Category Archives: Swarms

A tale of two swarms

Or … why it’s good practice to clip the wing of the queen.

After a cool start to May it’s now (s)warmed up nicely. Colonies are piling in nectar, mainly from the OSR, and building up really strongly.

It’s at times like these that vigilance is needed. A skipped inspection, a missed queen cell, and the season can go from boom to bust as 75% of your workforce departs in a swarm.

Not the entire season … but certainly the first half of it.

All beekeepers lose swarms … but should try not to

Natural comb

Natural comb …

All beekeepers lose swarms.

At least, all honest ones do 😉

However, I can think of at least four reasons why it’s pretty shoddy beekeeping practice to repeatedly lose swarms 1.

  1. Beekeepers like bees, but some of the general public do not. Some are frightened of bees and a few risk a severe (or even fatal) anaphylactic reaction if stung. Beekeepers have a responsibility not to frighten or possibly endanger non-beekeepers.
  2. Most swarms do not survive. Studies of ‘wild’ bees have shown that swarming is an inherently risky business 2. The swarm needs to find a suitable new home and then collect sufficient nectar to draw enough comb to build up the colony and store food for the  winter. The vagaries of the weather, forage availability and disease ensure that most swarms do not overwinter successfully.
  3. Swarms have a high Varroa load. The mites transfer a heady mix of unpleasant viruses within the colony, shortening the lives of the overwintering bees. With high virus and mite loads the swarm colony is likely to be robbed by nearby strong colonies. This effectively transfers the mites and viruses to nearby managed colonies, so risking their survival.
  4. The swarmed colony is left with a new virgin queen. She has to mate successfully to ensure the continued survival of the colony. Again, the vagaries of the weather mean that this isn’t certain.

And you get less honey 🙁

Regular inspections help prevent the loss of swarms. But it’s good to get all the help you can.

Here’s a brief account of two recent events that illustrate the differences between swarms from colonies with clipped queens or unclipped queens.

Swarm in an out apiary

I have an out apiary in a reasonably remote spot containing half a dozen colonies. I keep my poorly behaved bees there 🙂 There are other apiaries in the area as the forage is good.

I went to inspect the hives at the end of April. This was only the second inspection of the year. On arriving I found most colonies were very active, but one was suspiciously quiet.

Thirty metres away there was a swirling mass of bees settling in the low branches of a conifer.

My three initial thoughts were “Aren’t swarms a great sight?”“Dammit, they shouldn’t have swarmed!” and “Perfect timing, where’s the skep?”.

Skep and swarm

Skep and swarm

The skep was in the car. It usually lives there during the swarming season. The bees were spread over two or three branches, all drooping under the weight. After a bit of gardening I managed to drop the majority of the bees into the upturned skep 3.

I inverted the skep over a white sheet laid out on the grass and propped one side up using a bit of wood.

The air was full of bees. While I busied myself inspecting the lively (in more ways than one 😉 ) colonies, the swarm gradually started to settle into the skep.

Skep and swarm

Skep and swarm

There were lots of bees exposing the Nasonov’s gland at the end of the abdomen, fanning frantically at the entrance to the upturned skep. This is a pretty certain indication that I’d managed to get the queen into the skep.

Fanning bees

Fanning bees

An hour later I’d finished all but one inspection – the quiet colony – it was beginning to get cool and the light was fading.

I could no longer see eggs, not because there weren’t any but because I’m not an owl.

The swarm still needed to be hived so I left the quiet colony until the following day, wrapped the skep in the sheet and took it to another apiary.

Brrrr!

And then the temperature plummeted. For the following week the daytime highs barely reached double figures. Nighttime temperatures were low single digit Centigrade.

The swarm would likely have perished and had a virgin queen emerged in the ‘quiet hive’ she’d have not got out to mate.

I didn’t look in another hive until the 7th, but when I did I got a surprise.

The ‘quiet hive’ contained a marked laying queen. I’d requeened this colony late in 2018 and my notes were a little, er, shambolic 🙁

I’d not recorded whether the queen was clipped and marked (the usual situation), marked only (not entirely unusual) or clipped only (not unknown!).

Whatever, they hadn’t swarmed after all 🙂

They were quiet because they had a high Varroa load with overt signs of DWV infection. Mite and virus levels in late September had been checked and confirmed to be very low. Presumably the mites had been acquired by drifting or robbing late in the season 4.

The hived swarm contained an unmarked laying queen and are lovely calm bees 🙂

A swarm in my home apiary

Fewer photos for this one as I didn’t have a camera with me …

I arrange my hives with the frames oriented ‘warm way’ 5 and inspect them standing behind the hive to avoid returning foragers.

Number 29, your time is up.

Number 29, your time is up.

Earlier this week I noticed a few bees flying under the DIY open mesh floor (OMF) from behind one hive. It’s not unusual to have bees at knee height during inspections but since all I was doing was dropping a nuc off in the apiary I didn’t give it much more thought.

Later in the week I returned to do the weekly inspection.

There were more bees going underneath the hive.

With a bit of effort I peered under the floor to find a 5cm deep slab of bees almost entirely filling the space under the OMF.

Better notes means you know what to expect

My notes were much more comprehensive this time 😉

I knew that the colony had a 2018 white marked and clipped queen.

I removed the supers (which were reassuringly heavy) and quickly inspected the brood box.

Lots of bees, lots of sealed brood, some late-stage larvae but no eggs.

In addition I could see two queen cells … one sealed and one about 3-4 days old, unsealed and with a fat larva sitting in a thick bed of Royal Jelly.

Don’t panic

It was pretty obvious what had happened.

The colony had swarmed 6 but the clipped queen, being unable to fly, had crashed to the ground in a very unregal manner, climbed back up the hive stand and sheltered under the OMF. The swarm had then clustered around her.

They had probably been there for a few days.

Another swarm hived

I placed a new floor and brood box next to the swarmed colony, with the entrance facing the ‘back’. I removed the swarmed brood box and, with a sharp shake, dumped the entire slab of swarmed bees from underneath the OMF into the new hive.

Before adding back all the brood frames I peered into the box as a tsunami of bees started moving from the floor up the side walls.

There! A white marked clipped queen 🙂

White clipped and marked queen returning to the colony

You’ll now have a better chance of finding and keeping her if they swarm.

It’s always reassuring to know where the queen is … and to have good enough notes to know what to look for 😉

I assembled and closed up the new hive and put the swarmed hive back in its place. I then carefully went through every frame checking for queen cells again.

There were only two. I destroyed the sealed cell. I didn’t know how old it was and couldn’t be certain it contained a developing queen.

In contrast, I could ‘age’ the unsealed cell (3-4 days) and knew it contained a larva and copious amounts of food.

I prefer to know when a queen emerges rather than save a few days by leaving the sealed cell. I only generally leave one cell to prevent casts being lost.

There were very young larvae in the colony. It is therefore possible the bees could generate more queen cells in the next day or so. Since I know when the queen will emerge I can check the colony before then and destroy any further cells they generate.

Two swarms, the same outcome … lessons learned

As far as this beekeeper (and I hope the bees 7) is concerned both swarms had a satisfactory outcome.

A number of lessons can be learned from events like these:

  • All beekeepers ‘lose’ swarms. Weather, work, emergencies and life generally can conspire to interrupt the 7 day inspection cycle. Sod’s Law dictates that when it does, the colony will swarm. I’m reasonably conscientious about inspections but I completely missed the signs the home apiary colony was about to swarm.
  • The weather can change suddenly. The swarm in the conifer would have probably perished from the cold in early May. If the weather had stayed warm the scout bees would have found a welcoming church tower or roof space to occupy in a day or so. In both cases the swarm would have been truly lost.
  • It’s always good to carry equipment to capture a swarm. A sheet and a skep, or a large nuc box. Secateurs make ‘gardening’ easier (mine are no longer AWOL). Spare equipment (hives) is essential during the swarm season.
  • An obviously smaller-than-expected colony and a nearby swarm may well be completely unrelated. Check why the colony is weak and take remedial action if needed (mine has Apivar strips in now).
  • Colonies near my out apiary appear to have high mite levels. Since that’s where the conifer swarm came from this also now has Apivar strips in.
  • When is a lost swarm not lost? When the queen is clipped. The queen cannot go far so neither can the swarm. If she returns to the hive stand or the underside of the floor, so will the swarm. If she perishes for some reason the swarm usually returns to the original hive.
  • You can keep bees without knowing where the queen is, but it’s easier if you do. Marking her helps find her, clipping her wing helps keep her there 8.
  • Similarly, knowing when the queen will emerge allows you to predict when she will be mated and start laying. You can avoid interrupting her returning from her mating flight and – before then – you can remove other queen cells to prevent the loss of a cast from a strong colony.
  • Good notes help. Keep them 😉

It’s relatively easy to find unmarked queens in smallish colonies early in the season. It’s a lot harder to find them in a strong colony in mid-May.

