Category Archives: Beekeeping

If it quacks like a duck …

Quack

… it might be a trapped virgin queen.

I discussed the audio monitoring of colonies and swarm prediction last week. Whilst interesting, I remain unconvinced that it is going to be a useful way to predict swarming. 

And, more importantly, that replacing the manual aspects of hive inspections is desirable. I’m sure it will appeal to hands off beekeepers, though I’m not sure that’s what beekeeping is about.

However there was a second component to what was a long and convoluted publication 1 which I found much more interesting.

Listening in

If you remember, the researchers fitted hives with sensitive accelerometers and recorded the sounds within the hive for two years. Of about 25 colonies monitored, half swarmed during this period, generating 11 prime swarms and 19 casts.

In addition to the background sounds of the hive, with changes in frequency and volume depending upon activity, some colonies produced a series of very un-bee-like toots and quacks.

Have a listen …

The audio starts with tooting, the quacking starts around 8-9s, and there’s overlapping tooting and quacking from near the 21s mark.

Queen communication

I’ve previously introduced the concept of pheromone-based communication within the hive. For example, the mated queen produces the queen mandibular and queen footprint pheromones, the concentrations of which influence the preparation and development of new queen cells.

Tooting and quacking is another form of queen communication, this time by virgin queens in the colony.

It’s not unusual to hear some of these sounds during normal hive inspections, but only during the swarming season and only when the colony is in the process of requeening.

If you rear queens, and in my experience particularly if you use mini-mating nucs, you will regularly hear “queen piping” – another term for the tooting sound – a day or so after placing a mature charged queen cell into the small colony.

But we’re getting ahead of ourselves. 

How does the queen make these sounds?

Queen piping or tooting

Queen tooting has been observed. The queen presses her thorax tight down against the comb and vibrates her strong thoracic wing muscles. Her wings remain closed. The comb acts as a sounding board, amplifying the sound in the hive (and presumably transmitting the vibrations through the comb as well).

This doesn’t happen just anywhere … the virgin queen is usually near the cell she has recently emerged from. 

And this swarm cell is usually on the periphery of a frame.

This is because the laying queen only rarely ventures to the edges of frames, so the concentration of her footprint pheromone is lower in this area, eventually resulting in queen cells being produced there

In their study, accelerometers embedded in the periphery of comb were able to detect much stronger tooting and quacking signals, supporting the conclusions of Grooters (1987) 2 who had first published studies on the location of piping queens.

Queen tooting and quacking

Queen piping is usually recorded at around 400 Hz and consists of one or more 1 second long pulses, followed by a number of much shorter pulses. In previous studies the frequency of tooting had been shown to be age-related. It starts at ~350 Hz and rises in frequency to around 500 Hz as the virgin queen matures over several days.

Compare the image above with the audio file linked further up the post. The tooting is followed by an extended period of quacking, and then both sounds occur at the same time.

Going quackers

The duck-like quacking is presumably also made by queens vibrating their flight muscles while pressed up against the comb.

I say ‘presumably’ as I don’t think it has been observed, as opposed to heard.

The reason for this is straightforward, the queens that are quacking are still within the closed queen cell.

Quacking is a lower frequency sound (is this because of the confines of the queen cell, the way the sound is produced, or the ‘maturity’ of the queen’s musculature?) but has also been shown to increase in frequency – from ~200 Hz to ~350 Hz – the longer the queen remains within the cell.

Afterswarms = casts

Before discussing the timing of tooting and quacking we need to quickly revisit the process of swarming. I’ve covered some of this before when discussing the practicalities of swarm control, so will be brief.

  1. Having “decided” to swarm the colony produces swarm cells. Usually several.
  2. Weather permitting, the prime swarm headed by the original laying queen leaves the hive, on or around the day that the first of the maturing queen cells is capped.
  3. Seven days after the cell was capped the first of the newly developed virgin queens emerges. 
  4. If the colony is strong, this virgin also swarms (a cast swarm). Some texts, including the publication being discussed, call these afterswarms.
  5. Over the following hours or days, successively smaller cast swarms may leave the hive, each headed by a newly emerged virgin queen.

Not all colonies produce multiple cast swarms, but initially strong colonies often do.

From a beekeeping point of view this is bad news™. It can leave the remnants of the original colony too weak to survive and potentially litters the neighbourhood with grapefruit, orange and satsuma-sized cast swarms. 

Irritating 🙁

Whether it’s good for the bees depends upon the likelihood of casts surviving. The very fact that evolution has generated this behaviour suggests it can be beneficial. I might return to this point at the end of the post.

Tooting timing

The Grooters paper referred to earlier is probably the definitive study of queen tooting or piping. The recent Ramsey publication appears to largely confirm the earlier results 3, but has some additional insights on colony disturbance during inspections 4.

Here is the acoustic trace of an undisturbed colony producing a prime swarm and two casts.

Timing of tooting and quaking in a swarming colony

I’ve added some visible labels to the image above indicating the occurrence of tooting and quacking in an undisturbed naturally swarming colony.

  • The prime swarm exited the hive on the afternoon of the 13th. No tooting had been recorded before that date.
  • On the 17th tooting starts and increases in frequency over the next two days.
  • Quacking starts 6 hours after the tooting starts.
  • The first cast swarm (afterswarm) exits the hive on the 19th and is followed by a three hour break in tooting.
  • Tooting and quacking then continue until the second cast swarm on the afternoon of the 21st.

So, in summary, tooting starts after the prime swarm leaves and stops temporarily when the first cast leaves the hive. Quacking starts after the tooting starts and then continues until the last swarm leaves the hive.

Why all the tooting and quacking?

The timing of queen tooting is consistent with it being made by a virgin queen that has emerged from the cell. The cessation of tooting upon swarming (the first afterswarm) suggests that the virgin left with the swarm. The restarting of tooting a few hours later suggests a new virgin queen has been released from another cell and is announcing her presence to the colony.

In previous studies, Grooters had shown that replaying the tooting sound to mature virgin queens actively chewing their way out of a queen cell delayed their emergence by several hours. This delay allowed the attendant workers to reseal the cell and obstruct her emergence for several days.

These timings and the behaviour(s) they are associated with suggest they are a colony-level communication strategy to reduce competition between queens. 

The newly emerged virgin queen toots (pipes) to inform the workers that there is ‘free’ queen in the colony. The workers respond by holding back emergence of other mature queens. 

If all (or several) of the virgin queens emerged and ran around the hive simultaneously they would effectively be ‘competing’ for the hive resources needed for successful swarming i.e. the workers. 

By controlling and coordinating a succession of queen emergence, a strong colony has the opportunity to generate one, two or more cast swarms whilst sufficient workers remain in the hive. It presumably helps ensure the casts are of a sufficient size to give them the best chance of survival.

At what point does this succession stop or break down? One possibility is that this happens when there are insufficient workers to prevent additional virgin queens from emerging.

Unanswered questions

Why do mature virgin queens within the cell quack? It is clearly a response to tooting, rather than being standard behaviour of a soon-to-emerge queen. 

Hear! Hear the pipes are calling, Loudly and proudly calling (from Scotland the Brave)

Is the quacking to attract workers to help reseal the cell?

I suspect not. At least, I suspect there is a more pressing need to attract the workers. After all, wouldn’t it be easier for the queen to simply stop chewing her way out for a few hours? 

Isn’t there a risk that a quacking cell-bound queen might attract the virgin queen running around ‘up top’ who might attempt to slaughter her captive half-sister? 

Possibly, so perhaps the workers that are attracted to the quacking cell also protect the cell, preventing the loose virgin queen from damaging the yet-to-emerge queens.

This would make sense … if the virgin leaves with a cast, the workers that will remain must be sure that there will be a queen available to head the colony

And finally, back to the tooting. I also wonder if this has additional roles in colony communication. For example, what other responses does it induce in the workers? 

Does the increasing frequency of tooting inform the workers that the virgin is maturing and that they should ready themselves for swarming? Perhaps tooting above a certain frequency induces workers to gorge themselves with honey to ensure the swarm has sufficient stores?

In support of this last suggestion, studies conducted almost half a century ago by Simpson and Greenwood 5 concluded that a 650 Hz artificial piping sound induced swarming in colonies containing a single mobile (i.e. free) virgin queen.

Casts

The apparently self-destructive swarming where a colony generates a series of smaller and smaller casts seems to be a daft choice from an evolutionary point of view.

Several studies, in particular from Thomas Seeley, have shown that swarming is a risky business for a colony … and that the majority of the risk is borne by the swarm, not the parental colony. 

87% of swarmed colonies will rear a new queen and successfully overwinter, but only 25% of swarms survive. And the latter figure must only get smaller as the size of the swarms decrease. 

One possibility is that under entirely natural conditions a colony will not undergo this type of self-destructive swarming. Perhaps it is a consequence of the strength of colonies beekeepers favour for good nectar collection or pollination?

Alternatively, perhaps it reflects the way we manage our colonies. Ramsey and colleagues also record tooting and quacking from colonies disturbed during hive inspections. In at least one of these their interpretation was that there were multiple queens ‘free’ in the hive simultaneously, presumably because workers had failed to restrict the emergence of at least one virgin queen.

So, perhaps hive inspections that (inadvertently) result in the release of multiple virgin queens are the colonies that subsequently slice’n’dice themselves to oblivion by producing lots of casts.

I can only remember one colony of mine doing this … and it started days after the previous inspection, but that doesn’t mean the disturbance I created during the inspection wasn’t the cause.

I’d be interested to know of your experience or thoughts.


Colophon

The title of this post is derived from the Duck Test:

If it looks like a duck, swims like a duck, and quacks like a duck, then it probably is a duck.

This probably dates back to the end of the 19th Century. It’s a form of abductive 6 reasoning or logical inference. It starts with an observation or set of observations and then seeks to find the simplest and most likely conclusion from those observations. In comparison to deductive reasoning, logical inference does not lead to a logically certain conclusion. 

Inevitably, Monty Python stretched the logical inference a little too far in the Witch Logic scene from Monty Python and the Holy Grail:

What do you do with witches? Burn them! And what do you burn apart from witches? Wood! So, why do witches burn? ‘cos they’re made of wood? So; how do we tell if she is made of wood? Build a bridge out of ‘er! Ah, but can you not also make bridges out of stone? Oh yeah. Does wood sink in water? No, it floats! It floats! Throw her into the pond! What also floats in water? Bread! Apples! Very small rocks? Cider! Gra-Gravy! Cherries! Mud! Churches? Churches! Lead, Lead. A Duck! Exactly. So, logically… If she weighs the same as a duck, she’s made of wood… and therefore… a witch!

Listening to the bees – swarm prediction

Wouldn’t it be useful to know your colony was preparing to swarm?

With sufficient notice you could take preventative action.  You could conduct an artificial swarm or remove the queen to a nuc. With the major population of the hive now queenless the colony cannot swarm, though you will need to prevent casts by ‘discouraging’ too many virgin queens from emerging.

What is sufficient notice?

Certainly more than minutes or hours. You need to have time to collect the equipment you’ll need, you might need to wait until the rain clears, or you return from a long weekend in Rome (remember those?).

Inevitably, 2300 years ago Aristotle had both identified the problem (Are they about to swarm?) and found a way of answering the question.

When the flight of a swarm is imminent, a monotonous and quite peculiar sound made by all the bees is heard for several days 1.

Several days should be enough surely? The fact that you don’t see beekeepers hunched down by their hives listening intently suggests it’s not an entirely practical solution.

Depending where you live, the swarm season can extend from mid-April until mid-July. That’s a long time to be sat next to a hive with your ear glued to the brood box. 

Some sort of automated system is needed.

Woods’ Apidictor

In the 1960’s Edward Woods developed 2, patented and sold an electronic frequency analyser to “listen” to beehives. It incorporated analogue bandpass filters to screen out the background noise of the hive, focusing on the “monotonous and quite peculiar sound” (to quote Aristotle again) characteristic of a colony making swarm preparations.

Woods Apidictor

Woods sold about 300 Apidictors during the early 60’s. Analysing an individual colony took just minutes. In a 1965 article in Bee Craft Eddie Woods claimed that 60 colonies could be screened in 15 minutes.

In the right hands the Woods Apidictor was also accurate, predicting not only whether a colony was going to swarm, but also the particular stage it was at e.g. sealed queen cells present (presumably held back by bad weather), queenless colonies, superseding colonies, or even drone-laying queens 3.

One of the most impressive [demonstrations of accuracy] occurred when one purchaser complained that the instrument was “over-enthusiastic”. Our representative visited him and checked and predicted that seventeen out of twenty colonies in one apiary contained queen cells, even specifying the stage of development of the cells, a test which required only a few minutes. The manual examination, requiring hours, showed that indeed, the situation was as predicted. The three colonies which the instrument showed no swarm preparations were found to be clear. 4

Despite the fact that Woods only ever sold a limited number of Apidictors, the subsequent 60 years have seen continued interest in – literally – listening to the bees

The internet is littered with commercial and DIY solutions, all in various stages of development. I don’t intend to review them … Google is your friend. Make yourself a cuppa … there are over 2 million hits.

Importantly, the usefulness of this automation depends upon whether sounds in the hive are truly predictive of swarming, and our ability to identify the relevant sound that is predictive.

A monotonous and quite peculiar sound

When using sound as an indicator of swarming activity, false-positives will have us scurrying around performing artificial swarms when unnecessary, and false-negatives will mean the colony swarms.

Not the end of the world, but an irritation certainly.

So, what do we (or, more likely, our Raspberry Pi or Arduino-powered detectors) listen for? What is Aristotle’s “monotonous and quite peculiar sound”?

A recent paper by Martin Bencsik and colleagues addresses this and claims accuracy of greater than 90%, with successful swarming prediction up to 30 days prior to the event 5.

A beehive is a noisy environment. Some of the noises are constant, others vary during the day, or over longer periods. As the colony builds in strength during the early season the noise levels must increase. Similarly, the sound levels in the colony will be different at night than during a bright, sunny day with thousands of foragers working hard.

