The memory of swarms

I've used this title before, years ago, but it's too good to not use again. For many readers it will be novel, either because they've forgotten {{1}} or because they're new to beekeeping or new to this site.

If either of those last two apply … Welcome!

And, if you do remember when I last used the title, bear with me. The content has changed, even if the title has not.

How has the content changed?

To be honest, I'm not entirely sure.

I'm writing this (on Monday 14^th) during a major outage of the website, so I can't access anything to check. Something serious is kaputski in The Apiarist's data centre.

Either a minion has spilt the double-shot cappuccino I'd requested over the server rack, or the hamsters powering the mainframe are on strike.

Whatever the cause, everything is probably rather fraught in the control room at the moment.

I'm keeping a low profile.

I should add that use of the terms 'data centre', 'server rack', and 'control room' make it sound quite a bit larger, more complicated and expensive than it really is.

'Hamsters' is a lot closer to the mark.

But, to go back to my previous assertion, some content has changed — or is certainly new — as I'm going to provide additional information about trying to help determine why some swarms abscond (a topic introduced last month).

But I'm first going to briefly discuss the memory of swarms, and then provide a bit more detail on collecting and hiving swarms, and what to do with a swarm once you have safely hived it … before it absconds.

Spring colony build up

I did my first full colony inspections last week. We've had a fortnight of great weather, there's abundant willow flowering and the fields of oil seed rape (OSR; canola for US readers) are starting to look more yellow and less green.

Strong colonies are booming. Eight or more frames of brood, and now supered to provide them a bit of space and discourage swarm preparations. Despite the size and strength of these colonies, there are only limited amounts of drone brood, and almost no adult drones, so swarming is probably still 2–4 weeks away.

It's at this time of the season that the differences between strong, average and weak colonies is most marked.

This is where the adage 'it takes bees to make bees' starts to make sense.

Strong colonies contain sufficient bees to keep the developing brood covered and warm. Although the days have been warm and sunny, the nights have been cold, with frequent frosts. Weak colonies, short of bees to cover developing brood are held back significantly by these cold nights, and expand much more slowly.

These weaker colonies will only properly expand with warmer weather and better forage availability, so may not generate much excess from the OSR.

Not only do strong colonies overwinter better, but they build up faster in spring, so are more likely to produce a honey surplus.

And, they're likely to be the first to swarm.

Swarming is a two-stage process

There are exceptions, but swarming is generally a two stage process.

The colony occupying the original nest site swarms, settles nearby and establishes a bivouac, which subsequently relocates to a new nest site.

The bivouac is — tautologically — temporary. It might exist for hours or days, but it usually eventually moves on. It has one well-understood role, and I can think of two others it probably fulfils:

1. using the bivouac as a base, the scout bees survey the neighbourhood, return, and by dancing to recruit other scouts, eventually reaching a quorum decision about the 'best' nest site to relocate to {{2}}. The bivouac is therefore a decision-making entity, dedicated to facilitating dance-based communication about desirable nest sites without the forage-related dances getting in the way {{3}}.
2. the bivouac is clustered around the queen that swarmed. If, for whatever reason, the queen is impaired, the bivouac cannot form. Since the eventual survival of the colony, in part, depends upon getting the queen to a new location this is a form of 'quality control'.
3. it acts as a staging post that helps partition the flying bees from the hive. When a colony swarms, more leave the nest than cluster in the swarm. Some leave, presumably in all the excitement, and then return to their original hive.

The first is the well-understood role (after all, there are books on it), the second seems like common sense, and the last is a bit of a guesstimate on my part.

If the colony just swarmed (without bivouacking and partitioning) then some of the bees that 'left in all the excitement' might never get back to the original nest site, so leaving its population depleted.

Since swarming is honey bee reproduction, there's no point in doing it if the original colony is put at an unnecessary risk of not surviving (particularly when the survival of the swarm itself is no better than 25%).

Amnesia

Bivouacked swarms exhibit amnesia.

You can drop them into a box, and then dump the contents of the box into an empty hive in the same apiary as the one they came from, and they'll typically stay put.

