Category Archives: Economics

Cut more losses

This is a follow-on to the post last week, this time focusing on feeding and a few ‘odds and sods’ that failed to make it into the first 3000 words on reducing overwintering colony losses.

Both posts should be read in conjunction with one (or more 1 ) of my earlier posts on disease management for winter. Primarily this involves hammering down the mite levels before the winter bees are produced, so ensuring their longevity.

But also don’t forget to treat your colonies during a broodless period in midwinter to mop up mites that survived the autumn treatment, or have reproduced since then.

Why feed colonies?

All colonies need sufficient stores to get the colony through the winter until suitable nectar sources and good enough weather make foraging profitable the following spring.

How much the colony needs depends upon the bees themselves – some strains are more frugal than others – and the duration of the winter. If there is no forage available, or the weather is too poor for the bees to fly, then they will be dependent upon stores in the hive.

A reasonable estimate would probably be somewhere around 20 kg of stores, but this isn’t a precise science.

It’s better for the colony to have too much than too little. 

If the colony has stores left over at winter’s end you can always remove them and use them when you make up nucs later in the season. Just pull out the frames and store them safely until needed.

Unused winter stores

In contrast, if the colony starts the winter with too few stores there are only two possible outcomes:

  • the colony will starve to death, usually in late winter/early spring (see below)
  • you will spend your winter having to regularly check the colony weight and opening the hive to add “emergency rations” to get them through the winter

Neither of these is desirable, though you should expect to have to check the colony periodically in winter anyway.

Feeding honey for the winter … and meaningless anecdotes

By the end of the summer the queen has reduced her laying rate and the bees should be backfilling brood comb with honey stores. If you assume there’s about 5 kg of stores 2 in the brood box then they’ll need about another 15 kg. 

15 kg is about the amount of honey you can extract from a well-filled super. 

Convenient 😉

Some beekeepers leave a full super of honey on the hive, claiming the “it’s better for the bees than syrup”

Of course, it’s a free world, but there are two things wrong with doing this:

  • where is the evidence that demonstrates that honey is better than sugar-based stores?
  • it’s an eye-wateringly expensive way to feed your colonies

By evidence, I mean statistically-valid studies that show improved overwintering on honey rather than sugar.

Not ‘my hive with a honey super was strong in spring but I heard that Fred lost his colony that was fed syrup’ 3.

That’s not evidence, that’s anecdote.

If you want to get this sort of evidence you’d need to start with a lot of hives, all headed by queens of a similar age and provenance, all with balanced numbers of brood frames/strength, all with similar mite levels and other pathogens.

For starters I’d suggest 200 hives; feed 50% with honey, 50% with sugar … and then repeat the study for the two following winters.

Then do the stats 4.

The economics of feeding honey

If I were a rich man …

The 300 supers of honey used for that experiment would contain honey valued at about £80,000.

That’s profit, not sale price (though it doesn’t include labour costs as I – and many amateur beekeepers – work for free).

The honey in a single full super has a value of £250-275 … that’s an expensive way to feed your bees 5.

Particularly when it’s not demonstrably better than a tenner or so of granulated sugar 🙁

But there are more costs to consider

The economic arguments made above are simplistic in the extreme. However, there are other costs to consider when feeding colonies.

  • time taken to prepare and store whatever you will be feeding them with 6
  • feeders needed to dispense the food (and storage of these when not in use)
  • energetic costs for the colony in converting the food to stores

Years ago I stopped worrying (or even thinking much) about any of this and settled on feeding colonies fondant in the autumn.

Fondant mountain ...

Fondant mountain …

Fondant is ~78% sugar, so a 12.5 kg block contains about 9.75 kg of sugar.

This year I’m paying £11.75 for fondant which equates to ~£1.20 / kg for the sugar it contains.

In contrast, granulated sugar is currently about £0.63 / kg at Tesco.

The benefits of fondant

Although my sugar costs are about double this is a relatively small price I’m (more than) prepared to accept when you take into account the additional benefits.

  • zero preparation time and no container costs. Fondant comes ready-wrapped and stores for years in the box it is purchased in
  • no need for jerry cans, plastic buckets or anything to prepare or store it in before use
  • no need for expensive Ashforth-type feeders that sit around for 95% of the year unused When I last checked an Ashforth feeder cost £66 😯 
  • it takes less than 2 minutes to add fondant to a colony
  • no risk of spillages – in the kitchen, the car or the apiary 7.
  • fondant is taken down more slowly than syrup, so providing more space for the queen to continue laying. In addition, in the event of an early cold snap, fondant remains accessible whereas bees often stop taking syrup down

Regarding the energetic costs for the colony in storing fondant rather than syrup … I assume this is the case based upon the similarity of the water content of fondant to capped stores (22% vs. 18%), whereas syrup contains much more water and so needs to be ripened before capping to avoid fermentation.

Fondant block under inverted perspex crownboard – insulation to be added on top.

Whether this is correct or not 8, the colony has no problem taking down the fondant over a 2-4 week period and storing it.

What are the disadvantages of using fondant? 

The only one I’m really aware of is that the colony will not draw fresh comb when feeding on fondant (or at least, not enthusiastically). In contrast, bees fed syrup in the autumn and provided with fresh foundation will draw lovely worker brood comb. 

Do not underestimate this benefit.

They fancied that fondant

Brood frames of drawn comb are a very valuable resource. Every time you make up a nuc, or shift a nuc to a full-sized box, providing drawn comb significantly speeds up the expansion of the resulting colony.

Nevertheless, for me, the advantages of fondant far outweigh the disadvantages …

Finally, in closing, I’ve not purchased or used invert syrup for feeding colonies. Other than no prep time this has the same drawbacks as syrup made from granulated sugar. Having learnt to use fondant a decade or so ago from Peter Edwards (Stratford BKA) I’ve never felt the need to look at other options.

Let’s move on …

Ventilation and insulation

Bees can withstand very cold temperatures if healthy and provided with sufficient stores. In northern Canada bees may experience only 120 frost-free days a year, and cope with 3-4 week periods in winter when the temperature is -25°C (and colder if you consider the wind chill).

That makes anywhere in the UK look positively balmy.

Margate vs. the Maldives … a similar temperature difference to Margate vs. Manitoba in the winter

I’ve overwintered colonies in cedar or poly boxes for a decade and not noticed a difference in survival rates. Like the honey vs. sugar argument above, if there is a difference it is probably minor. 

However, colony expansion in poly boxes in the spring is usually better in my experience, and they often fill the outer frames with brood well before cedar boxes in the same apiary get there.

Whether cedar or poly I take care with three aspects of their insulation/ventilation:

  • the colonies have open mesh floors and the Varroa tray is only in place when I’m actively monitoring mite drop
  • all have insulation above the crownboard in the form of a 50 mm thick block of Kingspan (or Recticel, or Celotex), either integrated into the crownboard itself, placed above it or built into the roof
  • I ensure there is no upper ventilation – no matchsticks under the crownboard, no holes etc.
  • excess empty space in the brood box is reduced to minimise the dead air space the bees might lose heat to

In my experience bees actively dislike ventilation in the crownboard. They fill mesh with propolis …

Exhibit A … are you getting the message?

… and block up the holes in those over-engineered Abelo crownboards …

Exhibit B … ventilated hole in an Abelo crownboard

Take notice of what the bees are telling you … 😉

Insulation over the colony

I’ve described my insulated perspex crownboards before. They work well and – when inverted – can just about accomodate a flattened 9, halved block of fondant.

Perspex crownboard with integrated insulation

Finally, if it’s a small colony in a brood box 10 then I reduce the dead space in the brood box using a fat dummy

Fat dummy with integral feeder

Fat dummy …

I build these filled with polystyrene chips.