Late evening in the apiary

Late evening in the apiary

Many beekeepers will be aware of the sound a colony makes at night during a strong nectar flow. The entire hive hums as the workers drive off excess water prior to capping the cells. If you’ve not visited an apiary late on a calm, midsummer evening you should try; the smell of the honeysuckle in the hedgerow mingled with the scent of honey from the hive is a heady combination.

Toots and quacks and buzzes

In addition to the cumulative noises of tens of thousands of bees simply working in the hive, there are the noises individual bees make at certain times. 

Scout bees produce piping noises when doing their buzz runs as they encourage a swarm to leave the hive. Queens, in particular virgin queens, produce a variety of noises including duck-like quacks and piping before, during or after emergence. I’ll return to these in a future post as this paper also includes a lot of information on the timing and relevance of queen piping.

Marked queen surrounded by a retinue of workers.

If it quacks like a duck …

And if all that wasn’t sufficiently complicated there are additional acoustic signals such as the intermittent, but extensively repeated,’whooping‘ noise (and others), which may be similar to the ‘stop signals’ workers direct at dancing foragers advertising less than favourable locations.

All of which means you cannot just stick a microphone at the hive entrance and instantaneously determine whether they’re about to swarm.

In particular, the variable nature of sound over time needs to be taken into account. The steadily increasing background noise of a hive building up through the early spring and summer is probably not significant.

In contrast, a spike in the signal averaged over several hours or days is probably important, but there may also be characteristic sounds that – if present – indicate swarm preparation.

In the Ramsey paper the authors have used two machine learning techniques to analyse the sound from accelerometers (something that measures vibration) inside the hive.

Training data

Woods had identified a 250 Hz signal that he considered characteristic of a colony making swarm preparations. Modulation of this signal, which Woods termed “the warble”, in three test colonies was associated with swarming.

Ramsey and colleagues analysed the full spectrum using highly accurate accelerometers in about 25 hives, sampling continuously at 3 minute intervals, over a two year period. About 50% of these colonies swarmed during this time, generating 11 prime swarms and 19 casts.

This dataset was then analysed to find acoustic features characteristic of hives that did or did not swarm. Essentially the authors trained the algorithms to detect particular acoustic patterns that were – through empirical observation – associated with swarming (or not).

To do this they used two separate approaches:

The instantaneous alarm procedure.

In the first (the instantaneous alarm procedure) they took a one hour reading from the hive and then compared it to the trained data. By computationally analysing discriminant functions (i.e. acoustic features characteristic of swarming or non-swarming hives) they could determine whether the test colony fell within the “swarming” or “non-swarming” category.

In the diagram above they show the application of two discriminant functions, but the actual study used three. 

The second method used a much more complicated sounding three dimensional Fourier transform (conveniently abbreviated to 3DFT). In contrast to the first approach this involved analysis of the acoustic spectra collected over a ten day period.

3DFT sounds more complicated because it is more complicated. A Fourier transform converts a complex mix of signals into its individual components – for example, determining the individual volumes and frequencies (notes) in a musical chord. The diagram for this is a more colourful version of the one shown above, but is unlikely to help understand the process. If you insist you can view the original.

Application

Both methods were similar in that they used sound profiles collected from colonies known to have swarmed (or not) to define patterns characteristic of swarm preparation.

Interestingly, neither appear to show significant differences in the region of the spectrum Woods’ ‘warble’ occupied. 

Having trained the software they went on to analyse colonies in an unknown state in an attempt to predict swarming.

Using the instantaneous analysis 6 15 of 18 colonies that swarmed were correctly predicted, with no false positives in the colonies that did not swarm. Of those that swarmed, the prediction could be made an average of 22 days in advance of the first swarm leaving the colony. 

That sounds like a pretty convincing 90% prediction rate. However, looking at the primary data – all 33 Mb of supplementary figures – it is clear that many of the swarmed colonies produced “swarm-like” signals well after swarming, without repeated swarming. As the authors state “false positives are still triggered occasionally on an hourly basis, and this becomes exacerbated when the time duration of the season under scrutiny is extended to the rest of the summer”

So, it works OK for the first swarm of the year, but after that gives a lot of false positives.

It’s not clear from the figures what the range (or standard deviation) on the “22 day average warning” is. If it’s a range of 20-24 days that could be really useful, if it’s 3-45 days, less so.

Using the 3DFT methodology the authors could predict swarming in ~80% of colonies an average of 10±2 days before the swarm issued. Although this is a lower prediction rate, the clearly tighter time window might be more useful for practical beekeeping.

Again, the 3DFT approach produced signals that indicated swarming was imminent throughout the remainder of the season, often during periods of intense foraging. To exclude these the authors used averaged the night time values (midnight to 5am), rather than day-long assessments.

Take a deep breath

Overall, taking account of the false prediction rate and the false-positive triggering rate (the former being an overall incorrect prediction as to whether a colony will swarm, the second being ‘noise’ in the analysis when the threshold is reached), the authors favour the simpler “instantaneous” measurement method.

However, don’t be misled, this is not like Eddie Woods rocking up with his Apidictor, putting the stethoscope-like microphone on the side of the brood box and saying “take a deep breath”

These colonies are being constantly monitored, with accelerometers embedded in the frames, and the associated wiring dangling out of the brood box.

I have run colonies with embedded hive temperature and humidity monitors 7. The cabling is usually run under the crownboard and down between the frames. Along with 20,000 bees, it’s another thing that gets in the way during weekly inspections. In this paper Ramsey shows that the accelerometers can be fitted to any frame in the hive and still provide valid predictions. This offers the opportunity to perhaps use one of the ‘edge’ frames which would be more convenient than temperature monitors which have to be embedded in the centre of the brood nest.

I’m sure Woods’ Apidictor was not inexpensive in its day 8. This current implementation of in-hive technology, despite the advances in microelectronics and computing, uses accurate and sensitive accelerometers which are also not inexpensive 9. The apiary would need a power supply, computers and a way of transmitting a signal to the beekeeper (who is currently quaffing Barolo in a fancy trattoria anyway).

All of this is achievable.

But is it worth it?

And is it really needed?

Analogue beekeeping

The digital revolution and, most recently, the internet of things (IoT) has made monitoring “stuff” (like beehives, the house temperature, your fridge or coffee machine) inexpensive and relatively straightforward.

With smartphone apps you can be “in when you’re out” and get a warning that your colony is going to swarm … just as you sit down to lunch at Pierluigis.

The internet is littered with commercial and DIY hive monitoring equipment. Most of it is advertised, or at least promoted, as making beekeeping “easier”.

There’s the implication, stated or otherwise, that this type of automation reduces the need to conduct those pesky hive inspections.

But is that desirable? 

What about all the other things you check when inspecting a colony?

Nectar collection … how heavy are the supers? Yes, you can monitor this electronically as well with hive scales. But what about …

  • colony build up – how much space does the queen have to lay?
  • sufficient stores – are they going to starve if it rains for a week?
  • laying pattern of the queen – is she failing, is she a drone layer?
  • signs of disease
  • robbing etc.

I’m enthusiastic about technology but I’m not sure I’m enthusiastic about this technology. 

Beekeeping is in many ways, already ‘easy’. It’s also an intensely practical discipline.

A thorough hive inspection tells you a whole lot more about the colony than its likelihood of swarming.

I’d actually argue that the easiest thing to determine qualitatively is whether a colony is thinking of swarming. All of those other things listed above – and lots that aren’t – are both important and only acquired by standing hunched over the hive.

If your hive monitors discouraged you from checking colonies so often how would be ever learn, or know, these other important things?

Finally, in closing, I reckon I could open a colony in mid-April and – based upon its strength and knowing a little bit about the local nectar flows – predict with 90% confidence whether it will swarm later in the season 😉

What do you think? Are you in favour of automating some aspects of beekeeping? 


 

A June Gap

As far as the beekeeping season is concerned, we’ve had the starter and we’re now waiting for the main course. 

Like restaurants, the size of the ‘starter’ depends upon your location. If you live in an area with lots of oil seed rape (OSR) and other early nectar, the spring honey crop might account for the majority of your annual honey.

If you are in the west, or take your hives to the hills, you might have skipped the starter altogether hoping the heather is the all-you-can-eat buffet of the season.

Lockdown honey

In Fife they appear to be growing less OSR as the farmers have had problems with flea beetle since the neonicotinoid ban was introduced.

Nevertheless, my bees are in range of a couple of fields and – if the weather behaves – usually get a reasonable crop from it. My earlier plans to move hives directly onto the fields, saving the bees a few hundred yards of flying to and fro, was thwarted (like so much else this year) by the pandemic.

The timing of the spring honey harvest is variable, and quite important. You want it to be late enough that the bees have collected what they can and had a chance to ripen it properly so that the water content is below 20% 1.

However, you can’t leave it too late. Fast-granulating OSR honey sets hard in the frames and then cannot be extracted without melting. In addition, there’s often a dearth of nectar in the weeks after the OSR finishes and the bees can end up eating their stores, leaving the beekeeper with nothing 🙁

Judging all that from 150 miles away on the west coast where I’m currently based was a bit tricky. I had to timetable a return visit to also check on queen mating and the build up of all the colonies I’d used the nucleus method of swarm control on.

Ideally all in the same visit.

Blowin’ in the wind

I’d made up the nucs, added supers and last checked my colonies around the 17-19th of May. I finally returned on the 10th of June.

In the intervening period I’d been worried about one of my more exposed apiaries. I’d run out of ratchet straps to hold the hives together and was aware there had been some gales in late May.

Sure enough, when I got to the apiary, there was ample evidence of the gales …

How the mighty fall

The only unsecured hive was completely untouched and the bees were happily working away. However, one of the strapped hives had been toppled and was laying face (i.e. entrance) down. You can see the dent in the fence where it collided on its descent.

If she hadn’t already (and I expect she hadn’t based upon the date of the gales) I suspect the queen struggled to get out and mate from this hive 🙁

Nuked nucs

Two adjacent 8-frame nucs were also sitting lidless in the gentle rain. The lids and the large piece of timber they’d been held down with were on the ground. The perspex crownboards were shattered into dozens of pieces.

These bees were fine.

Both queens were laying and the bees were using the new top entrance (!) for entering and leaving the hive. They were a little subdued and the colonies were less well developed than the other nucs (see below). However, their survival for the best part of three weeks uncovered is a tribute to their resilience.

They were thoroughly confused how to get back into the hive after I replaced the lids 🙂

Slow queen mating

Other than extracting, the primary purpose of this visit was to check the queenright nucs from my swarm control weren’t running out of space, and to check on the progress of queen mating in the original colonies.

Queen mating always takes longer than you expect.

Or than I expect at least.

Poor weather hampered my inspection of all re-queening colonies but, of those I looked at, 50% had new laying queens and the others looked as though they would very soon.

By which I mean the colonies were calm and ‘behaved’ queenright, they were foraging well and the centre of the ‘broodnest’ (or what would be the centre if there was any brood) was being kept clear of nectar and had large patches of polished cells.

Overall it was a bit too soon to be sure everything was OK, but I expect it is.

However, it wasn’t too soon to check the nucs.

Overflowing nucs

In fact, it was almost too late …

With one exception the nucs were near to overflowing with bees and brood.

I favour the Thorne’s Everynuc which has an integral feeder at one end of the box. Once the bees start drawing comb in the feeder they’re running desperately short of space.

Most had started …

Here's one I prepared earlier

Here’s one I prepared earlier

I didn’t photograph any of the nucs, but the photo above (of an overly-full overwintered nuc) shows what I mean; the feeder is on the right.

The nucs had been made up with one frame of predominantly emerging brood, a few more nurse bees, two foundationless frames, a frame of drawn comb and a frame of stores.

They were now all packed with 5 frames of brood and would have started making swarm preparations within a few days if I hadn’t dealt with them.

Good laying pattern from queen in 5 frame nucleus

And the queens had laid beautiful solid sheets of brood (always reasonably easy if the comb is brand new).

Housekeeping and more swarm prevention

The beauty of the nucleus method of swarm control is that you have the older queen ‘in reserve’ should the new queen not get mated, or be of poor quality.

The problem I was faced with was that the new queens weren’t all yet laying (and for those that were it was too soon to determine their quality), but the older queen was in a box they were rapidly outgrowing.

I therefore removed at least three frames of brood 2 from each nuc and used it to boost the re-queening colonies, replacing the brood-filled frames with fresh foundation 3.

The nucs will build up again strongly and the full colonies will benefit from a brood boost to make up for some of the bees lost during requeening. Some of the transferred frames had open brood. These produce pheromones that should hold back the development of laying workers.

Finally, if the requeening colonies actually lack a queen (the weather was poor and I didn’t search very hard in any of them) there should be a few larvae young enough on the transferred frames for them to draw a new queen cell if needed.

I marked the introduced frames so I can check them quickly on my next visit to the apiary.

This frame needs to be replaced … but could be used in a bait hive next year

The additional benefit of moving brood from the nucs to the full colonies is that it gave me an opportunity to remove some old, dark frames from the latter.

Shown above is one of the removed frames. As the colony is broodless 4 and there’s the usual reduction in available nectar in early/mid June, many of the frames in the brood box were largely empty and can easily be replaced with better quality comb.

Everyone’s a winner 😉

Drone laying queen

One of the nucs made in mid/late May had failed. The queen had developed into a drone layer.

Drone laying queen

The laying pattern was focused around the middle of frame indicating it had been laid by a queen. If it had been laying workers the drone brood would be scattered all over the frames.

There was no reasonable or efficient way to save this colony. The queen was removed and I then shook the bees out in front of a row of strong hives.

I was surprised I’d not seen problems with this queen when making up the nucs in May 5. I do know that all the colonies had worker brood because the nucs were all made containing one frame of emerging (worker) brood.

Perhaps the shock of being dumped into a new box stopped her laying fertilised eggs. Probably it was just a coincidence. We’ll ever know …

Extraction

And, in between righting toppled hives, checking for queens, stopping nucs from swarming, moving a dozen hives/nucs, boosting requeening hives and replacing comb … I extracted a very good crop of spring honey.

Luvverrrly

Although I had fewer ‘production’ hives this season than previous years (to reduce my workload during the lockdown) I still managed to get a more than respectable spring harvest. In fact, it was my best spring since moving back to Scotland in 2015.

