Category Archives: Seasonal

Broodless?

Synopsis : The colony needs to be broodless for effective oxalic acid treatment in winter. You might be surprised at how early in the winter this broodless period can be (if there is one). How can you easily determine whether the colony is broodless?

Introduction

In late spring or early summer a broodless colony is a cause for concern. Has the colony swarmed? Have you killed the queen? Since worker brood takes 21 days from egg to emergence, a broodless colony has gone 3 weeks without any eggs being laid.

You’re right to be concerned about the queen.

Of course, since you’ve been inspecting the hive on a 7-10 day rotation, you noticed the absence of eggs a fortnight ago, so you’re well on your way to knowing what the problem is, and therefore being able to solve it 😉 .

But in late autumn or early winter a broodless colony is not a cause for concern.

It’s an opportunity.

Are they rearing brood? Probably by now … it’s mid-January

In my view it’s a highly desirable state for the colony to be in.

If the colony is broodless then the ectoparasitic Varroa mites cannot be hiding away under the cappings, gorging themselves on developing pupae and indulging in their – frankly repellent – incestuous reproduction.

Urgh!

Instead the mites will all be riding around the colony on relatively young workers (and in winter, physiologically all the workers in the hive are ‘young’, irrespective of their age) in what is incorrectly termed the phoretic stage of their life cycle.

This is incorrect as phoresy means “carried on the body of another organism without being parasitic” … and these mites are not just being carried around, they’re also feeding on the worker bees.

You can read all about phoretic mites, their diet and their repulsive reproductive habits in previous posts.

What is the opportunity?

A broodless colony in the winter is an opportunity because phoretic mites (whether misnamed or not) are very easy to kill because they’re not protected by the wax capping covering the sealed brood.

Total mite numbers surviving OA treatment depends upon the proportion in capped cells

And today’s post is all about identifying when the colony is broodless.

Discard your calendar

I’ve said it before 1 … the activities of the colony (swarming, nectar gathering, broodlessness 2 ) are not determined by the calendar.

Instead they’re determined by the environment. This covers everything from the available forage to the climate and recent weather 3.

And the environment changes. It changes from year to year in a single location – an early spring, a late summer – and it differs between locations on the same calendar date.

All of which means that, although you can develop a pretty good idea of when you need to intervene or manage things – like adding supers, or conducting swarm control – these are reactive responses to the state of the colony, rather than proactive actions applied because it’s the 9th of May 4.

And exactly the same thing applies to determining when the colony is broodless in the winter. Over the last 6 years I’ve had colonies that are broodless sometime between between mid October and mid/late December. They’re not broodless for this entire period, but they are for some weeks starting from about mid-October and ending sometime around Christmas.

Actually, to be a little more precise, I generally know when they start to be broodless, but I rarely monitor when they stop being broodless, not least because it’s a more difficult thing to determine (as will become clear).

Don’t wait until Christmas

A broodless colony is an opportunity because the phoretic mites can easily be killed by a single application of oxalic acid.

Many beekeepers treat their colonies with oxalic acid between Christmas and New Year.

It was how they were taught when they started beekeeping, it’s convenient because it’s a holiday period, it’s a great excuse to escape to the apiary and avoid another bellyful of cold cuts followed by mince pies (or the inlaws 5 ) and because it’s ‘midwinter’.

But, my experience suggests this is generally too late in the year.  The colony is often already rearing brood by the time you’ve eaten your first dozen mince pies.

If you’re going to go to the trouble of treating your colonies with oxalic acid, it’s worth making the effort to apply it to achieve maximum efficacy 6.

I’m probably treating my colonies with oxalic acid in 8-9 days time. The queens have stopped laying and there was very little sealed brood present in the colonies I briefly checked on Monday this week. The sealed brood will have all emerged by the end of next week.

It’s worth making plans now to determine when your colonies are broodless. Don’t just assume sometime between Christmas and New Year ’will be OK’.

But it’s too early now for them to be broodless … or to treat with oxalic acid

If your colonies are going to go through a broodless period this winter 7 it’s more likely to be earlier rather than later.

Why?

Because if the colonies had a long broodless period stretching into mid-January or later it’s unlikely they’ll build up strongly enough to swarm … and since swarming is honey bee reproduction, it’s a powerful evolutionary and selective pressure.

Colonies that start rearing brood early, perhaps as early as the winter solstice, are more likely to build up strongly, and therefore are more likely to swarm, so propagating the genes for early brood rearing.

But surely it would be better to treat with oxalic acid towards the end of the winter?

Mites do not reproduce during the misnamed phoretic stage of the life cycle. Therefore, aside from those mites lost (hopefully through the open mesh floor) due to allogrooming, or that just die 8, there will be no more mites later in the broodless period than at the beginning.

Since the mites are going to be feeding on adult workers (which is probably detrimental to those workers), and because it’s easier to detect the onset of broodlessness (see below), it makes sense to treat earlier rather than later.

Your bees will thank you for it 😉 .

How to detect the absence of brood

Tricky … how do you detect if something is not present?

I think the only way you can be certain is to conduct a full hive inspection, checking each side of every frame for the presence of sealed brood.

Perhaps not the ideal conditions for a full hive inspection

But I’m not suggesting you do that.

It’s a highly intrusive thing to do to a colony in the winter. It involves cracking open the propolis seal to the crownboard, prising apart the frames and splitting up the winter cluster.