You don’t need this sort of high-tech solution … some polystyrene wrapped tightly in a thick plastic bag and sealed up with gaffer tape works just as well.

Insulation ...

Insulation …

I’ve even used bubblewrap or that air-filled plastic packaging to fill the space around a top up block of fondant in a super ‘eke’ before now.

However, remember that a small weak colony in autumn is unlikely to overwinter as well as a strong colony. Why is it weak? Would you be better uniting it before winter starts?

Nucleus colonies

Everything written above applies equally well to nucleus colonies.

A strong, healthy nuc should overwinter well and be ready in the spring for sale or promoting to a full colony.

Here's one I prepared earlier

Here’s one I prepared earlier … an overcrowded overwintered nuc in April

Although I have overwintered nucs in cedar boxes I now almost exclusively use polystyrene. This is another economic decision … a well made cedar nuc costs about double the price of the best poly nucs

I feed my nucs fondant in preparation for the winter, typically by adding 1-2 kg blocks to the integral feeder.

Everynuc fondant topup

Everynuc fondant topup

Because of the absence of storage space in the nuc brood box it’s not unusual to have to supplement this several times during the autumn and winter.

You can even overwinter queens in mini-mating nucs like Apidea’s and Kieler’s.

Kieler mini-nuc with overwintering queen

This deserves a post of its own. Briefly, the mini-nuc needs to be very strong and usually double- or triple- height. I build fondant frame feeders for Kieler’s that can be quickly swapped in/out to compensate for the limited amounts of stores present in the brood box.

Kieler mini-nuc frame feeders

My greatest success in overwintering these was in winters when I provided additional shelter by placing the nucs in an unheated greenhouse. A tunnel provided access to the outside. However, I know several beekeepers who overwinter them without this sort of additional protection (and have done so myself).

Just because this can be done doesn’t mean it’s the best thing to do.

I’d always prefer to overwinter a colony as a 5 frame nuc. The survival rates are much better, their resilience to long periods of adverse weather is significantly greater, and they are generally much more useful in the spring.

Miscellaneous musings

Hive weight

A colony starting the winter with ample stores can still starve if the bees are particularly extravagant, or if they rear lots of brood but cannot forage.

The rate at which stores are used is slow late in the year and speeds up once brood rearing starts again in earnest early the following spring (though actually in late winter).

Colony weight in early spring

As should be obvious, this is a Craptastic™ sketch simply to illustrate a point 😉

The inflection point might be mid-December or even early February.

The important message is that, once brood rearing starts, consumption of stores increases. Keep checking the colony weight overwinter and supplement with fondant as needed.

I’m going to return to overwinter colony weights sometime this winter as I’m dabbling with a weather station and set of hive scales … watch this space.

An empty super cuts down draughts

Periodically it’s suggested that an empty super under the (open mesh) floor of the hive ‘cuts down draughts’, and is therefore beneficial for the colony.

It might be.

But like the ‘overwintering on honey’ (and being a pedant scientist) I’d always want to see the evidence.

There are two claims being made here:

  • a super under the floor cuts down draughts
  • fewer draughts benefits the colony which consequently overwinters better


There are ways to measure draughts but has anyone ever done so? Remember, the key point is that the airflow around the winter cluster would be reduced if there are fewer draughts. 

Does a super reduce this airflow significantly over and above that already caused by the sidewalls of the floor?

And, even if it does, perhaps the colony ‘reshapes’ itself to accommodate the draught from an open mesh floor.

What shape is the winter cluster?

For example, in an uninsulated hive (including no insulation over the cluster) with a solid floor the cluster is likely to be roughly spherical. They minimise the surface area.

With an open mesh floor are they more ellipsoid, so avoiding draughts from below? If so, is this improved much by an empty super below the open mesh floor? Does the cluster change shape or position? I don’t know as I’ve not compared cluster shapes in solid vs. open mesh floors plus/minus a super underneath.

And anyway, an open mesh floor looks very like a baffle to me … how much better can it get? How draughty is it in the first place?

Is this example 8,639 for my ‘Beekeeping Myths’ book?

I do know that top insulation tends to flatten the cluster against the warm underside of the crownboard.

Midwinter cluster

A strong colony in midwinter

Having worked out that draughts are (or are not) reduced … you still need another couple of hundred hives to test whether overwintering success rates are improved!

More winter bees

Finally, always remember that the survival of the colony is dependent upon the winter bees. All other things being equal (stores, disease etc.), a colony with lots of winter bees will overwinter better than one with fewer.

This is one of the reasons I stopped using Apiguard for mite control in autumn. Apiguard contains thymol and quite regularly (30-50% of the time in my experience) stopped the queen from laying, particularly in warmer weather. 

Apiguard works well for mite control, but I became wary that I was potentially stopping the queen at a time critical for late-season colony development. I worried that, once treatment was finished, a cold snap would shut down brood rearing leaving it with suboptimal numbers of winter bees.

I never checked to see whether the queen ‘made good’ any shortfall after removal of the treatment … instead I moved to Scotland where it’s too cold to use Apiguard effectively 🙁


Rational Varroa control

It’s the end of July … in the next two to three weeks the first eggs will be laid that will develop into the winter bees that get your colonies through to next spring. Protecting these winter bees is necessary to prevent overwintering colony losses.

I’ve written and lectured extensively on Varroa control and related topics for at least 5 years. The following article is published in August’s BBKA Newsletter and The Scottish Beekeeper. It provides an overview of what I term rational Varroa control.

I define this as effective mite management based upon our current understanding of the biology of bees and Varroa. The goal of this control is to minimise winter losses due to Varroa and viruses.

It is not a recipe with easy to follow if this, then that instructions. Neither does it provide a calendar-based guide of what to do and when to do it.

It does not even tell you what you should use for mite control.

Instead it focuses on the principles … understanding these will enable you to implement control strategies that help your bees, in your environment, survive.

This version is hyperlinked to additional, more expansive, posts on particular topics, is slightly better illustrated than those that appeared in print and contains some additional footnotes with caveats and exceptions.


Despite almost 30 years experience of Varroa in the UK, this ectoparasitic mite of honey bees remains the greatest threat to bees and beekeeping. With the exception of those fortunate to live in mite-free regions, all beekeepers must manage the mite population in their hives or risk losing the colony to the viruses transmitted when Varroa feeds on developing pupae. 

Fortunately, Varroa control is relatively straightforward; there are a range of approved and effective miticides that – used appropriately – reduce mite infestation levels significantly. The key words in that last sentence are ‘approved’, ‘effective’ and ‘used appropriately’. In reality annual colony losses, primarily occurring in the winter, often exceed 20% (Figure 1) and may be significantly higher in long or harsh winters 1. Many of these losses are attributable to Varroa and viruses. It is therefore clear that many beekeepers are not successful in managing Varroa; either they are not treating at all, or they are treating inappropriately.

Figure 1. BBKA winter survival survey – larger studies (COLOSS and BIP) often show much higher losses

This article is primarily aimed at relatively inexperienced beekeepers, but may also help the more experienced who still suffer with high levels of winter losses. It emphasises the importance of two, correctly timed, appropriate miticide treatments per season that should ensure colony survival. It is not going to deal with treatments of questionable or minor efficacy. These include the use of small cell foundation, drone brood culling or sugar dusting. These may reduce mite levels, but insufficiently to benefit colony health. Nor will it discuss the use of any miticides (or application methods) that are not approved by the Veterinary Medicines Directorate. I will also not discuss treatment-free beekeeping, selection of mite-resistant bees or advanced colony manipulations like queen trapping. In my view any or all of these could or should be tried … but only once a beekeeper can routinely successfully overwinter colonies using strategies similar to those described here.

