[BONUS] Short - Dr. Dewey Caron - Swarming

[Bonus] Short - Dr. Dewey Caron, "Swarming"

[music]

Jeff Ott: Welcome to Beekeeping Today Podcast Shorts, your quick dive into the latest buzz in beekeeping.

Becky Masterman: In 20 minutes or less, we'll bring you one important story, keeping you informed and up to date.

Jeff: No fluff, no fillers, just the news you need.

Becky: Brought to you by Betterbee, your partners in better beekeeping.

[music]

Dr. Dewey Caron: Hi. I am Dr. Dewey Caron. I come to you from Portland, Oregon. I present another audio postcard on communication in my continuing series of once monthly Beekeeping Today Podcast Shorts. The topic this month, in anticipation as colonies expand in spring, is Swarming. For these audio postcards, I've been discussing communication on three levels, bee scientist to beekeeper, beekeeper to bees, and bee to bee. Let's start with bee scientist to beekeeper.

The bee scientists I want to talk about today are the experienced beekeepers in your club. These individuals are now discussing swarming, both individually and collectively, to you and to other club members. Well, I agree that, strictly speaking, these individuals might not be bee scientists. They have a wealth of experience as practicing applied bee biologists. Knowledge of bee biology and skillful application of bee biology is absolutely one of the major factors to beekeeping success. Great bee biologists make great beekeepers.

What are experienced, knowledgeable beekeepers saying about swarming? Almost to a person, bee swarming is one of the big three challenges in successfully keeping bees. However, individual beekeepers might define success. These three challenges: swarming, varroa mite control, and successful overwintering. There are other emerging challenges, of course: bee nutrition, pesticide exposure, especially for commercial beekeepers, finding secure locations for colonies, and I would add, continuing challenges of bee diseases and pests.

The scientific literature on swarming is extensive, but not recent. I recommend a 2014 paper by Grozinger, Richards, and Mattila, from Apidologie, entitled, From Molecules to Societies: Mechanisms RegulatingSwarming Behavior in Honey Bees. We will list this as a reference for you to consult. It is behind a firewall, but the website ResearchGate has viewable access. I particularly recommend their figure 1 diagram, an explanation, which discusses the multitude of changes in a colony once the bees begin swarming behaviors. This begins two weeks in advance of actually the exodus of a swarm, plus both non-chemical and chemical signals of swarming colonies.

I also highly recommend the podcast, Honey Bee Obscura by Jim Tew in his regular column at Bee CultureMagazine. He has a two-part series on colony swarm biology and management, and the first part began in the April 2025 issue of Bee Culture. The advice bee biologists impart will include a mixture of proactive and reactive recommendations, though they might not use these exact terms.

Proactive swarm management means re-queening so the spring colony has a young queen, a queen who hasn't been through a heavy colony buildup. They suggest the spring colony has good air and humidity ventilation, sunny location, and room to expand the brood-rearing area, especially for prolific queens. Early supering helps provide room for incoming nectar and apiaries with early nectar flow potential. Managements such as box rotation, frame rearrangements, or checkerboarding frames in the brood area are all proactive management.

There are also general, more intensive managements, for example, using Snelgrove board or Demaree in colonies, with several variations that are also proactive if they are performed before queen cells are started.

The objective of proactive swarm management, sometimes termed preventive swarm management, is two-fold. Management to allow colonies to fully expand, avoiding congestion in the brood area, plus ensuring colonies are headed by quality queens from non-swarming stock that are daily capable of producing enough queen substance for the growing bee population, just to help ensure so that all the bees are aware of their queen and do not start the process of replacing her.

Swarming is more likely where the colony's adult worker age distribution, when it is a misdistribution, initially, for example, older bee-oriented in its composition, and then as the colonies expand, having many younger bees, which then leads to that congestion because they stay in the brood area. Reactive swarm management is needed when, upon frequent, we recommend weekly inspection of the growing colony, developing queen cells are observed.

The easiest way to determine if this might be happening in a colony is to manage the brood area in two boxes. Track the two boxes, tilt the upper one up so you can easily observe the bottom bars of the top box. If the colony is rearing swarm queens, you will observe at least one, usually several, queen cells hanging into the empty area between the boxes. If you manage bees in a single brood box, you need to remove the combs and look for developing queen cells on each frame with brood.

The earlier you are able to detect this change in colony behavior, i.e, this rearing of potential replacement queens, the greater your options for changing a colony's behavior. This means closely looking at cups to see if the queen has laid a fertilized egg in one, more likely more than one, of the vertically-oriented cups. Cells that contain larvae will show cell drawing. Hopefully, you will be able to find the cells before they become capped.

For beekeeper-to-bee communication, let's move to reactive swarm control. Reactive swarm control is really all about beekeepers seeking to communicate the message, "Stop," to their bee colonies. Honeybees know, by a series of behaviors, pheromones, and changes in their social activities, as illustrated and explained by that article by Grozinger, again, From Societies to Molecules, that they now need to up their preparations to swarm.