On a warm winter day that’s a disruptive process and the bees will show their appreciation 🙁 . On a cold winter day, particularly if you’re a bit slow checking the frames (remember, the bees will appear semi-torpid and will be tightly packed around any sealed brood present, making it difficult to see), it could threaten the survival of the colony.

And don’t even think about doing it if it’s snowing 🙁 .

Even after reassembling the hive the colony is likely to suffer … the broken propolis seals will let in draughts, the colony will have to use valuable energy to reposition themselves.

A quick peek

I have looked in colonies for brood in the winter. However, I don’t routinely do this.

Now, in mid/late autumn the temperature is a bit warmer and it’s less disruptive. I checked half a dozen on Sunday/Monday. It was about 11°C with rain threatening. I had to open the boxes to retrieve the Apivar strips anyway after the 9-10 week treatment period.

Recovered Apivar strips

I had repositioned the Apivar strips about a month ago, moving them in from the outside frames to the edges of the shrinking brood nest. By then – early October – most of the strips were separated by just 3 or 4 frames.

The flanking frames were all jam packed with stores. The fondant blocks were long-gone and the bees had probably also supplemented the stores with some nectar from the ivy.

Over the last month the brood nest continued to shrink, but it won’t have moved somewhere else in the hive … it will still be somewhere between the Apivar strips, and about half way is as good a place as any to start.

Apivar strip (red bars) placement and the shrinking brood nest

So, having removed the crownboard and the dummy board, I just prise apart the frames to release the Apivar strips and then quickly look at the central frame between them. If there’s no sealed brood there, and you can usually also have a look at the inner faces of the flanking frames down the ‘gap’ you’ve opened, then the colony is probably broodless.

It takes 45-60 seconds at most.

It’s worth noting that my diagram shows the broodnest located centrally in the hive. It usually isn’t. It’s often closer to the hive entrance and/or (in poly boxes) near the well insulated sidewall of the hive.

Hive debris

But you don’t need to go rummaging through the brood box to determine whether the colony is broodless (though – as noted earlier – it is the probably the only was you can be certain there’s no brood present).

The cappings on sealed brood are usually described as being ‘biscuit-coloured’.

Not this colour of biscuit

‘Biscuit-coloured’ is used because all beekeepers are very familiar with digestive biscuits (usually consumed in draughty church halls). If ‘biscuit-coloured’ made you instead think of Fox’s Party Rings then either your beekeeping association has too much money, or you have young children.

Sorry to disappoint you … think ‘digestives’ 😉 .

That’s more like it …

The cappings are that colour because the bees mix wax and pollen to make them air-permeable. If they weren’t the developing pupa wouldn’t be able to breathe.

And when the developed worker emerges from the cell the wax capping is nibbled away and the ‘crumbs’ (more biscuity references) drop down through the cluster to eventually land on the hive floor.

Where they’re totally invisible to the beekeeper 🙁 .

Unless it’s an open mesh floor … in which case the crumbs drop through the mesh to land on the ground where they’ll soon get lost in the grass, carried off by ants or blown away 🙁 .

It should therefore be obvious that if you want detect the presence of brood emerging you need to have a clean tray underneath the open mesh floor (OMF).

Open mesh floors and Correx boards

Most open mesh floors have a provision to insert a Correx (or similar) board underneath the mesh. There are good and bad implementations of this.

Poor designs have a large gap between the mesh and the Correx board, with no sealing around the edges 9. Consequently, it’s draughty and stuff that lands on the board gets blown about (or even blown away).

Good designs – like the outstanding cedar floors Pete Little used to make – have a close-fitting wooden tray on which the Correx board is placed. The tray slides underneath the open mesh floor and seals the area from draughts 10.

Open mesh floor and close-fitting Varroa tray by Pete Little

Not only does this mean that the biscuity-coloured crumbs stay where they fall, it also means that this type of floor is perfect when treating the colony with vaporised oxalic acid. Almost none escapes, meaning less chance of being exposed to the unpleasant vapours if you’re the beekeeper, and more chance of being exposed to the unpleasant vapours if you’re a mite 😉 .

Since the primary purpose of these Correx trays is to determine the numbers of mites that drop from the colony, either naturally or during treatment, it makes sense if they are pale coloured. It’s also helpful if they are gridded as this makes counting mites easier.

Easy counting ...

Easy counting …

And, with a tray in situ for a 2-3 days you can quickly get an idea whether there is brood being uncapped.

Reading the runes

The diagram below shows a schematic of the colony (top row) and the general appearance of debris on the Varroa tray (bottom row).

It’s all rather stylised.

The brood nest – the grey central circle is unlikely to be circular, or central 11.

The shrinking broodnest (top) and the resulting pattern on the Varroa tray (bottom)

Imagine that the lower row of images represent the pattern of the cappings that have fallen onto the tray over at least 2-3 days.

Biscuit-coloured cappings on Varroa tray

As the brood nest shrinks, the area covered by the biscuit-coloured cappings is reduced. At some point it is probably little more than one rather short stripe, indicating small amounts of brood emerging on two facing frames.

With just one observation highlighted should you plan to treat next week?

Let’s assume you place the tray under the open mesh floor and see that single, short bar of biscuity crumbs (highlighted above). There’s almost nothing there.