The problem

Varroa is an ectoparasitic mite that feeds on developing honey bee pupae. During feeding it transmits a range of honey bee viruses, the most important of which is deformed wing virus (DWV). DWV is present in honey bees in the absence of Varroa. In our studies, using sensitive PCR-based detection methods, we never detect bees – even those from mite-free regions of Scotland – without DWV. The virus is transmitted horizontally between bees during trophallaxis, and vertically from drones or the queen through sperm or eggs. These routes of transmission are rarely if ever associated with any significant levels of disease and virus only replicates to modest levels (perhaps 1-10 thousand viruses per bee). However, when Varroa transmits DWV the virus bypasses the bee’s natural defence mechanisms and replicates to very high levels in recipient pupae (billions per pupa, 1 – 10 million times higher than in unparasitised pupae). Studies from our laboratory have shown that ~75% of pupae with these high virus loads either do not emerge, or emerge exhibiting the characteristic “deformed wings” that give the virus its name (Figure 2; Gusachenko et al., Viruses 2020, 12, 532; doi:10.3390/v12050532). The ~25% of bees that do emerge and appear ‘normal’ exhibit a range of symptoms including reduced fitness, impaired learning and reduced foraging. However, most importantly they also exhibit reduced longevity. During the summer this is probably not critical; the lifespan of a worker is only ~6 weeks and, assuming the queen is laying well, there are thousands of half-sisters around with more being produced every day.

DWV symptoms

Figure 2. DWV symptoms

But during the winter, brood rearing either stops completely or drops to a very low level. The bees reared from late summer onwards are physiologically very different. These are the ‘winter bees’, also termed the diutinus bees (from the Latin meaning long-lived). Physiologically these bees resemble juvenile workers and they can survive for many months. And they need to … it is these bees that get the colony through the autumn, winter and into the following spring. They protect the queen, they thermoregulate the hive and, usually around the winter solstice, they start to rear small amounts of new brood for the season ahead.

The longevity of the bees in the hive in winter is critical to colony survival. If the winter bees have high DWV levels their longevity is reduced (in addition to the reduced numbers due to overt disease or non-viability). This means that the winter cluster shrinks in size faster than it would do otherwise. With reduced numbers of bees it cannot keep brood warm enough and so the colony fails to expand early the following season. In cold spells it may be unable to reach the food stores resulting in the colony perishing from ‘isolation starvation’. It may not be able to maintain sufficient warmth to protect the queen, or may simply freeze to death.

The goal of rational Varroa control

Successful overwintering requires lots of winter bees. The size of the winter cluster is directly related to its survival chances. Therefore the goal of rational Varroa control is to prevent the winter bees from being exposed to mites and mite-transmitted viruses during their development. Winter bee production is induced by a range of factors including photoperiod, nectar and pollen availability, brood and forager pheromones. Together these induce slowed behavioural maturation of the winter bees. This is not like flicking a switch, instead it is a seamless transition occurring as late summer segues into early autumn (Figure 3). Winter bee production is also influenced by the queen. Young queens lay later into the autumn, so increasing the numbers of winter bees. 

Figure 3. Colony age structure from August to December.

It is important to note that these events are environment-driven, not calendar-driven. It will not happen at precisely the same time each year, or at the same time in different locations (or latitudes) each year.

To protect these winter bees the colony needs to be treated with an effective miticide before the majority of the winter bees are produced. This ensures that the developing winter bee pupae are not parasitised by virus-laden mites and so do not suffer from reduced longevity. 

When are winter bees produced in the UK? 

Unfortunately, I’m not aware of any direct studies of this. Scientists in Bern (49.9°N) in 2007/08, where the average temperatures in November and December were ~3°C, showed that the Varroa- and virus-reduced longevity of bees was first measurable in mid-November, 50 days after emergence. By extrapolation, the eggs must have been laid in the first week of September. 

Doing large scale experiments of Varroa control is time-consuming and subject to the vagaries of the climate (and, as a molecular virologist, beyond me in terms of the resources needed). I have therefore used the well-established BEEHAVE program of colony development (from scientists in the University of Exeter; to model the numbers of developing and adult bees, and the mite numbers in a colony. BEEHAVE by default uses environmental parameters (climate and forage) based upon data from Rothamsted (51.8°N). Using results from this model system, the bees present in the hive at the end of December – by definition the diutinus winter bees – were produced from eggs laid from early/mid August (Figure 4).

Whatever the precise date – and it will vary from season to season as indicated above – at some point in September the adult bee population starts to be entirely replaced with winter bees. Large numbers of these need to live until the following February or March to ensure the colony survives and is able to build up again once the queen starts laying.

When to treat – late summer

The numbers of pupae and adult bees present in the colony are plotted in Figure 4 using dashed lines. Adult bee number decrease in early spring until new brood is reared. The influence of the ‘June gap’ on pupal numbers is obvious. Brood rearing gradually tails off from early July and stops altogether sometime in late October or early November. The shaded area represents the period of winter bee production – from early/mid August until brood rearing stops. 

Figure 4. Winter bee production and mite levels – see key and text for further details

Mite levels are indicated using solid lines. The impact on the mite population of treating in the middle of each month from July to November is shown (arrowed and labelled J, A, S, O and N) using the colours green, blue, red, cyan and black respectively. The absolute numbers of bees or mites is irrelevant, but bees (pupae and adults) are plotted on the left, and mites on the right hand axis, so they cannot be directly compared. The miticide treatment modelled was ‘applied’ for one month and was 95% effective, reproducing many licensed and approved products.

Mite levels peak in the colony in late September to October. If treatment does not occur until this time of the season then the majority of winter bees will have been reared in the presence of large amounts of mites. Unsurprisingly, the earlier the treatment is applied, the lower the mite levels during the period of winter bee production. 

Rational Varroa control therefore involves treatment soon after the summer blossom honey is removed from the hive, so maximising the winter bees produced in the presence of low mite numbers. If you leave treatment until mid-September, you risk exposing the majority of winter bees to high levels of Varroa in the hive. If your primary crop is heather honey, which is not harvested until September, you may need to consider treating earlier in the summer – for example during the brood break when requeening or during swarm control.

Why treat in midwinter?

A key point to notice from Figure 4 is that, paradoxically, the earlier the miticide is applied, the higher the mite levels are at the end of the year. Compare the August (blue) and October (cyan) lines at year end for example. This is because mites that survive treatment – and some always do – subsequently reproduce in the small amount of brood reared late in the season. This is what necessitates a ‘midwinter’ treatment. Without it, mite levels increase inexorably year upon year, and cannot be controlled by a single late-summer treatment. Beekeepers bragging on social media that their mite drop after the winter treatment was zero probably applied the summer treatment too late to effectively protect their winter bees.

And when is midwinter?

Historically beekeepers apply the ‘midwinter’ treatment between Christmas and New Year. This is probably too late. The usual miticide used at this time is oxalic acid, a ‘one shot’ treatment that is ineffective against mites in capped cells. For maximum efficacy this must be applied when the colony is broodless. Brood rearing usually starts (if it ends at all, again this is climate-dependent) around the winter solstice. By delaying treatment until a lull in the Christmas festivities or even early January some mites will already be inaccessible in capped cells. 

Figure 5. Biscuit coloured (or a bit darker) cappings indicating brood rearing in this colony

I check my colonies for brood – either by looking for biscuit-coloured cappings on the Varroa tray (Figure 5) or by quickly inspecting frames in the centre of the cluster – and usually treat in November or very early December. If I cannot check visually I apply the treatment during the first extended cold spell of the winter. By treating when the colony is broodless I can be certain my intervention will have maximal effect.

