Category Archives: Moving colonies

Seasonal scheming

Synopsis : Midwinter is the time for planning and preparation for the beekeeping season ahead. In addition to thinking about the normal season’s events – swarming, mite control, honey etc. – now is the time to be more expansive. What arrangements need to be made for the longer term sustainability of your apiary and beekeeping? 1


Introduction

Now is the winter of our discontent.

So said the young Richard 2 in a soliloquy celebrating the upturn in his fortunes.

For a beekeeper, this upturn might seem a little premature as it’s only 17 days since the winter solstice and there are currently less than 7 hours daylight.

The drowsy days of summer filled with the gentle buzzing of bees seem a lifetime away …

Snowing in the apiary

No cleansing flights today

… and it’s snowing in the apiary.

However, the days are slowly getting longer.

Actually, until the spring equinox, the daylength gets increasingly longer each day – by about a minute and a half on January 1st, to over 4 minutes a day by the end of the month and finally reaching a heady 4 minutes 48 seconds by the 20th of March 3.

All of which means that, although not quite ‘around the corner’ the beekeeping season will be here pretty soon.

So it’s not so much Now is the winter of our discontent as Now is the winter and the best time to prepare for the season ahead and build frames.

I’ve previously posted about building frames, so this post is about planning, though frames might get a mention in passing.

Planning for the season ahead

I was going to title this post Cunning plans but I think most of the cunning plans that Baldrick dreamt up were pretty catastrophic. It seemed sensible to choose a different title.

I have an entire talk on the topic of planning for the season ahead and am giving this talk a couple of times in the next few weeks. To avoid stealing my own thunder 4 I’m not going to talk in general terms about preparing for the season.

Instead I am going to concentrate on the things I’ll be doing in addition to all of the usual activities like swarm prevention, the honey harvest and mite control.

At this time of the year we have the luxury to stare idly off into the middle distance while simultaneously dreaming about bees and polishing off the remains of the Christmas cake. Once the season starts we’ll either be too busy, or there won’t be enough time to make some of the preparations.

So what will I be doing this year that differs from last year, or the one before that?

Long distance beekeeping

I finally moved from the east coast to the western extremities of Scotland last February after a couple of years of spending increasing amounts of time here. I’ve still got bees on both sides of the country (including colonies for research in Fife) and travel to and fro as needed to manage the colonies.

And, frankly, the novelty is starting to wear off.

It can get a bit wearing spending the day working with the bees and then driving for 4-5 hours to get home 5. Beekeeping can be hard work. There are lots of boxes to lift and it can get hot and tiring doing this for hours on a sweltering day in June.

Fortunately, this is Scotland, so the sweltering day bit doesn’t happen all that frequently 😉

However, the physical hard work does happen. I’ve previously calculated – using mental arithmatic on one of those long car journeys 6 – that my spring honey harvest might involve manhandling well over a ton of boxes over a couple of days. And that’s on top of the hive inspections.

Doing this ‘at a distance’ means everything tends to get squeezed into a 2-3 day trip every couple of weeks, or more frequently if I’m queen rearing as well.

OK, I’m not expecting much sympathy as you’ve probably also worked out by now how much honey all those supers contained 😉

Nevertheless, one priority this year is to reduce my hive count on the east coast, and increase it on the west coast.

Think of it as increasing the beekeeping : driving ratio.

Latitude and longitude

Don’t get me wrong, there are advantages of having apiaries 150 miles apart.

For a start, the timing of the key seasonal events – swarming and the nectar flows – are very different. Although there is only a fraction of a degree difference in latitude (perhaps equivalent to ~30 miles), the climatic differences are striking.

Warm and wet on the west coast, cold and dry on the east.

Or, more accurately as these things are all relative, warmer and wetter on the west coast, colder and drier on the east 😉

This, coupled with the geography, means that my bees in Fife are surrounded by intensively farmed land, whereas those on the west coast are in the howling wilderness.

A sweltering June day (!) in Fife with late-flowering OSR

And intensively farmed means oil seed rape (OSR). I don’t think there’s a single season I’ve been in Fife when OSR wasn’t available nearby. Even when the bees fail to collect a surplus the boost the colonies get from the bonanza of nectar and pollen is huge.

This means that the colonies are much bigger and stronger earlier in the season. They therefore make swarm preparations sooner and I can start queen rearing earlier.

All of which means that the 4-5 hours separation by car – less than 3° of longitude – is manifest as 3-4 weeks of difference in the beekeeping season.

And that means I don’t need the same equipment on both sides of the country at the same time.

Result 🙂

Local beekeeping

I think what these rambling comments really emphasise is the intensely local nature of beekeeping. The climate, geography and forage experienced by, or available to, colonies determines ‘what happens when’.

Specific advice on beekeeping can only meaningfully be applied if these factors are taken into account.

This is inevitably very confusing for beginners.

If a venerable sage pronounces on the discussion forums that ‘now is the right time’ for oxalic acid treatment, then it must be correct.

Yes?

Er, no.

The ‘right time’ reflects the combination of the mode of action of oxalic acid and the state of the colony. Oxalic acid is only effective against phoretic mites, so the colony should ideally be broodless. The timing of broodlessness will depend upon a host of factors, but will likely differ in different locations.

We’ve had a relatively mild winter (so far). My Fife colonies were broodless from late October through until sometime near mid/late November. A few I checked on the 7th of December had brood, and I expect they all did by Christmas (I’ve not checked since).

Cappings and a couple of mites – early December 2021, Fife

Had I not treated until the Christmas – New Year holiday my mite control would have been much less effective. Many mites would have escaped a drenching in oxalic acid as a consequence of being hunkered down in capped cells.

If you didn’t treat at all, or didn’t treat until the Christmas holidays, or didn’t treat when you know that the colony was broodless 7, keep a close eye on the mite levels as the colonies expand this spring. If the winter remains mild the mites will have ample opportunity to reproduce to disturbingly high levels.

I seem to have drifted off topic …

Local bees

My Fife bees were all reared locally and the queens are open mated. They do well in Fife and possibly wouldn’t do quite as well on the west coast. They also have Varroa whereas my west coast apiary is in a Varroa-free region.

I therefore cannot simply reduce my east coast colony numbers by moving them.

Instead I’ll have to use a combination of splitting some to produce nucs for sale and uniting others to make strong colonies for the summer nectar flow. Hopefully this should leave me with a few very strong colonies which will be easier to manage and/or hand on when I finally leave altogether.

Like last year I’ll therefore be doing quite a bit of long distance queen rearing. I’ll raise the cells in Fife and then transfer them, once sealed, to my recently completed portable queen cell incubator.

Have incubator, will travel

This frees up the cell raising colony for a second round of grafted larvae. I’ll then keep the cells with me until the queens emerge, maintaining them with a tiny bit of honey and water every day. On my next visit to Fife I’ll then be able to transfer them to introduction cages and place them in mating nucs.

A trial run doing this worked well last year.

There are several advantages of doing things this way:

  • The cell raising colony can be re-used about a week earlier than if I’d left the queens in it – either to emerge, or until they were ready for introduction as mature queen cells.
  • Any dud cells (i.e. those that don’t emerge) are ditched instead of only being discovered when checking the mating nucs a week or two later 8.
  • I can use the queens to fit in with my own travel timetable – which has other things dictating it like pesky meetings – rather than vice versa.