The crop wasn’t as large as I’d managed previously in Warwickshire, but the season here starts almost a month later.

A fat frame of spring honey

I start my supers with 10 or 11 frames, but once they are drawn I reduce to 9 frames. With a good nectar flow the bees draw out the comb very nicely.

The bees use less wax (many of my frames are also drawn on drone foundation, so even less wax than worker comb 6), it’s easier to uncap and I have fewer frames to extract.

Again … everyone’s a winner 😉

Not the June gap

Quite a few frames contained fresh nectar, so there was clearly a flow of something (other than rain, which seemed to predominate during my visit) going on. These frames are easy to identify as they drip nectar over the floor as you lift them out to uncap 🙁

In some years you find frames with a big central capped region – enough to usefully extract – but containing lots of drippy fresh nectar in the uncapped cells at the edges and shoulders. I’ve heard that some beekeepers do a low speed spin in the extractor to remove the nectar, then uncap and extract the ripe honey.

I generally don’t bother and instead just stick these back in the hive.

If there’s one task more tiresome than extracting it’s cleaning the extractor afterwards. To have to also clean the extractor during extracting (to avoid the high water content nectar from spoiling the honey) is asking too much!

Colonies can starve during a prolonged nectar dearth in June. All of mine were left with some stores in the brood box and with the returned wet supers. That, plus the clear evidence for some nectar being collected, means they should be OK.

National Honey monitoring Scheme

I have apiaries in different parts of Fife. The bees therefore forage in distinct areas and have access to a variety of different nectar sources.

It’s sometimes relatively easy to determine what they’ve been collecting nectar from – if the back of the thorax has a white(ish) stripe on it and it’s late summer they’re hammering the balsam, if they’ve got bags of yellow pollen and the bees are yellow and the fields all around are yellow it’s probably rape.

Mid-April in the apiary ...

Mid-April in a Warwickshire apiary …

But it might not be.

To be certain you need to analyse the pollen.

The old skool way of doing this is by microscopy. Honey – at least the top quality honey produced by local amateur beekeepers 7 – contains lots of pollen. Broadly speaking, the relative proportions of the different pollens – which can usually be distinguished microscopically – tells you the plants the nectar was collected from.

The cutting edge way to achieve the same thing in a fraction of the time (albeit at great expense) is to use so-called next generation sequencing to catalogue all the pollen present in the sample.

Pollen contains nucleic acid and the sequence of the nucleotides in the nucleic acid are uniquely characteristics of particular plant species. You can easily get both qualitative and quantitative data.

And this is exactly what the National Honey Monitoring Scheme is doing.

They use the data to monitor long-term changes in the condition and health of the countryside” but they provide the beekeeper’s involved with the information of pollen types and proportions in their honey.

National Honey Monitoring Scheme samples

Samples must be taken directly from capped comb. It’s a messy business. Fortunately the labelling on the sample bottles is waterproof so everything can be thoroughly rinsed before popping them into the post for future analysis.

I have samples analysed already from last year and will have spring and summer samples from a different apiary this season. I’ll write in the future about what the results look like, together with a more in-depth explanation of the technology used.

When I last checked you could still register to take part and have your own honey analysed.


Notes

Under (re)construction

Lockdown means there have been more visitors than ever to this site, with numbers up at least 75% over this time last year.

This, coupled with the need to upgrade some of the underlying software that keeps this site together, means I’m in the middle of moving to a bigger, faster, better (more expensive 🙁 ) server. I’m beginning to regret the bloat of wordpress over the lean and mean Hugo or Jekyll-type templating systems (and if this means nothing to you then I’m in good company) and may yet switch.

In the meantime, bear with me … there may be some broken links littering a few pages. If it looks and works really badly, clear your browser cache, re-check things and please send me an email using the link at the bottom of the right hand column.

Thank you

 

Does DWV replicate in mites?

Buckle up.

After a gentle tale of bad beekeeping last week 1 I think it’s time for a bit of science.

Does deformed wing virus replicate in Varroa mites?

Varroa destructor – focus stacked image

Actually, do any pathogenic virus of honey bees replicate in mites?

Does it matter?

Not really … in comparison to the 2.1 billion people who don’t have access to safe drinking water 2, it’s unimportant.

But if you’re interested in how viruses are transmitted between bees, or how the virus population evolves, then knowing whether the virus replicates in Varroa is important.

For example, perhaps replication in Varroa amplifies a particular sub-population of virus that are more virulent, or more transmissable?

Or causes bees to drift more, so spreading the virus more widely in the environment?

Behaviour-altering viruses are interesting. There has been recent a report that IAPV 3 changes the social behaviour of honey bees to potentially increase transmission 4.

So, if it does matter …

Why now?

Three things prompted me to write this post now:

  1. A recent paper on Black Queen Cell Virus replicating in Varroa was briefly discussed on the Bee-L mailing list. This paper repeated many of the errors of assumption in the historical literature  on virus replication in Varroa 5.
  2. The experiments done to address this question over the last couple of decades have been either contradictory or uninformative. Or both. Or just not very good 🙁
  3. We have just published a study 6 that specifically addresses whether deformed wing virus can replicate in mites. Inevitably 7 I think it’s the most complete answer to date but, as will become clearer, it raises more questions than it answers and I know we don’t yet understand the full story.

To understand the problem you need to have a little background on both viruses and Varroa. Our paper is on deformed wing virus (DWV) and I’ll almost exclusively be using this as an example. If I use the word ‘virus’ I mean DWV.

However, the generalities of the shortcomings in some of the historical studies and the way we tackled the problem is relevant to any virus of honey bees. In that regard, when I use the word ‘virus’ it could probably mean any virus of honey bees.

Background to viruses

Viruses are obligate intracellular parasites. They can only replicate inside a living cell. The majority of pathogenic viruses of honey bees have a genome composed of single stranded positive sense RNA.

I did remind you to buckle up? … here we go.

All single strand positive sense RNA viruses share a broadly similar replication strategy.

Virus replication – select for full size and legend.

The virus enters the cell and the genome is translated to make proteins. There are essentially two types of proteins made:

  • the structural proteins – these form the new progeny virus particles. They are what package the new virus genomes into particles (thereby protecting it from damage) to infect the next cell, or host.
  • the non-structural proteins – these proteins are the ‘motor’ that makes new virus genomes 8. They do not form part of the virus particle.

After translation the non-structural proteins replicate the virus genome. To do this they first make a single stranded negative-sense template from which they eventually copy hundreds or thousands of more positive-strands.

The positive strands (only) associate with the structural proteins to form new virus particles. These leave the cell and go on to infect another cell, or another bee.

It’s as simple as that 🙂

A few important things to remember:

  • negative strands are never present in the virus particle. Since they would be non-infectious the virus has evolved all sorts of elegant ways of excluding them from the particle.
  • there are lots of positive strands produced from each negative strand. A ratio of 1000:1 or higher is not unusual 9.
  • without the initial production of the non-structural proteins the virus cannot replicate.

Background to Varroa

I’ve discussed Varroa extensively in previous posts. A full description of the life cycle was presented in the post Know your enemy. For lots of juicy background detail please refer back to that post.

As far as this post is concerned the important facts are as follows:

  • Varroa feeds on developing honey bee pupae and, during the (misnamed) phoretic stage of the life cycle, on adult bees.
  • the mite ingests a rich ‘soup’ of cells and proteins from the bee. For a long time it was thought that the mite fed on haemolymph (effectively bee blood), but some currently favour the evidence that Varroa feeds on the fat body of bees. As far as this post goes, it’s irrelevant whether the mite feeds on haemolymph or the fat body 10.
  • when the mite feeds on a virus-infected bee is also ingests the virus.
  • when the mite subsequently feeds on a different bee (for example, to initiate another round of incestuous replication) it transmits some of the virus in its saliva to the new bee.

There, that wasn’t so bad was it?

Evidence for virus replication in Varroa

I’m not going to provide an exhaustive review the extensive literature here. It goes back to the mid-90’s and is pretty dull and rather hard going in places.

There are also lots of papers on DWV replication in bumble bees … does it?

Essentially the evidence for replication of viruses in mites is the presence of virus negative strands in the mite. Time and again this has been presented as “definitive proof” that the virus replicates in Varroa.

Does that seem reasonable?

You already know enough Varroa and virus biology to see the flaw in this conclusion.

Q. What did that mite last feed on?

A. A virus-infected pupa.

Q. And what was therefore present in abundance in that pupa?

A. Negative strands of the virus genome.

Just because viral negative strands are detectable in the mite does not mean that they were produced in the mite when (if?) the virus replicated.

Perhaps they were simply ingested with the soup of proteins and cells that the mite eats?

This is an error based upon a positive result. There is an assumption that the positive result tells you something … but it doesn’t, or at least it might not.

Evidence against virus replication in Varroa

This one is more subtle and – in contrast to the above –  is an error based on a negative result.

It’s always dangerous drawing scientific conclusions from negative results. Perhaps the experiment just didn’t work? Perhaps it wasn’t sensitive enough? This is why lots of controls are needed.

Scientists looked in detail at all of the proteins present in Varroa mites. They used a method called mass spectroscopy that detects tiny fragmented proteins which they identified by comparison with a database of known proteins.

Orbitrap ID-X Tribrid Mass Spectrometer

If one of the tiny fragments matches, there’s a reasonable chance that the entire protein was present. If lots of different tiny fragments match one protein there’s compelling evidence that the entire protein was present in the sample 11.

Using mass spectroscopy scientists detected the structural proteins of deformed wing virus. However, using the same methods, they could not detect the non-structural proteins.

Since the non-structural proteins were ‘absent’ the virus could not have been replicating in the mite as they are a prerequisite for replication.

Seems logical, but is again potentially wrong.

Perhaps the tiny protein fragments of the non-structural proteins of DWV are ‘sticky’ and remain associated with cellular fats and membranes 12 during the purification process?

What about controls? Did the authors demonstrate they could detect the non-structural proteins of a virus that does replicate in Varroa? Was the sensitivity of their assay sufficient to detect the levels of non-structural proteins expected to be present? Did they provide evidence they could detect other similarly low abundance proteins?

No.

Should honey bee viruses replicate in Varroa?

Viruses are obligate intracellular parasites. They depend upon proteins and processes in the cell for their replication. This often means that viruses are restricted to a very narrow range of hosts. Sometimes viruses will only replicate in certain tissues or cell types of a single host species.

Varroa and honey bees are both Arthropods, but belong to different classes (Arachnida and Insecta respectively) within this phylum. They are therefore rather distantly related.

This does not mean that a virus of honey bees cannot replicate in the mite. There are several human viruses that also replicate in the mosquito (Dengue, Yellow Fever, Zika for example) during transmission. However, it’s an interesting philosophical cul-de-sac which is distracting us from the main event.

Genetically engineered deformed wing virus

Keeping up?

Good.

Now we’re getting to the more exciting stuff 13.

For some time now my lab have been able to genetically engineer deformed wing virus. This means we can make changes to the virus that help us do interesting or informative experiments.

For example, Olesya ‘Alex’ Gusachenko in my team built a virus that expresses a protein that turns bees green.

Green bees

This is allowing us to look in detail at the specific tissues the virus replicates in, or at transmission of the virus between bees. I’ll discuss green bees again in the future.

To investigate whether deformed wing virus replicates in Varroa we used a virus that had been engineered to contain a tiny genetic tag. It was equivalent to altering 0.05% of the virus genetic material. This genetic modification had three really important features:

  • it was unique and was not present in any other strains of deformed wing virus
  • although present in the virus genome it did not change any of the characteristics of the virus 14.
  • it was easy to detect. Alex developed an assay that could detect really tiny amounts (probably less than 100 copies) of genomes that contained this modification.

An artificial diet for Varroa

The final thing I need to introduce is how to keep Varroa mites in the laboratory 15. The experts can maintain Varroa in incubators, feeding them on little drops of honey bee haemolymph in what are called feed packets.

We’re not experts. But we know people who are.

We collaborated with our friends Alan Bowman, Ewan Campbell and Craig Christie in Aberdeen University who helped us with the Varroa feed packet part of the experiment.

A mite-infested apiary in Aberdeen with Luke, from my lab, and Craig discussing craft beers.

Critically, Alan’s lab have developed a feed packet system that contains no honey bee material. They can maintain Varroa in the lab without feeding them on mushed up bees. This means we had total control over what our Varroa could eat.

The feed packet contents are a closely guarded secret 16 but will be published soon.

Enough! Enough! Does DWV replicate in mites?

This is how we did the experiment. We grew large amounts of our genetically-tagged virus in honey bee pupae.

We purified the virus and treated it with an enzyme called RNAse.

As described above, the genome of DWV is made from the chemical RNA. RNAse degrades and destroys RNA.

However, viruses are resistant to RNAse because the RNA genome is protected inside the structural protein coat that forms outer layer of the virus particle.

We treated the purified virus preparation with RNAse to remove all RNA that was not inside the virus particles. This contaminating RNA could otherwise compromise the experiment.

Importantly, RNAse degrades both positive and negative strand RNA molecules. Therefore, we could be certain that our virus input into the experiment contained no contaminating negative strand RNA (and confirmed this in several controls).

We then added our virus to the feed packets being used to maintain groups of ten Varroa. After 4 days we harvested the Varroa and extracted all the RNA from them. We also had control mites which were not fed our tagged virus, but were otherwise treated in an identical manner.

All the mites contained very large amount of DWV-specific positive strand RNA. This was unsurprising. Even if our tagged DWV did not replicate in mites they had been feeding on honey bee pupae packed with DWV only four days ago.

We then looked for the presence of negative strand RNA. Again, there were reasonable amounts present, entirely consistent with their previous diet of DWV-infected honey bees. The control mites contained good levels of negative strand RNA.

DWV replicates in Varroa

However, only the mites fed the tagged virus contained a variably weak but consistent signal for the unique genetic tag we had introduced.

We interpret that as very good evidence that DWV does replicate in Varroa.

Is this level of replication significant?

Significant in terms of what?

It’s significant in that this experiment demonstrates for the first time the de novo production of replication intermediates (the negative strand RNA) in mites.