Mid-May ... 45,000 bees, 17 frames of brood, one queen ... now marked

Mid-May … 45,000 bees, 17 frames of brood, one queen … now marked and clipped

But it’s worth finding her, marking her and clipping one wing.

If you don’t the swarm you lose might really be lost 😉


 

 

And they’re off …

I posted last week on the relative lateness of the start of the beekeeping season here in Scotland 1. Having been away for a few days I was both surprised and disconcerted to find this waiting for me when I arrived at the apiary to conduct the first inspections of the year.

When is a swarm not a swarm?

When is a swarm not a swarm?

Surprised because I’d missed all the seasonal clues that indicated swarming might be imminent.

Disconcerted because, in the interests of full disclosure, I’d have to admit to it 😉

The colony behind the near-invisible one inch entrance hole through the bee shed wall is a double brood colony in an Abelo poly hive. It was headed by a 2018 queen (or had been 🙁 ) and had a nice temperament and good manners.

The queen was marked blue and one wing was clipped to prevent her flying off.

But it wouldn’t have stopped her trying to fly off. Instead she would have ignominiously spiralled to the ground 2.

Usually what then happens is she attempts to climb back up and the swarm gathers around her. In a standard hive this is often this is underneath the hive stand.

My guess was that she’d made it up to the landing board and stopped or got stuck there.

I had a gentle prod about in the beard of well-tempered bees but could see no sign of her.

With about 20 more hives to inspect I quickly decided to walk them into a fresh hive … I’d let them do this while I got on with other colonies in the apiary.

Don’t think, do

Walk this way

Walk this way

I put together a new floor and a brood box of mostly foundationless frames. I put one or two frames of drawn comb in and gently dislodged a couple of clumps of bees into the box.

Within a very short time more bees were marching down the wall of the shed and clustering between the frames of drawn comb in the brood box.

What started as a trickle became – if not a torrent – then certainly a determined stream of bees taking up residence in the new box.

To encourage them I balanced a split board across the tops of the frames to provide a welcoming dark ‘cavity’ for them to occupy. Very soon you could see bees fanning strongly at the opening between the split board and the shed wall.

Fanning workers

Fanning workers

I interpreted this as meaning the queen had entered the box and the workers were encouraging others to join her.

After an hour or so I moved the hive a few inches away from the shed wall, placed a crownboard and roof on and carried on inspecting other hives in the apiary. By this time about 75% of the bees had left the ‘swarm’ and entered the brood box.

Not so fast

And that’s when everything ground to a halt.

There were no bees fanning at the hive entrance. No more bees entered the box through the entrance. Instead they started leaving in dribs and drabs.

I’ve hived swarms like this before, or done the classic ‘walk them up a sheet’ having dumped them from a skep outside a hive. Other than this being a real spectacle, one of the striking features is that what starts as a mass of bees ends being an absence of bees … they all enter the hive.

'Walking' a swarm into a hive

‘Walking’ a swarm into a hive

Clearly something was wrong and I was beginning to suspect that there wasn’t a queen in the ‘swarm’ at all.

So I did what I should have done in the first place. I had a look in the original hive.

Hello there!

Blue skinny queen

Blue skinny queen

I smoked the double brood box gently from the bottom, intending to encourage the queen (if she was there) into the upper box.

The box was busy but not packed with bees 3, there were good amounts of sealed brood (and a really nice tight laying pattern on many frames).

There were quite a few ‘play cups’ and a few had eggs in them. This is one of the early signs of swarming.

I found the queen on the 19th of 22 frames.

Perhaps I was too gentle with the smoke 🙄

She was the queen I was expecting. Marked blue, though the paint was beginning to rub off a bit, and with the left wing clipped.

She looked like she had lost a bit of weight.

Big fat queens in full laying mode (which they should be getting to by late April) aren’t very aerodynamic so workers slim the queen down before swarming to improve her flying ability.

This queen looked to me like she’d been on the F-plan diet (but remember I’d not seen her since last August). In addition, the number of eggs in the colony was relatively low. This would also be expected if the colony had been preparing to swarm as queens reduce their laying rate in the few days before swarming.

What else could be seen?

Stores and pollen levels were good.

The notable absence from the hive was of well developed, sealed or unsealed queen cells.

A colony will normally swarm once developing queen cells are capped. A colony with a clipped queen often delays swarming for a few more days. It’s therefore usual to find sealed queen cells in a swarmed colony. There may also be unsealed cells as well.

~3 day old queen cell ...

~3 day old queen cell …

There wasn’t anything close to a sealed queen cell in the colony 4. The best developed were, at the very most, a couple of days old.

So what happened?

Other than the absence of well developed queen cells the colony looked as though it had swarmed.

If it walks like a duck etc.

Since the queen was clipped she had eventually clambered back to the hive and re-entered, leaving many of the workers who had left with her clustered around the hive entrance.

That’s currently my best guess 5.

If that was the case, notwithstanding the current lack of well-developed queen cells, they’d be trying again as soon as the weather was good enough. I therefore decided to preempt them by doing a classic artificial swarm.

I moved the queen on a frame with a small patch of brood into the box I’d used to try and ‘walk’ the swarm into. I then moved the – now queenless – double brood box a couple of metres off to one side in the shed. Finally I placed the queenright box in the place the original colony had occupied.

And what will happen?

Full details are in the description of Pagden’s artificial swarm. The flying bees from the double brood box will return to the box with the queen. The hive bees in the double brood box will start to rear one or more new queens.

And at that point I’ll intervene.

The double brood box has lots of brood and stores spread across 21 frames. The bees are well tempered, stable on the comb and have no significant signs of chalkbrood or other diseases (and Varroa and virus levels are exceptionally low – I’d measured both 6).

They are a good stock to make increase from.

I’ll check them in a  few days and see how queen cells are developing. Once there are good sealed cells I’ll split the colony into several 3-5 frame nucleus colonies. The final number will depend upon the number of good queen cells and the number of bees left in the colony.

It should be possible to generate half a dozen good nucleus colonies from a suitable double brood colony without too much of a problem.

First inspection summary

I got through all my colonies (eventually). With a reasonable number to compare it’s easy to define the good, the bad and the indifferent ones.

It’s much easier to do this once the season is properly underway, which is a good reason not to inspect too soon in the year. Some colonies are very early-starters, others lag bit. If you inspect too early you might consider the slow ones are dud or failed queens.

I was pleased to see that most were good or at least indifferent, with only a couple clearly exhibiting undesirable personality traits – aggression, laziness, running, following – or, in one case, disease (rather too much chalkbrood). These will be destined for prompt requeening and drone brood will be removed to reduce their contribution to the gene pool.

My overwintered 5 frame nucs looked excellent, with a couple needing re-hiving immediately.

Here's one I prepared earlier

Here’s one I prepared earlier

The first inspection is really little more than a check that things are all OK. It doesn’t matter whether I see the queen. If there are eggs present I’m happy.

Eggs? Overt disease? Stores? Brood? Space? … next please!

Overwintering losses

I lost 10% of my colonies this winter – two from 20. This includes both full colonies and overwintered 5 frame nucs.

One colony drowned. The lid and crownboard blew away in a severe storm and they were subjected to a three-day deluge over a long weekend when I was away.