But, of course, it also involves a bit more work in maintaining and caging the queens. In addition, in my experience virgin queen introduction is slightly more risky than adding mature cells to a queenless colony.

However, in my view, the advantages outweigh the disadvantages.

Expansion

I’ve successfully reared queens for several years.

I’m certainly not an expert, but I’m experienced 9 enough to expect it to work. I’m disappointed when graft acceptance is below about 75%, or when less than three quarters of my virgin queens fail to mate successfully.

Capped queen cells

Capped queen cells produced using the Ben Harden queenright queen rearing system

Multiplied together (0.752) you get 0.56 … or ~50-60%. I therefore work out how many queens I need and graft twice the number of larvae and it usually works out about right.

So it is very frustrating when it doesn’t.

And it didn’t with my west coast queen rearing last season 🙁

Graft acceptance was low (though not catastrophic), but queen mating was very poor. I think this was due to a number of factors, some self-inflicted and some environmental:

  • Colonies developed much more slowly meaning queen rearing needed to start later in the season.
  • I had too few colonies, and certainly too few drones, to ensure enough ‘Summer lovin’ 🙂
  • The weather. It can be a bit hit and miss getting sufficient ‘dry, calm, settled’ weather for queen mating this far north and west.

July temperatures in Ardnamurchan

To expand my colony numbers on the west coast, and to generate surplus to help meet the demand for Varroa-free colonies in the area, I need to ‘up my game’ significantly.

Improved mating success 10

There’s nothing I can do to change the weather though I have started to take an unhealthy interest in it.

I’ve now got a personal weather station in the apiary which can generate graphs like that shown above (or for wind speed, sunlight, rainfall etc.). By retrospectively determining the local conditions that occurred during successful mating flights 11 I should be able to plan the timing of queen cell production a little better.

For example, if all that is needed is one half-decent day in an otherwise unsettled fortnight, it would make sense to produce a small number of mature cells over a long period. In contrast, if successful mating needs a longer period of settled weather – that might only occur once a season – then it might be better to have lots of queens (and mating nucs) ready for the time most likely to be suitable.

And the same considerations apply to drones.

Ardnamurchan is a very sparsely populated area … whether you’re counting people or bees. I strongly suspect that a major factor contributing to poor mating success was the relative sparsity of drones. To help compensate for this I am going to boost drone production in colonies by adding at least one full frame of drone foundation.

Drone-worker-drone

Drone-worker-drone …

Regular readers will know I use a lot of foundationless frames. The colony preferentially draws these as worker or drone comb to fit their needs at the time. Consequently, many of my colonies often have more drone brood than a hive just filled with frames of purchased worker foundation.

However, this year I’m not even going to give them the option … I’ll drop a frame of drone foundation into the box so they just have to get on with it!

Finally, I can certainly improve my understanding of colony development on the west coast. Do I need to provide a syrup or pollen (pollen sub) boost early in the season to compensate for a local dearth of nectar and pollen? Are there other ways I could manage the colonies to ensure they are strong enough at the right time for cell raising?

So, part of my planning is to improve a number of things that contribute to successful queen rearing. Some of these will inevitably impact honey production, but that’s something I’m happy to sacrifice (in the short term at least).

A new apiary

For the first time I’ve got bees in the garden … or what masquerades as a garden in this part of the world. More accurately it’s just a patch of rough hillside with some mixed woodland and a really boggy bit (and an unhealthy amount of rhododendron).

For convenience I need to find an additional apiary this year. This avoids overloading an area with too many bees, and provides an additional site for queen mating or simply moving colonies temporarily during certain manipulations.

The usual quote is “less than 3 feet or more than 3 miles” when it comes to moving bees.

However, those rules aren’t absolute.

Mountains and expanses of water both significantly reduce the distances bees will fly (they prefer to go round them rather than over them).

And we have lots of both 12.

Aspen over Loch Sunart

I’ve scouted out a couple of locations already and have a couple more to check. My main apiary will remain in the garden but I’ll have an out apiary when needed.

Learn something new

The motto of perl, my favoured (and now very much out of fashion) computer programming language, is there’s more than one way to do it.

And exactly the same motto could be applied to beekeeping.

If you think about swarm control for example, you could use any one of at least a half dozen widely used methods, each of which has pros and cons.

Pagden, Demaree, nucleus, vertical splits, Taranov, etc. 13. Any of them will do the job if properly applied. Some might be better than others, but they all get there in the end.

I’m a firm believer in learning to use one method really well before trying something new.

Learn its foibles, its strengths and weaknesses. Get good at it.

Then, and only then, try a different method. If you’re interested 14.

It’s only by being confident and successful with one technique you’ll be able to judge whether a different one might actually be better.

Last year I used a Morris board for the first time. It’s like a Cloake board, but half the width. It didn’t work as well as the queen rearing method I usually use (a Ben Harden system). I think I know why and will be trying again this season.

I’m also going to try cell punching as an alternative to grafting. Cell punching involves cutting out a cell plug containing a larva of a suitable age and then presenting the entire plug to a queenless cell raiser.

I see this (if you’ll excuse the pun, which will become obvious in a second) as a sort of ‘future-proofing’.

You need good eyesight and a steady hand for grafting. My presbyopia is becoming more marked and I’d like to be able to rear queens reliably when I need glasses so thick they don’t fit under my veil 😉

There are more schemes being schemed (including something about frames), but they’ll have to wait until another time as I’ve already written too much …


Note

Coincidentally, on the day I made some notes for the last paragraph, Jeremy Burbidge at Northern Bee Books sent out a flyer announcing Roger Patterson’s new book Queen Rearing Made Easy: The Punched Cell Method. Roger is a strong advocate of this method and has written about it on Dave Cushman’s website. I’ve not read the book, but I have watched a few YouTube videos … what could possibly go wrong?

Cut your losses

The stats for winter losses in the UK, Europe and USA can make for rather sobering reading.

In the UK, losses over the last 12 years have fluctuated between 9% and 34%. This self-selecting survey includes responses from about 10% of the British Beekeepers Association membership (primarily England and Wales, despite the name). The average number of hives maintained by a BBKA member is about 5, meaning – all other things being equal 1 – that most beekeepers should expect to lose about 1 hive every winter.

BBKA winter losses survey

About 30 countries, mainly Northern hemisphere, contribute to the COLOSS survey which is significantly larger scale. The most recent 2 data published (for the ’16/’17 winter) had data from ~15,000 respondents 3 managing over 400,000 hives. Of these, ~21% were lost for a variety of reasons. COLOSS data is presented as an unwieldy table, rather than graphically. Further details, including recently published results, are linked from their website.

In the USA the Bee Informed Partnership surveys losses – both winter and summer – and claims to have results that cover ~10% of all the colonies in the country (so probably between 250,000 and 275,000 hives). Winter losses in the USA are rarely reported at less than 20% and were as high as 35% in the ’18/’19 winter 4.

Bee Informed Partnership annual colony losses

Are these figures to be trusted?

Who knows?