A few swarms abscond within hours — I'll get to that shortly — but what the bees do not do is drift back to their original hive.

The rule not to move bees more than 3 feet, or less than 3 miles, appears not to apply.

Despite the fact that many of the bees in the swarm had already oriented (as recent foragers) to the original site, the act of swarming and bivouacking seems to have erased that location from their memory, and they stay with the swarm.

You can put them in a box adjacent to the swarmed hive, or on the other side of the apiary, or a mile away, and the swarm stays together {{4}}.

Collecting swarms

Bivouacked swarms are easy to collect.

At least, they are if they're (safely) reachable.

Whatever the location, the general principle is that if you get the queen into a receptacle, the rest of the bees will join her.

Since the queen is buried in the middle of the cluster, this usually means you need to get as many of the bees into the container as possible, in the hope that the queen is one of them.

The receptacle can be anything suitable; a skep, a large poly nuc with an integral floor, or a cardboard box. You may also need a large sheet, secateurs, a smoker, and a water mister. During the swarm season, it's worth carrying these with you when visiting the apiary out and about … the 'swarm kit'.

I use modified Paynes poly nucs. They're big enough for most swarms, light enough to handle up a ladder, have no moving parts, and I don't need to decant the bees into another box once I've transported them to the apiary.

What's not to like?

Capturing the bivouacked swarm 'simply' involves dropping it into the box, leaving it somewhere in the shade or semi-shade (Not in full sun … I've known large swarms overheat and die after collection when left in full sun; you can move them several feet from their bivouacked location to suitable shade) for any flying bees to join the queen, then — early that evening — wrap it in the sheet and take it to the apiary for hiving.

However, it's rarely quite that simple.

Ingenuity and insurance

More typically, the bees are completely out of reach, or smeared for yards up a lamp post, or buried deep within a bramble patch, or attached to something delicate, valuable or horribly public.

All I can suggest is:

• use your ingenuity
• take care

In my limited experience, the trickier they are to capture, the less likely the afternoon will end satisfactorily 😞.

Likewise, the more spectacular, daring or risky the attempt, the lower the chances of success.

A large bivouacked swarm hanging at chest height from a fruit tree in an orchard is well worth the effort expended in hiving it.

Your chances of success are about as good as they can be.

In contrast, one 15–20 metres up a gnarly old oak tree, in a field containing an excitable bull with an extensive bed of nettles underneath, is best avoided.

And, if the attempted recovery involves distracting the bull and simultaneously throwing a rope over the branch to shake them into strategically positioned open hive … don't bother.

Been there, done that … and failed {{5}}.

Two final tips, as nearly every scenario is different:

1. if it's a warm day there's a good chance the swarm may depart before you're ready to drop it into the box. Since the bees need to warm their flying muscles before take off, you can mist the swarm with water, which cools it down, and buys you a bit of time.
2. check your insurance … it generally does not cover 'reckless acts', so ask the owner to move his Bentley convertible (or excitable bull) before wobbling about up a ladder while trying to capture a swarm.

Thousands of swarms are lost every season. One more isn't a disaster, and is certainly preferable to risking life and limb.

Good luck!

Hiving a swarm

I discussed walking a swarm into a hive a few weeks ago.

The jokes about spotting the queen were old then, they're even older now.

If I don't use an 8–frame Payne's nuc box, I just shake them into a new hive. I remove some frames from the centre of the brood box, shake them out of the skep/cardboard box into the gap, gently add the additional frames and close the hive up.

If you want to 'go the extra mile' you can add an empty super to the hive, using it as a funnel and preventing bees from falling to the ground around the edge of the hive. Then gently smoke across the top of the hive, remove the super and close them up.

It's easier to collect them in a modified 8–frame nuc box … 😉.

I rarely feed swarms, and only do so in the case of a lengthy period of poor weather after hiving the swarm. Whatever the weather, don't feed them for at least three days. You want the honey carried by the swarm (25% by weight of the swarm is honey) to be used for building comb, rather than stored and used for brood rearing. This strategy should help reduce transmitting foulbrood infections.

Remember that swarm amnesia is temporary.