Mea culpa. I should have had more bricks on the roof.

Spot the drone laying queen

Spot the drone laying queen

In the second colony the queen failed and turned into a drone laying queen (DLQ). This had been my worst-tempered colony last year and was scheduled for requeening. However, the queen I found wasn’t the clipped and marked one I’d left there in August. Clearly there had been a late-season supercedure and the replacement queen was poorly mated.

Although she was a bee I didn’t keep it is great to be beekeeping again 🙂


Colophon

And they’re off! is the phrase used by horse racing commentators at the start of a race. It is also the title of a song composed by William Finn from the musical A New Brain. The song is about the damage gambling does to families. There’s a good cover version by Philip Quast on YouTube.

Natural vs. artificial swarms

I’ve now covered four of the most frequently used swarm control strategies. These are:

  • Pagden’s artificial swarm – the horizontal splitting of the colony
  • The vertical split – an equipment-frugal variant of the above involving a vertical separation of the colony
  • The nucleus method – in which the queen is removed with sufficient workers to make up a small (nuc) colony, leaving the original colony to rear another queen
  • The Demaree method – which, at its simplest, relocates the queen from the brood and associated nurse bees, but does not physically split the colony

If conducted correctly all should prevent loss of a swarm. However, the individual methods – even the first three which involve the physical separation of the bees in the hive – are not the same.

In addition, these swarm control methods do not recapitulate the separation of bees that occurs when a hive naturally swarms.

The purpose of this post is to contrast the original and new colony composition of the split-based methods of swarm control (i.e. Pagden and vertical) with natural swarms.

Temporal polyethism

I introduced this term when discussing the honey bee colony as a superorganism. It means that adult worker bees have different roles depending upon their age. For the first two and a bit weeks they have duties inside the hive such as cell cleaning, brood rearing and wax production.

They then transition through a period of being guard bees before becoming foragers, flying from the hive and collecting water, nectar and pollen.

For convenience I’ll refer to these two groups of bees as young, nurse or hive bees and flying bees.

Vertical and horizontal splits

The classic Pagden artificial swarm and the vertical split are fundamentally the same process.

If unsealed queen cells are found during a colony inspection the queen, with a frame of emerging brood, is moved to a new box. This box is placed on the site of the original hive.

The remaining bees and brood are moved, either to one side in the case of the Pagden or on top of the queen-containing box (separated by a split board) in a vertical split.

Split board ...

Split board …

Critically, the new box with the brood and bees is provided with a new hive entrance, located off to one side or on the opposite side of the original hive 1.

Flying home

Over the following day or two the flying bees leave the relocated brood box with the new entrance and return to the queen-containing brood box in the original location.

As a consequence of their excellent homing navigational skill, the hive manipulation results in the separation of the bees into two populations:

  1. The flying bees i.e. those over ~3 weeks of age that had orientated to the original hive location, which are now located with the queen.
  2. The nurse bees i.e. those less than 3 weeks old, which remain in the relocated brood box, together with the brood in all stages (eggs, larvae and pupae).
Artificial swarm separation of the colony

Artificial swarm separation of the colony

How does the artificial swarm compare with the age distribution of bees in a real swarm?

Real swarms

I’ve previously discussed prime swarms and casts. The former contain a mated queen. In contrast, casts are produced from very strong colonies after the prime swarm has left. Casts are headed by a virgin queen. These are sometimes called after swarms and are usually smaller than prime swarms.

What about the workers in the swarm? What might be expected?

Perhaps they’re primarily the older flying bees? After all, these are the bees that have finished their hive duties and are now routinely foraging outside the hive. It’s the natural place for them.

Swarm of bees

Swarm of bees

Alternatively, remember that swarms have no ‘homing’ instinct for a day or two after emerging. They can be readily moved and you can safely ignore the less than three feet or more than three miles rule. Perhaps this means that they’re primarily young bees that have yet to go on their orientation flights?

Real experiments and contradictory results

Enough speculation … how do you determine this experimentally?

There have been numerous studies of the age distribution of bees in natural swarms. However, the data tends to be rather contradictory though the methods used are often broadly similar.

How do you determine the age composition of workers in a swarm?

Essentially you ‘spike’ the colony with a set number of marked bees of a known age over about 8 weeks. This is easy to do, but tedious.

Workers are allowed to emerge in an incubator. On the day of emergence (0 days old) they are marked with a colour that distinguishes them from older or younger bees. Every three days 100 identically marked i.e. same age, bees are added to the study hive(s). Over the period May to July this will accumulate red, then yellow, then blue, then mauve, then cyan, then pink etc. cohorts of workers, each representing a known age class.

It must be a nightmare spotting the queen in these hives 😉

The colony is allowed to swarm, the swarm collected and the number of bees of the different age cohorts in the swarm counted.

I missed a step out there. Have you ever tried counting the bees in a swarm? It’s much easier if they don’t move.

1002, 1003, 1004, 1005, er, where was I? Damn!

1002, 1003, 1004, 1005, er, where was I? Damn!

Perhaps it’s best that I missed that step out 🙁

What you end up with is a count of the total number of bees in the swarm and the numbers of bees of each 3 day cohort over the last several weeks. You can therefore determine the age distribution of the workers in the swarm.

Is it as simple as that?

I’ve actually oversimplified things a bit. There’s a possibility that different age cohorts of bees die within the hive at different rates, perhaps depending upon forage availability or weather or something else.

Think about it. Assume there was a dearth of nectar in late May and the blue and red labelled cohorts added during that period were underfed and died prematurely.

If there were very low numbers of blue and red bees in the swarm you might assume that these ages were ‘left behind’ by the swarm … when actually they weren’t able to swarm at all.

The real question is therefore whether the age distribution of bees in the swarm is similar to that in the parental hive.

OK, OK … is it?

No.

Swarms do contain bees of all ages.

However there are significantly more young bees and many fewer old bees than would be expected from the age distribution of workers in the parental colony.

Age distribution of bees in swarms

Age distribution of bees in swarms

The o and e in the graph above represents the position of the observed and expected median age class for the expected distributions. So, in swarm C the observed median age is ~10 days old, whereas the originating hive median age was ~19 days.

The graph above comes from a 1998 study by David Gilley 2 and supports earlier work 3 by Colin Butler 4 which is often cited as one of the definitive studies on the ages of bees in a swarm.

Additional considerations

Is it surprising that young bees predominate in natural swarms?

Swarms usually emerge from the hive late morning or early afternoon on warm, sunny days. In fact, at exactly the time most older bees aren’t in the hive anyway because they’re out and about foraging.

Remember also that swarming is a precarious activity for the colony. Most swarms do not survive 5. Natural selection will have resulted in swarm populations that maximise their chance of survival.

Once bees start foraging their life expectancy is pretty short. It has been estimated that they experience about 10% mortality per day. If only old bees left in the swarm with the queen the newly established colony would very rapidly dwindle in size, perhaps before significant numbers of new brood emerged (which takes 21 days from the first egg being laid). This would likely limit the chances of survival of the new colony.

What has this got to do with artificial swarms?

As beekeepers (or at least as responsible beekeepers) we spend May and June rushing about like headless chickens trying to control swarming in our bees.

Many of us achieve this using a variety of methods which are generically referred to as artificial swarms. I suspect that many beekeepers think that the artificiality is because of our interventions.

Where have all my young girls gone?

Where have all my young girls gone?

It is … but it’s worth remembering that the artificial swarms we generate are very different in composition to natural swarms. Our artificial swarms predominantly leave the older bees associating with the queen, with the young bees remaining with the brood.

These old bees have to draw new comb and rear the new brood. These are activities they last did weeks ago (a long time in the life of a bee).

Final thoughts

There are artificial swarm control methods that were developed to better replicate the age distribution of bees in a natural swarm. One example of these is use of a Taranov board. I’ll cover this in a future post.

It’s also worth noting that the bees of different ages in a natural swarm have different roles even before they occupy a new location. The older bees form a mantle around the bivouacked swarm that protects it from inclement weather (amongst other things) and the oldest bees are the scouts responsible for finding a new nest site.