Do you assume that it will be OK to treat them with oxalic acid the following week?

Not so fast!

With just a single observation there’s a danger that you could be seeing the first brood emerging when there’s lots more still capped on adjacent frames.

It’s unlikely – particularly in winter – but it is a possibility.

Far better is to make a series of observations and record the trajectory of cappings production. Is it decreasing or is it increasing?

Multiple observations allows the expanding or contracting brood nest to be monitored

With a couple of observations 10-12 days apart you’ll have a much better idea of whether the brood area is decreasing over time, or increasing. Repeated observations every 10-12 days will give you a much better idea of what’s going on.

Developing brood is sealed for ~12 days. Therefore, if brood rearing is starting, the first cappings that appear on the Varroa tray are only a small proportion of the total sealed brood in the colony.

Very little cappings but certainly not broodless

Of course, in winter, the laying rate of the queen is much reduced. Let’s assume she’s steadily laying just 50 eggs per day i.e. about 12.5 cm2. By the time the first cappings appear on the Varroa tray (as the first 50 workers emerge) there will be another 600 developing workers occupying capped cells … and the worry is that they’re occupying those cells with a Varroa mite.

The cessation of brood rearing

In contrast, if there’s brood in the colony but the queen is slowing down and eventually stops egg laying, with repeated observations 12 the amount and coverage of the biscuit-coloured cappings will reduce and eventually disappear.

At that point you can be reasonably confident that there is no more sealed brood in the colony and, therefore, that it’s an appropriate time to treat with oxalic acid.

In this instance – and unusually – absence of evidence is evidence of absence 🙂 .

But my bees are never broodless in the winter

All of the above still applies, with the caveat that rather than looking for the absence of any yummy-looking biscuity crumbs on the tray, you are instead looking for the time that they cover the minimal area.

If the colony is never broodless in winter it still makes sense to treat with oxalic acid when the brood is at the lowest level (refer back to the first graph in this post).

At that time the smallest number of mites are likely to be occupying capped cells.

However, this assumption is incorrect if the small number of cells are very heavily parasitised, with multiple mites occupying a single sealed cell. This can happen – at least in summer – in heavily mite infested hives. I’ve seen 12-16 mites in some cells and Vincent Poulin reported seeing 26 in one cell in a recent comment.

Urgh! (again)

I’m not aware of any data on infestation levels of cells in winter when brood levels are low, though I suspect this type of multiple occupancy is unlikely to occur (assuming viable mite numbers are correspondingly low). I’d be delighted if any readers have measured mites per cell in the winter, or know of a publication in which it’s reported 13.

This isn’t an exact science

What I’ve described above sounds all rather clinical and precise.

It isn’t.

Draughts blow the cappings about on the tray. The queen’s egg laying varies from day to day, and can stop and start in response to low temperatures or goodness-knows-what-else. The pattern of cappings is sometimes rather difficult to discern. Some uncapped stores can have confoundingly dark cappings etc.

But it is worth trying to work out what’s going on in the box to maximise the chances that the winter oxalic acid treatment is applied at the time when it will have the greatest effect on the mite population.

By minimising your mite levels in winter you’re giving your bees the very best start to the season ahead.

Unrestricted mite replication – the more you start with the more you end up with (click image for more details)

The fewer mites you have at the start of the season, the longer it takes for dangerously high mite levels (i.e. over 1000 according to the National Bee Unit) to develop. Therefore, by reducing your mite levels in the next few weeks you are increasing your chances that the colony will be able to rear large numbers of healthy winter bees for next winter.

That sounds to me like a good return on the effort of making a few trips to the apiary in November and early December …


 

Winter covers and colony survival

Synopsis : A recent study shows increased overwinter colony survival of ‘covered’ hives wrapped in Correx and with insulation under the roof. What provides the most benefit, and are the results as clear cut as they seem?

Introduction

A recent talk by Andrew Abrahams to the Scottish Native Honey Bee Society coincided with me catching up my 1 backlog of scientific papers on honey bees. I’d been reading a paper on the benefits of wrapping hives in the winter and Andrew commented that he did exactly that to fend off the worst of the wet weather. Andrew lives on the island of Colonsay about 75 km south of me and we both ‘benefit’ from the damp Atlantic climate.

The paper extolled the virtues of ‘covered’ hives and the data the researchers present looks, at first glance, compelling.

For example, <5% of covered hives perished overwinter in contrast to >27% of the uncovered control hives.

Wow!

Why doesn’t everyone wrap their hives?

However, a closer look at the paper raises a number of questions about what is actually benefitting (or killing) the colonies.

Nevertheless, the results are interesting. I think the paper poses rather more questions than it answers, but I do think the results show the benefits of hive insulation and these are worth discussing.

Bees don’t hibernate

Hibernation is a physiological state in which the metabolic processes of the body are significantly reduced. The animal becomes torpid, exhibiting a reduced heart rate, low body temperature and reduced breathing. Food reserves e.g. stored fat, are conserved and the animal waits out the winter until environmental conditions improve.

However, bees don’t hibernate.

Winter cluster 3/1/21 3°C (insulation block removed from the crownboard)

If you lift the lift the roof from a hive on a cold midwinter day you’ll find the bees clustered tightly together. But, look closely and you’ll see that the bees are moving. Remove the crownboard and some bees will probably fly.

