A little about how much honey you might lose if your bees swarm, and some ways to prevent swarming or reduce the honey lost.
Greetings friends, and welcome to this episode of The Walrus and the honey bee, a podcast based mostly on the blog by Steve Donohoe of the same name. Steve is a UK based bee farmer who has written two books: Interviews with Beekeepers and Healthy Bees, Heavy Hives. My name is Imogen, and I help Steve out by doing these podcasts, so that he can hide away while I bask in the spotlight.
In this episode, we are investigating how much swarming hurts your honey crop. There are many reasons why you might want to prevent swarming, but losing honey is a pretty big one. So, grab a beverage and settle down. Here goes.
There are plenty of bad things to say about losing swarms from honey production colonies, but I’m particularly interested in the big one – loss of honey crop. Many people cheer themselves up after losing swarms by reflecting on how a brood break will benefit the bees, and how it’s a wonderful natural phenomenon, and so forth. Well, you can keep your ‘swarm positivity’ – I’m not falling for it. As far as I’m concerned, it’s a BAD THING. But how bad? To what extent does swarming hurt your honey crop?
The answer, of course, is the one that applies to nearly every beekeeping question, and that is: “It depends.” I am soon to be the eager recipient of several hive scales made by Wolf Waagen in Germany. Should I lose swarms from the hives sat on scales, I might be able to get a good assessment of lost honey. Some people don’t even notice that they have lost a swarm, but with a hive scale that is impossible. However, the real reason for trying out this particular hive monitoring solution is to find out for myself whether it is a good idea. And, perhaps more pertinently, do the benefits justify the cost? Oh, and so that I can write a review for a magazine.
Trying To Prevent Swarms
My methods for preventing swarms, written about extensively already, can be summarised as follows:
1. Using high-quality, young queens
2. Provision of laying space in the brood box
3. Adding supers early and often
4. Offerings to the Gods, prayer, good luck charms etcetera
The interesting one for me is item 2, providing laying space in the brood box. During April and May in our area, depending upon conditions, we at Walrus Apiaries are very keen on pulling out frames of honey and sealed brood from large colonies, and replacing with foundation or drawn comb. Strong colonies will draw comb in no time, and the new cells will quickly be full of eggs, but drawn comb gives space immediately.
This can seem counter-intuitive, and you have to keep an eye on the weather and the nectar flows in your area. You must also know when a colony is at the right stage for being ‘held back’ by stealing some of its brood. A balance must be struck. Sure, by removing a great slab of beautiful sealed brood, you are slowing down the population growth in the colony, and that could mean lost honey. More bees equals more honey, assuming a flow is on. However, should they get so strong and crowded that they decide to swarm, the honey lost will be far greater.
Lots Of Nukes
As long as there is honey in the supers, I’m not keen on them having more than one frame of it in the brood box. In April and May we find ourselves with a lot of honey and brood combs that we have removed from strong colonies. These go towards making cell builders or nucleus colonies, but that does lead to an ever escalating number of colonies. I have just passed a hundred colonies, excluding mating nukes. Presumably we will hit a point where we don’t want more, but for now, it’s quite a nice problem to have. We can remove old queens from hives at the end of summer and combine with nuclei that have newer queens. Going into winter with strong, healthy colonies, headed by young queens, is a good thing.
Clipping Queens
Oh, and another thing. We always get some swarms in our hives, whatever we do. Maybe we left too long between inspections, or just missed a cell – it happens. This is why clipping the wing of all queens is helpful. After the colony has swarmed, the queen will fall to the ground and be lost, but the bees will return to the hive. When we turn up to inspect, we find queen cells, no eggs, and no queen. We will still lose some honey, most likely, but it won’t be as bad as if the swarm had left and not returned. We either leave one cell, or knock them all down and add a sealed and protected cell from the incubator. Very rarely the queen crawls back home, which is something we saw recently. Having noted that they had swarmed, we left one queen cell. At the next visit the queen was back, the cell was torn down, and no more had been built.
Honey Lost – Calculation
So, to the big question of the day: how much will losing a swarm hurt my honey crop? This is just a theoretical exercise for a bit of fun; as we already know – it depends. We will consider two scenarios; a moderate colony in which 12,000 bees depart in the swarm, and a large colony which loses 25,000 bees.