Each survey is accompanied by a variety of statistics. However, since they all appear to be based upon voluntary reporting by a subset of beekeepers, there are opportunities for all sorts of data to be included (and even more to be missed entirely). 

The problem with surveys

Is the successful beekeeper who managed to get all her colonies through the winter more likely to respond?

A form of ‘bragging rights’.

What about the beekeeper that lost all his colonies?

Does he respond out of a sense of responsibility?

Or does he keep quiet because he doesn’t want to be reminded of those cold, quiet, mouldy boxes opened on the first warm day of spring?

One and two year beekeepers

What about the high level of annual ‘churn’ amongst beekeepers? They buy a nuc in May, filled with enthusiasm about the jars of golden honey they’ll have for family and friends in late summer.

To say nothing of all the “saving the bees” they’ll be doing.

But by late summer the colony is queenless and has an unpleasant temperament

Beekeeping should be enjoyable ...

Beekeeping should be enjoyable …

Psychopathic you might say … if you were feeling uncharitable.

Consequently the Varroa treatment goes on far too late,. Or is quietly forgotten. The winter bees have high viral loads and ‘die like flies’ 5, resulting in the colony succumbing by the year end.

But this colony loss is never recorded on any surveys.

The once enthusiastic beekeeper has moved on and is now passionate about growing prize-winning vegetables or cheesemaking or keeping chickens. 

Beekeeping associations train lots of new beekeepers and – although membership numbers are increasing – it’s well below the rate they’re trained at.

Some may not be ‘joiners’ and go their own way.

Many just quietly stop after a year or two.

How many people have you met that say “Oh yes, I used to keep bees”

Did you ask them whether they ever completed a winter losses survey?

I’m not sure any of the surveys listed above do much ‘groundtruthing’ to establish whether the data they collect is truly representative of the population actually surveyed. With large numbers of respondents spread across a wide geographic and climatic range it’s not an easy thing to do.

So, treat these surveys with a healthy degree of scepticism.

Undoubtedly there are high levels of winter losses – at least sometimes – and the overall level of losses varies from year to year.

Losses and costs

The direct financial cost of these colony losses to beekeepers is very high.

Ignoring time invested and ‘consumables’ like food, miticides and foundation these costs in ’16/’17 for just Austria, the Czech Republic and Macedonia were estimated at €56 million 😯  

These figures simply reflect lost honey production and the value of the lost colonies. They do not include the indirect costs resulting from lost pollination.

But, for the small scale beekeeper, these economic losses are irrelevant.

Most of these beekeepers do not rely on bees for their income.

The real cost is emotional 🙁

It still saddens me when I lose a colony, particularly when I think that the loss was avoidable or due to my incompetence, carelessness or stupidity 6.

Little snow, big snow. Big snow, little snow.

Your hives should be quiet in winter, but it hurts when they are silent in spring.

Anatomy of a death

The COLOSS surveys give a breakdown of winter losses in three categories:

  • natural disasters
  • queen problems
  • dead colonies

Natural disasters are things like bears, honey badgers, flooding or falling trees.

We can probably safely ignore honey badgers in the UK, but climate change is increasing the weather extremes that causes flooding and falling trees.

Moving to higher ground ...

Moving to higher ground …

Don’t assume that poly hives are the answer to potential flooding.

They do float, though not necessarily the right way up 🙁

Queen problems cover a variety of issues ranging from reduced fecundity to poor mating (and consequent drone laying) to very early or late – and failed – supersedure 7.

Beekeepers with a lot more experience than me report that queen problems are increasing.

Drone laying queen ...

Drone laying queen …

Perhaps the issues with fecundity and drone laying are related to toxic levels of miticides in commercial foundation? It’s certainly known that these residues reduce drone sperm fertility significantly. I intend to return to this topic sometime during the approaching winter … perhaps in time to encourage the use of some foundationless frames for (fertile) drone production 😉

In the ’16/’17 COLOSS data, natural disasters accounted for 1.6% of all overwintered colonies (so ~7.5% of losses), queen problems resulted in the loss of 5.1% of colonies (i.e. ~24% of losses) and the remainder (14.1% of colonies, ~68% of losses) just died.

Just died?

We’ll return to natural disasters (but not bears or honey badgers) and queen problems shortly. What about the majority of losses in which the colony ‘just died’?

If you discuss colony post-mortems with beekeepers they sometimes divide the ‘just died’ category (i.e. those not readily attributable to failed queens, marauding grizzlies or tsunamis) into four groups:

  • disease
  • isolation starvation
  • starvation
  • don’t know 

The most important disease associated with overwintering colony losses is high levels of Deformed wing virus (DWV). This results from uncontrolled or inadequately controlled Varroa infestation. For any new readers of this site, please refer back to many of the articles I’ve already written on Varroa management 8.

I strongly suspect that a significant proportion of the reported isolation starvation is actually also due to disease, rather than isolation per se.

A consequence of high levels of DWV is that winter bees die prematurely. Consequently, the colony shrinks faster than it would otherwise do. It starts the size of a basketball but (too) rapidly ends up the size of a grapefruit … or an orange.

Isolation starvation and disease

The small cluster is then unable to remain in contact with stores, and so starves. 

Yes, the colony died from ‘isolation starvation’, but the cause was the high levels of Varroa and the viruses it transmits.

Isolation starvation ...

Isolation starvation …

What about regular starvation?

Not because the cluster became isolated from the stores, but simply because they had insufficient stores to get through the winter.

Whose fault was that?

And the last category, the “don’t knows”?

I bet most of these are due to high levels of Varroa and DWV as well 🙁

Yes, there will be other reasons … but probably not a huge number. 

What’s more … if you don’t know the reason for the colony loss there’s very little you can do to mitigate against it in future seasons.

And, other than wild and increasingly vague speculation, there’s little I can write about if the reason for the loss remains unknown 9.

Avoiding winter losses

So, let’s rationalise those earlier lists into the probable (known) major causes of overwintering colony losses:

  • natural disasters
  • queen problems
  • starvation
  • disease (but probably mainly DWV and Varroa

As the long, hot days of summer gradually shorten and cool as early autumn approaches, you should be thinking about each of these potential causes of overwintering colony loss … and doing what you can to ensure it doesn’t happen to you (or, more correctly, your bees).

Ardnamurchan autumn

Ardnamurchan autumn

Some are easier to deal with than others.

Here’s a whistle-stop tour of some more specific problems and some practical solutions 10. Some, all or none may apply to your bees – it depends upon your location, your climate, your experience and future plans as a beekeeper. 

Natural disasters

These fall into two broad groups:

  • things you can do almost nothing about (but might be able to avoid)
  • things you can relatively easily solve

Flooding, falling trees, lightning, landslides, earthquakes, volcanoes, meteor strikes etc. all fall into the first group.

If you can avoid them, do. 

Your local council will have information on areas at risk from flooding. There are also searchable maps available from SEPA. Do not underestimate the severity of some of the recent flooding. Some parts of Scotland and Northern England had 600 mm of rain in two days in 2015.

You might be surprised (and from an insurance aspect, devastated) at the classification of some areas now ‘at risk’. 

Where did Noah keep his bees? In his Ark hive.

Where did Noah keep his bees? In his Ark hive.