I’m not unbiased ( 🙂 ) but I think this is some of the best evidence supporting DWV replication in Varroa. It also demonstrates the types of experiments that are probably needed to determine whether other honey bee viruses replicate in the mite. The presence of negative strands is not enough. As the figure above shows, at least in the case of DWV, the majority come from the bee pupa the mite last fed on and we have no way to determine whether they are newly replicated or not.

But is the replication significant in terms of the amplification of the virus?

The presence of this signal confirms that there is some replication of DWV in Varroa. The fact that the signal is weak suggests that virus replication is not very extensive or very fast.

For comparison, if we inject the equivalent of 10 DWV virus particles into a honey bee pupa 17 they will be replicate to produce 1,000,000,000 (one billion) viruses within 48 hours. Assuming a conservative ratio of positive to negative strands, these individual pupae would each contain a million copies of negative strand RNA two days after infection.

We have yet to fully quantify specific negative strand levels replicated in Varroa, but it looks a whole lot less than that to me.

These are technically very demanding experiments and will take some time to complete. In the meantime we can and should ask a more relevant question.

Is this replication significant in terms of the biology of the virus?

By ‘biology of the virus’ I mean things like differential amplification of specific variants of the virus in the mite, so changing the virus population. For example, does virus adaptation occur, selecting for DWV variants that are more transmissable by Varroa?

We don’t know yet, but at least we have a system which will allow us to test this.

Although we have additional genetically-tagged variants of DWV we can test in the future, in mixed infections one will only be consistently selected over the others if it has a growth advantage.

We don’t yet know such a growth advantage even exists and there might be better ways to determine if it does. These are not straightforward experiments to undertake.

Based upon the limited replication we see in mites I do not think that the replication is significant in terms of increasing the amount of infectious virus in the mite. In contrast, the very high level of replication in honey bees may well allow the evolution of particular strains with particular characteristics.

Where is the replicating virus in Varroa?

We treated the mite like a simple bag of RNA.

We didn’t determine whether the virus was present in muscle, or brain or the ovaries.

The location of the virus is really important.

If the virus is replicating in a tissue that facilitates transmission to the next bee 18, particularly if certain types of virus are being selected because they grow better there, then it might be significant.

Some tissues allow viruses to be transmitted, others do not.

For example, poliovirus is a very distant cousin of DWV. Poliovirus is transmitted faecal-orally 19 in contaminated water supplies. After ingestion it replicates really well in the small intestine. It then has a short distance to travel (!) until it is excreted again. So, the primary site of poliovirus replication (the gut), is ideal as it ensures an obvious route for transmission.

Actually, poliovirus replicates so well in the gut that in about 0.5% of infected people it escapes from the gut and enters the peripheral nervous system. It then travels to the spinal cord and finally reaches the brain.

Poliovirus replicates pretty well in the brain as well … so well that it destroys some of the grey matter causing paralytic poliomyelitis 20.

But, as far as the virus is concerned, the brain is a dead-end. There’s no way out. Virus that replicates in the brain can never infect another person. How could it get from the brain to a water supply?

What about DWV? Is DWV replicating in tissues that enables transmission to another host?

Replication in the gut, in salivary glands or possibly the ovaries would all be consistent with transmission (with the ovaries as a source for vertical transmission to progeny mites – though they have already fed at the same spot on the pupa so determining this might be difficult). However, if DWV is replicating in mite muscle or brain it may well be irrelevant in terms of honey bee virus biology as there’s no obvious way out of those tissues.

Questions and answers

We attempted to answer a seemingly simple question “Can DWV replicate in mites?

We think the answer is yes.

But, as you can see from the few paragraphs above, that short question and even shorter answer has generated lots more questions.

And some of them are much more difficult to answer than the one we tackled 🙁

Identifying the site(s) of virus replication in Varroa would normally require microdissection of a variety of different tissues. Is the virus present? Is it replicating?

But a virus that expresses a fluorescent green protein during replication should make things a lot more straightforward … but more on that some other time.


Notes

The paper containing this study is available – open access (i.e. free) – the full title and journal details are: Gusachenko et al., (2020) Green Bees: Reverse Genetic Analysis of Deformed Wing Virus Transmission, Replication, and Tropism. Viruses 12: 532.

The million drones fiasco

Accidents happen.

Sometimes they are due to stupidity, sometimes to forgetfulness, or sometimes they are just the result of plain dumb luck.

They’re also often caused or at least exacerbated by ‘local’ factors – like a rainstorm or a cancelled train preventing timely inspections. 

Or a countrywide lockdown necessitated by a global viral pandemic.

With the exception of the cancelled train my excuse for what follows is “all of the above” 😉

Social distancing

Beekeeping, like other activities involving livestock management, has been a permitted activity during lockdown. Beekeepers have been allowed to travel to their apiaries and to move bees for pollination etc

I was away when lockdown was imposed and opted 1 to stay where I was. For the first half of the season I’ve had to forego weekly colony inspections. I’ve not had the pleasure of watching the colonies build up, of queen rearing or of sweating profusely when shifting nectar-filled supers 🙁

Instead all my beekeeping – the first inspection of the season, the swarm prevention and the swarm control – have been squeezed into two visits, each of a few frantically busy days, in late April and mid-May.

And, inevitably, mistakes have been made.

Well, one mistake … that I’m currently aware of.

First inspections and swarm prevention

We’re late starters in Fife.

It’s not unusual to delay the full first inspection until the very end of April in this part of Scotland. A couple of years ago we had knee-high oil seed rape (OSR) ankle deep in snow at the end of April.

There seems little point in disturbing the colony if it’s too cold to have a leisurely look through the brood box. The bees get tetchy, the brood gets chilled and you don’t have time to look for the important things – like disease, or that elusive queen you failed to mark last autumn.

However, this season started well and I should have started colony inspections in the second week of April.

But by that time the world had changed dramatically …

I finally snatched a couple of days around the 25th of April to do the first inspections and swarm prevention all rolled into one … and coupled this with reducing my colony numbers by 50% to make management over the coming months easier 2.

I’ll discuss how I did all this in a couple of full-on days some other time. The end result was about a dozen united colonies, each topped with three supers, containing a good marked laying queen. Many of the colonies were very strong, with up to 15 frames of brood after uniting 3.

The colonies were strong and healthy. All were headed by a laying queen. I saw all but a couple of the queens 4 and clipped and marked all those I found that weren’t already 5.

Safely back in the hive

Three supers were overkill for the usual spring nectar flow. However, there was already a reasonable flow on and I wanted to give the colonies a good amount of space in the hope of delaying swarm preparations. 

Swarm control

Colonies usually start making clear their intent to swarm in the second half of May here. It varies a bit depending upon how advanced or otherwise the season is – one of those unknown knowns.

I kept in email contact with beekeeping friends about their own colony build up. By the time I received the first email saying charged queen cells were present (~16th of May) I was travelling back to do my own swarm control.

I decided to use the nucleus method whether queen cells were present on not.

Effectively I was going to implement preemptive swarm control on some colonies. By taking the queen out into a nuc the colonies would be forced to requeen, I’d then leave a single charged/capped queen cell and let them get on with it.

All looking good …

And for eleven of the colonies that’s precisely what happened. 

I removed the queen on a frame of emerging brood and shook some of the bees from a second frame into the nuc box. These were to be relatively small nucs but made sure each had a full frame of capped stores (saved from colonies at the first inspection). I also added a frame of drawn comb and two foundationless frames.

I sealed the nucs and moved them to another apiary.

Three of many … and hive number 29

Most of the brood boxes had play cups with eggs and about 50% had charged queen cells. There were no capped cells. I marked frames containing promising looking charged cells and closed the boxes up.

… and still looking good six days later

Six 6 days later I went carefully through every frame in the de-queened colonies.

One good queen cell, an old play cup and some rather old comb

All the boxes had good looking queen cells and I made sure I left just one in each colony. 

The nucs also all looked great when I checked them on the same day. 

New comb with queen already laying it up

The queens were laying well and the bees were drawing new comb. They would be fine for another few weeks. 

Come in Number 29, your time is up

One of the colonies proved more problematic.

Hive #29 … this had been left as a strong single brood colony on the 25th of April.

Three weeks later it was – unsurprisingly – still a strong single brood colony. The bees were busy and the supers were already filling nicely 7.

What was missing from the brood box in mid-May were eggs, larvae or capped brood 🙁

Had I inadvertently killed the queen 8 at the last inspection? The 21-22 day interval would have meant that all worker brood would have matured and subsequently emerged 9.

However, the temperament of the colony suggested it wasn’t queenless. The bees were calm, they were foraging well and bringing in good amounts of OSR pollen.

With a sense of dread I had a look in the supers …

Let there be drones

About 75% of my many super frames are drawn on drone cell foundation. For the same amount of wax – by weight – you store more honey. I also think there may be advantages when spinning it out in terms of honey recovery 10.

In addition, if you use drone cell comb immediately over the brood box, you dissuade a strong colony from storing an arch of pollen over the brood nest in the super … 

Drone comb in super

… though they do often leave cells empty, ready for the queen to lay.

But she can’t do that because she’s trapped under the queen excluder. 

Right?

Wrong 🙁

The middle few frames of the lower couple of supers were wall to wall capped drone brood and drone larvae. The queen was busy laying up some of the remaining space that wasn’t already filled with nectar.

I found the marked and clipped queen on the very first super frame I removed.

Sod it.

Snatching victory from the jaws of defeat

Perhaps.

Here was the dilemma. Hive #29 was strong and healthy but effectively queenless. Time was against me. I didn’t have the luxury of simply plonking her beneath the QE and checking the colony didn’t make swarm preparations in another three or four weeks 11

I’d already united all my other colonies and made up the nucs. I didn’t want to disassemble any of these to accommodate this colony.

With bad weather approaching in a few days I decided to make up a nuc with the queen and, in due course, donate a queen cell from another colony.

Which is what I did. 

An adjacent colony helpfully raised several very good looking cells which I knew were charged. One of these, on a frame holding a sideplate-sized patch of brood, was added to the colony just before the rain arrived.

Open the box, open the box

But on the same day I added the queen cell I also checked the supers thoroughly.

I wanted to make sure that every frame was drone foundation and that I’d not missed a queen cell drawn from any worker comb in the supers. That might have resulted in a virgin queen running about in my supers and, knowing my luck, squeezing through the QE and slaughtering the queen from the cell I’d just introduced. 

There were lots of “queen cells” in the supers. However all were little more than play cups drawn along the top edge of the drone comb, against the top bar. 

Lots of drone brood … but no real queen cells

None contained eggs. It was as though the bees, sensing the colony was now truly queenless, had known what to do but had no primary material to work with.

Over the next fortnight or so this hive was going to generate hundreds thousands lots of drones. Not in itself a bad thing – this was a good colony and the positve influence on local bee genetics might be beneficial.

However, all the drones would emerge in the supers and be prevented from exiting the hive due to the queen excluder.

When this happens the drones die in their droves stuck half way through the excluder.

This is a distressing sight and, for a drone, a demoralising experience (I would imagine 12).

Under normal circumstances I would simply return every 3-4 days, pop the lid off the hive and release them. This wasn’t possible living four hours away … 

… so I played the ‘get out of jail free’ card by adding a thin eke and upper entrance.

Upper entrance

When I next check the colony I expect the drone brood to have all emerged and, largely, left the supers. I hope there’s a mated laying queen in the bottom box and there should be some capped worker brood.

What there’s unlikely to be is three full supers of honey 🙁

With no worker brood being reared for at least 5 weeks the foraging workforce will be significantly depleted. I hope they manage to defend what they’ve already collected … time will tell.

What went wrong?

After finding the supers full of drone brood I wrote “dodgy” on both sides of the queen excluder frame as I replaced it with a plastic spare.

I assumed the queen had found a bent wire and   s  q  u  e  e  z  e  d  her way through to have a field day – actually three weeks – in the supers.

However, I think the explanation is more prosaic than that 13.

My notes indicated I’d not seen the queen in this hive during the April inspection. In this instance evidence of absence was not absence of evidence … there were lots of eggs and brood in all staged. The colony was queenright and the queen was in the right place.

At least before I opened the hive 😉

And this is where stupidity, forgetfulness and plain dumb luck played their part. I … 

  • stupidly botched the inspection, taking the strength and health of the colony as the most important signs that all was well, but …
  • forgot that the next inspection – when I would be making up nucs – would also need worker eggs in the brood box to rear new queens from.
  • There’s more … I also presumably forgot to thoroughly inspect the queen excluder before laying it to the side, allowing …
  • dumb luck to intervene when the queen scooted around to the other side of the excluder and so end up trapped in the supers when I reassembled the hive.

Mea culpa.

That’s my best guess anyway.

Did I do the right thing?

Hive #29 was the last to be inspected after a hard day of beekeeping in late April.

Coincidentally it was also the last to be checked in mid-May 14

This limited my options somewhat and I made a judgement call as to the best course of action. Doing what I describe above risks the queen failing to emerge or mate. It also potentially risks the box being robbed as the workforce diminish, particularly with the upper entrance I’ve added.

Both of these could lead to the loss of the hive, but the loss/problem would be all mine. At the time, standing there swearing sweating in my beesuit, gasping for a beer, it seemed like the safest bet. It also seemed like the responsible course of action in the middle of a global pandemic.

I chose not to just dump the queen back into the brood box, add the upper entrance and leave them to it. Had the colony subsequently swarmed 15 the problem might then have been someone else’s

Did I do the right thing?

We’ll know soon enough … 😉


 

Queenright … or not?

A brief follow-up to the (ridiculously long) post last week about leaving queen cells in the colony after a) it swarms, or b) implementing swarm control 1.

How long does it take for the new queen to emerge, mate and start laying? 

And what if she doesn’t?

How did we get here?

We are approaching the peak of the beekeeping season. Colonies have built up strongly and should now be topped by comfortingly heavy supers of spring honey. 

Mind your back 😯 

The box you inspected in early April and found three frames of brood in is now bursting at the seams with bees and brood. Everything is getting busier and bigger. You may have already run out of supers or – lucky you – are frantically extracting to free-up supers to return to the colonies.

Depending upon your location you may already have discovered that your swarm prevention efforts, whilst temporarily effective, were soon treated with disdain as the colonies started to build queen cells.