The cluster conserves warmth and there is a temperature gradient from the outside – termed the mantle – to the middle (the core).

If chilled below ~5.5°C a bee becomes semi-comatose 2 and unable to warm herself up again. The mantle temperature of the cluster never drops below ~8°C, but the core is maintained at 18-20°C when broodless or ~35°C if they are rearing brood. I’ve discussed the winter cluster in lots more detail a couple of years ago.

The metabolic activity of the clustered winter bees is ‘powered’ by their consumption of the stores they laid down in the autumn. It seems logical to assume that it will take more energy (i.e. stores) to maintain a particular cluster temperature if the ambient temperature is lower.

Therefore, logic would also suggest that the greater the insulation properties of the hive – for a particular difference in ambient to cluster temperature – the less stores would be consumed.

Since winter starvation is bad for bees (!) it makes sense to be thinking about this now, before the temperatures plummet in the winter.

Cedar and poly hives

I’m not aware of many comparative studies of the insulation properties of hives made from the two most frequently used materials – wood and polystyrene. However, Alburaki and Corona (2021) have investigated this and shown a small (but statistically significant) difference in the inner temperature of poly Langstroth hives when compared to wooden ones.

Poly hives were ~0.5°C warmer and, perhaps more importantly, exhibited much less variation in temperature over a 24 hour period.

Temperature and humidity in poly and wood hives

In addition to the slight temperature difference, the humidity within the wooden hives was significantly higher than that of poly.

The hives used in this study were occupied by bees and the temperature and humidity were recorded from sensors placed in a modified frame in the ‘centre of the brood box’. The external ambient temperature averaged 0°C, but fluctuated over a wide range (-10°C to 20°C) during the four month study 3.

Temperature anomalies

Whilst I’m not surprised that the poly hives were marginally warmer, I was surprised how low the internal hive temperatures were. The authors don’t comment on whether the ‘central’ frame was covered with bees, or whether the bees were rearing brood.

The longitudinal temperature traces (not reproduced here – check the paper) don’t help much either as they drop in mid-February when I would expect brood rearing to be really gearing up … Illogical, Captain.

The authors avoid any discussion on why the average internal temperature was at least 5-8°C cooler than the expected temperature of the core of a clustered broodless colony, and ~25°C cooler than a clustered colony that was rearing brood.

My guess is that the frame with the sensors was outside the cluster. For example, perhaps it was in the lower brood box 4 with the bees clustered in the upper box?

We’ll never know, but let’s just accept that poly hives – big surprise 😉 – are better insulated. Therefore the bees should need to use less stores to maintain a particular internal temperature.

And, although Alburaki and Corona (2021) didn’t measure this, it did form part of a recent study by Ashley St. Clair and colleagues from the University of Illinois (St. Clair et al., 2022).

Hive covers reduce food consumption and colony mortality

This section heading repeats the two key points in the title of this second paper.

I’ll first outline what was done and describe these headline claims in more detail. After that I’ll discuss the experiments in a bit more detail and some caveats I have of the methodology and the claims.

I’ll also make clear what the authors mean by a ‘hive cover’.

The study was conducted in central Illinois and involved 43 hives in 8 apiaries. Hives were randomly assigned to ‘covered’ or ‘uncovered’ i.e. control – groups (both were present in every apiary) and the study lasted from mid-November to the end of the following March.

Ambient (blue), covered (black) and control (dashed) hive temperatures

There were no significant differences in internal hive temperature between the two groups and – notably – the temperatures were much higher (15°-34°C) than those recorded by Alburaki and Corona (2021).

All colonies, whether covered or uncovered, got lighter through the winter, but the uncovered colonies lost significantly more weight once brood rearing started February. The authors supplemented all colonies with sugar cakes in February and the control colonies used ~15% more of these additional stores before the study concluded.

I don’t think any of these results are particularly surprising – colonies with additional insulation get lighter more slowly and need less supplemental feeding.

The surprising result was colony survival.

Less than 5% (1/22) of the covered hives perished during the winter but over 27% (6/21) of the control hives didn’t make it through to the following spring.

(Un)acceptable losses

To put these last figures into context the authors quote a BeeI Informed Partnership survey where respondents gave a figure of 23.3% as being ’acceptable’ for winter colony losses.

That seems a depressingly high figure to me.

However, look – and weep – at the percentage losses across the USA in the ’20/’21 winter from that same survey 5.

Bee Informed Partnership 2021 winter colony losses (preliminary data)

This was a sizeable survey involving over 3,300 beekeepers managing 192,000 colonies (~7% of the total hives in the USA).

If hive covers reduce losses to just 5% why does Illinois report winter losses of 47%? 6

Are the losses in this manuscript suspiciously low?

Or, does nobody use hive covers?

I don’t know the answers to these questions, but I also wasn’t sure when I started reading the paper what the authors meant by a hive ‘cover’ … which is what I’ll discuss next.

Hive covers

The hives used in this study were wooden Langstroths and the hive covers were 4 mm black corrugated polypropylene sleeves.

This is what I call Correx … one of my favourite materials for beekeeping DIY.

These hive covers are available commercially in the USA (and may be here, I’ve not looked). At $33 each (Yikes) they’re not cheap, but how much is a colony worth?

Significantly more than $33.

I’ve not bothered to make the conversion of Langstroth Deep dimensions (always quoted in inches 🙁 ) to metric and then compared the area of Correx to the current sheet price of ~£13 … but I suspect there are savings to be made by the interested DIYer 7.