Consider moving hives to higher ground before the winter rains start. One consequence of climate change is that heavy rainfall is now ~20% heavier than it was a few decades ago. This means that floods occur more frequently, are more extensive and the water levels rise faster. You might not have a chance to move the hives if flooding does occur,

More rain and stronger winds (particularly before leaf fall) mean more trees will come down. You might be able to identify trees potentially at risk from falling. It makes sense to remove them (or site your hives elsewhere). 

No risk of this larch tree falling on my hives

Lightning, earthquakes, volcanoes, meteor strikes … all a possibility though I would 11 probably worry about Varroa and woodpeckers first 😉

Solvable natural disasters

The ‘solvable’ natural disasters include preventing your colonies being robbed by other bees or wasps. Or ransacked by mice or woodpeckers after the first hard frosts start. A solution to many of these are ‘reduced size entrances’ which either enable the colony to better defend itself, or physically restricts access to critters.

The L-shaped ‘kewl floors‘ I use prevent mice from accessing the brood box. They are also easier for the colony to defend from bees/wasps, but can also easily be reduced in size with a narrow piece of hardwood. If you don’t use these types of floor you should probably use a mouseguard.

Polyhives and polythene

Polyhives and polythene …

Woodpeckers 12 need to cling onto the outside of the hive to hammer their way through the side. You can either place a wire mesh cage around the hive, or wrap the box in something like damp proof membrane (or polythene) to prevent them gaining purchase on the side walls.

Keep off Woody

Keep off Woody

Doing both is probably overkill though 😉

Strong colonies

Before we move onto queen problems – though it is related – it’s worth emphasising that an even better solution to prevent robbing by bees or wasps is to maintain really strong colonies.

Strong colonies with a well balanced population of bees can almost always defend themselves successfully against wasps and robbing bees.

Nucs, that are both weaker and – at least shortly after being made up – unbalanced, are far less able to defend themselves and need some sort of access restriction.

By ‘balanced’ I mean that the numbers and proportions of bees fulfilling the various roles in the nucleus colony are reflective of a full hive e.g. nurse bees, foragers, guard bees. 

Reduced entrance ...

Reduced entrance …

But the benefits of strong colonies are far greater than just being able to prevent wasps or robbing bees. There is compelling scientific evidence that strong colonies overwinter better

I don’t mean strong summer colonies, I mean colonies that are strong in the late autumn when they are fully populated with the winter bees.

Almost the entire complement of bees in the hive are replaced between late summer and late autumn. Remember that a really strong summer colony may not be strong in the winter if Varroa and virus levels have not been controlled.

How do you ensure your colonies are strong?

  1. Minimise disease by controlling Varroa levels in early autumn to guarantee the all-important winter bees are reared without being exposed to high levels of DWV.
  2. Try and use a miticide treatment that does not reduce the laying rate of the queen.
  3. Avoid blocking the brood nest with stores where the queen should be laying eggs.
  4. Requeen your colonies regularly. Young queens lay more eggs later into the autumn. As a consequence the colonies have increased populations of winter bees.
  5. Unite weak colonies (assuming they are disease-free) with stronger colonies. The former may well not survive anyway, and the latter will have a better chance of surviving if it is even stronger – see below. 
  6. Use local bees. There’s good evidence that local bees (i.e. reared locally, not imported from elsewhere) overwinter better, not least because they produce stronger colonies.

Uniting – take your losses in the autumn

My regular colony inspections every 7-10 days during May and June are pretty much abandoned by July. The risk of swarming is very much reduced after the ‘June gap’ in my experience. 

I still check the colonies periodically and I’m usually still rearing queens. However, the rigour with which I check for queen cells is much reduced. By July my colonies are usually committed to single-mindedly filling the supers with summer nectar.

They are already making their own preparations for the long winter ahead.

Although the inspections are less rigorous, I do keep a careful watch on the strength of each colony. Often this is directly related to the number of supers I’ve had to pile on top.

Colonies that are underperforming, and – more specifically – understrength are almost always united with a stronger colony.

An Abelo/Swienty hybrid hive ...

An Abelo/Swienty hybrid hive …

Experience has taught me that an understrength colony is usually more trouble than it’s worth. If it’s disease-free it may well overwinter reasonably well. However, it’s likely to start brood rearing more slowly and build up less well. It may also need more mollycoddling 13 in the autumn e.g. protection from wasps or robbing bees.

However, a colony that is not flourishing in the summer is much more likely to struggle and fail during the winter. Perhaps the queen is not quite ‘firing on all cylinders’ and laying at a really good rate, or she might be poorly mated.

Far better that the workforce contributes to strengthening another hive, rather than collect an underwhelming amount of honey before entering the winter and eventually becoming a statistic.

My winter losses are low and, over the last decade, reducing.

That’s partly because my Varroa management is reasonably thorough.

However, it’s probably mainly due to ensuring only strong colonies go into the winter in the first place.

Newspaper

I’ve dealt with uniting in several previous posts.

It’s a two minute job. 

You remove the queen from the weak colony, stack one brood box over the other separated by a sheet or two of newspaper with a very small (~3mm) hole in the middle. Add the roof and leave them to get on with things.

I don’t think it makes any difference whether the strong colony goes on the top or the bottom.

I place the colony I’m moving above the box I’m uniting it with. My – wildly unscientific – rationale being that the bees in the top box will have to negotiate the route to the hive entrance and, in doing so, will help them orientate to the new location faster 14.

If you unite colonies early or late in the day most foragers will be ‘at home’ so not too many bees will return to find their hive missing.

If there are supers on one or both hives you can separate them with newspaper as well. Alternatively, use a clearer the day before to empty the supers prior to uniting the colonies. You can then add back the supers you want and redistribute the remainder to other hives in the apiary.

Successful uniting ...

Successful uniting …

Don’t be in too much of a hurry to check for successful uniting.

Leave them a week. The last thing you want is for the queen to get killed in an unseemly melee caused by you disturbing them before they have properly settled.

Done properly, uniting is almost foolproof. I reckon over 95% of colonies I unite are successful.

That’s all folks … more on ‘Cutting your losses’ next week 🙂


Notes

At just over 3000 words this post got a bit out of control … I’ll deal with more significant queen problems, feeding colonies, the weather and some miscellaneous ‘odds and sods’ next week.

Absconding

One of the few principles I have ( 😉  ) is that the posts here should be based upon practical experience. When I write about swarm control I describe the methods that I use. When I write about Varroa management I discuss Apivar and oxalic acid in detail as I have a lot of experience using these compounds. I’ve not written about MAQS as I don’t use it.

For the same reasons, you won’t see a discussion about top bar hives or the Bee Guardian piezoelectric gadgets that causes the varroa mites stop to reproduce and go away from the hive” 1.

The topic today is absconding. My qualification to write about this is extremely limited, but just about sufficient. I think I’ve had only one colony abscond in the last decade. It’s not something I take any notice of (or precautions against) in my regular beekeeping. However, it’s an interesting subject as there’s some relevant science associated with absconding and honey bee migration, so it’s worth discussing.