What to treat with?

I have deliberately avoided – other than mentioning oxalic acid – specific miticides. Rational Varroa control involves the choice of an appropriate miticide and its correct application. Examples of incorrect or inappropriate miticide choice include; use of Apistan when resistance is known to be very widespread, use of Apiguard when the average ambient temperature is below 15°C (which makes Apiguard of little use for effective control in much of Scotland) or the use of Api-Bioxal when there is capped brood present. In addition, use of a half-dose or a reduced period of application will both reduce efficacy and potentially lead to the selection of resistance in the mite population. Used correctly – the right dose at the right time and for the right duration – the majority of the currently licensed miticides are be capable of reducing mite levels by over 90%. If they do not, use one that does. Miticide choice should be dictated by your environment and the state of the colony.

All together now

Most beekeepers grossly underestimate the movement of bees (and their phoretic mites) between colonies. Numerous studies have shown that drifting and (to an even greater extent) robbing can result in the transfer of large numbers of mites from adjacent and, in the case of robbing, more distant colonies. 

Gaffer tape apiary

Figure 6. Gaffer tape apiary …

Rational Varroa control therefore involves treating all colonies within an apiary, and ideally the wider landscape, in a coordinated manner. In communal association apiaries (Figure 6), where beekeeping experience and therefore colony management and health can vary significantly, this is particularly important. Coordinated treatment is only relevant in late summer when bees are freely flying.


Swarms originating from unmanaged or poorly managed colonies will have high mite levels. The bee population in a swarm is biased towards younger bees; these are the bees that phoretic mites preferentially associate with. Studies have shown that ~35% of the mite population of a colony leaves with the swarm.

Figure 7. Varroa treatment of a new swarm in a bait hive…

Since swarms contain no sealed brood until ~9 days after they are hived oxalic acid is the most appropriate treatment. I usually treat them using vaporised oxalic acid late in the evening soon after they are hived (Figure 7). Even casts get this treatment and I have not experienced any issues with the queen not subsequently mating successfully. I’d prefer to have a queenless low-mite colony than a queenright one potentially riddled with Varroa.

Midseason mite treatment

The text above describes the mite management strategies I have used for several years. I apply Apivar immediately the summer honey is removed and treat with oxalic acid when broodless before the end of the year. Doing this has almost never required any additional midseason treatments; if mite levels are sufficiently low at the beginning of the season they cannot rise to dangerous levels before the late summer treatment. I still get winter colony losses, but they are almost always due to poor queen mating and rarely due to Varroa and viruses.

Figure 8. Queenright splits and the window(s) of opportunity

However, if midseason treatments are required – either because there are signs of overt infestation, because regular mite counts have shown there is a problem, or to have low mite colonies after the heather honey is collected – then there are two choices. Treat with MAQS which is approved for use when there are supers on the hive and, more importantly, is effective against mites in capped cells 2. Alternatively, treat during swarm control. With care, the majority of splits (e.g. the Pagden artificial swarm or the nucleus method) can be performed to give a broodless period for both the queenright (Figure 8) and queenless partitions. That being the case, a single application of an oxalic acid-containing miticide can be very effective in controlling the mite population.


Many beekeepers complain about the cost of licensed and approved miticides. However, some perspective is needed. A colony with low levels of mites will be more likely to survive overwinter, so reducing the costs of replacement bees. In addition, a healthy colony will be a stronger colony, and therefore much more likely to produce a good crop of honey (and potentially an additional nuc). Over the last 5-6 years my miticide costs are equivalent to one jar of honey per colony per year. This is an insignificant amount to pay for healthy colonies.


Rational Varroa control requires an understanding of the goals of treatment – protecting the winter bees and minimising mite levels for the beginning of the following season – and an appreciation of how this can best be achieved using miticides appropriate for the environment and the state of the colony. Like so much of beekeeping, it involves judgement of the colony and will vary from season to season and your location. I’ve applied my midwinter treatment as early as the end of October or as late as mid-December, reflecting variation in timing of the broodless period. Rational Varroa control also involves an understanding of the biology of bees and an awareness of the influence of beekeeping (e.g. crowding colonies in apiaries which increases mite and disease transmission) on our bees. However, none of this is difficult, expensive or time consuming … and the benefits in terms of strong, healthy, productive colonies are considerable.


A version of this post appeared in the BBKA Newsletter, August 2021

A version of this post appeared in The Scottish Beekeeper, August 2021

Brexit and beekeeping

The ‘oven ready’ deal the government struck with the EU in the dying hours of 2020 was a bit less à la carte and a bit more table d’hôte.

The worst of the predictions of empty supermarket shelves and the conversion of Essex into a 3500 km2 lorry park have not materialised 1.

But there are other things that haven’t or won’t appear.

And one of those things is bees.

Bee imports

There is a long history of bee imports into the UK, dating back at least a century. In recent years the number of imports has markedly increased, at least partially reflecting the increasing popularity of beekeeping. 

Going up! Imports of queens, nucs and packages to the UK, 2007-2020 (National Bee Unit data)

Queens are imported in cages, usually with a few attendant workers to keep them company. Nucs are small sized colonies, containing a queen, bees and brood on frames. 

Packages are the ‘new kid on the block’ (in the UK) with up to 2500 per year being imported after 2013. Packages are queenless boxes of bees, containing no frames or brood.

Empty boxes after installing packages of bees

They are usually supplied in a mesh-sided box together with a queen. The bees are placed into a hive with frames of foundation and the queen is added in an introduction cage. They are fed with a gallon to two of syrup to encourage them to draw comb.

Installing a package of bees

It’s a very convenient way to purchase bees and avoids at least some of the risk of importing diseases 2. It’s also less expensive. This presumably reflects both the absence of frame/foundation and the need for a box to contain the frames.

But, post-Brexit, importation of packages or nucs from EU countries is no longer allowed. You are also not allowed to import full colonies (small numbers of these were imported each year, but insufficient to justify adding them to the graph above).

Queen imports are still allowed.

Why are were so many bees imported?

The simple answer is ‘demand’.

Bees can be reared inexpensively in warmer climates, such as southern Italy or Greece. The earlier start to the season in these regions means that queens, nucs or packages can be ready in March to meet the early season demand by UK beekeepers.

If you want a nuc with a laying queen in March or April in the UK you have two choices; a) buy imported bees, or b) prepare or purchase an overwintered nuc.

I don’t have data for the month by month breakdown of queen imports. I suspect many of these are also to meet the early season demand, either by adding them to an imported package (see above) or for adding to workers/brood reared and overwintered in a UK hive that’s split early in the season to create nucleus colonies.

Some importers would sell the latter on as ‘locally reared bees’. They are … sort of. Except for the queen who of course determines the properties of all the bees in the subsequent brood 🙁

An example of being “economical with the truth” perhaps?

Imported queens were also available throughout the season to replace those lost for any number of reasons (swarming, poor mating, failed supersedure, DLQ’s, or – my speciality – ham-fisted beekeeping) or to make increase.

And to put these imports into numerical context … there are about 45,000 ‘hobby’ beekeepers in the UK and perhaps 200+ bee farmers. Of the ~250,000 hives in the UK, about 40,000 are managed by bee farmers.

What are the likely consequences of the import ban?