Again, both topics for another post … I’ve got bait hives to set out 🙂


 

Bait hive guide

Spring this year is developing well. Even here on the chilly east coast of Scotland colonies are looking good and flying strongly when the sun is out. Large amounts of pollen are being taken in and there’s every sign that the hives are queenright and rearing lots of brood 1.

It’s too soon 2 to open the colonies but it’s not too soon to be thinking about the consequences of the inevitable continued expansion over the next few weeks.

Most healthy colonies will make preparations to swarm, often between late April and mid-June. The timing varies depending upon a host of factors including colony strength, climate, weather, forage, build up and beekeeper interventions.

Swarm prevention and control

You, like all responsible beekeepers, will use appropriate swarm prevention methods. Supers added early, ensure the brood box has space for laying etc.

In due course, once the colony gets bigger and stronger, you’ll notice queen cells and immediately deploy your chosen swarm control method e.g. the classic Pagden artificial swarm, the nucleus method I described last week, Demaree, vertical splits or – if you’re feeling ambitious – a Taranov board 3.

Which will of course be totally successful 😉

But just in case it isn’t …

… and just in case the beekeeper a couple of fields away is forgetful, unobservant, clumsy, on holiday, in prison or has some other half-baked excuse, be prepared for swarms.

As an aside, other than just walking around the fields, you can easily find hives near you by searching on Google maps and you can get an idea of the local beekeeper density 4 using the National Bee Unit’s Beebase.

You might think you know all the local beekeepers through your association, but it’s surprising the number who just ‘do their own thing’.

Swarms

This isn’t the place to discuss swarms in much detail. Here’s a quick reminder:

  1. The colony ‘decides’ to swarm and starts to make queen cells.
  2. Almost certainly, scout bees start to check out likely sites the swarm could occupy in the future 5.
  3. The swarm leaves the hive on the first calm, warm, sunny day, usually early in the afternoon, once the queen cells are capped. The prime swarm contains the mated, laying queen and about 75% of the worker bees 6.
  4. The swarm gathers around the queen and sets up a bivouac hanging from a convenient spot (tree, gatepost, bush, fence etc.) near to the hive. They rarely move more than 50 metres. It’s worth emphasising here that the spot they choose is convenient to the bees, but may be at the top of a 60 foot cypress. It may not be particularly convenient for the beekeeper 😉
  5. Scout bees continue to check out likely final sites to establish the new colony, returning to the swarm and ‘persuading’ other scouts (by doing a version of the waggle dance) so that, finally, a consensus is reached. This consensus is essentially based upon the suitability of the sites being surveyed.
  6. The scout bees lead the swarm to the new location, they move in and establish a new colony.

If you’re lucky you will be able to recapture the swarm if the spot they choose for their bivouac is within reach, not above a stream, in a huge thorny bush or on an electricity pylon.

A small swarm ...

A small swarm …

I say ‘recapture’ because, since the bivouac is usually near the issuing hive, it’s probably come from one of your own hives (unless you are snooping around your neighbouring apiaries 7).

But what if you miss the bivouacked swarm? Or if your neighbour misses it?

Those bees are going to look for a suitable location to set up home.

If you provide a suitable location, you can get them to hive themselves without the grief of falling off a ladder, toppling into a stream, getting lacerated with thorns or electrocution

This is where the bait hive comes in. Leave a couple in suitable locations and you can lure your own and other swarms to them.

Freebees 🙂

What do scouts look for?

The scout bees look for the following:

  1. A dark empty void with a volume of about 40 litres.
  2. Ideally located reasonably high up.
  3. A solid floor.
  4. A small entrance of about 10cm2, at the bottom of the void, ideally south facing.
  5. Something that ‘smells’ of bees.

What I’ve just described is … a used beehive 8.

More specifically, it’s a single National brood box (or two stacked supers) with a solid floor and a roof, containing one old dark frame of drawn comb pushed up against the back wall.

No stores, no pollen 9, just a manky old dark comb. The sort of thing you should be turning into firelighters.

That’s all you need.

However, you can improve things by giving the bees somewhere to start drawing comb and siting the hive in a location that makes your beekeeping easier.

Des Res

The first thing swarms do when they move in is start drawing comb. You can populate the bait hive with a few foundationless frames so they’ve got somewhere to start.

Bait hive ...

Bait hive …

In my view foundationless frames are much better than frames with foundation for bait hives. The scout bees measure the size of the void by flying around randomly inside 10. If you have sheets of foundation they’ll crash into it frequently, effectively giving them the impression that the void is smaller than it really is. And therefore making it less attractive to the scouts.

You can improve the smell of the hive by adding a little lemongrass oil to the top bar of one of the frames. Don’t overdo it. A drop or two every 7-10 days is more than ample.

If you do use foundationless frames make sure the hive is level. If you don’t the comb will be drawn at an angle to the frames which makes everything harder work later in the season. Your smartphone probably contains a spirit level function that makes levelling the bait hive very easy.

Location

But not if it’s above head height, or you’re teetering on top of a ladder …

It was Tom Seeley who worked out most things about scout bees and swarms (see his excellent book Honeybee Democracy). This included the observations that they favoured bait hives situated high up.

Believe me, it’s a whole lot easier if the bait hive is on a standard hive stand. It’s easier to level, it’s easier to check and it’s easier – in due course – to retrieve.

Bait hive

Bait hive

I’ve previously discussed how far swarms prefer to move from their original hive. Contrary to popular opinion (and perhaps illogically) they tend to prefer to move shorter distances i.e. 20m >> 200m >> 400m. However, there are also studies that show swarms moving a kilometre or more.

Don’t get hung up on this detail. Stick out a bait hive or two and, if there are swarming colonies in range, they’ll find it.

I always leave a bait hive in my apiaries and one or two in odd corners of the garden. In the last few years I’ve never failed to attract swarms to the bait hives, and know for certain that some have moved in from over a mile away as the bee flies (thanks Emma 😉 ).

Mites and swarms

Assuming you don’t have the luxury of living in Varroa-free areas of the UK (or anywhere in Australia) then the incoming swarm will contain mites. Studies have shown that ~35% of the mite population of a colony leaves with the swarm.

But, for about the first week after the swarm sets up home in your bait hive, what’s missing from the new arrivals is sealed brood. Therefore the mites are all phoretic.

Do not delay. Treat the swarm with an appropriate miticide to knock back the mite population by ~95%. An oxalic acid-containing treatment is ideal. Single dose, relatively inexpensive, easy to administer (trickled or vaporised) and well tolerated by the bees.

Varroa treatment ...

Varroa treatment …

You have eight days from the swarm arriving to there being sealed brood in the colony

Far better to slaughter the mites now. In a few months their numbers will have increased exponentially and the majority will be in capped cells and more difficult to treat.


 

Superorganism potential

The term superorganism can be used to refer to a colony of honey bees. The term gained prominence in the mid/late noughties having been reintroduced by the world-renowned myrmecologist 1 E.O. Wilson.

Bees, like ants (myrmex, “ant”, from the Greek μύρμηξ), are social insects in which there are divisions of labour. Different individuals within the colony perform different tasks. Some of these roles are defined by the castes in the colony – queen, worker and drone in a colony of honey bees for example – and some are defined by physiological differences between individual members of the same caste.

The term superorganism describes the entirety of the colony and is defined as a group or association of organisms which behaves in some respect like a single organism.

Essentially, a superorganism has characteristics and behaviours that the individuals within the colony – due to caste or physiological specialisation – do not exhibit.

The superorganism operates as a unified entity, collectively working together to maintain and reproduce the colony.

Division of labour and temporal polyethism

Drones and queens have relatively straightforward roles in the colony. Drones, like teenage boys, lounge around eating and thinking about sex. The queens are egg-laying machines.

An egg laying machine

An egg laying machine

Although there’s undoubtedly work involved in laying your bodyweight in eggs at the height of the season, the real work in the colony is – appropriately – done by the workers.