And perhaps more science to do …

But first some definitions

Colony reproduction involves swarming. The colony rears one or more new queens. Once the queen cells are capped, the current queen and up to 75% of the adult bees leave the hive as a swarm. Prior to leaving, scout bees have scoured the environment for suitable new nest sites. These scouts lead the swarm to the chosen new location 2.

The swarm leaves behind all the brood and most of the stores. Together with the adult bees that remain, this colony has a good chance of survival (~80%) which is probably a reflection on queen mating success rates 3.

‘Most of the stores’ because the swarming bees gorge themselves on honey prior to leaving the hive (or nest site if it’s a feral colony). Something like 40% by weight of the swarm is honey stores. They need these stores to survive – to build new comb, to tide them over a period of bad weather and while they scout the environment for forage. Swarming is a risky business, only about 20% of natural swarms survive.

Absconding is very different. During this process the entire colony – the queen and all the flying bees – leave the nest site (hive). They usually leave behind almost nothing. There may be very limited amounts of capped brood/larvae or eggs remaining, but the stores are usually gone. Absconding therefore does not involve colony reproduction. There are no queen cells produced. You start with one colony and end with one.

However, although absconding is very different, it’s not completely different. It still involves scout bees and it still involves waggle dances to communicate distance and direction.

Like swarming, it’s also a completely natural process. In certain parts of the world there are annual cycles of absconding and colony migration.

In the discussion that follows I’m going to try and make a distinction between absconding by managed and unmanaged colonies. 

The consequences of either type of colony absconding are probably the same. 

The drivers that result in the colony absconding are sometimes different.

My experience

Let’s get this out of the way … 4

To my knowledge the only colony I have ever had abscond was from a Kieler mini-nuc. The mini-nuc had been primed with a mugful of bees and a queen cell a week or so earlier. The queen had emerged and may (or may not?) have gone on a mating flight 5.

An Apidea mini-nuc ‘catching a few rays’

One baking hot June afternoon I turned up at the apiary just as a small swirling mass of bees disappeared over the fence. 

Never to return 🙁

The mini-nuc was low on stores (but far from empty) and devoid of bees (or brood). There was drawn comb so the queen would have been able to lay (if she had been mated). I can’t remember whether there were eggs present … this was several years ago 6.

‘Natural’ absconding and colony migration

This mini-nuc wasn’t the one pictured, but it was similarly exposed. In full sun these can rapidly overheat and there is a real risk of the small colony absconding. I now always site my mini-nucs out of the heat of the full sun – even in Scotland – in dappled shade, at the bottom of a hedge or somewhere similar.

Of course, I don’t know that overheating caused this little colony to abscond, but it seems like a reasonable assumption.

Bees living in temperate and tropical regions exhibit gross behavioural differences that reflect the climate and availability of forage. Those in temperate climates swarm annually, coinciding with the predictable period of forage availability, and are quiescent over ‘winter’.

In contrast, bees in tropical climates have no ‘winter’ to survive as the temperature is high enough all year for brood rearing and comb building. What differs though is the availability of forage and water. If these are limiting the bees migrate to other areas.

This annual migration involves the colonies absconding … and it has been quite well studied by scientists.

Adverse environmental conditions are one of the recognised drivers of absconding. In addition to overheating, these include a dearth of resources during the wet season. 

The other major driver of absconding is disturbance, for example by predators such as ants (or beekeepers). Disturbance is a lot less predictable than environmental factors, and it is the latter that has been better studied.

Preparing to migrate

Absconding and migration appear to be a characteristic of strong, healthy colonies. Prior to absconding the colony reduces brood rearing drastically although the queen continues to lay a very limited number of eggs until the bulk of the worker brood has emerged 7.

Colonies tended to abscond within a day of this worker brood emerging, leaving almost nothing in the original nest site. 

So, this isn’t a spur of the moment decision, it’s a protracted process taking at least a fortnight from the near-cessation of brood rearing. This means the colony benefits from the resources they have invested in rearing brood, rather than leaving behind slabs of capped brood that would otherwise be doomed.

How does the colony know where to go when it absconds?

Actually, these preparations probably take more than a fortnight. Analysis of the waggle dances for several weeks prior to absconding show that the foraging area and distances were both increasing and becoming more variable. 

Schneider and McNally 8 showed that these waggle dances regularly communicated distances of up to 20 km from the nest site.

However, these weren’t typical dances … the distance component was variable, the dance occurred during periods of little flight activity and the dance was not associated with forage sources. They interpreted this as a generalised signal to fly for a long (but unspecified) distance in a particular direction, rather than to a specific location.

I’m not aware of follow-up studies to these. Do the bees go through the same sort of decision-making process to ‘agree’ on the final direction as the scout bees do when a colony swarms? I suspect not, the distance component was very variable and there was no direct evidence that the dancing bees ever made the entire journey anyway.

Perhaps these waggle dances simply indicate “Things are better a long way south of here. When we go, that’s the direction to take”.

Stopovers

If a colony absconds due to adverse environmental conditions – such as a lack of forage, or overheating – it seems unlikely that things would be much better only 20 km away. “environment” is local, but not necessarily that local.

In reality, colonies abscond and migrate much further than this when necessary, resting in temporary stopover locations when necessary. In the case of Apis mellifera I’m not aware of any studies of these sites. However, in the Giant honey bee (Apis dorsata) some of these stopover locations appear to be re-used annually. 

Apis dorsata migrates up to 200 km and has even been reported crossing 50 km of open water between Sumatra and Malaysia. These long migrations take up to a month and the bees bivouac on trees, resting and replenishing their stores (by foraging locally) 9.

Giant honey bee (Apis dorsata) temporary stopover bivouac

Analysis of scout bee dancing activity on the surface of these bivouacked colonies show that this again determines the direction (and possibly distance) of the next stage of the journey. 

Absconding and managed colonies

I think it’s reasonable to assume that at least some of the factors that induce colonies to abscond in tropical regions also trigger absconding in our managed colonies in the UK. 

Very small colonies – like the mini-nuc described above – are poor at thermoregulation. There are simply too few bees present to cool the colony in very hot weather.

Although I’m aware that colonies may abscond due to disturbance – from wax moth, Varroa or small hive beetle infestation – I’ve no experience of this 10.

What about disturbance by beekeepers managing colonies? It’s a possibility I suppose. Clearly the regular weekly inspections are not sufficient disturbance to trigger absconding, but perhaps a daily rummage through the brood box might not be tolerated 11.

Absconding swarms

In temperate climates most beekeepers associate absconding with recently hives swarms.

Here’s a typical scenario …

The beekeeper is called out to a bivouacked swarm hanging – conveniently and precariously, just out of reach – in a tree.

By the time they’ve collected the ladder, the skep, the white sheet and the secateurs it’s late afternoon. Never mind … A swarm in May is worth a bale of hay etc.

A spring swarm in a skep

They drop the swarm into the skep, avoid toppling off the ladder, allow the flying bees to join the queen, wrap everything in the sheet and return triumphantly to their apiary 12.

In time honoured tradition they assemble a new hive, prop the entrance open and build a sheet-covered ramp onto which they unceremoniously dump the collected swarm.

'Walking' a swarm into a hive

‘Walking’ a swarm into a hive

And the bees calmly walk up the slope into the hive.

It’s one of the great sights in beekeeping … and one I now never bother to do.