I think there are likely to be at least four consequences from the ban on the importation of nucs and packages to the UK from the EU:

  1. Early season nucs (whatever the source) will be more expensive than in previous years. At the very least there will be a shortfall of ~2000 nucs or packages. Assuming demand remains the same – and there seems no reason that it won’t, and a realistic chance that it will actually increase – then this will push up the price of overwintered nucs, and the price of nucs assembled from an imported queen and some ‘local’ bees. I’ve seen lots of nucs offered in the £250-300 range already this year.
  2. An increase in imports from New Zealand. KBS (and perhaps others) have imported New Zealand queens for several years. If economically viable this trade could increase 3.
  3. Some importers may try and bypass the ban by importing to Northern Ireland, ‘staging’ the bees there and then importing them onwards to the UK. The legality of this appears dubious, though the fact it was being considered reflects that this part of the ‘oven ready’ Brexit deal was not even table d’hôte and more like good old-fashioned fudge.
  4. Potentially, a post-Covid increase in bee smuggling. This has probably always gone on in a limited way. Presumably, with contacts in France or Italy, it would be easy enough to smuggle across a couple of nucs in the boot of the car. However, with increased border checks and potential delays, I (thankfully) don’t see a way that this could be economically viable on a large scale.

Is that all?

There may be other consequences, but those are the ones that first came to mind.

Of the four, I expect #1 is a nailed-on certainty, #2 is a possibility, #3 is an outside possibility but is already banned under the terms of the Northern Ireland Protocol which specifically prohibits using Northern Ireland as a backdoor from Europe, and #4 happens and will continue, but is small-scale.

Of course, some, all or none of this ban may be revised as the EU and UK continue to wrangle over the details of the post-Withdrawal Agreement. Even as I write this the UK has extended the grace period for Irish sea border checks (or ‘broken international law’ according to the EU). 

This website is supposed to be a politics-free zone 4 … so let’s get back to safer territory.

Why is early season demand so high?

It seems likely that there are three reasons for this early season demand:

  1. Commercial beekeepers needing to increase colony numbers to provide pollination services or for honey production. Despite commercials comprising only ~0.4% of UK beekeepers, they manage ~16% of UK hives. On average a commercial operation runs 200 hives in comparison to less than 5 for hobby beekeepers. For some, their business model may have relied upon the (relatively) inexpensive supply of early-season bees.
  2. Replacing winter losses by either commercial or amateur beekeepers. The three hives you had in the autumn have been slashed to one, through poor Varroa management, lousy queen mating or a flood of biblical proportions. With just one remaining hive you need lots of things to go right to repopulate your apiary. Or you could just buy them in.
  3. New beekeepers, desperate to start beekeeping after attending training courses through the long, dark, cold, wet winter. And who can blame them? 

For the rest of the post I’m going to focus on amateur or hobby beekeeping. I don’t know enough about how commercial operations work. Whilst I have considerable sympathy if this change in the law prevents bee farmers fulfilling pollination or honey production contracts, I also question how sensible it is to depend upon imports as the UK extricates itself from the European Union.

Whatever arrangement we finally reached it was always going to be somewhere in between the Armageddon predicted by ‘Project Fear’ and the ‘Unicorns and sunlit uplands’ promised by the Brexiteers.

Where are those sunlit uplands?

And that had been obvious for years.

I have less sympathy for those who sell on imported bees to meet demand from existing or new beekeepers. This is because I think beekeeping (at least at the hobbyist level) can, and should, be sustainable.

Sustainable beekeeping

I would define sustainable beekeeping as the self-sufficiency that is achieved by:

  • Managing your stocks in a way to minimise winter losses
  • Rearing queens during the season to requeen your own colonies when needed (because colonies with young queens produce brood later into the autumn, so maximising winter bee production) and to …
  • Overwinter nucleus colonies to make up for any winter losses, or for sale in the following spring

All of these things make sound economic sense. 

More importantly, I think achieving this level of self-sufficiency involves learning a few basic skills as a beekeeper that not only improve your beekeeping but are also interesting and enjoyable.

I’ve previously discussed the Goldilocks Principle and beekeeping, the optimum number of colonies to keep considering your interest and enthusiasm for bees and the time you have available for your beekeeping.

It’s somewhere between 2 and a very large number. 

For me, it’s a dozen or so, though for years I’ve run up to double that number for our research, and for spares, and because I’ve reached the point where it’s easy to generate more colonies (and because I’m a lousy judge of the limited time I have available 🙁 ).

Two is better than one, because one colony can dwindle, can misbehave or can go awry, and without a colony to compare it with you might be none the wiser that nothing is wrong. Two colonies also means you can always use larvae from one to rescue the other if it goes queenless.

And with just two colonies you can easily practise sustainable beekeeping. You are no longer dependent on an importer having a £30 mass-produced queen spare.

What’s wrong with imported bees?

The usual reason given by beekeepers opposed to imports is the risk of also importing pathogens.

Varroa is cited as an example of what has happened. 

Tropilaelaps or small hive beetle are given as reasons for what might happen.

And then there are usually some vague statements about ‘viruses’. 

There’s good scientific evidence that the current global distribution of DWV is a result of beekeepers moving colonies about.

More recently, we have collaborated on a study that has demonstrated an association between honey bee queen imports and outbreaks of chronic bee paralysis virus (CBPV). An important point to emphasise here is that the direction of CBPV transmission is not yet clear from our studies. The imported queens might be bringing CBPV in with them. Alternatively, the ‘clean’ imported queens (and their progeny) may be very susceptible to CBPV circulating in ‘dirty’ UK bees. Time will tell.

However, whilst the international trade in plants and animals has regularly, albeit inadvertently, introduced devastating diseases e.g. Hymenoscyphus fraxineus (ash dieback), I think there are two even more compelling reasons why importation of bees is detrimental.

  1. Local bees are better adapted to the environment in which they were reared and consequently have increased overwintering success rates.
  2. I believe that inexpensive imported bees are detrimental to the quality of UK beekeeping.

I’ve discussed both these topics previously. However, I intend to return to them again this year. This is partly because in this brave new post-Brexit world we now inhabit the landscape has changed.

At least some imports are no longer allowed. The price of nucs will increase. Some/many of these available early in the season will be thrown together from overwintered UK colonies and an imported queen.

These are not local bees and they will not provide the benefits that local bees should bring.

Bad beekeeping and bee imports

If imported queens cost £500 each 5 there would be hundreds of reasons to learn how to rear your own queens. 

But most beekeepers don’t …

Although many beekeepers practise ‘passive’ queen rearing e.g. during swarm control, it offers little flexibility or opportunity to rear queens outside the normal swarming season, or to improve your stocks.

In contrast, ‘active’ queen rearing i.e. selection of the best colonies to rear several queens from, is probably practised by less than 20% of beekeepers.

This does not need to involve grafting, instrumental insemination or rows of brightly coloured mini-nucs. It does not need any large financial outlay, or huge numbers of colonies to start with.

But it does need attention to detail, an understanding of – or a willingness to learn – the development cycle of queens, and an ability to judge the qualities of your bees.

Essentially what it involves is slightly better beekeeping.

But, the availability of Italian, Greek or Maltese queens for £20 each acts as a disincentive.

Why learn all that difficult ‘stuff’ if you can simply enter your credit card details and wait for the postie?

Overwintering 5 frame poly nuc

Overwintering 5 frame poly nuc

And similar arguments apply to overwintering nucleus colonies. This requires careful judgement of colony strength through late summer, and the weight of the nuc over the winter.

It’s not rocket science or brain surgery or Fermat’s Last Theorem … but it does require a little application and attention.

But, why bother if you can simply wield your “flexible friend” 6 in March and replace any lost colonies with imported packages for £125 each?

Rant over

Actually, it wasn’t really a rant. 

My own beekeeping has been sustainable for a decade. I’ve bought in queens or nucs of dark native or near-native bees from specialist UK breeders a few times. I have used these to improve my stocks and sold or gifted spare/excess nucs to beginners.

