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!

Footnotes

  1. Ramsey, M., Bencsik, M., Newton, M.I. et al. The prediction of swarming in honeybee colonies using vibrational spectraSci Rep 10, 9798 (2020).
  2. Grooters, H. J. (1987) Influences of queen piping and worker behaviour on the timing of emergence of honeybee queens. Insec. Sociaux 34(3), 181–193.
  3. I suspect the part of the paper on tooting and quacking was below some sort of self-imposed (or journal imposed) minimal publishable unit, and was therefore lumped together with the swarm prediction stuff simply to get it published.
  4. Which I’m going to skip as it doesn’t add much to the understanding of the overall story.
  5. Simpson, J. & Greenwood, S. P. Influence of artificial queen-piping sound on the tendency of honeybee. Apis Mellifera, colonies to swarm. Insec. Sociaux 21, 283–287 (1974).
  6. Abducktive?

22 thoughts on “If it quacks like a duck …

  1. Mary Ratcliffe

    Hi David,
    A really interesting post (as always). I’ve just tried to buy you a couple of coffees, but keep getting the message “pop up window blocked” will try again in a while!
    All the best,
    Mary

    Reply
    1. David Post author

      Many thanks Mary

      I’ll ask the barista to be a little more welcoming now that lockdown is being eased 😉

      David

      Reply
  2. Rachel

    Fascinating reading. Can’t imagine ever getting to this sort of level with my beekeeping but I love reading your posts and your sense of humour is brilliant 😊

    Reply
    1. David Post author

      Thanks Rachel

      Pleased you enjoyed the post (and the humour). When I started beekeeping I had no interest in anything but getting a few jars of honey. I read Ted Hooper’s book and skipped all the stuff on queen rearing as – like you – I never felt it was ever going to be of either interest or relevance to me. But I was wrong. It’s a great pastime as there are so many interesting aspects to it (particularly to a biologist).

      Enjoy your beekeeping 🙂
      David

      Reply
  3. Andrew Cameron

    Very good Post David. And summed up my hive No1 ( SUN) to a T.
    Normal inspection on 17th April this year, surprised that this early in season I found a rammed brood box and heard piping /tooting while inspecting and remembering that I had read and heard about that but not really sure what it meant. Found 4 queen cells at time of inspection and saw queen so felt happy to remove the cells, gave an early super and boxed back up happy that although to late for swarm prevention I did think that I had performed an early and adequate swarm control. I WAS WRONG 08/05/20 I was unlucky/lucky enough to witness the prime swarm decide to perform a rather amazing impression of a tornado, swirling and rising high in my garden, the noise was amazing, hopeful I awaited them alighting on a near by bush, tree but I guess I was to late and think they had already been resting nearby and already planned their new home as they on mass flew Eastwards at speed. On reflection due to inexperience, thinking to early in season to swarm and , to many bees to clearly find them alI, I missed a few queen cells!!! The other 5 hives were very closely checked and no more swarms noted. So this post has made me realise that the Tooting is a good sign that swarming is a day or two away? and I need to perform more robust queen cell checks. cheers for the knowledge, Andy C

    Reply
    1. David Post author

      Hi Andy

      Prime swarms, indeed any swarms (but the larger the better), are a fabulous sight.

      Interesting that your virgin was apparently tooting with the old queen still present. That’s different to the situation reported in the paper under discussion here … the piping virgin queen post-dated the prime swarm leaving by a few days. Perhaps the weather had been too dodgy to allow the swarm to leave?

      We all miss queen cells. It’s a rite of passage for a beekeeper. Along with thinking that squidging queen cells is swarm control 🙁

      Cheers
      David

      Reply
  4. Dave Stokes

    I have the strong memory from my early bee keeping days of opening a hive and seeing a handful of virgin queens emerging as I carried out the inspection. Not knowing how to deal with the situation and with very little time to think, I let the first run into the hive and dispatched all the others as they popped out.

    On a different front, I wonder if the colonies that throw off multiple casts are bred largely from imported stock from nice warm countries where smaller swarms are viable. It’s not a thought that has occurred to me before.
    Cheers,
    Dave.

    Reply
    1. David Post author

      Hi Dave

      There’s so much interbreeding between imports and native stock it might be difficult to work out who does what. You could ask the Q the other way round perhaps … do native bees generally not produce one or more casts when swarming. This is a question for the SNHBS folk. Of course, the question is never quite that simple. If native bees generally have smaller colonies they may never be strong enough to generate cast after cast. Whatever … I’ll give it some thought.

      Separate email to you sometime over the w/e.

      Cheers
      David

      Reply
  5. Jackie

    What a fantastic communicating style you have David. Very interesting as usual. Thank you for providing an interesting article every week.😊

    Reply
    1. David Post author

      Many thanks Jackie

      Almost time to think about something for next week already … only 57 articles in the drafts folder … but most are less than 10 words long 🙁

      David

      Reply
  6. Raffaele

    Nice post, congrats.