Sealed queen cell ...

Sealed queen cell …

You are now using some form of swarm control and the colony now contains a mature queen cell.

Or they swarmed … leaving a mature queen cell 🙁

Queenless colonies

Is a colony with a charged, capped, queen cell queenless? 

A philosophical question 🙂

I guess the answer is technically no, but practically yes.

There’s clearly a queen in the hive, but she’s really a potential queen. To be useful to the colony (and the beekeeper) she has to emerge, mature, mate and start laying.

It’s at that stage that the colony can be described as queenright.

All of this takes time and all of which significantly changes the tempo of the season.

Colonies that are requeening should generally not be disturbed and the change from full-on to full-off can feel strange.

Doubly so, because the lack of reassuring inspections can make the wait seem interminable. 

It’s tempting to have a quick peek … after all, what harm could it do?

Tick tock

The development of a queen takes 16 days from egg to eclosed virgin. The first three days as an egg, then six days as a larva before a further week as a developing pupa. The rapid development is due to the very rich diet that queens are fed in the first couple of days. This triggers a host of changes in gene expression 2 which dramatically alters the morphology, behaviour and longevity of the queen from the genetically identical worker.

After a virgin queen emerges she needs to mature sexually which takes 5-6 days. During this period they don’t look or behave much like queens. They tend to be quite small and, if disturbed, rush about the frame skittishly. They are also a lot more willing to fly than a mature laying queen – you have been warned! 3

Where have all my young girls gone?

What a beauty

Virgin queens are not lavished with attention by a retinue of workers, all of which often makes them more difficult to find in the hive.

The queen goes on one or more mating flights which usually take place on warm, calm, sunny early afternoons.

She then returns to the hive and, 2-3 days later, starts laying eggs. A queen that has just started laying sometimes lays more than one egg per cell. However, she settles down fast and will usually lay in a reasonably tight pattern in the centre of one of the middle frames in the brood nest.

Have patience

Add all those timings up and you have a minimum of two weeks between the capping of the queen cell and the day when she starts laying.

To be sure, you need to know when the queen cell was capped which is difficult if you’re dealing with a colony that swarmed. Was the cell capped on the day the colony swarmed (not unusual), or was it capped during the lousy weather a few days earlier that then delayed the emergence of the swarm?

It is unwise to disturb a virgin queen.

All sorts of things can go wrong. You might inadvertently crush her during an inspection 4 or scare her into taking flight and getting lost in the long grass.

Equally calamitous would be inspecting the colony on the nice, calm, warm mid-afternoon when she decides to go off on her mating flight. She’ll be off consorting with the local drones for about 10 – 30 minutes, and may go on more than one flight on subsequent days. If she returns to find the roof and supers off, the brood frames out and smoke being puffed everywhere she may never find the hive entrance.

Inspecting a colony

None of the above ends well.

Minima and maxima

The two weeks detailed above is the absolute minimum. I don’t check these things routinely but think the only time I’ve really seen it taking that short a period (from cell sealing to a mated laying queen) is when queen rearing using mini-mating nucs.

Mini-nucs …

Queens tend to get mated in these very fast if the weather is suitable. I don’t know why 5.

But, if the weather is unsuitable, irrespective of the hive type, mating will be delayed.

By ‘unsuitable’ I mean lousy. If it’s raining persistently or blowing a hoolie the queen will not venture forth.

If it’s cool (16 – 18°C) and cloudy she might, particularly if she’s of the darker Apis mellifera mellifera strain. 

But then again, she might not 🙁 

All of which means that the two weeks quoted really is a minimum.

What if it rains for a month? The virgin queen has a ‘shelf life’. If she does not get mated within ~26-33 days of emergence she is unlikely to get successfully mated at all.

Here we go again ...

No queen mating today …

To summarise, it will take a minimum of two weeks from queen cell capping to having a laying queen in the hive. If 40 days elapse before the queen is mated (again from cell capping) it is likely that she will be a dud.

Three weeks

Assuming the weather has been OK for queen mating I usually leave a minimum of three weeks between closing the hive up with a capped queen cell and looking for the mated queen. 

There’s little to be gained by rummaging around the hive before then … and a whole lot to be potentially lost.

If you do open the hive up too early – assuming none of the nightmare scenarios above occur – what can you expect to see?

Lift the dummy board out, prise out the last frame and then split the hive somewhere in the middle of the remaining frames i.e. don’t work through frame by frame, this isn’t a routine inspection, it’s a Royal Checkup.

If you look around the middle of the face of the central frames you can often see polished cells. These have been cleaned and prepared by the workers for the queen to lay in. They’re particularly obvious if the comb is a bit old and dark – then they really do look polished and shiny.

If there are polished cells present, but no eggs, I’m then reasonably confident that there’s a queen in the hive but that she’s not started laying yet (but is probably mated).

There’s no point in looking for her. Close the hive up and leave it another week.

Brood frame with a good laying pattern

If she is laying, leave her be. Wait until she’s laid up a few frames and you can tell she has a good laying pattern of worker brood i.e. look at the appearance of the sealed brood, then find her and mark her 6.

Breathe a sigh of relief … your colony is again queenright.

Five weeks

If five weeks 7 have elapsed between leaving a freshly capped cell in the hive and the non-appearance of eggs I start to fear the worst.

The colony will now have no brood – it all emerged about two and half weeks ago – and the lack of brood pheromone means there’s a possibility that the colony will develop laying workers

Laying workers ...

Laying workers …

There may be a queen present, but she’s rapidly becoming an ageing spinster

In this situation it is probably wise to decide what Plan B is … how will you ‘rescue’ the colony?

If you leave the colony for another week or fortnight you might find a laying queen, but you probably won’t. During this period the colony will dwindle further in size and strength 8

Plan B

You effectively have four choices:

  1. Unite the colony with a known queenright colony.
  2. Requeen the colony with a mated, laying queen 9.
  3. Add a mature capped queen cell to the colony. Start nervously pacing the apiary again waiting for her to emerge, mature, mate and start laying.
  4. Allow the colony to rear their own queen by providing a frame of eggs (see below).

It is important to find and dispatch the ‘failed’ queen if you are going to do 1, 2 or 3. The queen may have failed to get mated but she might still be able to kill a challenger queen in the hive. 

Uniting the colony is often the best and safest option. It’s quick. It uses the bees remaining in the colony immediately and it strengthens another hive. It’s my preferred option … but I have quite a few colonies to work with. If you have just one (and you shouldn’t have) it’s clearly a non-starter. 

An Abelo/Swienty hybrid hive ...

An Abelo/Swienty hybrid hive …

Adding an expensive purchased mated laying queen (or a cheap one) can be risky. Terminally queenless and broodless colonies are often tricky to requeen. The most successful way I’ve found to do this 10 is to use a large cage pinned over a frame of emerging brood. And even then it doesn’t always work 🙁 

If you already have laying workers it is not worth trying to requeen the colony – they’ll almost certainly kill her. I usually try once to ‘rescue’ a laying worker hive (details here), but then shake them out.

Adding a capped queen cells can work if the colony is queenless but you will have another long wait ahead of you … and all the time the colony is dwindling in size.

She emerges into a population of geriatric workers. Far from ideal.

But what if you can’t find the queen?

Is the colony really queenless?

Perhaps she mated quite late because of poor weather and is about to get started?

Perhaps she failed to mate and is just lurking in there waiting to slaughter the £40 Buckfast queen you’re about to add 🙁 

Frame of eggs

Most of these questions can be answered by adding a ‘frame of eggs’.

A queenless colony will start to rear a new queen if presented with eggs and larvae.

A queenright colony will not.

If you are unsure whether a colony is queenright add a frame containing a good number of eggs. I usually like to use a full brood frame also containing some larvae and sealed brood. The brood pheromone will help hold back laying worker development. The new young bees that emerge will bolster the hive population and will be there to help the new queen when she returns from getting mated.

If you have the luxury of choosing a frame of eggs on relatively new fresh comb the bees will find it easier to draw queen cells. However, don’t worry if you don’t … if they’re queenless they’ll be thankful for anything.

Check the colony a few days after adding the frame of eggs. If they’ve started queen cells 11 then I just let them get on with it and check again in about a month or so for a laying queen. They won’t swarm or generate casts as – by this time – bee numbers are significantly depleted. 

However, if they don’t start queen cells it means there’s a queen somewhere in the hive. Check the other frames in the hive for eggs. It’s not at all unusual to find the original queen has now started laying. Again, leave her to get on with it.

But if there are no eggs on other frames and no queen cells (on the frame you added) you need to find the non-functioning queen … and we’ll deal with that sometime in the future 😉

Good luck


Colophon

The usual dictionary definition of queenright just references a colony of bees that contains a queen. The OED has references going back to 1911 (When a colony is found that is not queen-right, it is remorselessly broken up, and distributed among other colonies, or united with a weak colony having a good queen, C.C. Miller in Fifty Years among Bees) including some from Wedmore and E.O Wilson.  

However, none specifically state whether the queen is laying. Or what she’s laying. A queenless colony is easy to define. But what about a colony containing a virgin queen? Or a drone laying queen? 

I’d argue that in these situations the colony contains a queen, but things aren’t really ‘right’ (as in correct). In my view, queenright means a mated, laying queen. 

Please, no pedantic questions or comments about a colony containing a well mated queen that, because there’s a nectar dearth, has stopped laying … 😉

Queen cells … quantity and quality

How many queen cells should I leave in my hive?

This question pops up year after year at this time of the season.

Up and down the country we’re all busy implementing swarm control because our swarm prevention, er, didn’t 🙁

The majority of swarm control methods leave part of the colony to rear a new queen. Once she has emerged, matured, mated and proved her worth by laying up a frame or two you can then decide what to do with the old queen. 

Irrespective of the swarm control method you use – e.g. Pagden, nucleus method or a vertical split – the colony often produces quite a few queen cells. 

Similarly, if both your swarm prevention and swarm control failed and a prime swarm disappeared over the fence, there are likely to be several (or possibly lots of) queen cells left in the colony.

Queen cells – the good, the bad and the ugly

How many of these queen cells should you leave in the hive? 

Which one(s) should you leave?

Assumptions

I’m in the middle of my own swarm control at the moment and so intend to keep this relatively short and simple 1.

I am going to assume you start with one hive and you want to finish with one hive at the end of the process (i.e. you do not want to make increase). I’ll briefly mention rescuing queenless colonies and stock improvement as it’s relevant.

I’m also going to keep this as generic as possible. It’s not going to depend upon the method of swarm control employed or – with some caveats to be discussed later – whether the colony has naturally swarmed.

Here’s the starting position.

Your hive is making preparations to swarm. You apply a swarm control method that removes the old queen from the original brood box 2. This box therefore contains brood in all stages (BIAS) – eggs, larvae and sealed brood. This brood probably occupies most of the frames in the brood box. 

Also in the box are a very large number of adult bees, both workers and drones 3

And there will probably be one, several or lots of unsealed queen cells 4 present as well 🙂

Why do anything? or What’s the worst thing that could happen?

When a colony swarms naturally about 75% of the adult bees leave with the old queen. This figure is similar whether the colony is large or small. 

If you start with a large double brood colony it might contain 60,000 bees. Let’s assume a large swarm leaves as the first queen cells are capped (which is when the swarm usually scarpers).

There are still 15,000 bees and perhaps 15-18 frames of brood, several frames of which are close to emerging. The queen laying rate 3 weeks prior to the swarm was probably 1,000 to 2,000 eggs per day, meaning that number of adult workers are now emerging per day. 

Honey bee development

Honey bee development

About eight days after the queen cells were capped and the swarm left the new virgin queens emerge (see the bottom row in the picture above). By this time the worker population in the hive might well be over 20,000 again (some adult worker will have died of old age in the intervening period).

20,000 bees is more than enough to swarm again if several queens emerge 5.

These secondary swarms are called casts. They are headed by a virgin queen. They can be quite large if the original colony was very strong. 

However, with a lot of virgin queens emerging around the same time a strong colony can produce several casts, one after another. These are usually successively smaller and smaller 6. Not only are these casts too small to form an effective colony, but the originating colony can be weakened sufficiently to make its survival doubtful.

What’s the alternative?

Imagine the same double-brood colony. The old queen heads for the hills with 75% of the workforce. A week later the colony strength has been boosted by the emergence of a further 7 – 10 thousand workers … but this time there is only one capped queen cell developing.

The queen emerges.

If this queen also disappeared in a cast swarm the original colony would inevitably perish.

Why?

Because a week after the original swarm leaves there are no eggs or larvae in the colony young enough to be reared as new queens. 

She’s gone …

Swarming is reproduction of the honey bee ‘superorganism’. The survival of natural swarms is low (~25%) whereas the survival of swarmed colonies is reasonably high (>75%).

From an evolutionary perspective it makes no sense for the only queen to also leave, heading a cast swarm. The colony would have ‘traded’ a ~1:5 chance of producing two viable colonies for a 1:16 chance 7

It’s a no brainer as they say 8.

So, you can probably see where this is going now …

Swarm control

The three relatively generic and representative swarm control methods –  Pagden, a nucleus method or a vertical split – all involve manipulation of the hives one week after the initial intervention.

In the ‘classic’ Pagden method the original hive is moved from one side of the artificial swarm to the other. This has the effect of ‘bleeding off’ some of the workforce, so weakening the hive. The resulting reduced worker population often tear down all but a small number of queen cells. The reduced bee numbers also make the production of casts less likely as the colony is weaker.

Pagdens' artificial swarm ...

Pagdens’ artificial swarm …

In a vertical split the hive is reversed on the stand after 7 days, achieving exactly the same outcome on a much smaller footprint with less equipment 🙂 9

In both these methods the flying bees that have reoriented to the initial new position of the queenless hive return to find the hive moved. They then enter the nearest hive, which is the queenright component (i.e. the artificial swarm). 

I’ll get to the nucleus method in a moment.

Sometimes you will see it recommended that you also check the queenless colony at this one week timepoint to ensure that there are not large numbers of queen cells still present 10. It’s not usually necessary but – assuming you are careful – it does not cause any harm. As I explain below, it can help give you confidence.