I just dump the swarm into the hive and close it up. 

Boring, but quick 😉

Back to the absconding swarm scenario …

The beekeeper returns late the following morning to find the swarm has gone 🙁

Is this typical absconding?

Other than one or two typical circumstances such as a freshly painted (and still smelly) hive, I think that these swarms may abscond because they have already chosen an alternative nest site

The scout bees from the bivouacked colony (collected a day or two previously) had been busy surveying the environment for suitable nest sites. This process can take several days until a sufficient number of the scouts are convinced of the benefits of a particular site.

Once that decision is made the colony leaves the bivouac and flies to the new nest site. However, this flight tends to happen in the middle of the day, not late in the afternoon.

The beekeeper who hived our hypothetical swarm in the scenario above may have actually interrupted this process, which simply continued the following morning.

I don’t know if scout bees conduct waggle dances overnight to reinforce nest site choices (but the normal waggle dance for forage resources can occur during the night). If they do, this might account for the bees disappearing soon after being hived.

How do you stop hived swarms absconding?

There are three methods I’m aware of.

One is foolproof and I use every season. The other two are reported to work with variable levels of success, but which I have never used.

Adding a frame of open brood is reported to help stop the colony absconding. Alternatively, placing a queen excluder under the brood box (but above the floor) ‘traps’ the queen and prevents the colony leaving.

The first of these provides brood to care for, brood pheromones and the general ‘pong’ of a hive, all of which are likely to be beneficial. As I’ve not used this method I’m unsure how effective it is.

The queen excluder seems a heavy-handed and rather crude solution. The colony may well still try and abscond, but the queen will remain trapped. This seems like a great way to induce considerable stress in the colony.

And it’s unlikely to be successful long-term if the swarm is a cast with a virgin queen 😉

And the totally foolproof method?

Swarm arriving at bait hive ...

Swarm arriving at bait hive …

Bait hives.

I’ve never had a swarm that voluntarily arrived in a bait hive abscond. Even if I move the bait hive to another apiary, they still happily stay 🙂

Citizen science

I almost never hive bivouacked swarms these days as I am sufficiently successful in attracting swarms with bait hives 13.

I’m therefore unable to conduct the following experiment that I think would be quite interesting.

I’ve predicted above that a swarm collected from a bivouac that absconds may have already decided on the new nest site. By ‘hiving’ the swarm all the beekeeper is doing is moving the bivouac.

That being the case, I’d expect that collected swarms would be less likely to abscond if they’re moved to an area the scout bees have no knowledge of.

Scout bees survey the environment at least 3 km from the original nest site although swarms tend to occupy new nest sites well within this distance.

There are two things that would be interesting to monitor:

  1. Are swarms hived over 8 km from the location the swarm is collected less likely to abscond?
  2. Is the delay between hiving a swarm and it absconding related to the distance between the original bivouac and the initial location it is hived in?

I’ve chosen 8 km because you cannot always be certain where the bivouacked swarm came from (and because it’s a convenient 5 miles for these post-Brexit times). If you assume that the bivouac is always within a few dozen metres of the original nest site this ‘removal’ distance could be decreased to about 4 km.

The time delay addresses a slightly different question. I’m assuming here that the scout bees have yet to reach a quorum decision and are continuing to survey the environment. The further you move them, the more the environment changes, so potentially necessitating a longer decision making period.

As the 2021 season starts to wind down that’s something to think about for the year ahead.


Note

Please don’t email me with all the gruesome details of swarms you’ve had abscond in the past. It’s not that I’m not interested … I’m just completely swamped with correspondence.

If there’s sufficient interest in this post over the next few months (and as a bit of ‘Citizen Science’ experiment which are all the rage) – determined by page accesses and comments – I’ll create a simple web form to log everything to a database. No individual beekeeper is likely to collect sufficient swarms to generate a meaningful amount of data. I doubt even if an entire association could do so. However, the thousands of readers a week are surely able to have enough hived swarms abscond to test the hypothesis?

Darwinian beekeeping

A fortnight ago I reviewed the first ten chapters of Thomas Seeley’s recent book The Lives of Bees. This is an excellent account of how honey bees survive in ‘the wild’ i.e. without help or intervention from beekeepers.

Seeley demonstrates an all-too-rare rare combination of good experimental science with exemplary communication skills.

It’s a book non-beekeepers could appreciate and in which beekeepers will find a wealth of entertaining and informative observations about their bees.

The final chapter, ‘Darwinian beekeeping’, includes an outline of practical beekeeping advice based around what Seeley (and others) understand about how colonies survive in the wild.

Differences

The chapter starts with a very brief review of about twenty differences between wild-living and managed colonies. These differences have already been introduced in the preceding chapters and so are just reiterated here to set the scene for what follows.

The differences defined by Seeley as distinguishing ‘wild’ and ‘beekeepers’ colonies cover everything from placement in the wider landscape (forage, insecticides), the immediate environment of the nest (volume, insulation), the management of the colony (none, invasive) and the parasites and pathogens to which the bees are exposed.

Some of the differences identified are somewhat contrived. For example, ‘wild’ colonies are defined fixed in a single location, whereas managed colonies may be moved to exploit alternative forage.

In reality I suspect the majority of beekeepers do not move their colonies. Whether this is right or not, Seeley presents moving colonies as a negative. He qualifies this with studies which showed reduced nectar gathering by colonies that are moved, presumably due to the bees having to learn about their new location.

However, the main reason beekeepers move colonies is to exploit abundant sources of nectar. Likewise, a static ‘wild’ colony may have to find alternative forage when a particularly good local source dries up.

If moving colonies to exploit a rich nectar source did not usually lead to increased nectar gathering it would be a pretty futile exercise.

Real differences

Of course, some of the differences are very real.

Beekeepers site colonies close together to facilitate their management. In contrast, wild colonies are naturally hundreds of metres apart 1. I’ve previously discussed the influence of colony separation and pathogen transmission 2; it’s clear that widely spaced colonies are less susceptible to drifting and robbing from adjacent hives, both processes being associated with mite and virus acquisition 3.

Abelo poly hives

50 metres? … I thought you said 50 centimetres. Can we use the next field as well?

The other very obvious difference is that wild colonies are not treated with miticides but managed colonies (generally) are. As a consequence – Seeley contends – beekeepers have interfered with the ‘arms race’ between the host and its parasites and pathogens. Effectively beekeepers have ‘weaken[ed] the natural selection for disease resistance’.

Whilst I don’t necessarily disagree with this general statement, I am not convinced that simply letting natural selection run its (usually rather brutal) course is a rational strategy.

But I’m getting ahead of myself … what is Darwinian beekeeping?

Darwinian beekeeping

Evolution is probably the most powerful force in nature. It has created all of the fantastic wealth of life forms on earth – from the tiniest viroid to to the largest living thing, Armillaria ostoyae 4. The general principles of Darwinian evolution are exquisitely simple – individuals of a species are not identical; traits are passed from generation to generation; more offspring are born than can survive; and only the survivors of the competition for resources will reproduce.

I emphasised ‘survivors of the competition’ as it’s particularly relevant to what is to follow. In terms of hosts and pathogens, you could extend this competition to include whether the host survives the pathogen (and so reproduces) or whether the pathogen replicates and spreads, but in doing so kills the host.