As beekeepers, we learn what the bees already know, and it's being communicated to the colony's worker population. We're just catching up with the bees that have started several days earlier. Therein lies one of our difficulties in dealing with controlling swarming. Proactive anticipation is experience management compared to reactive catching up. How do we communicate to the colony that we know and to communicate the message, "Stop"?

As experienced beekeepers know, and new beekeepers soon learn, there's no one way to say stop. There are several effective, some less successful, and plenty of suggestions that will not be of much value, or so complicated that only a dedicated beekeeper will attempt to implement them. Some seasons and, of course, some colonies are swarming, which means in those years of colonies, the challenge is on steroids.

Our management options come down basically to separating either the queen, or the brood, or the bees in a colony-rearing swarm cells during spring buildup of a colony. Use of the Snelgrove board or practicing some variation of the Demaree method are basically separating the queen from brood, and directing the older adult bees to a greatly reduced brood area of queen with two frames of active brood. The rest of the brood frames go above a queen excluder and supers, usually, particularly in Demaree, or above a double screen if you're using a Snelgrove board variation.

If done as proactive management, this management is formed before queen cells are present. Once queen cells are present, all the queen cells are removed from the two frames of brood left in the lowest box with the queen, and either eliminated from all the remaining columns that go above or left, for example, when you use the Snelgrove double screen. The whole stack of boxes becomes two columns once again, and then queens will emerge in the upper brood box, then becomes queen right.

It's basically seeking to force the colony-rearing swarm cells back to the beginning of spring, and then allowing the reorganized colonies to start spring increase all over again. With an older population, a greatly reduced, uncongested brood area, as occurs when they initially begin spring expansion, and a queen that can now produce enough queen pheromone to satisfy the reduced new, and nurse-age worker daughter population in the box below. The foragers, as we know, do not need the same level of pheromone that the younger and nurse-age bees require.

Another method to communicate stop is to create a nucleus colony. Remove the queen and anywhere from one to three brood frames, depending upon how early in the colony increase season, the management is performed. Transfer of more brood frames will make a stronger nuc and a greater reduction in the size of the colony with swarm cells. With the reorganization, change the position of the colonies, placing the nuc at the site of the mother colony, the one that has the swarm cells, and moving the mother colony to a new site at least 3 feet away. The oldest foragers will return to the nuc upon return from their foraging flights.

Some recommend making a queenless nuc, adding an adult-mated queen, if you have one, one or more developing queen cells that you found in the mother colony, or allowing the nuc to rear an emergency queen, leaving the mated queen in the mother colony after destroying all the developing queen cells. If this option is elected, the large mother colony needs to be monitored, as it may quickly recommence rearing queens. Queenless nuc, too, needs to be supplemented with nurse bees at establishment and monitored for adequate population size, especially if the nuc, rather than the mother colony, is moved to a different site in the apiary.

Removal of brood via transfer of weaker colonies after developing queen cells are removed and adult bee population shaken from all frames into a new box with foundation frames is another swarm control technique. This is called sometimes shook swarming. You need additional hives to place brood frames. By shaking all the bees, you communicate that swarming has been accomplished. The adult bees have plenty of work to draw the foundation frames like they need to do when they actually swarm and move into a hollow tree cavity or hollow building, so the essence of swarming is accomplished. You have pooled the bees, perhaps.

Finally, bee-to-bee communication. There are numerous messages, chemical pheromone, and behaviors in preparation in a colony that is beginning to do the preparations to swarm. Lack of adequate pheromone or congestion disrupting the distribution of pheromone results in queens seeking queen cups so they may lay their fertilized eggs. Workers begin holding more honey stomach contents as a pre-preparation behavior to leaving. The vertical cell orientation of queen cells versus horizontal for worker and drones, a very powerful message.

The chemicals from a developing queen larvae are all power signals. We lack good information on what might be the signals for bees to actually swarm, that is, in their exodus from their mother colony. We have better information on the sounds of behaviors for clustered swarms to leave bivouac sites, that is where the swarm goes initial in clusters, to move to a new home site. The bee-to-bee signals of the swarm bivouac have been elegantly described by Tom Seeley in several articles and summarized in Chapters 4 through 6 in his book Piping Hot Bees and Boisterous Buzz-Runners.

There's a relatively small subset of the swarm population, the scout bees, who must reach a consensus with their waggle dancing, used to indicate possible new homes that are visited by the majority of the scouts. They then will then lead the bees using working piping behavior to tell their sisters to warm up their bodies so flight muscles can work to drop off the cluster on the limb or on the side of a building, or wherever they've clustered their bivouac, to get into the air. That is the message to get ready. This is effectively followed by the buzz runners who provide the message, "It is time to leave."

Scout bees excitedly run on top and through the bivouac cluster with excited piping sounds to give it as time to leave safe. Non-scout bees, which, of course, are the majority of the swarm population, are then guided by the scouts in the moving swarming mass of bees to the new home site, if all is going successfully.

Swarming, the bee postcard for this month. I trust you are able to learn what your bees are communicating to you and their colony members about swarming, and you take on the challenge and are able to do something about swarm prevention control, assuming you are ready to accept the challenge and to be proactive in your bee matters. Be well.

[music]

[00:15:03] [END OF AUDIO]