I’ve caught a lot of swarms in bait hives and used the best to improve my bees, and the remainder to strengthen other colonies.

The photographs of packages (above) are of colonies we have used for relatively short-term scientific research. 

I’m going to be doing a lot of queen rearing this season. Assuming that goes well, I then expect to overwinter more nucs than usual next winter. 

I then hope that the bee import ban remains in place for long enough until I can sell all these nucs for an obscene profit which I will use to purchase a queen rearing operation in Malta. 😉

And I’m going to write about it here.


BBKA statement made a day or two after this post appeared. The BBKA and other national associations are concerned about the potential import of Small Hive Beetle (SHB) into the UK via Northern Ireland. Whilst I still think this breaches the Northern Ireland Protocol, it doesn’t mean it won’t be attempted (and there’s at least one importer offering bees via this route). It’s not clear that the NI authorities have the manpower to inspect thousands of packages.

It’s worth noting that SHB was introduced to southern Italy in 2014 and remains established there. The most recent epidemiological report shows that it was detected as late as October 2020 in sentinel apiaries and is also established in natural colonies.

With a single exception – see below – every country into which SHB has been imported has failed to eradicate it. As I wrote in November 2014:

“Once here it is unlikely that we will be able to eradicate SHB. The USA failed, Hawaii failed, Australia failed, Canada failed and it looks almost certain that Italy has failed.”

And Italy has failed.

The one exception was a single import to a single apiary in the Portugal. Notably, the illegal import was of queens, not nucs or packages. Eradication involved the destruction of the colonies, the ploughing up of the apiary and the entire area being drenched in insecticide.

The Beekeepers Quarterly

This post also appeared in the summer 2021 edition of The Beekeepers Quarterly published by Northern Bee Books.

Preparing honey

Whisper it … Christmas is fast approaching.

It may seem premature to be discussing this at the end of November, but there are some things that require a bit of preparation.

I presume you’ve already made the Christmas cake? 1

I sell more honey in the few weeks before Christmas than almost any other time of the year … and I also jar a lot as gifts for family and friends.

Jarring 2 honey is one of those topics that hardly gets a mention on these pages, yet is one of the few ‘real’ beekeeping activities we can do in depths of winter.

Although I’ve written a few posts about jarring honey in the past, they’re scattered around the place and are several years old, so it seemed timely to revisit the subject again.

Quality and quantity

Let’s deal with these in reverse order so you appreciate the scale of things.

The average number of colonies managed by UK beekeepers was about 5. There are about 45 to 50 thousand beekeepers managing a quarter of a million colonies, with a few tens of thousands over that number managed by a small number of bee farmers 3.

BBKA surveys report the average honey production per hive varies from ~8-31 lb per year 4. Let’s assume, as I’ve done previously, that the ‘average’ hive produces 25 lb, so the ‘average’ beekeeper generates 125 lb of honey a season.

However, these averages probably obscure the real distribution of hives and honey. The majority of BBKA survey respondents run only 1-2 colonies, with others running ten or more. The real distribution of hives therefore resembles a U shaped curve.

More experienced beekeepers, running more colonies successfully, will produce disproportionately more honey. Annual averages of 50 – 75 lb of honey per colony are readily achievable with good management and good forage. Honey production is more likely to resemble a J shaped curve.

I’m a small scale beekeeper with 10-12 (honey) production colonies and the same number again for work, queen rearing etc., most of which usually produce little honey.

In a good year I produce enough honey to make jarring and labelling a bit dull and repetitive, but not enough to justify anything more automated than my trusty and long-suffering radial extractor.

No fancy uncapping machine, no automated honey creamer, no computer controlled bottling line and no bottle labeller.

In my dreams perhaps … but in reality just about everything is done manually.

Whether it’s 10 lb or 1000 lb anything I discuss below could be done using the same manual methods, and with the same overall goal.

And that goal is to produce a really top quality honey – in appearance and flavour – that makes an attractive gift or a desirable purchase.


In Fife there are two honey harvests. Spring, which is predominantly (though not exclusively) oilseed rape (OSR), and summer which is much more variable. Some years we get an excellent crop from the lime, in other years it’s the more usual Heinz Honey containing 57 varieties of hedgerow and field nectars.

Heinz Honey

My production colonies are in two main apiaries and I extract each separately. That way, distinctive nectars that predominate in particular areas remain separate.

If customers want identical honey, jar after jar after jar, they can buy any amount of the stuff – often at absurdly cheap prices – in the supermarket.

Conversely, if they want a unique, high quality product they buy locally produced honey and expect variation depending upon the apiary and the season.

I run the extractor with the gate open, through coarse and fine filters, directly into buckets for storage. Warming the supers over the honey warming cabinet makes extraction and simultaneous filtering much easier.

I almost never get single crop honey and don’t harvest mid-season.

If you look at different frames it’s not unusual to have dark honey stored in one and lighter honey elsewhere, or as two distinct areas within the same frame. I know I’m missing the opportunity to produce some wonderfully distinct honeys, but pressure of work, queen rearing and a visceral loathing for cleaning the extractor restricts me to two harvest per season.

~90 kg of honey from my home apiary

Wherever possible entire supers are extracted into single 30 lb plastic buckets. Each is weighed, and the water content measured using a refractometer. Both numbers are written on the bucket lid and in my notes (an Excel spreadsheet). This becomes relevant when preparing honey for jarring.

Storage and crystallisation

Honey is stored in a cool location (~12-15°C), sealed tightly to avoid absorbing water from the environment.

High-glucose early season OSR honey crystallises rapidly. It usually sets rock hard well within a month of extraction.

Summer honey is much more variable and often takes many months to fully crystallise. I’ve just checked a few buckets that were extracted in early August and all are still liquid. However, if you looked carefully 5 you would almost certainly find micro-crystals already present.

All good quality honey will eventually crystallise. Tiny impurities – which are different from contaminants – such as pollen grains, act as nuclei onto which the sugars attach. These tiny crystals sink through the viscous honey to the bottom of the bucket.

Over time the honey at the bottom of an undisturbed bucket can be cloudy or gauzy in appearance with diffuse crystals. For the optimal appearance of the final bottled product these will need to be removed.

Clear summer honey

Clear summer honey is warmed and fine filtered again before jarring. I usually filter it through a nylon straining cloth. If you don’t do this then there’s a good chance it will crystallise relatively quickly in the jar.

Clear and not so clear honey

This spoils the appearance (and texture) but has no effect on the flavour.

It will still sell, but it will look less appealing, particularly to customers who are used to the homogenous unwavering bland sameness of supermarket honey.

Soft set honey

Well prepared soft set or creamed honey is a premium product. The fact that it can be prepared from large quantities of predominantly OSR honey is a bonus.

Honey warming cabinet. The Apiarist

Honey warming cabinet …

Many customers automatically choose clear honey. There’s certainly a greater demand for it. However, it’s worth always having a tester jar of soft set available. Disposable plastic coffee stirrers are an efficient way of sampling the tester and avoid the coarseness on the tongue of wooden stirrers.