However, knowing (and loving) Correx, what strikes me is that it seems unlikely to provide much insulation. At only 4 mm thick and enclosing an even thinner air gap, it’s not the first thing I’d think of to reduce heat loss 8.

4 mm Correx sheet

Thermal resistance is the (or a) measure of the insulating properties of materials. It’s measured in the instantly forgettable units of square metre kelvin per watt m2.K/W.

I couldn’t find a figure for 4 mm Correx, but I did manage to find some numbers for air.

A 5 mm air gap – greater than separates the inner and outer walls of a 4 mm Correx hive cover – has a thermal resistance of 0.11 m2.K/W.

Kingspan

It’s not possible to directly compare this with anything meaningful, but there is data available for larger ‘thicknesses’ of air, and other forms of insulation.

An air gap of 100 mm has a thermal resistance of about 0.17 m2.K/W. For comparison, the same thickness of Kingspan (blown phenolic foam wall insulation, available from almost any building site skip) has a thermal resistance of 5, almost 30 times greater.

And, it turns out, St. Clair and colleagues also added a foam insulation board on top of the hive crownboard (or ‘inner cover’ as they call it in the USA). This board was 3.8 cm thick and has somewhat lower thermal resistance than the Kingspan I discussed above.

It might provide less insulation than Kingspan, but it’s a whole lot better than Correx.

This additional insulation is only briefly mentioned in the Materials and Methods and barely gets another mention in the paper.

A pity, as I suspect it’s very important.

Perspex crownboard with integrated 50 mm Kingspan insulation

I’m very familiar with Kingspan insulation for hives. All my colonies have a 5 cm thick block present all year – either placed over the crownboard, built into the crownboard or integrated into the hive roof.

Two variables … and woodpeckers

Unfortunately, St. Clair and colleagues didn’t compare the weight loss and survival of hives ‘covered’ by either wrapping them in Correx or having an insulated roof.

It’s therefore not possible to determine which of these two forms of protection is most beneficial for the hive.

For reasons described above I think the Correx sleeve is unlikely to provide much direct thermal insulation.

However, that doesn’t mean it’s not beneficial.

At the start of this post I explained that Andrew Abrahams wraps his hives for the winter. He appears to use something like black DPM (damp proof membrane).

Hive wrapped in black DPM (to prevent woodpecker damage)

Andrew uses it to keep the rain off the hives … I’ve used exactly the same stuff to prevent woodpecker damage to hives during the winter.

It’s only green woodpeckers (Picus viridis) that damage hives. It’s a learned activity; not all green woodpeckers appear to know that beehives are full of protein-rich goodies in the depths of winter. If they can’t grip on the side of the hive they can’t chisel their way in.

When I lived in the Midlands the hives always needed winter woodpecker protection, but the Fife Yaffles 9 don’t appear to attack hives.

Here on the west coast, and on Colonsay, there are no green woodpeckers … and I know nothing about the hive-eating woodpeckers of Illinois.

So, let’s forget the woodpeckers and return to other benefits that might arise from wrapping the hive in some form of black sheeting during the winter.

Solar gain and tar paper

Solar gain is the increase in thermal energy (or temperature as people other than physicists with freakishly large foreheads call it) of something – like a bee hive – as it absorbs solar radiation.

On sunny days a black DPM-wrapped hive (or one sleeved in a $33 Correx/Coroplast hive ‘cover’) will benefit from solar gain. The black surface will warm up and some of that heat should transfer to the hive.

And – in the USA at least – there’s a long history of wrapping hives for the winter. If you do an internet search for ‘winterizing hives’ or something similar 10 you’ll find loads of descriptions (and videos) on what this involves.

Rather than use DPM, many of these descriptions use ‘tar paper’ … which, here in the UK, we’d call roofing felt 11.

Roofing felt – at least the stuff I have left over from re-roofing sheds – is pretty beastly stuff to work with. However, perhaps importantly, it has a rough matt finish, so is likely to provide significantly more solar gain than a covering of shiny black DPM.

I haven’t wrapped hives in winter since I moved back to Scotland in 2015. However, the comments by Andrew – who shares the similarly warm and damp Atlantic coastal environment – this recent paper and some reading on solar gain are making me wonder whether I should.

Fortunately, I never throw anything away, so should still have the DPM 😉

Winter losses

Illinois has a temperate climate and the ambient temperature during the study was at or below 0°C for about 11 weeks. However, these sorts of temperatures are readily tolerated by overwintering colonies. It seems unlikely that colonies that perished were killed by the cold.

So what did kill them?

Unfortunately there’s no information on this in the paper by St. Clair and colleagues.

Perhaps the authors are saving this for later … ’slicing and dicing’ the results into MPU’s (minimal publishable units) to eke out the maximum number of papers from their funding 12, but I doubt it.

I suspect they either didn’t check, checked but couldn’t determine the cause, or – most likely – determined the cause(s) but that there was no consistent pattern so making it an inconclusive story.

But … it was probably Varroa and mite-transmitted Deformed wing virus (DWV).

It usually is.

Varroa

There were some oddities in their preparation of the colonies and late-season Varroa treatment.

