swarming is a "sudden happening", or that there were few or no warning signs to the beekeeper, and swarming is just one of those "unfortunate problems" of beekeeping. None of these conclusions have any meaning or truth in them. When the BROOD CHAMBER becomes congested with too much brood, too many young nurse bees, not enough laying space for the queen, no cell space for pollen and nectar, and the older foraging bees are "fighting their way through the crowd" to get to and from the front entrance, THIS IS BROOD CHAMBER CONGESTION, and the bees initiate their swarming program! They just can't swarm "on the spot", but take 7-12 days of preparation before the swarm issues. Queen cells have to be built (5 or 10 or even 20), the queen has to lay a worker egg in each, the nurse bees have to produce lavish amounts of royal jelly to provide excess food for these gluttonous larvae that are to be converted from worker bees into virgin queen bees, the bees have to stop or reduce the feeding of the old queen so she can reduce enough weight that she can fly with the swarm, scouts must be sent out looking for a new home for the swarm, and the normal work of foraging for pollen and nectar is partially given up while most of the bees just "sit around the hive" waiting for the signal to swarm. This is the swarming program in SWARM SEASON before a major nectar flow!

When a nectar flow comes about, bees give up all thoughts of swarming and concentrate on nectar collection. If the beekeeper has NOT provided enough super space, the bees will try to make storage space by building burr comb in every nook and cranny of the hive including the frame tops, and finally stop the queen from laying eggs by filling empty brood cells with nectar. At that point, even during the nectar flow, they start swarm preparations because the beekeeper was too lazy or not smart enough to provide adequate super space at the correct time. 7-10 days later, the bees SWARM, and this was not caused by the weather, dumb bees, a stupid queen, or any other reason except it was 100% BEEKEEPER'S FAULT because of lack of super space when needed!

In bygone years, there were 3 techniques universally used in attempts to prevent swarming, and they often failed and were labor intensive. Briefly they were to cut out all queen cells every 7 days during swarm season, clip a queen's wings so she could not fly, and use the very labor intensive Demaree method of swarm prevention. When one resorts to cutting out queen cells every 7 days, not only is that a lot of work, but you only have to MISS cutting out ONE queen cell, and you lose a swarm, or suppose you just can't do it every 7 days, so you decide to do it in 10 days or 12 days, and you lose a swarm. Although it is true that bees will not swarm WITHOUT a queen, if you have a clipped wing queen, the bees will return to the colony when the queen can't join them and they will try to swarm again in a couple of days. However, a virgin queen has just emerged, so the bees kill the old queen, and swarm with the new virgin queen and leave your colony queenLESS. Further, in any case, the bees have been preparing to swarm for 7-12 days and during that time they were NOT collecting much nectar for you to make honey because they were busy making swarm preparations. Pray tell, what are the new techniques that prevent or at least diminish swarming that are used today?

Perhaps the most important technique is REVERSING the BROOD boxes. Note that I did NOT say anything about SUPER boxes! Regardless of whether you use 2 deep boxes or 3 medium boxes for brood chambers, queens do NOT like "going downhill", and after laying in all the empty space in the top brood box, she either stops laying or prepares for swarming rather than go DOWN to an empty lower brood box to lay eggs. YOU simply REVERSE the position of the boxes. by removing the empty lower brood box and place it on top of the highest brood box, so the queen now has empty laying space above her. This should be started in late winter or very early spring, about 75 days before a good nectar flow commences; and depending on whether you are using 2 or 3 brood boxes, the fecundity of your queen, initial bee population, and other variables, you might have to reverse 2, 3, or even 4 times during these 75 days. There is a danger in REVERSING, and that is splitting the brood (i.e., one group of brood left in the TOP of a frame while there is another group of brood left in the BOTTOM of a different frame. I STRONGLY suggest you read my old PINK PAGES or the Hive & Honey Bee about HOW TO REVERSE.)

Of course, this may not prevent swarming if your queen bee is over 9 months old! (In order that nothing screws up my honey production in April and May in Maryland, I requeen every colony in late August in my apiary, so my queens are very young in the ensuing spring). Today, the great majority of commercial beekeepers (and many have no other income except honey production) requeen every colony every year, and some migratory beekeepers even requeen TWICE each year. When I asked many of them WHY? Their response was to "prevent swarming" Spending $15 on a new queen to save a honey crop of 100-150 pounds that sells for $3.50 per pound is a pretty good gamble!

Supers are of no value if they are in your garage or in your basement! Bees may need additional space in the BROOD CHAMBER area, so install one super without any queen excluder under it about 15-30 days prior to the start of a major nectar flow. If the bees need space, they will either store new nectar collected here or move nectar or honey up out of the brood chamber area in to this super in order to give the queen plenty of laying space. Just before the nectar flow starts, or if this first super is at least half full, make sure the queen is down in the brood chamber area, insert a queen excluder (it is NOT a honey excluder) between the brood chambers and the super, and then add 4 more supers ALL AT THE SAME TIME on top of the partially filled super. Use ONLY frames of DRAWN COMB! YOU CAN NOT INSTALL MORE THAN ONE SUPER OF FOUNDATION AT ANY GIVEN TIME If you do not have any frames or enough frames of drawn comb, look up one of my old PINK PAGES at that is entitled "Foundation is NOT drawn comb", and this will describe exactly how to properly install supers of foundation to be made into drawn comb Remember my saying: Drawn comb is a beekeeper's most valuable possession!

I am sure that you are aware of how difficult it is to stop some people from smoking, drinking to much alcoholic drinks, or cease using drugs. There is a great similarity about these human problems and the problem of honey bee swarming. After bees set their program on swarming and perform some of the PRE-swarm steps, it is extremely difficult to stop this colony from swarming unless drastic measures are quickly used, like dividing the colony into 2 parts, removing the queen, or removing all brood, and even then, these drastic measures may not work. Very often, these drastic measures to prevent swarming CANNOT WAIT UNTIL TOMORROW OR THE WEEKEND, BUT MUST BE DONE IMMEDIATELY to be successful!. Things you can look for that may provide you a clue of how close your bees are to swarming are: construction of fresh queen cells should give you some warning, a larvae floating in royal jelly in a queen cell means the swarm program is just a week or less from swarm issuance, a fully CAPPED queen cell implies that the swarm will occur within the next 24-48 hours if the weather is nice. It has been said that "Bees have a one-track mind", and if they have made swarm preparations, it is very difficult to re-orient their thinking to some mundane task like nectar collecting. Prior to suffering strokes, I had over 100 colonies, and by using the procedures that I have outlined above, I rarely had more than 3-4 swarms each year.

George Imirie
Certified EAS Master Beekeeper