Once the flying bees reorientate to their new location the '3–feet/3–miles' rule applies again. If I hive them one evening, I'd be happy to shift them to a nearby (i.e. less than 3 miles away) apiary the following morning. However, after 36 hours of good weather I'd expect to lose some flying bees that had already fixated on the site where I'd hived them.

There's some interesting research on the differences between primary orientation flights (by new foragers) and ones made when the bees have been moved after swarming … something for another post, as I'm running out of space (Degen et al., 2018).

Swarms and Varroa

Swarms may carry significant levels of Varroa if the originating colony was heavily infested. This is because the swarm population is biased towards younger bees with which phoretic mites more frequently associate.

But the solution is easy, if you act promptly.

Swarms have no brood and won't have for 8–9 days after being hived (assuming the queen is mated, longer if not). You can therefore treat once with dribbled or vaporised oxalic acid and — in one simple and inexpensive step — slaughter over 90% of the mites, so giving the swarm a great start.

Do not procrastinate.

Oxalic acid is a natural product, is very well tolerated by the bees, leaves no residues in the wax, and massacres mites.

You have a window of opportunity of about a week … grab it 😄.

I treat all swarms, whether hived by me or arriving in a bait hive, within a day or two of getting them. I don't care whether the queen is mated and laying, or a virgin that has yet to mate. Treat in the evening (so avoiding any issues with queen orientation or mating flights) and you'll be doing your new bees a huge favour.

Slide a Varroa tray underneath the swarm-containing hive, you will be astounded/horrified at the mite levels some swarms turn up with.

Absconding

Some swarms abscond.

You hive them, and in the following hours or days, they disappear for pastures new.

I've speculated this might be because the scout bees had already 'decided' on a new nest site, but — before they could relocate — the beekeeper captured them.

If that's right, the rate at which swarms abscond should be inversely related to the distance between the bivouac and where they were eventually hived. For example, they would be more likely to abscond if re-hived in the original apiary than 5 miles down the road.

But I don't think that anyone has ever tested this, or that any one person could test it.

Swarms abscond relatively rarely, so an individual beekeeper might take years to hive sufficient swarms to get some meaningful numbers of distance vs. absconding.

But together, the readers of this site might be able to determine whether swarms are more likely to abscond if they're only moved short distances from the bivouac site.

If I'm right it would mean that advice when hiving a swarm could include 'move it at least X km to prevent absconding'.

That would save beekeepers who have risked being gored by bulls, or covered in nettle rash, or falling on Bentley's, from the disappointment of finding their riskily-captured and carefully-hived swarm … gone.

Of course, I might be wrong. I wouldn't be surprised. But, if I am, it's still useful information. Far better to know what absconding is probably not related to than not having a clue.

The swarm form

I've created a 'swarm form' to collect some basic data on swarm collection and absconding. The only information I'm interested in is:

• date
• latitude of the site the swarm was collected
• distance the swarm was moved from collection to where it was hived
• whether the swarm absconded and, if so, by when
• any relevant comments

The data is collected anonymously. The data will not be used for anything other than the analysis of swarming and absconding. There are no GDPR implications and completing the form is taken as consent that you understand the purpose of the survey and are content for your responses to be used.

The latitude and date allows me to 'follow' the wave of swarm activity as it moves north during the spring and early summer. Barnstaple and Folkestone are about the same latitude, but 360 km apart; knowing the latitude is no help in defining a location.

The distance and latitude are easily measured from a map; see below.

The information will be automagically collated in a spreadsheet and, assuming there are enough submissions, discussed in a post this autumn or winter.

You need to be subscribed to The Apiarist to access the 'swarm form'. This, like the need to be subscribed to comment on posts, is to safeguard against spam or bot submissions. Subscription is free. You do not have to be a paying sponsor to access the form.

If your beekeeping association operates a swarm line for the public to report swarms I'd be delighted if the swarm coordinator could provide multiple responses, one for each swarm hived. If so, please add a comment such as 'on behalf of Basingstoke & District BKA' or whatever {{6}}.