Worker bees exhibit temporal polyethism i.e. they display different patterns of behaviour depending upon their age. They have a maturational schedule in which they sequentially undertake age-correlated roles in the colony:

  • Young bees work in the hive in a series of roles starting with cell cleaning (days 1-2), nursing developing larvae (nurse bees; days 3-11) and wax production (days 12-17).
  • After two to three weeks the workers undergo significant physiological changes (weight loss, changes in immune function, reduced stress resistance) which prepare them for a productive life outside the hive. During this period the bees transition through a period when they act as guard bees.
  • Older bees (the ‘flying’ bees) perform a range of foraging activities including water carrying, pollen collection and nectar gathering.

And then they die in the field 🙁

Behavioural plasticity

This behavioural maturation is controlled by a so-called negative feedback loop between vitellogenin (Vg 2) and juvenile hormone (JH).

Nurse bees have high Vg levels which are reduced at the transition to foraging. Conversely JH levels increase with the onset of foraging (I know this sounds counterintuitive). These changes are responsible for a range of physiological changes in the worker bee.

Behavioural maturation in worker bees

Behavioural maturation in worker bees

But it’s not as simple as that. High Vg levels can block JH synthesis, so delaying maturation and foraging. Similarly, JH may reciprocally inhibit Vg synthesis and induce early foraging.

Clearly that last couple of sentences indicates that worker maturation is not an invariant process. It doesn’t always occur after 2-3 weeks.

In fact, the maturation or ageing process in honey bees is a very interesting phenomenon.

Ageing exhibits seasonal variability and remarkable plasticity.

Nurse bees can survive for at least 130 days and overwintering bees may survive up to 280 days. Clearly ageing in bees is a remarkably variable process. Overwintering bees ‘mature’ into either nurse bees or foragers. Presumably this has evolved as an effective mechanism of allowing spring colony build up (by having sufficient bees for the different roles) once environmental conditions improve.

In addition, there is another striking feature of the maturation process of honey bees.

Under certain social environmental conditions maturation is reversible.

This reversible maturation can be demonstrated by removing the nurse bees from the hive. Under these conditions some of the younger foragers revert, both behaviourally and physiologically, to nursing tasks. JH levels drop and Vg levels increase.

Old foragers are unable to undergo this rejuvenation.

Reversible maturation in worker bees

Reversible maturation in worker bees

Which finally and in a round the houses way gets me to the subject I meant to cover in the first place this week …

Brood and the superorganism

The honey bee colony superorganism not only contains a queen, workers and drones. It also contains brood. In the following text I’ll use the term brood as a collective noun meaning all the eggs, unsealed larvae and sealed pupae in the colony (unless otherwise specified).

Is the brood a component of the superorganism?

It certainly is.

Laying workers ...

Laying workers …

Remember previous discussion of laying workers. These are workers that lay unfertilised eggs which develop into drones. Egg laying by workers is suppressed by pheromones produced from unsealed brood 3. Therefore brood does influence the behaviour of the colony 4.

If the complete colony – brood, workers, drones and a queen – is a superorganism, which components of the colony, individually or together, have the potential to form the superorganism?

And why should this matter?

Swarming and the superorganism

During swarming, either naturally during colony reproduction, or during manipulation by the beekeeper, the ‘superorganism’ is broken up.

During natural swarming the (old) mated queen leaves the colony with 60-75% of the workers to establish a new colony. By the time the swarm leaves, the original colony – which has all the eggs, larvae and brood (obviously) – is usually already well on the way to rearing a new queen. The (new) virgin queen emerges, gets mated, and the colony has successfully reproduced.

Many of the colony manipulation methods that are used to prevent the loss of natural swarms exploit the potential of the components in the colony to form a complete new colony.

Most ‘artificial swarms’ work by breaking the colony – the superorganism – into two parts:

  1. The queen and the ‘flying’ bees. Even young bees can fly, so the term ‘flying’ bees refers to the older bees from the colony that have matured sufficiently to leave the hive.
  2. The nurse bees and all the brood.
Swarms, splits and superorganisms

Swarms, splits and superorganisms

These two parts both have the potential to create a new colony.

The queen and the flying bees that form the swarm (or the queenright part of an artificial swarm) occupy a new site (or hive 5), draw comb in which the queen lays, the larvae are fed 6, pupate and emerge. At the same time, foragers collect the necessary nectar and pollen to maintain the new colony.

The swarmed colony (i.e. the queenless part of an artificial swarm) contains ample stores and the nurse bees. What they don’t have is a queen. But they do have eggs and young larvae. The nurse bees select and feed one or more of these young larvae with copious amounts of Royal Jelly. A few days later a virgin queen emerges, matures, mates and returns to the colony to start laying eggs.

Sealed queen cell ...

Sealed queen cell …

Therefore both natural and artificial swarms exploit the potential in both parts of the original colony to eventually reproduce the colony.

No potential

Not all components of the colony have the potential to give rise to a new colony or superorganism. A solitary queen doesn’t even have the ability to feed herself properly, let alone double up for egg laying and nursing larvae duties.

This comes as a surprise to some people. If you frequent any of the online discussion forums you’ll sometime see questions posted like this:

What sort of hive do I need to buy to put a queen bee in to make honey?

Followed by some polite, or not so polite, responses saying that there’s a little bit more to beekeeping than that 7.

The ‘flying’ bees alone, in the absence of a queen, also have no potential. They can lay eggs (as laying workers, see above), but since the eggs are unfertilised the colony will be doomed. It’s not unusual for a queen from an artificial swarm (or from a cast) to fail to return from a mating flight, so condemning the workers in the hive to oblivion.

Swarms and behavioural plasticity

The classic artificial swarm involves moving the nurse bees and the brood to a new site, leaving the queen and the flying bees in the original location.

You do this so that the flying bees that have orientated to the position of the original hive – whether out in the field actively foraging or in the moved hive – eventually return and so become separated from the nurse bees and the brood.

In doing this you remove the urge to swarm and you weaken the queenless hive.

The majority of those flying bees are foragers.

And this is where behavioural plasticity is essential. remember that the artificial swarm predominantly contains foragers, not the nurse bees needed to feed developing larvae.

Some of these foragers undergo rejuvenation to produce wax or to become nurse bees. These build new comb and, in a few days, feed larvae that have hatched from the eggs laid by the queen.

This behavioural plasticity contributes to the potential of the artificial swarm to produce a new colony or superorganism.

A small swarm ...

A small swarm …

Do the same processes happen in natural swarms?

That requires a discussion of the worker composition of swarms which is not straightforward and will have to wait for another day 😉


 

Swarm and mite partitioning

Clipped queen swarm

Clipped queen swarm

When a honey bee colony swarms, what proportion of the bees in the colony leave with the queen?

A simple question and one that has been addressed using elegantly simple experiments.

But swarms don’t leave without also taking Varroa mites with them 1.

What proportion of the Varroa mites in the colony leave with the swarm? In both cases partitioning refers to the proportion that remains with the original colony (bees or mites) and the proportion that disappears over the fence (or appears in your bait hive).

Why does this matter?

If you’re interested in honey from your bees the answer to the first question is very relevant. The more bees that leave, the less remain to forage … so you’ll get less honey.

If you collect swarms or use bait hives to attract them, the answer to the second question is particularly relevant as it emphasises the importance of Varroa treatment of newly-hived swarms.

Does size matter?

Colonies swarm when they are strong, which is usually – but doesn’t have to be – when the colony is big. There are a number of factors that influence swarming, but the strength of the colony i.e. lots of bees in the space available, is one of the most important. A strong nucleus colony of only 3 frames will swarm under similar conditions that induce a huge double-brooded hive to swarm; the latter might contain 75,000 bees, the former perhaps only about 7500.

