“How can I prevent swarming?” is a common question. An equally common answer is, “Give the bees more space so they are not crowded.” From this we get, “Crowding causes swarming.” Let’s look at that a little more closely.
In his book Honeybee Democracy, Thomas Seeley writes, “To this day, no one knows what specific stimuli the worker bees are sensing and integrating when they make the critical decision to start the swarming process.” To me, that statement makes a whole lot more sense than, “crowding causes swarming.”
Swarming correlates with crowding
Seeley admits that several things correlate with swarming, including “congestion of the adult bees, numerous immature bees, and expanding food reserves.” But causation and correlation are two different things. We don’t know if crowding causes swarming or if swarming causes crowding or if there is a third factor that causes both. All we know is that these conditions often occur at roughly the same time.
I can say for a fact that a colony will often release a secondary or tertiary swarm shortly after the first. The colony at that point has lost perhaps 2/3 of the adult population, so it is no longer overcrowded. Still, the swarms leave anyway. Swarming is complex, and the reasons for things are not at all obvious.
Experimenting with bees
Now, since there is a correlation between crowding and swarming, it makes sense to experiment with crowding to see if we can prevent swarming by alleviating the crowded conditions. What some beekeepers have found is they can delay or sometimes prevent swarming by opening up honey barriers that have been built above the brood nest. There is nothing wrong with trying these methods, even though we can’t say exactly why they sometimes work.
However, these machinations, such as spreading the brood nest or checkerboarding above the brood nest, need to be performed in advance of the colony’s decision to swarm. Once the colony has made the decision, there is little a beekeeper can do—short of splitting—to stop the progression. Like an avalanche tumbling down the mountainside, once it starts it just keeps going.
So if you want to prevent swarming using one or more of the “foolproof” methods that have surfaced over the years, you must be proactive. You cannot wait until bees begin flowing from the hive entrance to drop a super on the hive.
Unfortunately, this is the point when I usually hear from beekeepers. “I thought my bees were going to swarm so I gave them an extra super and they swarmed anyway.” Or worse, “My mentor said my bees were going to swarm, so he added a super and they swarmed anyway.” Mentor? If the bees have already decided to swarm, you can add 17 supers and it won’t change a thing.
Swarming is a process
So when do the bees decide to swarm? Well, it’s hard to say. But the first thing you might notice is the construction of swarm cells, or perhaps backfilling of the brood nest with nectar. Once the queen cups are begun and an egg laid, it takes approximately 16 days for a mature virgin to emerge. That tells you that the decision to swarm must come at least two weeks before the event.
During that time, a lot of changes are made in the colony. Queen rearing goes full throttle. Egg laying by the queen is reduced, and the queen is made skinny so she can fly. Also during this time, the workers’ wax glands are gearing up for production, the workers stuff themselves with honey, and the whole lot of them become lethargic—often hanging around the hive entrance waiting for the signal to leave. In addition, scouts may start looking for real estate.
Too little, too late
With all the preparation that takes place within the colony, and all the physiological changes occurring within the bees themselves, you can see that dropping a super on your hive will make little impression on them. They are simply not going to say, “Oh look, more space! Let’s call this off.” Nope. Not on your life.
The take-home message is clear. There is nothing wrong with playing with your bees and trying to prevent them from swarming. We’ve all done it. But if you’re serious about it, you need to start before they start. Have a plan. Know what you’re trying to do, and don’t be surprised if they end up swarming anyway.
Honey Bee Suite