If you don’t perform the one week hive manoeuvre you really should check for queen cells and reduce the number present.

In the nucleus method I describe the beekeeper must manage queen cell numbers in the queenless hive. Not doing so almost certainly risks losing multiple casts when the queens emerge together.

How many queen cells should you leave?

The queenless component of your swarm control only needs one queen cell

Any less than that and the colony will be non-viable without further intervention from the beekeeper.

Any more and there’s a risk that the colony will generate one or more casts. 

A very strong queenless colony with large numbers of queen cells is a recipe for disaster … or, if not a disaster, then a lot of frustration as you scurry around trying to catch the casts and/or rescue the colony from swarming itself to destruction.

Workers in very strong colonies can ‘hold back’ queens, effectively trapping them in the cell, so that emergence is more-or-less simultaneous. Should you chance to open a colony in this situation all hell breaks loose, with virgin queens dashing about all over the place.

Been there, got the T-shirt 🙂

Although entertaining – at least is retrospect – it’s better to avoid this sort of situation by restricting queen cell numbers.

All your eggs in one basket

And this is where the beginner starts to experience some trepidation.

They have to reduce queen cell numbers … to one.

That queen will head the colony for the next year or three. She’ll mother tens of thousands of workers who will make countless foraging trips and collect tens or (hopefully) hundreds of pounds of honey.

Choosing that one queen cell feels like a lot of responsibility.

The consequences of choosing a dud feel very serious indeed.

Surely leaving two or three would be a ‘safer’ bet? 

Backups, if you will … just in case the first one turns out to be a dud.

How do you know which one to pick?

Trust the bees

And this is where you need to trust the bees. They’ve been doing this pretty well for several million years.

You don’t need to choose a single egg from the thousands possibly present in the colony. The one egg that will be cared for, fed copious amounts of royal jelly and eventually emerge to head the colony.

The bees have already made those decisions 11.

They’ve started several queen cells, the majority of which are likely to be suitable. You just need to choose one of those queen cells to leave in the hive. 

It’s not a one in thousands chance of choosing a ‘winner’, it’s more like one in ten … in which any of the ten would probably be OK.

With a few caveats …

What are the features of a good queen cell?

You open the hive and find a number of sealed and unsealed queen cells.

Which to choose?

What are the features you are looking for?

What are the features you can see?

Sealed queen cell ...

Sealed queen cell …

Size, shape and appearance are the obvious ones. Position on the comb might also influence your choice.

What are the features you cannot see?

Is is a charged cell i.e. does it contain a developing pupa? Has that pupa been well fed as a larva?

Size, shape, appearance and position

Mature queen cells are large, about 3 cm long. The position on the comb – whether on the face or edge can influence the apparent size. They are generally conical, more or less evenly tapering to a neatly rounded tip. Queen cells that have been well-tended by the bees are often heavily sculpted on the outside. This is generally taken to be a “good thing”, but note that this doesn’t happen until after the queen cell is capped (see the photo above). Uncapped cells are usually smooth (see the next photo).

I think the position on the frame is irrelevant in terms of queen cell quality, but it does influence which I choose. The cell should be drawn from worker comb (!) 12 and – particularly if I’m likely to be either cutting the cell out or moving the entire frame – I like it to be in a position unlikely to get damaged as I manipulate the frames in the hive.

The edge of drawn comb, with space below and to the side, makes things easy. The central face of the comb, especially if it’s on fresh comb and not near a wire in the foundation, is also a good bet. 

The position is more important if you’re going to do something with the cell or frame other than let it emerge in situ.

Charged cells

How do you know there’s a well-fed pupa in the cell?

Ted Hooper (in his Guide to Bees and Honey) describes gently prising the cap off a sealed queen cell to check it is occupied, then re-sealing it to let development run its course. He finishes discussing how to re-seal the cell with the words “you have to do a good job or the bees will tear it down.”

I bet 😉

There are easier ways.

Firstly you can be pretty sure that any well-shaped sealed cell with a good, well sculpted appearance is likely to be occupied. Alternatively, you can identify these cells in advance and only allow those you know contain a developing larva sitting on a thick bed of royal jelly to mature.

A practical example

A few days ago I used the nucleus method for swarm control in all my colonies in one apiary. Due to work constraints and lockdown some colonies were only just starting to make preparations to swarm. None of the colonies had well developed, charged queen cells. Some had ‘play cups’ with eggs present.

Three days after making up the nucs I checked the queenless parent colonies. All had a few developing queen cells.

Here is the same photograph as above, with some cells numbered on the frame.

Queen cells – capped, open and just plain dodgy

Which do you choose?

Here is the view from below of the same frame.

Queen cells – practical example

  1. A sealed cell, perhaps a bit small 13
  2. Is a nice looking unsealed cell with a thick bed of royal jelly supporting a larva inside.
  3. Also unsealed and with a good space underneath for the cell to be drawn out as it develops.
  4. Is very similar to #2. Smooth exterior as it’s only 3 days old and unsealed.
  5. A thickened play cup from a previous season. There is no egg, larva or royal jelly inside it.

Remember that this is only 3 days after implementing swarm control.

I destroyed the sealed cell #1. Since it was already sealed it was probably made from an older larva. Cells are sealed on the eighth day after the egg is laid. Since this was only 72 hours after removing the queen the larva was probably two days old before being reared as a queen – i.e. 8 minus 3 days since queen removal minus the three days it would have already spent as an egg. Alternatively, it might have been present when I removed the queen, though I did check reasonably thoroughly.

I couldn’t be sure of the contents of this cell and I suspected that it may not have been fed on copious amounts of royal jelly during the very early days after hatching from the egg.

Cell #3 was also squidged. If you look closely from below you can clearly see the larva but no thick bed of royal jelly. I doubted it had been fed well enough in the early days. Here’s an enlargement …

Cells #1 to #4 enlarged.

Why risk it? There are better cells on the frame.

I ignored #5. It’s not a queen cell and never will be.

Uncapped cells #2 and #4 were retained. They are the right size, have a good appearance and are well placed on the frame.

I marked the top of the frame with a queen marking pen to remind me where to check, and more importantly where to be careful, when I inspect the colony a week after making up the nuc.

X marks the spot

Note that the photo above is a different hive to the numbered photo of queen cells (which I forgot to photograph).

Hold on … not so fast

Go back and look again at the numbered photo of queen cells.

There is another cell, uncapped and filled with royal jelly, to the left and a little higher than the sealed queen cell #1.

This cell is actually pretty obvious. There are relatively few bees on the frame and it is not particularly well ‘hidden’. 

Miss a couple more like that in a very strong hive and there’s a chance the colony will throw off several casts when the queen emerge. The unlabelled cell, and cells #2 and #4 are all very similar in age and appearance and would likely emerge within hours of each other.

Seven days after implementing swarm control

The hives are checked again 14.

I know which frames have good, charged developing queen cells. They are the ones that are marked. I therefore :

  • treat these frames very carefully. Do not shake the bees off the frame!
  • make sure the cells are now capped and starting to be sculpted by the bees.
  • gently inspect the remainder of the frame for other queen cells.
  • destroy any new cells that I find

I choose one of the queen cells and destroy any others on the frame. If there is more than one marked frame and I don’t need the cell for another colony (see below) then I destroy the cells on the other marked frame as well.

I then thoroughly inspect every frame in the brood box, shaking all the bees off the frames and checking for any queen cells I may have missed previously. There will be some.

All I find are destroyed.

I close the hive up and leave it undisturbed for the queen to emerge, mate and start laying. I’ll discuss this – apparently interminable – period in the future sometime.

I’m confident the cell contains a well fed pupae. It was the the bees that really selected the queen … all I did was whittle down their selection to the final choice.

Using ‘spare’ queen cells

In the photo above there are two marked frames. This is a good colony. Frugal, productive, well behaved etc. 15

There is another colony in the apiary which is poorly tempered. They are also requeening and are at the same stage.

Assuming the cells on both marked frames are good I’ll transfer one to the badly behaved colony when I conduct the seven day inspection. You can transfer the entire frame or you can gently cut the queen cell out and use it directly 16

All of the developing queen cells in the badly behaved colony will first be destroyed. Since there are no eggs or young larvae in that colony (and no queen as she was removed a week ago) they cannot rear another from their own genetic material.

The new queen will be better quality.

Similarly, you can use a ‘spare’ queen from a good hive to rescue a terminally queenless colony, or to replace an underperforming or substandard queen.

A really dodgy queen cell

I wanted to squeeze in a picture of what not to choose. 

Bride of Frankenstein queen cell

There are so many things wrong with this.

Where to start?

It’s drawn from drone comb and is not neatly tapering and conical. It’s poorly sculpted considering its age and size, which is far too big.

Whatever emerges from this cell, if anything, will not be any use to me or the bees 🙁

Seven day only inspection

The process described above involves an additional inspection 3-4 days after implementing swarm control. I think this is a modest amount of additional work for:

  • the peace of mind it gives when selecting the final cell to leave
  • the time saved when going through the colony at the seven day inspection

However, often it’s not possible. In that case I refer you back to the description of what a good sealed queen cell looks like.

Choose one of those.

Just one 😉


Notes

With gale force winds predicted for the next 2-3 days I ended up checking the ‘example’ colony (above) on day 6 after implementing swarm control measures. Here is the same frame:

Just one!

I removed two less convincing queen cells on either side of the one selected (#2 in the labelled photograph further up the page). There were a small number of queen cells elsewhere in the colony. All were removed. I’m leaving just one cell sealed, I know it contains a well fed larva. She’ll emerge in about a week and should be mated – weather permitting – a week or so after that.

And now the wait begins … 😉

 

The memory of swarms

I’m writing this waiting for the drizzle to clear so I can go to the apiary and make up some nucs for swarm control. Without implementing some form of swarm control it’s inevitable that my large colonies will swarm 1.

Swarming is an inherently risky process for a colony. Over 75% of natural swarms perish, often because they do not build up strongly enough to overwinter successfully.

As a mechanism for reproduction swarming is somewhat unusual in that the intact colony is split into two not fully functional ‘halves’ 2.

By not fully functional I mean that neither the swarmed colony, nor the swarm are guaranteed to survive.

The swarmed colony lacks a queen, but has ample stores.

The swarm has a queen but has only the stores carried in the bellies of the workers.

The swarmed colony needs to rear a new queen. The swarm needs to find a new nest site, move there, build comb, rear brood, forage etc.

That seems like the very opposite of intelligent design, but it’s the way evolution has made things work. This being the case it involves a whole range of compromises and quick fixes that make it work.

One of these involves the memory of worker bees, which is what this post is about.

Two-stage swarming

A range of events within the hive – which for reasons that will become obvious I will term the original nest site – trigger the urge to swarm. I discussed some of these when covering swarm prevention. Swarming is then essentially a two-stage process. 

The two stage process of swarming

The first stage is the swarm leaving the original nest site and establishing a bivouac nearby. This is the classic cluster of bees hanging from a branch.

The bivouac sends out scout bees to search the nearby area for potential new nest sites. After ‘discussion’ (comprehensively covered by Thomas Seeley in Honeybee Democracy) between the scouts they reach a consensus of the best site.

The second stage is the relocation of the bivouacked colony to the new nest site. For example, this could be the church tower, a hollow tree or a bait hive. This site is likely to be within a few hundred metres of the original nest site, but can be further away.

All of which should raise some questions in the minds of beekeepers who are familiar with the “less than 3 feet or more than 3 miles” rule.

Have these bees not read the rules?

If you want to move a hived colony of bees you’ll often be told, or have read, that you need to move them either less than three feet or more than 3 miles.

Worker bees have a foraging range of about 3 miles. Within this range they have an uncanny ability to return to the hive location using features of the landscape to orientate themselves. The ‘final approach’ uses scent from the hive entrance.

Therefore, if you move a colony 3 feet they’ll still find the general location using landscape features, and then orientate to the hive entrance using scent.

If you move a colony 10 miles away everything is new to them and they’ll embark on some orientation flights to learn the new landscape features.

But if you move the colony a mile they’ll use the landscape features to return to the site of the original hive … to find it gone 🙁 3

Swarms break all these rules.

The bivouac is (in my experience) always more than 3 feet from the hive entrance. If the scout bees make the choice (e.g. selecting a bait hive to occupy), the swarm always relocates to a new nest site less than three miles from the site it left 4.

And a beekeeper who drops a bivouacked colony into a skep can move it wherever she wants, even back to the same hive stand it recently vacated.

If the swarm followed the rules, the majority of the workers would return from the bivouacked swarm to the original nest site.

At least they would if they had orientated to the original nest site in the first instance.

Are the bees naive?

About half of a workers life is spent as a forager collecting water, pollen or nectar. But before they venture out of the hive, the first half of a worker bees life is spent building comb, nursing larvae or cleaning cells.

Therefore, one possibility is that the bees present in a swarm have no knowledge of the hive location because they’ve never before left the hive.

We know that the proportion of workers that leave the colony when it swarms is about 75%. This has been determined in a number of independent studies and is remarkably consistent, irrespective of the size of the colony that swarms.

If 75% of the workers leave the colony when it swarms it is mathematically impossible for the swarm not to include older foragers (assuming the laying rate of the queen is steady).

In fact, we don’t need to resort to any underhand mathematics as the age classes of bees in a swarm have been measured. I’ve discussed this before when comparing natural and artificial swarms.

Age distribution of bees in swarms

Age distribution of bees in swarms

The median age of adult bees in the hive is 19 days. The median age of bees in a swarm is 10 days. Therefore swarms do contain younger bees, but not exclusively so.

One of the reasons for this bias towards younger bees must be to do with the relatively short lifespan of foragers. Many of the older bees in the swarm will have perished long before the new brood laid by the queen emerges.

Permanent amnesia?

The bivouacked swarm doesn’t dwindle in size as the older foragers drift back to the original nest site. Other than a few hundred scout bees, the majority of the bivouacked swarm huddle together to protect the queen, buried somewhere in the centre, from the elements.

They don’t fly or forage … they’re waiting for the signal from the scout bees that a new nest site has been located.

And, once they relocate to the church tower, the hollow tree or a bait hive, the older foragers stay in the new nest location. It’s as though the bees in a swarm that previously knew where the original nest site was have amnesia.

