Tag Archives: swarming

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!

An Inspector Calls

Hive inspections are the preventative maintenance of the beekeeping year. Conducted properly, they include all the necessary checks to ensure all is well now and will be until the next inspection.

Inspections are an essential part of beekeeping. Beekeepers who don’t conduct inspections probably won’t be beekeepers for long … the colony swarms, goes irretrievably queenless or succumbs to disease.

Or all three 🙁

Actually, there’s another reason … I suspect that beekeepers who don’t regularly inspect colonies are more interested doing something else. They’d prefer to be playing golf or building model railways or potholing. I covered this a few months ago when discussing beekeeping principles and practice.

Shouldn't you be inspecting your bees today?

Shouldn’t you be inspecting your bees today?

Their enthusiasm to properly manage their colonies that is, not potholing 😉

Preventative maintenance

The clue is in the name … the purpose of inspections are to maintain the colony in a productive state and to prevent things from happening that might stop this being achieved.

‘Productive’ usually means collecting nectar for honey 1, but could equally well refer to making lots of bees for nucleus colony production. Or, for that matter, maximising drone production to flood the area with good genes for queen mating.

Essentially you’re checking the colony to ensure it’s best able to do what you want it to do.

And, if there are signs that things are going awry, you’re putting in place the preventative measures that help avoid a partial or complete disaster.

Brace comb

Brace comb …

A beekeeping “disaster” … let’s keep things in perspective. Swarming, queenlessness, laying workers, robbing, wasps, disease, Varroa infestation, brace comb and all the rest.

Quick or thorough but probably not both

Inspections can either be quick or they can be thorough, but rarely both. The definition of the term ‘inspection’ means “looking narrowly into; careful scrutiny or survey; close or critical examination”.

Therefore, unless you’re only checking one thing, for example whether the queen cells are sealed in a queenright queen rearing colony, it’s likely that the inspection will take some time.

Cell bar frame with three day old queen cells, The Apiarist.

3 day old queen cells …

How long depends upon experience. It probably takes me ~12-15 minutes to go through a box thoroughly and I have a reasonable amount of experience and get quite a bit of practice 2. This is a snail’s pace when compared with commercial beekeepers who can conduct a pretty comprehensive inspection in ~4 minutes.

A beginning beekeeper might take significantly longer than 15 minutes to inspect a colony.

But speed is not the issue. 

Why conduct inspections?

The issue – in a routine inspection – is determining the answer to at least the following five key questions (paraphrased from Ted Hooper in his Guide to Bees and Honey):

  1. Has the colony sufficient room?
  2. Is the queen present and laying as expected?
  3. Is the colony building up as expected (early season)? Are there queen cells present (mid season)?
  4. Are there signs of disease?
  5. Has the colony sufficient stores?

All of which, done properly, takes a reasonable amount of time.

So that’s the Why? What about when and how should inspections be conducted? These need to be addressed before considering the questions above 3.

When?

There are several ‘when’ questions to be considered. When should you conduct the first inspection of the year? When – as in what sort of day – should you conduct the inspection? How frequently do the inspections need to be conducted?

Unless you’re looking very quickly in a hive for a specific reason inspections should only really be conducted when the exposed brood aren’t going to get chilled. This means you should choose a day when the temperature reaches at least the mid-teens (°C). ‘Shirtsleeve’ weather some call it.

This influences both the timing of the first inspection of the year and – particularly early or late in the season – the time of day that the inspection occurs. On the East coast of Scotland I did my first thorough inspection this year on the 19th of April. Last year – although the winter was nominally shorter and warmer – some hives weren’t inspected until early May because there was never a suitable day.

Lots of hive entrance activity …

Use your own judgement about whether the weather is suitable for early season inspections. The bees should be flying well. This is both an indication that the weather is good enough and reduces the hive population making the condition and amount of brood easier to determine.

Hive entrance activity ...

Hive entrance activity …

Don’t base your decision to inspect on reports you read on beekeeping discussion forums (fora?) about others with their hives bulging with brood. They may be beekeeping in a warmer part of the country. They might be in a different country altogether. It’s also worth remembering that there’s a well-documented tendency – as with online reviews – for contributors to over-exaggerate the positives (and negatives) 4.

I also wouldn’t bother inspecting on an unseasonably warm day very early in the year. It’s unlikely you’ll be able to deduce a whole lot about the state of the colony.

I’ve started, so I’ll finish …

The frequency of inspections is largely dictated by the development time of a queen bee, and to a lesser extent by the strength of nectar flow in your locality.

If a colony is going to swarm they first prepare one or several queen cells. These are capped around day 9 after the egg is laid. Once there are capped queen cells and suitable weather the colony is likely to swarm.

That means you need to inspect more frequently than every 9 days during the peak swarming period of the season – in Fife that’s an ~8 week period from early May late June. In warmer regions, or in years with atypical weather, regular inspections might have to start earlier and continue later.

Queen cells ...

Queen cells …

“Around 9 days” really means anything from 8 days, so a 7 day inspection cycle makes most sense. If a careful inspection one week fails to find evidence of queen cells being developed there’s no chance the colony can swarm for a further 7 days at least (because there are no queen cells that are sufficiently developed).

“fails to find evidence” means you have to inspect carefully. A small charged queen cup, with a day old larva and a bed of Royal Jelly will be capped 6 days later … then they’ll be off 🙂

Generally 5 a colony with a clipped queen will take a little longer to swarm, allowing intervals between inspections to be extended to up to 10 days.

However, don’t rely on this … I’ve seen them (er, mine) swarm earlier than this. Inevitably it’s you’re strongest colony and best honey producer 🙁

Relax, but don’t be complacent

Once the peak swarming season is over the frequency of inspections can be reduced. I’m usually on a two-week cycle by mid-July, with most colonies getting their last inspection in mid/late August. This coincides with the optimum time to start applying Varroa treatments to minimise exposure of winter bees to deformed wing virus.

However, remember that a strong colony can fill a super very quickly during a good nectar flow. Inspections are required to ensure the colony has enough space – for brood expansion and for stores.

How to inspect

We’re running out of space … I’ll deal with this in more detail in a future post (and link to it from here).

Essentially, because the goal is to check the state of the colony, you need to ensure that the inspection is conducted in a way that best allows you to determine this.

An agitated colony or one stirred up to be highly defensive makes inspections much harder. It’s therefore important to be as gentle as possible, to be calm and measured in your movements and to avoid jarring the colony.

Use the minimal amount of smoke possible, don’t wave your hands over the top of the frames and don’t crush bees.

And if it all goes pear-shaped, if despite your best efforts the colony gets really stroppy, if you kick a frame over on the ground, drop your hive tool into the open brood box or the smoker goes out at a critical moment 6 … close up the box and try again another day.

Swarm arriving at bait hive ...

Swarm arriving at bait hive …


Colophon

An Inspector Calls

An Inspector Calls

An Inspector Calls is a play by J.B. Priestley. Set in 1912 and first performed in the mid-1940’s, it involves a man – calling himself Inspector Goole – questioning a well-to-do family about the suicide of a working class woman, Eva Smith. Over three acts it is clear that, independently, all in the family are responsible for her exploitation, abandonment, social ruin and eventual death through poisoning. “Inspector Goole” leaves, but the secrets are now out. Subsequent checks with the police and the infirmary show there is no “Inspector Goole” or recent suicides. The play ends with a phone call from the police about the suspicious death of a young woman by poisoning …

Alistair Sim starred in the 1954 film version of the play, where the surname of the lead character was changed from Goole to Poole.