Prior to ‘winterizing’ colonies they treated them with Apivar (early August) and then equalised the strength of the colonies. This involves shuffling brood frames to ensure all the colonies in the study were of broadly the same strength (remember, strong colonies overwinter better).

A follow-up Varroa check in mid-October showed that mite levels were still at 3.5% (i.e. 10.5 phoretic mites/300 bees) and so all colonies were treated with vaporised oxalic acid (OA).

Sublimox vaporiser

Sublimox vaporiser … phoretic mites don’t stand a chance

In early November, mite levels were down to a more acceptable 0.7%. Colonies received a second OA treatment in early January.

For whatever reason, the Apivar treatment appears to have been ineffective.

When colonies are treated for 6-10 weeks with Apivar (e.g. early August to mid-October) mite levels should be reduced by >90%.

Mite infestation levels of 3.5% suggest to me that the Apivar treatment did not work very well. That being the case, the winter bees being reared through August, September and early October would have been exposed to high mite levels, and so acquired high levels of DWV.

OA treatment in mid-October would kill these remaining mites … but the damage had already been done to thediutinus’ winter bees.

That’s my guess anyway.

An informed guess, but a guess nevertheless, based upon the data in the paper and my understanding of winter bee production, DWV and rational Varroa management.

In support of this conclusion it’s notable that colonies died from about week 8, suggesting they were running out of winter bees due to their reduced longevity.

If I’m right …

It raises the interesting question of why the losses were predominantly (6 vs 1) of the control colonies?

Unfortunately the authors only provide average mite numbers per apiary, and each apiary contained a mix of covered and control hives. However, based upon the error bars on the graph (Supporting Information Fig S1 [PDF] if you’re following this) I’m assuming there wasn’t a marked difference between covered and control hives.

I’ve run out of informed guesses … I don’t know the answer to the question. There’s insufficient data in the paper.

Let’s briefly revisit hive temperatures

Unusually, I’m going to present the same hive temperature graph shown above to save you scrolling back up the page 13.

Ambient (blue), covered (black) and control (dashed) hive temperatures

There was no overall significant difference in hive temperature between the control and covered colonies. However, after the coldest weeks of the winter (7 and 8 i.e. the end of February), hive temperatures started to rise and the covered colonies were consistently marginally warmer. By this time in the season the colonies should be rearing increasing amounts of brood.

I’ve not presented the hive weight changes. These diverged most significantly from week 8. The control colonies used more stores to maintain a similar (actually – as stated above – marginally lower) temperature. As the authors state:

… covered colonies appeared to be able to maintain normal thermoregulatory temperatures, while consuming significantly less stored food, suggesting that hive covers may reduce the energetic cost of nest thermoregulation.

I should add that there was no difference in colony strength (of those that survived) between covered and control colonies; it’s not as though those marginally warmer temperatures from week 9 resulted in greater brood rearing.

Are lower hive temperatures ever beneficial in winter?

Yes.

Varroa management is much easier if colonies experience a broodless period in the winter.

A single oxalic acid treatment during this broodless period should kill 95% of mites – as all are phoretic – leaving the colony in a very good state for the coming season.

If you treat your colonies early enough to protect the winter bees there will inevitably be some residual mite replication in the late season brood, thereby necessitating the midwinter treatment as well.

I’m therefore a big fan of cold winters. The colony is more likely to be broodless at some point.

I was therefore reassured by the similarity in the temperatures of covered and control colonies from weeks 48 until the cold snap at the end of February. Covered hives should still experience a broodless period.

I’m off for a rummage in the back of the shed to find some rolls of DPM for the winter.

I don’t expect it will increase my winter survival rates (which are pretty good) and I’m not going to conduct a controlled experiment to see if it does.

If I can find the DPM I’ll wrap a few hives to protect them from the winter weather. With luck I should be able to rescue an additional frame or two of unused stores in the spring (I often can anyway). I stack this away safely and then use it when I’m making up nucs for queen mating.

I suspect that the insulation over the crownboard provides more benefit than the hive ‘wrap’. As stated before, all my colonies are insulated like this year round as I’m convinced it benefits the colony, reducing condensation over the cluster and keeping valuable warmth from escaping. However, wrapping the hive for solar gain and/or weather protection is also worth considering.


References

Alburaki, M. and Corona, M. (2022) ‘Polyurethane honey bee hives provide better winter insulation than wooden hives’, Journal of Apicultural Research, 61(2), pp. 190–196. Available at: https://doi.org/10.1080/00218839.2021.1999578.

St. Clair, A.L., Beach, N.J. and Dolezal, A.G. (2022) ‘Honey bee hive covers reduce food consumption and colony mortality during overwintering’, PLOS ONE, 17(4), p. e0266219. Available at: https://doi.org/10.1371/journal.pone.0266219.

Mellow fruitfulness

Synopsis : Final colony inspections and some thoughts on Apivar-contaminated supers, clearing dried supers, feeding fondant and John Keats’ beekeeping.

Introduction

The title of today’s post comes from the first line of the poem ’To Autumn’ by John Keats:

Season of mists and mellow fruitfulness

The poem was written just over 200 years ago and was the last major work by Keats (1795-1821) before he died of tuberculosis. Although it wasn’t received enthusiastically at the time, To Autumn is now one of the most highly regarded English poems.

The poem praises autumn, using the typically sensuous imagery of the Romantic poets, and describes the abundance of the season and the harvest as it transitions to winter.