In addition, because the survival of swarms is influenced by their size (see below) we need to be aware that large and small colonies may behave differently. For example, if only 5000 bees formed a ‘viable’ swarm, the 3 frame nuc described above could generate just one, whereas the double-brooded monstrosity could produce a prime swarm and loads of similarly-sized casts 2. Since swarms of all sizes are seen, it suggests a fixed proportion of the bees leave, rather than a fixed amount …

Counting the bees in a swarm

Occupied bait hive

Occupied bait hive …

Counting large numbers of bees is not a trivial task. Of course, counting the bees in a swarm is pretty straightforward … catch the swarm, weigh it and divide by the weight of a ‘single bee’ 3.

But this doesn’t tell you the number of bees in the original hive. You need to know this to determine the proportion of bees that leave with the queen.

Thomas Seeley from Cornell University used an elegant solution 4 to count the size of the original colony before and after swarming. He established several 3-frame narrow observation hives between gridded glass panels. The hive was so narrow that only a single layer of bees could occupy the beespace between the glazing and the comb. By counting bees in about 10% of the grid squares, averaging and multiplying he could accurately determine the total number of bees in the colony … which was about 7600.

He determined the number of bees in the colony early every morning during the swarming season. Immediately after swarming he counted the bees remaining in the hive. By dividing the number of bees present after the swarm left with the number present that morning he could determine the proportion of the adult workers present in the swarm.

And the answer is …

75%

When Seeley’s small colonies swarmed, 75% of the workers departed in the swarm 5. This figure is in good agreement with previous studies conducted by Getz and colleagues 6 using two larger colonies (~30,000 bees in each, 72% of which left with the swarm), and with work from the 1960’s 7 using small and large colonies (73% and 66% respectively).

Swarm partitioning therefore appears to be colony size-independent, with about 75% of the adult workers departing with the queen.

So, if size doesn’t matter, why does size matter?

A small swarm ...

A small swarm …

Juliana Rangel and Thomas Seeley went on to establish swarms of different sizes – small medium and large, containing 5000, 10,000 and 15,000 bees respectively … and a queen. The large swarms developed into fully-established colonies better (drawing more comb, collecting more nectar and rearing more brood). Most significantly, large swarms had a much higher survival rate. Almost 90% of the small or medium swarms failed to overwinter, whereas 75% of the large swarms survived.

Again, there were precedents for this … in the mid-80’s Lee and Wilson had monitored survival of natural swarms and showed that larger swarms were more successful.

So size matters for swarm survival.

This is perhaps not surprising when you consider all the ‘work’ the colony needs to do to survive the winter – draw out a large area of comb, store about 20kg of honey and rear thousands of new workers.

In addition, it turns out that larger swarms are probably better at choosing suitable nest sites to occupy. This is because they have a larger number of scout bees to find the sites faster, thereby improving the decision-making process.

And, of course, size also matters if you want your colonies to spend their time collecting nectar for honey production. When a colony swarms 75% of the workforce leaves and, inevitably, the productivity of the hive is significantly reduced for an extended period.

Mite partitioning … simple maths surely?

The only mites that can leave the colony when it swarms are those that are phoretic i.e. riding around the colony on adult bees. The remainder are safely tucked away in capped cells gorging themselves on pupae.

Poly Varroa tray from Thorne's Everynuc with visible mites.

Gotcha! …

If we assume that all the adult bees are workers 8 it is a simple calculation to work out the proportion of mites in the colony that leave with the swarm … 0.75 * X, where X is the proportion of mites in the colony that are phoretic.

So, if 10% of the total number of mites are phoretic, 7.5% of the total mites would disappear with the swarm. This could explain the small colony size and frequent swarming of Varroa-tolerant feral colonies … every time they swarm, over 90% of the mites are left behind.

But … there’s always a but …

% of mites in capped cells

% of mites in capped cells

The proportion of phoretic mites in a colony is unfortunately not static. It fluctuates with the availability of suitably-aged larvae to infest. It is therefore influenced by the egg laying rate of the queen.

Numbers often quoted for the experimentally-determined proportion of phoretic mites range from 10-50% (or more), a range reflected in a well-established model for the seasonal reproduction of Varroa 9.

Remember that the graph (right) is modelled data. In a real-world situation there will be brood earlier and later in the year. However, in a first attempt at calculating mite partitioning during swarming in May/June the modelled data is close enough to experimentally-determined data to be usable.

Predicted and real mite partitioning numbers

The extreme values from the May/June (the swarming season) predictions in the graph above indicate that phoretic mites proportions range from 15-50% of the total in the colony. A swarm containing 75% of the adult bees in the hive would therefore also leave with somewhere between 11% and 37% of the Varroa from the colony.

The higher of these figures is quoted by Thomas Seeley in his study of the frequently swarming Varroa-tolerant colonies in the Arnot Forest, though this is calculated from his own swarm partitioning studies and data from others, and was not directly measured.

However, Jerzy Wilde and colleagues have conducted one of the few studies that have experimentally measured mite partitioning in natural and artificially-swarmed colonies. Of seven large colonies (~30,000 bees) which swarmed naturally, 25 ± 9% of mites left the colony with the swarm. Using a Taranov board, 36 ± 11% of mites left the colony with the swarm fraction in the artificially-swarmed colonies.

Sublimox vaporiser

Sublimox vaporiser …

A quarter of all the mites in a heavily infested colony is a lot of mites.

Which is why it’s always sensible to treat swarms you catch/attract/buy 10 for mites.

By definition, all the mites in a swarm are phoretic, so they’re easy to kill using miticides – such as those based on oxalic acid (either trickled or sublimated) – that work best on broodless colonies.

Caveats and future considerations

I have a few concerns about the Wilde study. The size of the swarms generated was significantly smaller than usual, containing only ~45% of adult workers. In addition, the initial mite-infestation levels were quite low, implying that the available open brood was unlikely to be rate-limiting in terms of mite reproduction and the phoretic period.

I’ll return to this in a future post but it’s worth remembering that the queen markedly reduces her egg-laying rate as the colony prepares to swarm. This results in fewer 5-day larvae and so decreases the opportunities for phoretic mites to hide themselves in capped cells.

Swarming colonies may actually have elevated phoretic mite levels …


 

Prime numbers and cast offs

This post was prompted by a recent search used to reach this website. The question posed was can a prime swarm be led by virgin queen if [the] old clipped queen dies trying to lead a swarm?”

Swarming is the natural way that honey bee colonies reproduce. The process is triggered by a number of factors – overcrowding and diminishing levels of queen pheromone being two of the most important.

A small swarm

A small swarm …

Both these are, directly or indirectly, measures of how strong the colony is. If the queen has nowhere to lay because the box is wall-to-wall brood or stuffed with nectar, the colony is effectively overcrowded. In contrast, if the colony has ample space but there are so many bees that the queen pheromone is ‘diluted’, the colony will sense this indirect measure of strength and make swarm preparations.

In addition, as queens age they naturally produce less queen pheromone; colonies headed by older queens are therefore more likely to swarm than those headed by first year queens.

Prime swarms

You’ll see two definitions of prime swarms. Some define it as the swarm headed by the mated, laying queen and others use it to mean the first swarm to issue from a hive.

They’re usually one and the same thing.

Developing queen cells in the hive are capped on the 9th day after the egg they contained was laid. If the weather conditions are suitable – typically early afternoon on a warm, sunny day – the mated queen leaves the hive with up to half the workers.

This swarm – headed by the mated queen and often containing perhaps 20 – 30,000 bees – is the prime swarm. It’s the first to leave the hive … but it might not be the last …

Captured swarm in 8 frame poly nuc

Captured swarm in 8 frame poly nuc …

Casts (or cast swarms)

Seven days after the queen cells were sealed the new, virgin queen emerges (or ecloses). For the continued viability of the original colony this queen needs to be mated and return to the colony. She does this on a warm, sunny day a few days after eclosion.

However, there are often several developing queen cells remaining in a hive after a prime swarm disappears over the fence to the howling wilderness.

This is where things get interesting.

All sorts of things can happen at this point. If the colony is strong enough it will throw off one or more casts. These are small swarms, headed by a virgin queen. Small is a relative term. They’re small in comparison to a prime swarm. Once started a colony can continue to throw off smaller and smaller casts. Some are these small in comparison to a mug of tea.