    To my experience swarming behaviour is very different among subspecies… some raise few cells other hundreds, some swarm with open queen cells, other wait for capping, other wait for virgin queen to emerge.. thus I am wondering if enlarging those studies to several subspecies might add insights. Additionally, as raised, managment play a role: swarm sounds&behaviour in natural nesting cavity is to be studied as well, hopefully a topic to cover by HoneyBeeWatch.com

    Reply
    1. David Post author

      Hi Raffaele

      All good points. I’m well aware of the colonies that raise QC’s on five or six different frames, and those that generate one or two only. Of course, swarming behaviour is also significantly influenced by the local weather … some are only held back by a deluge, whereas others seem to wait for a sunny, calm, warm afternoon.

      Simply inserting accelerometers into a natural nesting cavity is going to be a challenge – I wish whoever is doing it luck!

      Cheers
      David

      Reply
  7. Raffaele

    I am not convinced local weather play that important role: having run experiments with different subspecies I can tell they do have a memory of their original environment, and when you compare them in the same environment, under same management, the differences are amazing.

    Yes, installing an accelerometer in a natural cavity will be a challenge.. but doable and when not, log hives can offer a fair compromise

    Reply
    1. David Post author

      Re. local weather … I was meaning that the local conditions influence the swarming behaviour, but not equally. Some colonies (strains) swarm even if it’s dull and overcast, others don’t move until the conditions are perfect.

      Which I think is what you’re saying as well 😉

      Queen mating is the same … some will get mated even if the conditions are sub-optimal, others wait, and wait, and wait … 🙁

      Cheers
      David

      Reply
  8. vince poulin

    A “Hoot-of-an-Audio”. Reminds me of sitting at my desk huddled away from family blowing for the first time a duck call. Laughingly trying to mimic the “Toots and Quacks” of a lonely mallard only to be just as silly when attempting the high pitch of incoming snow geese. Should I again practice I had better shut the office door least I sent our bees the wrong message.

    Reply
  9. vince poulin

    For sure. Getting a snow goose call sorted is no easy task. I had a friend who could belch the high-pitch aawk-aawk-aawk (we hear it on your “reminder” audio) while lying on his back in a duck punt. He didn’t use a chunk of wood or plastic but his own throat. Astonishing to see him pull a juvenile bird out of a flock followed by the rest. Snow geese are special. Ours breed on Wrangle Island in Russia then fly down the Pacific Coast to Vancouver in the 10’s of thousands. 60-80,000 arriving in some years. They eventually move on to California but then return in mid-March – early April.

    Reply
    1. David Post author

      Hi Vince

      In Fife we get thousands of pink-footed and greylag geese overwintering. I always associate the skeins of them flying over ‘honking’ in the half-darkness with the end of year and the arrival of winter. I think they’re from Greenland, Iceland and Svalbard mainly.

      Cheers
      David

      Reply
  10. Dorothie

    Great post as always. I heard my first queen piping this year and was surprised how loud it was! It was a colony that I had several sealed qc in (oops) so I knocked down all the others in the assumption that this volume of piping indicated an emerged vjrgin. Seemed to have worked and swarms prevented!

    Reply
    1. David Post author

      Thanks Dorothie

      I first heard piping queens when queen rearing using mini nucs. It’s quite a distinctive noise once you know what to listen for, and relatively easy to hear over the general noise of the hive.

      My swarm control has been rigorous and my apiary visits have been very few and far between, so I’ve only heard it once this year from a virgin I released from a cell in an overcrowded nuc. She now heads a good colony, though one of her first acts was regicide I’m afraid to say 🙁

      Cheers
      David

      Reply
  11. PChollock

    Great post, thank you. This is my favourite topic in beekeeping, absolutely fascinating. I have a couple of recent observations (being a first year beekeeper, they are generally all recent!).

    I have seen a feral colony, up in an inaccessible old roof for apparently at least one winter, give off at least two casts this July (minimum of three small clusters, but one may have been a re-cast after they refused to be hived. Is it known for casts to return home and fly out a day later?). Down to grapefruity size. The prime swarm was apparently huge. It seems to be a real queen factory, but lives without any disturbance by human hand.

    I also lately heard a calling quite similar to piping on the surface of a stores frame. Is this common enough among workers? I’ve heard some impressively loud calls by chance from bees on a perspex coverboard before, which seemed to act like a drumskin. This seemed to be coming from an isolated bee who was sprinting about the comb, and didn’t have the pattern of queen piping, just the frequency and length of the first, rising “phrase” of a queen. It was hypnotic but a bit alarming since I hadn’t seen the queen. I’d love to have a constant feed of hive sounds to tune in to.

    Reply
    1. David Post author

      Hello

      Re. swarms/casts returning … I’ve not seen it personally, but they do have a memory of where they came from.

      Workers (or it may be scouts – can’t remember and don’t have the book to hand – you need to read Honeybee Democracy by Tom Seeley) preparing to swarm do what are called “buzz runs” to activate other bees in the cluster to join in. Again the noise is made by intense contraction of the flight muscles without moving the wings.

      You can also hear individual bees if you inadvertently trap a wing or leg when manipulating the frames … 🙁

      You can buy hive monitoring equipment or it is pretty straightforward to develop some sort of homegrown system using an Arduino or Raspberry Pi microcomputer hooked up to a simple microphone and amplifier. There are lots of DIY hive monitoring systems described online.

      Cheers
      David

      Reply

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