Honey taken by the bees
We know that the bees gorge on honey before they leave, and I will assume that each takes away 40 milligrams in their honey stomach. For 12,000 bees that amounts to about 0.5 kg, whereas for 25,000 bees it is 1.0 kg. It’s not a lot, but it’s something.
Lost foragers
Only a small minority of the workers who leave in a swarm are seasoned foragers. Studies indicate that the percentage of foragers is around 5%–15%, so let’s call it 10%. Even if there is enough emerging brood to replace the lost foragers, it will take such brood about 21 days to become foragers. So we can say that some honey is lost by the colony being without those lost foragers for 21 days.
Apparently, foragers can carry 60 miiligrams of nectar, and they make an average of 4.6 trips per day. So 60 multiplied by 4.6 equals 276 milligrams of nectar per day, per forager. But only about 37% of this will become honey (the rest is water that will evaporate). Therefore, that comes to about 0.1 grams of honey per forager per day.
Moderate swarm: 12,000 lost bees, of which 10 percent are foragers, loses 2.5 kg of honey over 21 days.
Large swarm: 25,000 lost bees equates to 5.25 kg of lost honey over 21 days.
Brood break
Once the queen has disappeared with the swarm, there will be no eggs laid until they have made a new one, and she has been mated. That brood break will lead to a period of time when no foragers are being produced. Assuming that the new virgin queen emerges 8 days after the swarm, and that she is mated and laying within another 12 days, we will have lost 20 days of brood production, but it will be 40 days before that new brood becomes foragers. During the period that no new foragers are coming online (apart from existing young bees) – the existing forager force will gradually reduce as they die off.
I think it’s reasonable to assume that you lose about half of the foragers during the period of the brood break and the time it takes the new workers to become new foragers. But how much honey you lose will depend on whether there is a flow on at that time; if it’s in the “June gap” it might actually be beneficial to have fewer bees.
The amount of honey lost due to the brood break really is a big “it depends”. I’m going to pluck these randomly out of the ether:
Moderate colony: 7 kilograms
Large colony: 10 kilograms
It could be double those figures in a honey flow. In a dearth, the loss could be zero, or even negative.
Total honey lost by swarming
Bringing it all together, in this example we have:
Moderate colony: 0.5 kilograms taken in the bees' stomachs plus 2.5 kilograms due to the lost foragers plus 7 kilograms due to the brood break equals 10 kilograms of lost honey.
Large one: Similarly the larger swarm results in 16.25 kilograms of lost honey
Last season my average honey crop per colony was 38 kilograms, so losing a swarm represents a good chunk of that colony’s production (about a third). Apparently, the average UK beekeeper makes about 15 kilograms of honey per colony, so the swarm would pretty well wipe out the honey production of that hive.
Reducing The Brood Break
Even with queen clipping, the brood break element of honey loss still applies, sadly. By destroying all cells and introducing a queen cell that is about to emerge (from queen rearing activities) you might reduce the brood break a little, and successfully introducing a mated queen would speed things up further, but the bees will often kill her.
You would need to ensure that they are hopelessly queenless before releasing a mated queen into a swarmed colony, which would be about a week after swarming. However, it occasionally happens that the bees will let the new queen lay some eggs, kill her, then make more cells from her eggs, which seems crazy. The way to avoid that, according to Manley, is to wait until day 18 after swarming before introducing the mated queen. But if that’s the case, a queen cell that’s about to emerge might be better, depending on the weather (for mating).
Lose Swarms, Lose Honey
It comes down to this: if your bees swarm, you will almost certainly lose some honey, and possibly the majority of your crop from that hive. Giving the bees plenty of space (laying space in the brood box and plenty of supers above), holding back some colonies by removing a frame of sealed brood, and using young queens, are ways to put the bees off swarming and preserve the crop. Note for beginners: a box of undrawn combs slapped above a brood box is often not considered ‘space’ by the colony. The first super on should be drawn comb, extracted last season.
Other swarm prevention manoeuvres like the Demaree can work well too, if you like that sort of thing. Remember, that is something you do BEFORE there are queen cells in your colony. Once cells have begun to be built, I take the queen away in a nuke, and leave just one cell, ideally not a sealed one, so that you can see it contains a larva. The way this season has started, I reckon I’ll be doing a lot of that.
Okay, that's the end of this piece written by Steve. I hope you learned something, or found it interesting. If you did, please share this with other beekeepers. Thanks, and have a great week.