The continued loss of bees means the colony may effectively ‘swarm-out’, reducing in strength until perhaps only 10% of the original colony remains. If this happens any opportunity of a honey harvest is also lost and there’s a chance the colony will not recover sufficiently in time to overwinter successfully.

To complicate matters further, if multiple queens emerge casts can contain more than one queen. Sometimes you’ll open a hive at the same time as multiple queens are emerging. It can be bedlam trying to catch half-a-dozen virgins scuttling around a busy brood box.

Hiving casts

Large casts – perhaps football-sized – are worth catching and dumping into a nuc. Once the queen gets mated they can develop into a worthwhile colony. Ted Hooper describes ‘rescuing’ smaller casts by uniting them over a queen excluder on top of the supers on a strong hive. The bees unite and the queen is prevented from entering the hive by the excluder. I’ve not had to do this. I’ve lost one or two colonies that swarmed out but missed the ever-diminishing casts altogether.

A cast ...

A cast …

The cast swarm above was collected in a skep and allowed to settle for a few hours. When I lifted the skep from the sheet to dump the bees into a nuc there was a single bee corpse remaining … a dead queen. The cast obviously contained at least two queens. On checking the nuc a week later, after a week of almost continuous rain, I found a single skittish queen running around. Her behaviour suggested she hadn’t yet had an opportunity to get out and mate.

A cast in the skep ...

A cast in the skep …

And the answer is … ?

Consider again the original question … can a prime swarm be led by virgin queen if [the] old clipped queen dies trying to lead a swarm?”. The answer isn’t necessarily straightforward.

I think I’d argue that a swarm led by a virgin queen, despite being the first swarm to leave the hive, is not a prime swarm. It’s viability still depends absolutely on the virgin getting mated.

I would consider it as a cast.

Clipped queen ...

Clipped queen …

Clipped queens have one wing trimmed to restrict their flight. This is a well-established method of swarm control. If the colony swarms the queen drops to the ground and the swarm often clusters with her under the hive. Colonies with clipped queens usually swarm a bit later in the development cycle of the new queen(s) in the colony. However, they are only delayed by a day or two.

I’m therefore puzzled why – as suggested in the question – there was both a clipped queen and an emerged virgin in the colony simultaneously. Or perhaps there wasn’t, but the query was whether a subsequent emerging virgin would head the swarm …

I’m afraid the puzzle will remain. The question came from an internet search … unless the person who posed it reads this and responds all we can do is speculate.


Or perhaps to establish themselves in your neighbours soffits. The same neighbour who has always complained about your bees chasing their dog and stinging their children. Reason enough to try and not lose swarms.

‡ I know this was a cast headed by a virgin queen because it came from a vertical split in which the queenless half was left overly strong. The clipped and mated queen was ‘all present and correct’ in the queenright half of the split – I checked. I’m intending to write a bit more about how to prevent casts in the future … once I’m a little better at it than I’ve been this Spring  😥

Scouting for girls

A swarm of bees is a wonderful sight … if it’s arriving in your bait hive. It’s still dramatic, but perhaps slightly less wonderful, if it’s disappearing over the fence from your apiary 😉

Although some will disagree, I think beekeepers have a responsibility to both control swarming of their own stock, and capture – or attract – swarms lost by others. Although perhaps incomprehensible to us, some don’t share our passion for bees. Many are frightened and a large swarm is an intimidating sight for the melissophobic.

A small swarm ...

A small swarm …

Aside from frightening people, if they move into the church tower or an old hollow tree, they’re likely to develop high levels of Varroa and the pathogenic viruses the mite transmits. As a consequence, they can act as a source of disease to bees in local apiaries, until they’re killed off in the winter. Which they almost certainly will be.

I therefore always put out bait hives in late Spring, well ahead of the expected start of the swarming season (which often coincides with the oil seed rape finishing). I’ve described the basics of bait hives previously – a National-sized, bee-smelling box containing one frame of old, dark comb and half a dozen foundationless frames. I often use stacked supers from the, otherwise-awful, Paradise poly hives for this purpose.

Dyb dyb dyb

One of the greats sights of the swarming season is the appearance of the first scout bees at the bait hive. First one or two, then a dozen and, within hours or days, hundreds. They check out the entrance and the inside the bait hive. They fly all around the perimeter. They’re unaggressive and you can get up close to watch them at work. If you listen carefully you can hear them pinging into the sidewalls and floor of the bait hive as they move about inside.

They actually probably measure the volume by a combination of walking around the inner walls and determining the mean free path length – the average length of all straight lines from wall-to-wall in the hive – in short flights. For an interesting and easily readable discussion of the physics behind this I recommend the short paper by Nigel Franks and Anna Dornhaus (PDF) How might individual honeybees measure massive volumes?

In my view, this alone is a good reason to use foundationless frames in a bait hive.

Scouts often arrive early at the bait hive and leave late. Their numbers will fluctuate with weather and temperature – they’ll disappear altogether in the rain, but reappear in force once a shower has passed.

Scouting around

This short video was taken about 9am, two or three days before a large prime swarm occupied the bait hive. The first scout bees I’d seen had been almost two weeks previously. By midday there were hundreds of bees checking the hive.

However, if you look closely, their behaviour is distinctively different from a colony ‘in residence’. They’re much more hesitant in entering the hive and they tend to check the immediate environment much more closely. In contrast, foragers returning to a colony don’t bother doing a couple of laps of the hive … they approach directly and enter with minimal delay.

Seeley’s swarms

The definitive guide to how scout bees choose suitable locations and then ‘persuade’ the swarm to relocate is Honeybee Democracy by Tom Seeley. This is an outstanding book, beautifully written and illustrated.

Swarm of bees

Swarm of bees

Swarming is a two-stage process. The queen and flying bees leave the hive and settle nearby – on a branch, a fence post or (irritatingly) the top of a nearby conifer – creating the classic ‘beard-shaped’ cluster of bees. If you’re lucky with your timing and their location you can knock these into a box and, voila, you have a new colony.

Tom Seeley describes his own studies (based on the equally elegant work of Martin Lindauer in the 1950’s) that determine how scout bees convince the swarm to move from this temporary staging post to a new nesting location – a tree cavity, the church tower or your bait hive. The scout bees use a variation of the classic waggle dance – on the surface of the swarm hanging in the tree – to ‘persuade’ other scouts to check out the location they’ve found. Through repeated cycles of recruitment and reinforcement a consensus is reached and the scouts then lead the swarm to their new home.

That’s the abridged version. Read the book. There are subtleties and anecdotes throughout Honeybee Democracy that mean it’s the sort of book you can go back to time and time again, learning something new each time.

Early scouts

I was puzzled by the swarm that arrived in my bait hive. The first scouts appeared early in the first week of May. I was abroad from the 7th to the 14th and confidently expected the swarm to be waiting for me when I got back. However, it wasn’t until at least another week had elapsed – during which scout bee interest continued unabated – that the swarm arrived.

Honeybee democracy

Honeybee democracy

I went back to Honeybee Democracy and re-read the second chapter (‘Life in a honeybee colony’) and learnt – or was reminded – that there are early scout bees that are able to judge both nest site quality and the state of the colony preparing to swarm. These scouts are at work before the colony swarms. Uniquely these bees are judging both the availability and suitability of new homes and the readiness of the colony to swarm.

They can also tell whether it’s a nice day. The coincidence of these factors – good weather, readiness of the colony to swarm (i.e. sealed queen cells) and potential nest sites – initiate a behavioural change in these scouts that leads to the colony swarming.

Are these scouts the earliest sign of swarm preparation?

What Seeley doesn’t say is just how early in the swarming cycle these scout bees start their initial explorations.

Queens take 16 days to develop from new-laid eggs to eclosion, and just nine days to the sealing of the queen cell. If we assume that the first scouts I saw were from the same hive that subsequently swarmed (and delivered itself to my bait hive) then these scouts were out and about well-before queen cells were even started.