And this makes sense. If they did return to the original nest site the swarm (whether bivouacked or relocated) would shrink in size and it’s chances of surviving would be severely diminished. Other than a full belly of honey a swarm can rely on nothing. They need as many bees as possible to take on all the roles needed to establish a new colony – comb builders, nurses, foragers etc.

But have they really forgotten the original nest site?

Temporary amnesia?

It turns out that swarms do retain a memory of their original nest site.

In 1993 Gene Robinson and colleagues demonstrated that a swarm shaken out from its new nest site preferentially returns to the original nest site, rather than to an equidistant alternate 5.

This ability must rely on the memory of the foragers in the swarm. Therefore it is likely to be lost in a relatively short time (days, not weeks) 6.

Firstly, the foragers will be busy reorienting to the new nest site, effectively overwriting the memory of the original nest location. In good weather this takes just a couple of days.

Secondly, these ageing bees don’t have long to live, so there will be ever-decreasing numbers of them to lead a shaken out swarm back to the original location.

Rain stops play

Sometimes the bivouacked colony never relocates to a new nest site. Either the scouts never achieve a consensus or – more likely – bad weather forces the swarm to hunker down.

When you hive a bivouacked swarm you will often find a small crescent or two of new wax on the branch they were clinging to. If the bees get trapped by bad weather I think the comb building continues. It’s not unusual to find comb in hedgerows near apiaries where bees that have got trapped have ended up trying to make a new nest.

Natural comb

Natural comb …

What does the memory – or lack of it – of swarms mean for practical beekeeping?

The (temporary) amnesia of swarms means you can collect a bivouacked swarm and move it wherever you want. A swarm that relocates to your bait hive can also be moved, but don’t wait too long. Within just a few days of a swarm arriving the bees will have reoriented to their new location. I always try and move bait hives to their final location within three days of a swarm appearing.


Notes

The drizzle stopped and I spent the entire day finding queens and making up nucs.

Note to self … a super-strong colony with no queen cells, wall-to-wall brood and no very young larvae or eggs probably has a faulty queen excluder 🙁

Second note to self … Sod’s law dictates that the colony with the faulty queen excluder probably has supers filled with drone comb 🙁

Aristotle’s hairless black thieves

Aristotle not in his beesuit

Almost every article or review on chronic bee paralysis virus 1 starts with a reference to Aristotle describing the small, black, hairless ‘thieves‘, which he observed in the hives of beekeepers on Lesbos over 2300 years ago 2.

Although Aristotle was a great observer of nature, he didn’t get everything right.

And when it came to bees, he got quite a bit wrong.

He appreciated the concept of a ‘ruling’ bee in the hive, but thought that the queen was actually a king 3. He also recognised different castes, though he thought that drones (which he said “is the largest of them all, has no sting and is stupid”) were a different species.

He also reported that bees stored noises in earthenware jars (!) and carried stones on windy days to avoid getting blown away 4.

However, over subsequent millenia, a disease involving black, hairless honey bees has been recognised by beekeepers around the world, so in this instance Aristotle was probably correct.

Little blacks, maladie noire, schwarzsucht

The names given to the symptomatic bees or the disease include little blacks or black robbers in the UK, mal nero in Italy, maladie noire in France or schwarzsucht (black addiction) in Germany. Sensibly, the Americans termed the disease hairless black syndrome. All describe the characteristic appearance of individual diseased bees.

Evidence that the disease had a viral aetiology came from Burnside in the 1940’s who demonstrated the symptoms could be recapitulated in caged bees by injection, feeding or spraying them with bacterial-free extracts of paralysed bees. Twenty years later, Leslie Bailey isolated and characterised the first two viruses from honey bees. One of these, chronic bee paralysis virus (CBPV), caused the characteristic symptoms described first by Aristotle 5.

CBPV causes chronic bee paralysis (CBP), the disease first described by Aristotle.

CBPV infection is reported to present with two different types of symptoms, or syndromes. The first is the hairless, black, often shiny or greasy-looking bees described above 6. The second is more typically abnormal shivering or trembling of the wings, often associated with abdominal bloating 7. These bees are often found on the top bars of the frames during an inspection. Both symptoms can occur in the same hive 8.

CBP onset appears rapid and the first thing many beekeepers know about it is a large pile (literally handfuls) of dead bees beneath the hive entrance.

It’s a distressing sight.

Despite thousands of bees often succumbing to disease, the colony often survives though it may not build up enough again to overwinter successfully.

BeeBase has photographs and videos of the typical symptoms of CBPV infection.

Until recently, CBP was a disease most beekeepers rarely actually encountered.

Emerging and re-emerging disease

I’ve got a few hundred hive year’s worth 9 of beekeeping experience but have only twice seen CBP in a normally-managed colony. One was mine, another was in my association apiary a few years later.

A beekeeper managing 2 to 3 colonies might well never see the disease.

A bee farmer running 2 to 3 hundred (or thousand) colonies is much more likely to have seen the disease.

As will become clear, it is increasingly likely for bee farmers to see CBP in their colonies.

Virologists define viral diseases as emerging if they are new in a population. Covid-19, or more correctly SARS-CoV-2 (the virus), is an emerging virus. They use the term re-emerging if they are known but increasing in incidence.

Ebola is a re-emerging disease. It was first discovered in humans in 1976 and caused a few dozen sporadic outbreaks 10 until the 2013-16 epidemic in West Africa which killed over 11,000 people.

Often the terms are used interchangeably.

Sporadic and rare … but increasing?

Notwithstanding the apparently sporadic and relatively rare incidence of CBP in the UK (and elsewhere; the virus has a global distribution) anecdotal evidence suggested that cases of disease were increasing.

In particular, bee farmers were reporting increasing numbers of hives afflicted with the disease, and academic contacts overseas involved in monitoring bee health also reported increased prevalence.

Something can be rare but definitely increasing if you’re certain about the numbers you are dealing with. If you only have anecdotal evidence to go on you cannot be certain about anything very much.

If the numbers are small but not increasing there are probably other things more important to worry about.

However, if the numbers are small but definitely increasing you might have time to develop strategies to prevent further spread.

Far better you identify and define an increasing threat before it increases too much.

With research grant support from the UKRI/BBSRC (the Biotechnology and Biological Sciences Research Council) to the Universities of Newcastle (Principle Investigator, Prof. Giles Budge) and St Andrews, and additional backing from the BFA (Bee Farmers’ Association), we set out to determine whether CBPV really was increasing and, if so, what the increase correlated with (if anything).

This component of the study, entitled Chronic bee paralysis as a serious emerging threat to honey bees, was published in Nature Communications last Friday (Budge et al., [2020] Nat. Comms. 11:2164 https://doi.org/10.1038/s41467-020-15919-0).

The paper is Open Access and can be downloaded by anyone without charge.

There are additional components of the study involving the biology of CBPV, changes in virus virulence, other factors (e.g.environmental) that contribute to disease and ways to mitigate and potentially treat disease. These are all ongoing and will be published when complete.

Is chronic bee paralysis disease increasing?

Yes.

We ‘mined’ the National Bee Units’ BeeBase database for references to CBPV, or the symptoms associated with CBP disease. The data in BeeBase reflects the thousands of apiary visits, either by call-out or at random, by dedicated (and usually overworked) bee inspectors. In total we reviewed almost 80,000 apiary visits in the period from 2006 to 2017.

There were no cases of CBPV in 2006. In the 11 years from 2007 to 2017 the CBP cases (recorded symptomatically) in BeeBase increased exponentially, with almost twice as much disease reported in commercial apiaries. The majority of this increase in commercial apiaries occured in the last 3 years of data surveyed.

Apiaries recorded with chronic bee paralysis between 2006 and 2017.

BeeBase covers England and Wales only. By 2017 CBPV was being reported in 80% of English and Welsh counties.

During the same period several other countries (the USA, several in Europe and China) have also reported increases in CBPV incidence. This looks like a global trend of increased disease.

But is this disease caused by CBPV?

It should be emphasised that BeeBase records symptoms of disease – black, hairless bees; shaking/shivering bees, piles of bees at the hive entrance etc.

How can we be sure that the reports filed by the many different bee inspectors 11 are actually caused by chronic bee paralysis virus?

Or indeed, any virus?

To do this we asked bee inspectors to collect samples of bees with CBPV-like symptoms during their 2017 apiary visits. We then screened these samples with an exquisitely sensitive and specific qPCR (quantitative polymerase chain reaction) assay.

Almost 90% of colonies that were symptomatically positive for CBP were also found to have very high levels of CBPV present. We are therefore confident that the records of symptoms in the historic BeeBase database really do reflect an exponential increase of chronic bee paralysis disease in England and Wales since 2007.

Interestingly, about 25% of the asymptomatic colonies also tested positive for CBPV. The assay used was very sensitive and specific and allowed the quantity of CBPV to be determined. The amount of virus present in symptomatic bees was 235,000 times higher than those without symptoms.

Further work will be needed to determine whether CBPV is routinely present in similar proportions of ‘healthy’ bees, and whether these go on and develop or transmit disease.

Disease clustering

Using the geospatial and temporal (where and when) data associated with the BeeBase records we investigated whether CBPV symptomatic apiaries were clustered.

For example, in any year were cases more likely to be near other cases?

They were.

Across all years of data analysed together, or for individual years, there was good evidence for spatial clustering of cases.

We also looked at whether cases in one year clustered in the same geographic region in subsequent years.

They did not.

Clustering of CBPV – spatial and temporal analysis.

This was particularly interesting. It appears as though there were increasing numbers of individual clustered outbreaks each year, but that the clusters were not necessarily in the same geographic region as those in previous or subsequent years.

The disease appears somewhere, increases locally and then disappears again.

Apiary-level disease risk factors

The metadata associated with Beebase records is relatively sparse. Details of specific colony management methods are not recorded. Local environmental factors – OSR, borage, June gap etc. – are also missing. Inevitably, some of the factors that may be associated with increased risk are not recorded.

A relatively rare disease that is spatially but not temporally clustered is a tricky problem for which to define risk factors. Steve Rushton, the senior author on the paper, did a sterling job of analysing the data that was available.

The two strongest apiary-level factors that contributed to disease risk were:

  1. Commercial beekeeping – apiaries run by bee farmers had a 1.5 times greater risk of recording CBP disease.
  2. Importing bees – apiaries which had imported bees in the two preceding years had a 1.8 times greater risk of recording CBP disease.

Bee farming is often very different from amateur beekeeping. The colony management strategies are altered for the scale of the operation and for the particular nectar sources being exploited. For example, colonies may already be booming to exploit the early season OSR. This may provide ideal conditions for CBPV transmission which is associated with very strong hives and/or confinement.

Bee imports does not mean disease imports

There are good records of honey bees imported through official channels. This includes queens, packages and nucleus colonies. Between 2007 and 2017 there were over 130,000 imports, 90% of which were queens.

An increased risk of CBP disease in apiaries with imported bees does not mean that the imported bees were the source of the disease.

With the data available it is not possible to distinguish between the following two hypotheses:

  1. imported honey bees are carriers of CBPV or the source of a new more virulent strain(s) of the virus, or
  2. imported honey bees are susceptible to CBPV strain(s) endemic in the UK which they were not exposed to in their native country.

There are ways to tease these two possibilities apart … which is obviously something we are keen to complete.

All publicity is good publicity …

… but not necessarily accurate publicity 🙁

We prepared a press release to coincide with the publication of the paper. Typically this is used verbatim by some reporters whereas others ask for an interview and then include additional quotes.

Some more accurately than others 🙁

The Times, perhaps reflecting the current zeitgeist, seemed to suggest a directionality to the disease that we certainly cannot be sure of:

The Times

Its sister publication, The Sun, “bigged it up” to indicate – again – that bees are being wiped out.

The Sun

And the comments included these references to the current Covid-19 pandemic:

  • “Guess its beevid – 19. I no shocking”
  • “It’s the radiation from 5g..google it”
  • Local honey is supposed to carry antibodies of local virus and colds – it helps humans to eat the stuff or so they say. So it could be that the bees are actually infected by covid. No joke.

All of which I found deeply worrying, on a number of levels.

The Telegraph also used the ‘wiped out’ reference (not a quote, though it looks like one). They combined it with a picture of – why am I not surprised? – a bumble bee. D’oh!

The Telegraph

The Daily Mail (online) had a well-illustrated and pretty extensive article but still slipped in “The lethal condition, which is likely spread from imports of queen bees from overseas …”. The unmoderated comments – 150 and counting – repeatedly refer to the dangers of 5G and EMFs (electric and magnetic fields).

I wonder how many of the comments were posted from a mobile phone on a cellular data or WiFi network?

😉

Conclusions

CBPV is causing increasing incidence of CBP disease in honey bees, both in the UK and abroad. In the UK the risk factors associated with CBP disease are commercial bee farming and bee imports. We do not know whether similar risk factors apply outside the UK.

Knowing that CBP disease is increasing significantly is important. It means that resources – essentially time and money – can be dedicated knowing it is a real issue. It’s felt real to some bee farmers for several years, but we now have a much better idea of the scale of the problem.

We also know that commercial bee farming and bee imports are both somehow involved. How they are involved is the subject of ongoing research.

Practical solutions to mitigate the development of CBP disease can be developed once we understand the disease better.


Full disclosure:

I am an author on the paper discussed here and am the Principle Investigator on one of the two research grants that funds the study. Discussion is restricted to the published study, without too much speculation on broader aspects of the work. I am not going to discuss unpublished or ongoing aspects of the work (including in any answers to comments or questions that are posted). To do so will compromise our ability to publish future studies and, consequently, jeopardise the prospects of the early career researchers in the Universities of St Andrews and Newcastle who are doing all the hard work.

Acknowledgements

This work was funded jointly by BBSRC grants BB/R00482X/1 (Newcastle University) and BB/R00305X/1 (University of St Andrews) in partnership with The Bee Farmers’ Association and the National Bee Unit of the Animal and Plant Health Agency.

The nucleus option

The definition of the word nucleus is the central and most important part of an object, movement, or group, forming the basis for its activity and growth”.