That’s as maybe … the last few lines of the first verse raises some doubts about Keats’ beekeeping skills:

And still more, later flowers for the bees,
Until they think warm days will never cease,
 For summer has o’er-brimm’d their clammy cells.

It’s certainly true that there are late summer flowers that the bees can forage on 1. However, he’s probably mistaken in suggesting that the bees think in any sense that involves an appreciation of the future.

And what’s all this about clammy cells?

If there’s damp in the hive in late summer then it certainly doesn’t bode well for the winter ahead.

Clammy is now used mean damp; like vapour, perspiration or mist. The word was first used in this context in the mid-17th Century.

‘Clammy’ honey

But Keats is using an earlier meaning of ’clammy’ … in this case ’soft, moist and sticky; viscous, tenacious, adhesive’, which dates back to the late 14th-Century.

And anyone who has recently completed the honey harvest will be well aware of how apt that definition is 😉 … so maybe Keats was a beekeeper (with a broad vocabulary).

And gathering swallows twitter in the skies

That’s the last line of ’To Autumn’ (don’t worry … you’ve not inadvertently accessed the Poetry Please website). The swallows are gathering and, like most summer migrants, already moving south. Skeins of pink-footed geese have started arriving from Iceland and Greenland.

Skein of geese over Fife

My beekeeping over the last fortnight has been accompanied by the incessant, plaintive mewing of buzzards. These nest near my apiaries and the calling birds are almost certainly the young from this season.

A few nights ago, while hosing the extractor out in the bee-free-but-midge-filled late evening, I was serenaded by tawny owls as the adults evicted their young from the breeding territory in preparation for next season.

These are all signs, together with the early morning mists, that summer is slipping away and the autumn is gently arriving.

Morning mist clearing over the loch

The beekeeping season is effectively over and all that remains is preparing the colonies for winter.

Supers

All the supers were off by the 22nd of August. There was still a little bit of nectar being taken in but the majority was ripe and ready. As it turns out there was fresh nectar in all the colonies when I checked on the 10th of September, but in such small amounts – no more than half a frame – that it wouldn’t have been worth waiting for.

At some point you have to say … enough!

Or, this year, more than enough 🙂 .

Most of the honey was extracted by the end of August. It was a bonanza season with a very good spring, and an outstanding summer, crop. By some distance the best year I’ve had since returning to Scotland in 2015.

Of course, that also meant that there were more supers to extract and return and store for the winter ahead.

Lots of lifting, lots of extracting and lots of buckets … and in due course, lots of jarring.

Storing supers wet or dry?

In response to some recent questions on storing supers wet or dry I tested ‘drying’ some.

I’ve stored supers wet for several seasons. I think the bees ‘like’ the heady smell of honey when they are added back to the hives for the spring nectar flow. The supers store well and I’ve not had any problems with wax moth.

However, this year I have over two full carloads of supers, so – not having a trailer or a Toyota Hilux 2 – I have to make multiple trips back to put them in storage 3. These trips were a few days apart.

I added a stack of wet supers to a few hives on the 1st of September and cleared them on the 9th. All these supers were added over an empty super (being used as an eke to accommodate a half block of fondant – see below) topped with a crownboard with a small hole in it (no more than 2.5 cm in diameter, usually less).

Converting wet supers to dry supers – note the crownboard with a small central hole

When I removed the supers on the 10th they had been pretty well cleaned out by the bees. In one case the bottom super had a very small amount of fresh nectar in it.

So, 7-8 days should be sufficient for a strong colony to clean out 3-4 supers and it appears as though you can do it at the same time as feeding fondant … result 🙂 .

Feeding fondant

I only feed my colonies Baker’s fondant. I add this on the same day I remove the honey-laden supers. I’ve discussed fondant extensively here before and don’t intend to rehash the case for its use again.

Oh well, if you insist 😉 .

I can feed a colony in less than two minutes; unpacking the block, slicing it in half and placing it face down over a queen excluder (with an empty super as an eke) takes almost as much time to write as it does to do.

Take care with sharp knives … much easier with a slightly warm block of fondant

But speed isn’t the only advantage; I don’t need to purchase or store any special feeders (an Ashforth feeder costs £66 and will sit unused for 49 weeks of the year). I’ve also not risked slopping syrup about and so have avoided encouraging robbing bees or wasps.

I buy the fondant through my association. We paid £13 a block this year (up from about £11 last year). That’s more expensive than making or buying syrup (though not by much) and I don’t need to have buckets or whatever people use to store, transport and distribute syrup. Fondant has a long shelf life so I buy a quarter of a ton at a time and store what I don’t use.

All gone! 12.5 kg of fondant added on 22/8/22 and photographed on 9/9/22

And, contrary to what the naysayers claim, the bees take it down and store it very well.

What’s the biggest problem I’ve had using fondant?

The grief I get when I forget to return the breadknife I stole from the kitchen … 😉 .

Apivar-contaminated honey and supers

Last season I had to treat a colony with Apivar before the supers came off. This was one of our research colonies and we had to minimise mite levels before harvesting brood.

I’ve had a couple of questions recently on what to do with supers exposed to Apivar … this is what I’ve done/will do.

Apivar

The Apivar instructions state something like ’do not use when supers are present’ … I don’t have a set of instructions to check the precise wording (and can’t be bothered to search the labyrinthine VMD database).