A surprising number who try soft set honey, buy soft set honey … and then return for repeat business 🙂

The key points when preparing soft set honey are:

  • Have a suitable soft set ‘seed’ prepared. You can use shop bought for this, or grind a crystallised honey in a pestle and mortar 6. You need ~10% by weight of the seed.
  • Warm the set bucket of OSR honey sufficiently to melt the crystals. The honey should be clear and, when tested, leave no grittiness on the tongue. Mix periodically to aid heat transfer. I do this in my honey warming cabinet, but a water bath is much more efficient.
  • Cool the OSR honey to ~36°C and warm the seed honey to the same temperature. Do not melt the seed … you’re dependent upon the crystal structure of the seed to create the final product.
  • Add the seed to the melted OSR and mix thoroughly.
  • Allow the mixed honey to gradually cool to ~12-14°C, with regular stirring (at least twice a day). You can do this with a spoon, but as the honey crystallises and thickens it becomes very hard work. An electric drill and corkscrew or spiral mixer works well 7. This mixing may take several days.
  • Warm the honey to ~36°C and jar it 8.
  • Keep some of the seed for the next batch. If you’re jarring more in the next week or two, just leave 2-3 lb in the bucket. If longer, I store it in clip-seal containers.

Small batches

Honey keeps for years if stored in buckets at a cool temperature.

I tend to bottle honey in relatively small batches. This allows me to be certain the honey will look its very best for the short time it sits on the shelf.

This applies whatever the location of the shelf – by you door, if selling directly to the public, or in an artisan cafe or food store if selling via a third party.

Or even if the shelf is in your cupboard before you give it away to friends or relatives.

Preparing one or two buckets at a time for jarring makes sense. It’s a manageable number of jars (no more than 120 x 227g, or a smaller number of 340g or 454g jars) so I don’t die of boredom when subsequently labelling them. That number also fits into the dishwasher and on the worktop without too much of a problem.

Ready for delivery

I use the stored buckets in order of decreasing water content. Whether this makes a difference I’m unsure as all of my stored honey is below the 20% cutoff when measured. Interestingly, some seasons produce honey with consistently low water content. Spring 2018 was ~2% lower than this season averaged across 10-15 buckets.

Bottling it

I wash jars prior to using them and only use brand new jars. When jarring honey I dry and heat the jars in a 50°C oven so that, by the time they’re under the honey tap, they’re still warm.

Honey bucket tipper

The actual process of bottling honey is made much easier with my honey bucket tipper. I built this several years ago and it’s been used for thousands of jars in the intervening period. Amazingly, for something I built, I got it almost perfect from the start 9. I’ve changed the size of a couple of the wedges to tip the bucket, but that’s about all.

Almost always I can process the full bucket of honey, leaving only one final (incomplete) jar with the remnants of the bubbly scum from the surface of the honey.

The dregs

These are the jars I use for honey to go with my porridge 🙂

It’s worth noting that you can remove excess bubbly scum from a bucket by overlaying it with a sheet of clingfilm, then swiftly and carefully removing the clingfilm. Take care to avoid drips. It requires some deft handwork, but is remarkably effective in leaving just jarrable honey in the bucket.

Settling in, or out

Inevitably the process of jarring honey can introduce bubbles. Even if you take care to run the honey down the pre-warmed side of the jar you can end up with very obvious bubbles in clear honey.

And invisible bubbles in the opaque soft set honey.

These bubbles reduce the attractiveness of the finished product.

I therefore add lids to the jars and return the honey to my honey warming cabinet set at ~35°C for a few hours. The bubbles rise to the top and … pfffft … disappear, leaving the honey bubble free and crystal clear.

Settling out

Except for soft set honey of course. This is full of tiny crystals which produce that magic “melt on the tongue” sensation. However, I think that this final settling period helps minimise frosting in soft set honey.

After a few hours in the warming cabinet the jars are removed, allowed to cool to room temperature and labelled, ready for sale or gifting.


The honey labelling regulations are a minefield. I’m pretty confident my labels meet the requirements but – before you ask – will not provide advice on whether yours do 😉 Mine carry a unique batch number, the country of origin, a best before date (two years after the date of jarring), the relevant contact details and the weight of the metric jar contents in a font that is both the right size and properly visible.

Honey label

All my labels are home printed on a Dymo LabelWriter. I’ve got nothing to hide and want the customer to see the honey, rather than some gaudy label covering most of the jar. This works for me, but might not suit you or your customers. I’ve certainly not had any complaints, either from shops, or customers who buy from the door as gifts for their friends or family, and plenty of people return time and again for more.

I always add an anti-tamper label connecting the lid to the jar. Even purchased in rolls of 1000 at a time these are the most expensive of the three labels – front (with weight and origin), anti-tamper and rear (batch number, best before date and QR code). DIY labels cost less than 8p/jar in total.

It should go without saying that the outside of the jar should not be spoiled with sticky fingermarks! If you use black lids, as I do, it’s worth wiping them before attaching a clear anti-tamper seal to avoid fingerprints being preserved forever under the label.


The batch number is a unique five character code that allows me to determine the jar weight, bucket (weight and water content), apiary and season/year. If there was a problem with a particular batch 10 this would help recover any sold through a shop. The information is vaguely interesting to me; for example, looking back over the records it shows the inexorable rise in popularity of the 227 g jar as the proportion of these used increases year on year.

However, particularly in times of social distancing and when selling through a third party, this information on the provenance of the honey can be of interest to customers.

How many times did you sell a jar ‘at the door’ and get into a long conversation about whether the long avenue of limes north of the village produced nectar this year? Or whether the bees from my apiary could have pollinated the apple trees in the customers orchard?

Remember … many of the people who purchase local honey, or indeed any honey not carrying the dreaded Produce of EU and non-EU countries warning label, care about the origins of their food or the gifts they are making.

I’ve therefore been exploring linking the batch number to an online information page for the honey. By scanning a QR code on the jar 11 the customer can tell where and when the honey was produced. They can read about the area the bees forage in, the types of forage available and even the pollen types present in the honey. New Zealand beekeepers selling specialist manuka honey have been doing this sort of thing for a few years. My system is not ready for ‘prime time’ yet, but all the coding is done to get the information in and out of the backend database. Some customers already use it.

Even if the customer has no interest whatsoever, I still need to record the batch number, so it’s an example of added value to what I hope is perceived as a premium product.


Locally adapted bees

This is a follow up to the last post on Strong hives = live hives which was written in response to the oft-repeated mantra that ‘local bees are better adapted to the local environment’.

In that previous post a study of the overwintering survival of colonies headed by queens from very different locations was discussed. There was no difference whether the queen (and consequently all the workers she subsequently mothered) had come from Vermont or Florida.

Instead, the primary correlate of overwintering success was the strength of the colony 1 going into the winter.

Migratory beekeeping

Despite the size differences between the US and UK (or Europe), the honey bee population structure is actually more distinct on this side of the Atlantic.

In the USA the huge impact of migratory beekeeping causes considerable mixing of the bees on the continent. Those on the east and west coasts are distinct, but those in the north and south, or across smaller geographic scales, are really rather similar.

It’s not only commercial migratory beekeeping that enforces this, it’s also some of the very large-scale queen rearing operations. These ship queens all across the USA ensuring that there is less genetic diversity than you’d expect from the vast geographic (and climatic) differences.

Bee caravan

Bee caravan …

So, perhaps the study I discussed last week was not particularly surprising after all … ? 2

In contrast to the US, beekeeping activities in the UK and Europe are rather more localised.

In the UK we still import thousands of queens, but we don’t move our hives across the continent – often more than once a season.

We might take a dozen hives to the heather moors 150 miles away, but we never take them 2500 miles to pollinate almonds.

‘Local’ bees in Europe

Probably as a consequence of less large-scale migratory beekeeping, and less ‘centralisation’ of commercial queen rearing, there is genetic evidence for ‘local’ strains of bees in Europe.

In addition, there is evidence that these genetic differences result in changes to the individual proteins that the bee expresses … and that these may result in local ecological adaptations.

However, this still doesn’t get us to ‘local bees are better adapted to the local environment (and this explains why local bees survive better)‘ …

Andalucian apiary

Local Andalucian apiary

But there is even some evidence to support this last statement as well.