Remember that evolution is unpredictable and essentially directionless … we don’t know what it is likely to produce next.

Seeley doesn’t provide a precise definition of Darwinian beekeeping (which he also terms natural, apicentric or beefriendly beekeeping). However, it’s basically the management of colonies in a manner that more closely resembles how colonies live in the wild.

This is presumably unnnatural beekeeping

In doing so, he claims that colonies will have ‘less stressful and therefore more healthful’ lives.

I’ll come back to this point at the end. It’s an important one. But first, what does Darwinian mean in terms of practical beekeeping?

Practical Darwinian beekeeping

Having highlighted the differences between wild and managed colonies you won’t be surprised to learn that Darwinian beekeeping means some 5 or all of the following: 6

  • Keep locally adapted bees – eminently sensible and for which there is increasing evidence of the benefits.
  • Space colonies widely (30-50+ metres) – which presumably causes urban beekeepers significant problems.
  • Site colonies in an area with good natural forage that is not chemically treated – see above.
  • Use small hives with just one brood box and one super – although not explained, this will encourage swarming.
  • Consider locating hives high off the ground – in fairness Seeley doesn’t push this one strongly, but I could imagine beekeepers being considered for a Darwin Award if sufficient care wasn’t taken.
  • Allow lots of drone brood – this occurs naturally when using foundationless frames.
  • Use splits and the emergency queen response for queen rearing i.e. allow the colony to choose larvae for the preparation of new queens – I’ve discussed splits several times and have recently posted on the interesting observation that colonies choose very rare patrilines for queens.
  • Refrain from treating with miticides – this is the biggy. Do not treat colonies. Instead kill any colonies with very high mite levels to prevent them infesting other nearby colonies as they collapse and are robbed out.

Good and not so good advice

A lot of what Seeley recommends is very sound advice. Again, I’m not going to paraphrase his hard work – you should buy the book and make your own mind up.

Sourcing local bees, using splits to make increase, housing bees in well insulated hives etc. all works very well.

High altitude bait hive …

Some of the advice is probably impractical, like the siting of hives 50 metres apart. A full round of inspections in my research apiary already takes a long time without having to walk a kilometre to the furthest hive.

The prospect of inspecting hives situated at altitude is also not appealing. Negotiating stairs with heavy supers is bad enough. In my travels I’ve met beekeepers keeping hives on shed roofs, accessed by a wobbly step ladder. An accident waiting to happen?

And finally, I think the advice to use small hives and to cull mite-infested colonies is poor. I understand the logic behind both suggestions but, for different reasons, think they are likely to be to the significant detriment of bees, bee health and beekeeping.

Let’s deal with them individually.

Small hives – one brood and one super

When colonies run out of space for the queen to lay they are likely to swarm. The Darwinian beekeeping proposed by Seeley appears to exclude any form of swarm prevention strategy. Hive manipulation is minimal and queens are not clipped.

They’ll run out of space and swarm.

Even my darkest, least prolific colonies need more space than the ~60 litres offered by a brood and super.

Seeley doesn’t actually say ‘allow them to swarm’, but it’s an inevitability of the management and space available. Of course, the reason he encourages it is (partly – there are other reasons) to shed the 35% of mites and to give an enforced brood break to the original colony as it requeens.

These are untreated colonies. At least when starting the selection strategy implicit in Darwinian beekeeping these are likely to have a very significant level of mite infestation.

These mites, when the colony swarms, disappear over the fence with the swarm. If the swarm survives long enough to establish a new nest it will potentially act as a source of mites far and wide (through drifting and robbing, and possibly – though it’s unlikely as it will probably die – when it subsequently swarms).

A small swarm

A small swarm … possibly riddled with mites

Thanks a lot!

Lost swarms – and the assumption is that many are ‘lost’ – choose all sorts of awkward locations to establish a new nest site. Sure, some may end up in hollow trees, but many cause a nuisance to non-beekeepers and additional work for the beekeepers asked to recover them.

In my view allowing uncontrolled swarming of untreated colonies is irresponsible. It is to the detriment of the health of bees locally and to beekeepers and beekeeping.

Kill heavily mite infested colonies

How many beekeepers reading this have deliberately killed an entire colony? Probably not many. It’s a distressing thing to have to do for anyone who cares about bees.

The logic behind the suggestion goes like this. The colony is heavily mite infested because it has not developed resistance (or tolerance). If it is allowed to collapse it will be robbed out by neighbouring colonies, spreading the mites far and wide. Therefore, tough love is needed. Time for the petrol, soapy water, insecticide or whatever your choice of colony culling treatment.

In fairness to Seeley he also suggests that you could requeen with known mite-resistant/tolerant stock.

But most beekeepers tempted by Darwinian ‘treatment free’ natural beekeeping will not have a queen bank stuffed with known mite-resistant mated queens ‘ready to go’.

But they also won’t have the ‘courage’ to kill the colony.

They’ll procrastinate, they’ll prevaricate.

Eventually they’ll either decide that shaking the colony out is OK and a ‘kinder thing to do’ … or the colony will get robbed out before they act and carpet bomb every strong colony for a mile around.

Killing the colony, shaking it out or letting it get robbed out have the same overall impact on the mite-infested colony, but only slaying them prevents the mites from being spread far and wide.

And, believe me, killing a colony is a distressing thing to do if you care about bees.

In my view beefriendly beekeeping should not involve slaughtering the colony.

Less stress and better health

This is the goal of Darwinian beekeeping. It is a direct quote from final chapter of the book (pp286).

The suggestion is that unnatural beekeeping – swarm prevention and control, mite management, harvesting honey (or beekeeping as some people call it 😉 ) – stresses the bees.

And that this stress is detrimental for the health of the bees.

I’m not sure there’s any evidence that this is the case.

How do we measure stress in bees? Actually, there are suggested ways to measure stress in bees, but I’m not sure anyone has systematically developed these experimentally and compared the stress levels of wild-living and managed colonies.

I’ll explore this topic a bit more in the future.

I do know how to measure bee health … at least in terms of the parasites and pathogens they carry. I also know that there have been comparative studies of managed and feral colonies.

Unsurprisingly for an unapologetic unnatural beekeeper like me ( 😉 ), the feral colonies had higher levels of parasites and pathogens (Catherine Thompson’s PhD thesis [PDF] and Thompson et al., 2014 Parasite Pressures on Feral Honey Bees). By any measurable definition these feral colonies were less healthy.

Less stress and better health sounds good, but I’m not actually sure it’s particularly meaningful.

I’ll wrap up with two closing thoughts.

One of the characteristics of a healthy and unstressed population is that it is numerous, productive and reproduces well. These are all characteristics of strong and well-managed colonies.

Finally, persistently elevated levels of pathogens are detrimental to the individual and the population. It’s one of the reasons we vaccinate … which will be a big part of the post next week.


 

More local bee goodness?

Before the wind-down to the end of the year and the inevitable review of the season I thought I’d write a final post apparently supporting the benefits of local bees. This is based on a recently published paper from the USA 1 that tests whether local bees perform better than non-local stocks.