Of course, I have no way of telling whether the first scouts I saw were from the same colony that finally swarmed and arrived. Nevertheless, it’s an interesting thought. Perhaps scout bee interest in a bait hive pre-dates the first definitive swarm preparation signs beekeepers can usually recognise – the appearance of charged queen cells?

Considering the density of beekeepers (by which I mean apiaries 😉 ) in the UK it’s not easy to see how this would be useful … unless you’re the only beekeeper on an isolated island.

However, if you see do scout bee activity at your bait hives it might be worth being more assiduous than usual when checking your own colonies in the neighbourhood.

 


Dyb dyb dyb is an abbreviation for ‘do your best‘. This was part of a cub (not scout) ceremony and was followed by Dob dob dob (‘do our best‘). It was abandoned in the late sixties, but lives on in tricky questions on Qi.

Colophon

Scouting for Boys

Scouting for Boys …

The title of this post is a play on ‘Scouting for Boys‘, the book on Boy Scout training, written and illustrated (originally) by Robert Baden-Powell and published in 1908. The book contains sections on scoutcraft, woodcraft, tracking, camp life, endurance, chivalry, life saving and patriotism. It was the inspiration for the scout movement and Baden-Powell was the founder and first Chief Scout of the Boy Scouts Association (and the founder of the Girl Guides). It is estimated that 4 million copies sold in the UK alone, with global sales in the 20th Century exceeding 100 million.

The book even contains reference to honey bees with the statement that bees form a ‘model community, for they respect their Queen and kill their unemployed’.

The Boy Scouts of America used to offer merit badges in Beefarming (1915-1955) and Beekeeping (from 1955). The Beekeeping merit badge was discontinued in 1995.

Scouting for Girls is an English pop rock band. They have recently announced their 10th Anniversary Tour (Oct/Nov 2017) which means they’re much too new for me to know any of their music 😉

 

Those pesky mites

DWV symptoms

DWV symptoms

If you haven’t yet treated your colonies to reduce Varroa levels before the winter arrives it may well be too late. High Varroa levels are known to result in the transmission of virulent strains of deformed wing virus (DWV). These replicate to very high levels and reduce the lifespan of bees. If this happens to the ‘winter bees’ raised in late summer/early autumn there’s a significant chance that the colony will die during the winter.

Mite levels in most of my colonies have been very low this year. Partly due to thorough Varroa management in the 2015/16 winter (the only thing I can take credit for), partly due to the relative sparsity of beekeepers in Fife, partly due to the late Spring and consequent slow build-up of colonies and partly due to an extended mid-season brood break when requeening. Most colonies yielded only a small number of mites (<50) during and after a 3 x 5 day treatment regime (to be discussed in detail in a later post) by sublimation.

Infested arrivals

The low mite drop definitely wasn’t due to operator error or vaporiser malfunction. At the same time I treated a swarm that had moved into a bait hive in early June …

Out, damn'd mite ...

Out, damn’d mite …

This is ~20% of the Varroa tray. Have a guess at the number of mites in this view only. Click on the image to read the full legend which includes the mite count.

The image above was taken on the 18th of September, a day or two after starting the second round of 3 x 5 day treatments. The colony really was riddled. When a colony swarms 35% of the mites in the colony leave with the swarm (or, in this case, arrives with it). For this reason the swarm was treated for mites shortly after it arrived in June. It did have a reasonably high mite load but subsequently built up very quickly and didn’t experience the mid-season brood break my other colonies benefitted from.

The colony now has an acceptable mite drop (<1 per day). Similar colonies are still rearing brood – I’ve not checked this one, but they are bringing in some pollen from somewhere – so there’s a possibility the majority of the remaining mites are tucked away in sealed cells. I’ll keep a close eye on this colony through the next few weeks and will be treating again midwinter to further reduce the parasite burden.

Treat ’em right

If you are treating this late in the season make sure you use a miticide that is appropriate for the conditions. Apiguard (a thymol-containing treatment) is almost certainly unsuitable unless you’re living in southern France as it needs a temperature of 15°C to be effective. MAQS has a recommended temperature minimum of 10°C which may be achievable.

Hard chemicals such as Apivar and Apistan can be used at lower temperatures but there’s little point in treating with Apistan unless you’re certain all your mites are sensitive. They almost certainly are not as Apistan/Bayvarol resistance is very widespread in the UK mite population. Just because you get an increased mite drop in the presence of Apistan does not mean treatment has been effective. Perhaps all you’ve done is killed the sensitive mites in the population, leaving the remainder untroubled. This is what’s known as a bad idea … both for your bees next season and for your neighbours.


 I’m posting this now due to the large number of searches for, and visits to, pages on use of Apiguard or other Varroa treatments. These are currently running second to ‘fondant‘ in one form or another.

No, not really …

Was it good for you? … No, not really.

I recently posted the weather forecast for the week beginning the 15th of August. I was pleased that the forecast was for near-perfect queen mating conditions – sunny, warm and calm – as I had three colonies which should have contained virgin queens that were due to emerge a few days before.

The forecast was very accurate. Conditions were wonderful. I wasn’t around as I had disappeared to Torridon and Skye for a few days. On checking the colonies at the end of the week after I returned, all three contained queens at least two of which were laying.

Beinn Eighe

Beinn Eighe …

All good then …

Well, not entirely, because mid-afternoon on the previous Wednesday I’d been sent an email from my friend at the apiary that read … “Incredible roaring noise attracted me outside the workshop – a swarm moving west through the garden and into the trees.  All caught on camera”. I didn’t receive the email as I was in the howling wilderness. Not that I could have done much about it.

A very quick inspection of the colony in question on my return confirmed that they’d swarmed. D’oh! I’d obviously missed at least one additional queen cell (mistake #1) on the last inspection and a large cast (the queen must have been a virgin as the original queen had been removed from the colony) had disappeared over the fence … mistake #2. There was a queen present but bee numbers were significantly down. I closed the colony up and disappeared on business for a further three weeks … mistake #3.

The weather had been great the entire week I was away in Torridon. I suspect the colony swarmed on the Monday or Tuesday, that it hung around in a nearby tree until the Wednesday while the scout bees found somewhere more desirable to relocate to, and that my friend had seen it leaving the neighbourhood that afternoon.

Lessons learned

  1. Don’t let the colony decide how many queens should emerge. Instead leave only one known charged (occupied) queen cell to emerge. I’d left an open queen cell on a marked frame, but had not returned a few days later to check that a) it was safely sealed and b) that they hadn’t raised anymore. They had 🙁  Consequently they swarmed when the first queen emerged, leaving one or more additional queens to emerge, fight it out and then head the now much-depleted colony (see 3, below).
  2. Leave a bait hive in or near the apiary, even if the main period of swarming has passed. I’ve been very successful with bait hives over the years, successfully attracting my own and others’ swarms. In this instance the main swarming period was well-passed and I’d packed away my bait hives until next Spring. Wrong. Had I left one near the apiary I may well have managed to attract the swarm and so a) not lost the bees, and b) not potentially inflicted the  bees on someone else. I view bait hives (and queen clipping) as part of being a good neighbour.
  3. Don’t leave a weakened colony late in season. On returning from my three week absence for work I discovered the colony had been robbed out and destroyed. Clearly it had been unable to defend itself from robber bees or wasps and had perished. I should have instead made an executive decision on discovering the colony had swarmed and probably sacrificed the virgin queen and united the weakened colony with a strong colony nearby. In retrospect this was an obvious thing to do … the colony was weak, wasps were beginning to be a problem, there was little or no nectar coming in and the weather was uncertain. As it turned out the weather was good enough for queen mating while I was away. However, the combination of a dearth of nectar, a weakened colony and strong neighbouring colonies meant that robbing was inevitable and – for the colony in question – catastrophic.
Skye ...

Skye …

Had I thought carefully about things in mid-August I may have been able to prevent the inevitable carnage when the colony was robbed out. In my defence I’ve only been around for a day or two over the last month, with extended periods out of the country on business. Nevertheless, this was clearly a case of a lesson (or three) learned the hard way …


† If you’ve not read Tom Seeley’s outstanding Honeybee democracy about how a swarm decides where to relocate to you should.