Therefore a nucleus colony of honey bees is something smaller than a full colony, but that has inherent capability to grow into a full and active colony.

A nucleus colony is usually abbreviated to nuc (pronounced nuke), often prefixed by an indication of its size e.g. five frame nuc or 2-frame nuc. The very fact that the size of the nuc is often included is an indication that they can exist in a range of different sizes. 

If the size is not defined a nuc is likely to have 5 brood frames. In this post I’ll stick to that convention; unless otherwise specified I’ll use the term nuc to mean a 5-frame nuc. 

What’s in a nuc … ?

A nuc is a fully functional colony of honey bees, just on a smaller scale than a full colony. Therefore it will contain stores, adult bees, brood in all stages and a queen.

5 frame nuc colony

5 frame nuc colony …

Of course, when first prepared it may be missing some of these components. However, to be fully functional, and to have the capacity to grow into a full colony, it must contain everything that would be expected in a full hive, just less.

Other than queens. To be functional a nuc, like a full colony, needs no less than one queen 😉

And, of course, no more than one 🙂

Part of the skill in preparing good quality nucs – for whatever purpose – is to ensure they are a balanced and functional mini-colony. They need enough adult bees to rear brood, to defend the colony and to forage effectively. They need sufficient stores to avoid starvation during a bout of bad weather, and they need a mated, laying queen to help the mini-colony expand.

… and what’s it in?

A nuc is usually housed in an appropriately sized nucleus hive, but actually doesn’t need to be. Commercially-purchased nucleus hives almost always take 5 brood frames 1, though there are exceptions. Paynes Beekeeping sell a very widely used 6 frame National nuc. Paradise Honey polystyrene Langstroth nucs also take 6 frames and, to add further confusion, can be divided easily longitudinally into two 3-frame nucs. 

Here's three I prepared earlier ...

Everynuc poly nucs

Of course, if you make your own – or butcher commercial offerings – a nucleus hive can be any size you want. As the need arises 2 I use two, three, five and eight frame nucs.

Two frame nuc box

Two frame nuc box … a bit too small for the nucleus method of swarm control (but usable at a pinch)

But the nucleus colony does not have to occupy the entire hive.

A well-prepared nuc can expand in size quite quickly. One of the biggest problems in working with nucs is their tendency to get overcrowded. As I discussed a fortnight ago, overcrowding is a well-established trigger for swarming, and a nuc is perfectly capable of swarming … thereby undoing all your efforts in establishing it in the first place.

Therefore, bearing in mind the necessity to produce a functional and balanced mini-colony, it is not unusual to create the nucleus colony smaller than the hive it is housed in, so providing some space for future expansion.

National hive dummy boards DIY

Dummy boards …

As described below, three frames in a five frame hive hive can start a new nucleus colony. You can even put the frames into a full brood box. In both cases the unoccupied space needs to be reduced or at least separated from the developing colony. With the frames pushed against the sidewall of the hive the addition of a dummy board against the ‘open’ face of the colony is usually sufficient.

Warmth and weighty matters

Being smaller than a full colony, and containing fewer bees, a nuc is less able to keep the cluster warm if the weather turns cold. This isn’t usually an issue during the late spring and summer, but is a major concern if you want to overwinter nucleus colonies.

To make things a bit easier for the bees many commercial nucleus hives are made out of expanded polystyrene. These are mass produced from moulds and sometimes include integral feeders or other design ‘features’. Some of the features included are better than others … and some are pretty useless. In my experience 3 none of the poly nucleus hives sold are perfect, but some are very good and almost all are perfectly usable.

MB poly nuc

MB poly nuc …

I’ve discussed several – now rather ageing – commercially-sold poly nucs previously. I may mention them again in passing, but will focus on the contents of the nuc for most of this post.

The low weight of polystyrene nucleus hives is an additional bonus. Less weight to carry when moving them between apiaries, when selling them or when stacking them up empty for the winter.

But nucleus hives don’t have to be made of polystyrene. For summer use only (or when preparing nuc colonies for sale) you can get nucleus hives made of folded Correx for a few pounds. I’ve also got a few lovely cedar nucleus hives built by Peter Little of Exmoor Bees. These have separate open mesh floors, tightly-fitting removable Varroa trays and deep roofs. They’re beautifully made but usually languish unused in the shed in favour of the poly Everynuc’s I routinely use.

Why prepare a nuc?

There are all sorts of reasons to prepare a nucleus colony, but – at least in my beekeeping – the three main ones are:

  • swarm control – the nucleus colony houses the old queen while the original colony requeens. If this is successful the nuc can either be expanded to a full colony or, after removal of the old queen, united with the original colony so strengthening the hive to exploit the summer nectar flows. I wrote about a nucleus method of swarm control last year.
  • making (limited) increase – a strong colony can almost always be used to prepare a nuc without jeopardising the chance of getting a good honey crop. Depending when the nuc is prepared it will either be strong enough to fill a full hive by the season’s end, or can be overwintered as a nuc. Splitting a nuc off a strong colony can also help delay swarming.
  • much greater increase – a variant of the above is to completely split a strong colony into 4 – 8 nucs. The final number depends upon the strength of the original colony 4. Remember that you need a queen or queen cell for each prepared nuc. I’ve discussed this approach previously when queen rearing using a Cloake board and in doing circle splits.

Whatever the reason, the basic mechanics of preparing nucleus colonies is the same. The important point to remember is that the goal is to produce a fully functional colony, just on a smaller scale. Unless it has sufficient stores, enough bees of the right type or a functional (or soon to be functional) queen it will struggle, and it may not survive.

Stores

I start all my nucs with a frame of largely or completely sealed stores pushed up against the sidewall of the box in which I’m going to house them.

During the first or second inspection of the season I am usually able to remove at least one frame of stores from every full colony. This is leftover from the winter and, with the spring nectar flows underway, no longer needed.

Spreading the brood nest

I replace the removed frame(s) with either drawn comb or, more usually, a new foundationless frame. These are inserted at the edges of the brood nest – effectively spreading the brood nest – rather in the space directly occupied by the frame of stores.

The colony benefits from the additional space to draw new comb for the queen to lay, so delaying the urge to swarm. And I benefit from ~2kg (5lb) of stores in the removed brood frames which I carefully hoard until I need them 🙂

Make sure you store them somewhere safe where wasps, bees and rodents cannot get at them.

Bees

This is where things start to get a little more complicated. The amount of bees – both brood and workers – added to the nuc depends upon a number of things, most important of which are:

  • where the nuc is going to be located after it has been made up. If it being moved to an out apiary more than a couple of miles away then you can usually add fewer bees. Conversely, if it is staying in the same apiary (or being moved nearby) you have to expect many of the flying bees will return to the original hive and make allowances for this by adding more at the start.
  • whether the nuc will be started with a laying queen, a virgin queen or a queen cell. A laying queen can and will start laying eggs immediately, with the resulting workers emerging in ~21 days from making up the nuc. A virgin will have to go out and mate and start laying, so adding several days to this period. If you start the nuc with a queen cell there may be a few more days to be added as well.

Remember that the flying worker bees you add as you create the nuc will all likely have died before any new bees emerge from eggs laid in the nuc. Therefore, to ensure there is a continuity of foragers you need to prime the nuc with sealed brood and plenty of young bees.

So, the next thing to add to the nucleus hive, adjacent to the frame of stores is a frame of sealed brood together with all the bees on the frame. Unless you also intend to place the queen from the original hive into the nuc make sure the queen is not on this frame.

If there is also some emerging brood on this frame as well, all the better. These will help bolster the young bee population you add, enabling them to help rear more brood and get established faster.

If the original colony is particularly strong or you want to create a strong nuc you can add a second frame of brood (and adhering bees), but this is not necessary. What is necessary is to ensure there are enough bees to compensate for ageing foragers and the loss of bees back to the original hive.

Flying bees and hive bees

When you remove a brood frame from the hive it has two general sorts of workers on it – the so-called ‘flying’ bees and the ‘hive’ bees. The former are the foragers, the latter the younger nurse bees. You can crudely separate them by deftly shaking the frame once 5. The flying bees are dislodged, the hive bees hang on tight.

Nurse bees will, as they age, mature into guards and foragers. These will be needed before adult workers emerge from any new eggs laid in the nuc. 

Therefore, I almost always shake in a frame or two of nurse bees into the nuc that is being setup. 

Doing this takes just a few moments … 

  • Lift a brood frame from the original colony and check that the queen is not on it 6
  • Shake the frame once over the original hive to displace the flying bees
  • Shake the remaining adhering ‘hive’ bees into the empty gap in the nucleus hive between the frame of brood and the sidewall
  • Return the brood frame to the original hive

Space to expand

The nucleus hive now probably contains two frames (one of stores and one of brood) and, assuming it’s in a 5-frame box, the bees have space to expand as the colony builds up.

But they also need frames to occupy.

Therefore, add a single foundationless frame, or a frame with foundation or – the 5 star deluxe treatment – a frame of drawn comb to the nucleus hive. The last is a real luxury and means the queen will have somewhere to start laying immediately.

Go on … spoil them 😉

My precious …

With the exception of a queen (see below), the nuc is now complete for the moment. Since I predominantly use foundationless frames I usually add a dummy board to isolate the colony from the echoing space in the 5-frame nuc box. For convenience I’ll usually place the two foundationless frames on the far side of the dummy board so I don’t need to remember them when the colony expands.

The arrangement of frames is therefore:

  • Stores
  • Brood (sealed and emerging), plus adhering bees
  • Drawn comb, or undrawn foundation or foundationless frame
  • Dummy board
  • Foundationless frame
  • Foundationless frame
Foam block ...

Foam block …

If the nuc is to be moved to a remote apiary I’ll also add a closed cell foam block to stop the frames moving about during transport.

Queen

When first created nucs are too small and unbalanced (in terms of the composition of bees in the box) to successfully rear a good quality queen from an egg or young larva.

They will try, but it is not a recipe for success. You’ll often end up with an undersized and underperforming scrub queen. 

Don’t let them.

Why bother putting all those valuable stores, brood and bees into a box without giving them the very best chance of flourishing?

Instead, you need to provide them with a queen – either mated and laying, a virgin or as a mature queen cell. I don’t want to cover the sometimes tricky subject of queen introduction here, so will restrict myself to the two most common scenarios:

  • using the mated queen from the hive you split the nuc off
  • making up a nuc with a ripe queen cells 

The first instance is straightforward. Either make sure the frame(s) transferred to the nucleus hive include the queen or find her in the original hive and transfer her to the nuc.

Transferring her on a frame is easy. Adding her subsequently means picking her up and gently placing her on the top bar of the transferred brood frame in the nucleus hive. Do this carefully and quickly and she will be accepted without any issues 7.

Queen cells

Although also needing care, starting a nuc with a mature, ripe queen cell is even easier.

You can make up the nuc with a frame already containing a sealed queen cell. This is simplicity itself. Just ensure you do not bump, jar or bruise the queen cell during the transfer process.

Sealed queen cell ...

Sealed queen cell …

Alternatively you can add a queen cell from another frame. This can be from the original hive, or from another colony altogether 8

  • Cut around the queen cell  to leave a wide margin of comb. A couple of centimeters isn’t too much.
  • Choose a space on the face of the brood frame in the nucleus hive. If there isn’t one, make one by pushing the comb down with your thumb.
  • Place the sealed queen cell vertically in the gap and use the wide margin of wax to fix it in place by squeezing the wax together. 

You want the queen to emerge onto brood, not stores, and you want the cell roughly central in the cluster of bees to ensure it’s well looked after until she emerges. I usually fix the cell under the top bar.

All gone ...

All gone …

Of course, if you rear your own queens (or have a friend/mentor who does), the queen cells are usually attached to small plastic cups which can simply be hung in place between the top bars.

Location and relocation of nucs

If the new nuc is to remain in the original apiary you should expect that many of the flying bees will return to the original hive. Help discourage them by stuffing the nuc entrance with grass for 48-72 hours.

By the time the grass has dried and the bees have pushed their way out they’ll realise things have changed and will reorientate to their new home.

Stuffed

Stuffed …

It’s also worth checking the population of bees a few days after making up the nuc. If your nucleus hive has a perspex crownboard this can be done with minimal disturbance to the bees. If the nuc looks sparsely populated you can shake in more nurse bees from the original colony (see above).

5 frame nuc ...

5 frame poly nuc …

If you move your nuc a few miles from the apiary it was prepared in the bees will be forced to reorientate to the new location. You’ll therefore lose far fewer of the flying bees, so maintaining a reasonable foraging force during the initial establishment of the new colony.

When transporting nucs take all the normal precautions. Seal the entrance, strap the box up tightly and orientate them with the frames in line with the direction of travel.

Maintenance of nucs

Nucs need a little more TLC 9 than full colonies. Particularly when first set up they are less able to defend themselves as the population of bees is unbalanced.

This is a very good reason not to feed nucs syrup from the start. Workers returning to their original hive may take back news of a readily-available source of ‘nectar’ and induce robbing.

Later in the season, once a nuc is established it may still benefit from a reduced size entrance to give the bees less to defend. 

Being smaller than a full hive they have less space for stores and less space for expansion. Unsurprisingly the two major problems are starvation and overcrowding. Both are readily avoided by regular inspection.

Requeening a nuc ...

Requeening a nuc …

Finally, if you start a nuc with a queen cell it makes sense to find and mark 10 her before moving the colony to a larger hive. Queens are always easier to find in nucs than in full colonies.

There are far too many additional tips and tricks to preparing nucs than I have space for here, but at least it’s a start. The key point to remember is that nucs are far more likely to be successful if set up and managed with a balanced population of bees and ample resources.


Colophon

The title of this post is a modified version of the nuclear option. Formally this is a parliamentary procedure in the US senate. More generally, by analogy to nuclear warfare, it means the most drastic or extreme response possible to a particular situation.

Preparing nucleus colonies is nothing like this. Indeed, it is one of the most useful things to do in beekeeping.

I’ve no idea how this post grew to over 3000 words … my version of filibustering which the nuclear option can be used to defeat. Next week we return to science with an exciting new study 11 on the rise and rise of chronic bee paralysis virus as a threat to beekeeping in general, and beefarming in particular.