However, in my view the study is incomplete and – whilst broadly supportive – needs further work before it can really be seen as an example of better performing local bees. I suspect there’s actually a different explanation for their results … that also demonstrates the benefits of local bees.

This is a follow-up to a post three weeks ago that provided evidence that:

  1. Colonies derived from different geographic regions show physiological adaptations (presumably reflecting underlying genetic differences) that seem pretty logical e.g. bees from Saskatchewan express more proteins involved in heat production, whereas Hawaiian bees show higher levels of protein turnover (which would make sense if they had evolved locally to have high metabolic rates).
  2. In a study by Büchler, European colonies survived better overwinter in their local environment; a fact subsequently attributed to the colonies being stronger going into the winter. In turn, this agrees with a recent study that clearly demonstrates the correlation between overwintering success and colony strength.

I suggest re-reading 2 that post as I’m going to try and avoid too much repetition here.

Strong colonies

Strong colonies overwinter better and – if you’re interested in that sort of thing – are much more likely to generate a profit for your honey sales.

So how can you ensure strong colonies at the end of the season?

What influences colony strength?

One thing is colony health. A healthy colony is much more likely to be a strong colony.

In the ambitious 600-colony Büchler study in Europe they didn’t do any disease management. The colonies were monitored over ~2.5 years during which time 84% of colonies perished, at least half due to the ravages of Varroa.

Clearly this is not sustainable beekeeping and doesn’t properly reflect standard beekeeping practices.

Study details

The recent Burnham study makes a nice comparison to the Büchler study.

It was conducted in New York State using 40 balanced 3 colonies requeened in late May.

Queens were sourced from California (~4000 km west) or Vermont (~200km east in the neighbouring state, and therefore considered ‘local’) and colonies were assigned queens randomly.

Unlike some previous studies the authors did not evidence the genetic differences between queens.

A local queen

A local queen

However, the queens looked dissimilar and the stocks were sourced from colonies established in California or Vermont for at least 10-15 generations. I think we can be reasonably confident that the queens were sufficiently distinct to be relevant for the tests being conducted.

Colonies were maintained using standard beekeeping practices, Varroa levels were managed using formic acid (MAQS for European readers) and the colony weight and productivity (frames of bees) was quantified, as was the pathogen load.

In contrast to the Büchler study, Burnham and colleagues only followed colonies over one beekeeping summer season. This was not a test of overwintering survival, but mid-season development.

Results

The take-home message is that colonies headed by the ‘local’ Vermont queens did better. The colonies got heavier faster and brood levels built up better.

Bigger, faster, stronger …

It’s notable that colony weight built up before any brood would have emerged from the new queen (upper panel) and that brood level in colonies headed by the local queen recovered much better after formic acid treatment (arrow in lower panel).

Nosema levels

However, Nosema levels were significantly different (above) as were the levels of Israeli Acute Paralysis Virus (IAPV; below).

Virus loads (DWV, BQCV and IAPV)

There were no significant differences in the Varroa loads before or after treatment (not shown), or in the levels of DWV or Black Queen Cell Virus (BQCV).

Taken together – bigger, heavier, stronger colonies and lower pathogen loads (at least of some pathogens) – seems good evidence to support the contention that local bees are beneficial.

The benefits are precisely what you want for good overwintering – strong, healthy colonies.

That’s a slam-dunk then?

Case proven?

No.

IAPV is a virus rarely detected in the UK. It causes persistent and systemic infections in honey bees and can be found in every caste (drones, workers, queens) and at every stage of the life cycle.

As IAPV is detectable in eggs and larvae – neither of which are Varroa-exposed – it is assumed to be vertically transmitted from the queen. IAPV is also found in the ovaries of the queen, which is additional evidence for vertical transmission.

At the first timepoint (12 days post requeening) the levels of IAPV are different between the two colony types, but not significantly so. However, by 40 days (T2) the levels are very different. At this later timepoint all the bees in the colony will be have come from the introduced queen.

The authors explain the differences in IAPV levels in terms of local bees being more resistant to ‘local’ pathogens … in much the same way that Pizarro’s 168 conquistadors, being more resistant to smallpox, defeated the might of the Inca Empire with the help of the virus diseases they inadvertently introduced to Peru.

I suspect there’s another explanation.

Perhaps the Californian queens were IAPV infected from the outset?

If this was the case they could introduce a new and virulent strain of IAPV to the research colonies and – over time – the levels would increase as more and more workers in the colony were derived from the new queen. IAPV is present in ~20% of US colonies so it seems perfectly reasonable to suggest it might have been largely absent from the Vermont queens and the test colonies, but present in the queens introduced from California.

How should they have tested that?

The obvious thing to do would be to characterise the IAPV present in the colony. IAPV shows geographic variation across the USA. If the predominant virus was of Californian origin it would suggest it was brought in with the queen. This is a relatively easy test to conduct … a sort of 23andme to determine bee virus provenance.

Alternatively, though less conclusively, you could do the experiment the other way round … ship Vermont queens to California and compare their performance with colonies headed by Californian queens on their own territory. If the Californian queens again performed less well it undermines the ‘local bees do better’ argument and suggests another explanation should be sought.

Nosema is sexually transmitted but it is not vertically transmitted, so the same arguments cannot be made there. Why the Nosema levels drop so convincingly in colonies headed by the local queens is unclear. Nosema was present at the start of the study and was lost over time in the stronger colonies headed by the local queens.

One possibility of course is that the stronger colonies were better fed – more workers, more foragers, more pollen, more nectar. Improved diet leads to a more active and effective immune system and an increased ability to combat pathogens. Simplistic certainly, but it is known that diet influences pathogen resistance and colony performance.

So what does this paper show?

I suspect it doesn’t directly show what the authors claim (in the title) … that local queens head colonies with lower pathogen levels.

This largely reflects the lack of proper or complete controls. However, it does not mean that local bees are not better.

More than anything I think this paper demonstrates the impact queen quality has on colony performance.

Perhaps the Vermont-sourced queens were just better queens. Local certainly (on a USA scale definition of the word local), but not better because they were local, just better because they were better.

However, if my interpretation of the source of the IAPV is correct i.e. introduced from the Californian queens, I think the paper indirectly demonstrates one of the most compelling reasons why local bees are preferable.

If they’re local – your apiary, your neighbours, someone in your association – there is little chance they will be bringing with them some unwanted baggage in the form of an undetected exotic pathogen.

Or a more virulent strain of one already circulating relatively benignly.

Extensive bee movements, whether of queens, packages or full colonies, risks spreading parasites and pathogens.

There is compelling evidence that hosts and pathogens co-evolve to reduce the pathogenicity of the interaction. Naive hosts are always more susceptible to introduced pathogens, or novel strains of pre-existing pathogens. After all, look what happened to the Peruvian Inca when they met the measles- and smallpox-ridden conquistadors.

So, when thinking about the claims being made by bee importers (or, for that matter, strong advocates of local bee breeding), it’s worth considering all of the factors at play – queen quality per se, genetic adaptation of the queen to the local environment and the potential for the introduction of novel pathogens with introduced non-local stock.

And that’s before you also consider the benefits to your beekeeping of being self-sufficient and not reliant on others to produce your stocks.

I never said it was simple 😉