So let’s look at each of these points in turn 3.

Genetically diverse bees

Biologists use the terms genotype and phenotype to describe the genetic makeup of an organism and its appearance. Most beekeepers are familiar with the different phenotypes of honey bee – the dark ‘native’ bees, carniolans, Buckfast etc.

The phenotype is defined and determined by the genotype, but we don’t necessarily know which genes determine which physical characteristic. Population geneticists therefore often use different genetic features to discriminate between different groups or populations.

Microsatellites are DNA markers that contain variable numbers of short tandem repeat sequences. In honey bees, microsatellites are abundant and highly variable. They are therefore very useful for differentiating between populations or groups of populations, though how this is done is outside the scope of this post.

In 1995 Arnaud Estoup and colleagues reported the microsatellite analysis of 9 populations of honeybees from Africa (intermissa, scutellatacapensis) and Europe (mellifera, ligustica, carnica, cecropia), previously distinguished phenotypically. In their enticingly titled paper Microsatellite Variation in Honey Bee (Apis Mellifera L.) Populations: Hierarchical Genetic Structure and Test of the Infinite Allele and Stepwise Mutation Models 4 they support the earlier morphometric (phenotypic) definition by Ruttner of three distinct evolutionary branches of honey bee.

In a series of particularly impenetrable tables and phylogenetic trees they also demonstrate the the European lineages are genetically distinct and, importantly, that sub-populations could be readily identified 5.

Ecological adaptation of bees

Microsatellites are essentially non-functional genetic markers that we can use for analysis. They are carried alongside the thousands and thousands of genes that encode the proteins that make the wings, eyes, guts, feet etc. of honey bees. Other proteins also influence the behaviour of bees – how and when they swarm, their cold tolerance, there longevity.

We can now measure genetic variation of individual genes easily through so-called ‘next generation sequencing’ of the whole genome of the honey bee. However, the variation we see is one step removed from the variation at the protein level that directly influences how the bee copes in (or is adapted to) different environments.

But, it turns out, we can measure the variation at the protein level as well using a technique termed proteome profiling.

If distinct genetic populations of bees have adapted to particular environments (through selection, either natural or by beekeepers) we would expect the proteins they express – that both make the bee and determine its behaviour – should be different.

For example, simplistically, if a bee had evolved to live in a very windy environment we might expect the proteins forming the flight muscles would be stronger, enabling the bee to fly on windier days 6.

Collect the data, decipher what it all means …

Alternatively, you could turn the analysis around:

  • Identify the differences in the proteins that are expressed
  • Work out (or look up) what those particular proteins do and …
  • Conclude that those adaptive changes are required by that sub-population of bees in a particular ecological environment.

And, using proteome profiling, this is exactly what Robert Parker and colleagues reported in 2010 7. They compared proteins from adult bees sourced from geographically dispersed locations (Canada, New Zealand, Chile, USA).

They then grouped proteins into particular pathways e.g. energy metabolism, and observed significant differences.

Pathway analysis of honey bee midgut proteins across the populations studied.

As far as we’re concerned here – which is evidencing that locally adapted bees are actually different from each other in a meaningful way – the precise differences Robert Parker and colleagues aren’t too important.

But … if you insist.

Cold-adapted bees e.g. those from Saskatchewan (SK1, SK2), exhibited much higher levels of proteins involved in heat production in the mitochondria. In contrast, bees from warmer climates e.g. Hawaii (HI), showed higher levels of proteins involved in biosynthesis/folding and degradation of proteins.

Importantly, distinct populations of bees from geographically-distant regions exhibit differences that, logically, could be expected to make them better adapted to that environment.

But, there’s a bit still missing …

The key phrase in that last sentence is ‘could be expected’.

What was not shown in these two studies is that the differences observed are responsible for the better performance or survival of those bees in those environments.

Which finally brings me to a study by Ralph Büchler entitled The influence of genetic origin and its interaction with environmental effects on the survival of Apis mellifera L. colonies in Europe 8.

Local bees do survive better

This was an ambitious and large scale study of the survival of ~600 colonies in 21 apiaries in Europe. The colonies included 5 sub-species (carnicaligusticamacedonia and mellifera) and 16 different genotypes of bees.

In each of the 21 apiaries a local genotype was tested in parallel with at least two non-local genotypes. The large team of scientists/beekeepers involved used standardised management protocols which excluded any form of disease management e.g. no control of Varroa or other diseases. Consequently (many) colonies were lost to Varroa and were removed from the study once infestation levels had reached 10% (i.e. 1 in 10 workers carried phoretic mites) or bee numbers dropped below 5000.

The study started in autumn 2009 and ended in March 2012. During this ~2.5 years 84% of the colonies perished. Almost half of these losses were attributable to Varroa … not a particular surprise.

There are a lot of variables in this study – sub-species (5), genotypes (16), apiaries (21) – so the statistics and analysis are a bit of a minefield.

Count the corpses

Essentially the researchers ‘counted the corpses’ (i.e. colonies that died). They then looked at the survivors and tried to determine the characteristics they shared.

Unsurprisingly, survival of colonies in different apiaries was not the same. Graphed below is the percentage of colonies that survived (vertical axis) in each of the 21 apiaries against time (horizontal axis).

Trajectories of colony survival for the different locations.

These differences are presumably due to local forage availability, colony management, climate etc. We know that bees do better in some places than others 9.

When survival of different genotypes was compared they were much of a muchness, with two outliers.

Trajectories of colony survival for the 16 different genotypes

But, very significantly, colonies headed by local queens did significantly better than colonies headed by non-local queens.

Trajectories of colony survival for the origin of the queens

Why do local bees survive better?

The differences between the two lines – local and non-local queens – in the Kaplan-Meier survival curve above may not look particular good … they both drop disconcertingly quickly, indicating lots of dead colonies.

But it is.

The authors unequivocally demonstrate this statistically, but for beekeeping purposes it’s perhaps even more convincing to simply state that:

“colonies with local queens survived on average 83 ± 23 days longer than those with non-local queens”

That’s a key quote from the paper. It also probably explains why colonies headed by local queen survive better.

In a follow-up paper to Büchler et al., 2014, the same authors did a more in-depth analysis of a range of colony parameters that correlated with survival 10 which contains an additional piece of the jigsaw explaining why colonies headed by local queens survived better.

“colonies of local origin had significantly higher numbers of bees than colonies placed outside their area of origin”

And, by significantly higher, I mean ~20% higher.

Which finally completes the story and brings us back to the Strong hives = live hives from last week.

Local queens head up colonies that survive better in the local environment to which they (and their workers) are adapted.

The colonies survive significantly longer because the colonies are significantly stronger.

Caveats and conclusions

There are a number of caveats to the ‘count the corpses’ study conducted by Büchler and colleagues.

For example, the local bees might have actually been adapted to the local beekeeping management practices. In future experiments there might be ways to control for this 11.

The absence of Varroa control meant colonies were always weaker in the second year of the study. For the majority of beekeepers this is not a sustainable way to manage colonies. A fourth year would have been impossible as they would have run out of colonies.

Nevertheless, under the conditions tested, this is confirmation that ‘local bees are better adapted to the local environment (and survive better)‘.

But as a scientist there’s always another ‘Why?’ question.

Why are the colonies stronger? Is it increased longevity of worker bees? Perhaps it is better foraging skills, meaning more brood can be reared? Is it an adaptation of the queen to the chemicals in the local pollen that increases her fecundity?

Question, questions, questions …

I can think of at least two additional compelling reasons why local bees and queens are preferable. I’ll cover these at some point in the future.