I'll apply an arbitrary cut-off of two weeks after hiving to consider absconding as scout bee-related. The justification is simple; a) about 75% of scout bees will have perished within a fortnight, b) you should have checked them by then and know whether they stayed put, and c) they should have started rearing brood (so are far less likely to abscond).

Honey bees are globally distributed. If you collect swarms in New York or Newfoundland, in New South Wales or New Zealand, feel free to make a submission {{7}}.

How to record data

I'm interested in all bivouacked swarms captured, whether they abscond or not, that way I can get an idea of the proportion that abscond.

I'm not interested in any swarms that arrive, self-propelled, in your bait hive, or that you were given/bought/inherited (or stole?) from an unknown location. In these, the scout bees have either already implemented their choice of new sites, or the location is going to be uninformative.

I'm UK based, so will use UK format dates (dd/mm/yyyy), but I'm a Europhile, so please record distances in kilometres (km).

Latitude can be defined in a variety of ways, but I'll use decimal degrees north (or south) for convenience as that's what Google Maps usually returns.

Both the latitude and distance information are easy to get using from Google Maps. I have included instructions on the 'swarm form', but show it here as a short video.

To access the swarm form, remember that you may need to subscribe and/or sign in. There's advice on signing in on the FAQ.

In closing

A swarm of bees is a fantastic sight.

Best of all are the swarms you see arriving in your bait hives, though I still marvel at the sight of a swarm I lose as it flies off into the afternoon sun.

Swarms that abscond are frustrating.

You've probably gone to a lot of effort to get them from the bivouac to the hive (those high in gnarly oaks protected by nettles and excitable bulls are disappointingly frequent when compared with those appearing chest-high in a well-grazed orchard) so it's annoying when they aren't appropriately grateful and disappear again.

If we understood why swarms abscond we might be able to do something about it.

I'm sure they abscond for plenty of reasons other than the scout bees leading them away. However, the hypothesis I've suggested is simple, is based upon our understanding of scout bee activity and swarm relocation, and it can be readily tested.

If swarms abscond less frequently when moved longer distances from the bivouac site, then the solution is straightforward. No need for queen excluders, or frames of brood, just hive them a few miles away from where they were bivouacked.

I've simplified the data collection to the bare minimum. If there is an inverse relationship between absconding and hiving distance we can run the survey again with some more focused questions.

Do swarms usually bivouac again when absconding? When, after hiving, are swarms most likely to abscond? Is absconding related to disturbance (e.g. inspecting too soon) or miticide treatment?

But all that can wait for another time.

Good luck collecting swarms

Notes

It wasn't a hamster taking industrial action, or a cappuccino spillage … the server went down because the Kubernetes cluster was rate-limited to only 3,600 requests an hour.

Obviously 😉.

No, I've no idea what that means either, and I've even less of an idea about how to fix it. Fortunately, The Apiarist is excellently hosted on MagicPages and Jannis did know what it meant and how to fix it. And so he did, but it wasn't easy. Thanks Jannis 👍.

Apologies if you were affected by the outage. I'm buying a couple of new hamsters and oiling their wheel 'just in case'.

References

Degen, J., Hovestadt, T., Storms, M., and Menzel, R. (2018) Exploratory behavior of re-orienting foragers differs from other flight patterns of honeybees. PLOS ONE 13: e0202171 https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0202171.

Robinson, G.E., and Dyer, F.C. (1993) Plasticity of spatial memory in honey bees: reorientation following colony fission. Animal Behaviour 46: 311–320 https://www.sciencedirect.com/science/article/pii/S0003347283711929.

{{1}}: As I had. It wasn't until I did a web search for the title that I rediscovered its first appearance.

{{2}}: And, if you don't know this story, I'd strongly recommend reading Thomas Seeley's Honeybee Democracy.

{{3}}: The foragers in a bivouacked swarm (temporarily) do not forage.

{{4}}: Or 10 miles away, but then they'd have no knowledge of the area and so could not return anyway.

{{5}}: More than once actually.

{{6}}: Assuming you're from Basingstoke & District BKA 😉.

{{7}}: Readers in the Southern Hemisphere might have to wait a few months.