Of course, you’re free to use Apivar whenever you want.

What those instructions mean is that honey collected if Apivar is in the hive will be ’tainted’ and must not be used for human consumption.

But, it’s OK for the bees 🙂 .

So, I didn’t extract my Apivar-exposed supers but instead I stored them – clearly labelled – protected from wasps, bees and mice.

This August, after removing the honey supers I added fondant to the colonies. In addition, I added an Apivar-exposed super underneath the very strongest colonies – between the floor and the lower brood box.

I’ll leave this super throughout the winter. The bees will either use the honey in situ or will move it up adjacent to the cluster.

In spring – if I get there early enough – the super will be empty.

If I’m late they may already be rearing brood in it 🙁 … not in itself a problem, other than it means I’m flirting with a ridiculous ’double brood and a half’.

Which, of course, is why I added it to the strongest double brood colonies. It’s very unlikely the queen will have laid up two complete boxes (above the nadired super) before I conduct the first inspection.

But what to do with the now-empty-but-Apivar-exposed supers?

It’s not clear from my interpretation of the Apivar instructions (that I currently can’t find) whether empty supers previously exposed to Apivar can be reused.

WARNING … my reading might be wrong. It states Apivar isn’t to be used when honey supers are on but, by inference, you can use and reuse brood frames that have been exposed to Apivar.

Could you extract honey from brood frames that have previously (i.e. distant, not immediate, past) been Apivar-exposed?

Some beekeepers might do this 4.

It’s at this point that some common sense it needed.

Just because re-using the miticide-exposed supers is not specifically outlawed 5 is it a good idea?

I don’t think it is.

Once the bees have emptied those supers I’ll melt the wax out and add fresh foundation before reusing them.

My justification goes something like this:

  • Although amitraz 6 isn’t wax-soluble a formamidine breakdown product of the miticide is. I have assumed that this contaminates the wax in the super.
  • I want to produce the highest quality honey. Of course this means great tasting. It also means things like wings, legs, dog hairs and miticides are excluded. I filter the honey to remove the bee bits, I don’t allow the puppies in the extracting room and I do not reuse supers exposed to miticides.
  • During a strong nectar flow bees draw fresh comb ‘for fun’. They’re desperate to have somewhere to store the stuff, so they’ll draw out comb in a new super very quickly. Yes, drawn comb is precious, but it’s also easy to replace.

Final inspections

I conducted final inspections of all my colonies in Fife last weekend 7.

For many of these colonies this was the first time they’d been opened since late July. By then most had had swarm control, many had been requeened and all were busy piling in the summer nectar.

Why disturb them?

The queen had space to lay, they weren’t likely to think about swarming again 8 and they were strong and healthy.

Midsummer inspections are hard work … lots of supers to lift.

If there’s no need then why do it?

Of course, some colonies were still busy requeening, or were being united or had some other reason that did necessitate a proper inspection … I don’t just abandon them 😉 .

I don’t just abandon them … introducing a queen to a nucleus colony

But now the supers were off it was important to check that the colonies were in a suitable state to go into the winter.

I take a lot of care over these final inspections as I want to be sure that the colony has the very best chance of surviving the winter. 

I check for overt disease, the amount of brood in all stages (BIAS; so determining if they are queenright) and the level of stores.

And, while I’m at it, I also try and avoid crushing the queen 🙁 .

Queenright?

I don’t have to see the queen. In fact, in most hives it’s almost impossible to see the queen because the box is packed with bees. If there are eggs present then the queen is present 9.

But, there might not be a whole lot of eggs to find.

Firstly, the queen is rapidly slowing down her egg laying rate. She’s not producing anything like 1500-2000 eggs per day by early autumn.

A National brood frame has ~3000 cells per side. If you find eggs equivalent in area to one side of a brood frame she’s laying at ~1000/day. By now it’s likely to be much less. At 500 eggs/day you can expect to find no more than half a frame of eggs in the hive.

Remember the steady-state 3:5:13 (or easier 1:2:4) ratio of eggs to larvae to pupae? 10

Several of my colonies had about half a frame of eggs but significantly more than four times that amount of sealed brood … clear evidence that the laying rate is slowing dramatically.

The shrinking brood nest – note the capped stores and a little space to lay in the centre of the frame

Secondly, the colony is rapidly filling the box with stores, so reducing the space she has to lay. They’re busy backfilling brood cells with nectar.

Look and ye shall find …

So I focus carefully on finding eggs. I gently blow onto the centre of the frames to move the bees aside and search for eggs.

In a couple of hives I was so focused on finding eggs that – as I prepared to return the frame to the colony – I only then saw the queen ambling around on the frame. D’oh!

Some colonies had only 3-4 frames of BIAS, others had lots more though guesstimating the precise area of brood is tricky because of the amount of backfilling taking place.

I still need to check my notes to determine whether it’s the younger queens that are still laying most eggs … I’d not be surprised.

Stores

Boxes are now heavy but not full. All received (at least) half a block of fondant in late August and more last weekend. There’s also a bit of late nectar. The initial half block was almost finished in a week.

Once the bag is empty I simply peel it away from the queen excluder. If you’re doing this, leave the surrounding super in place. It acts as a ‘funnel’ to keep the thousands of displaced bees in the hive rather than down your boots and all over the floor.

Although the bees were flying well, the bees in and around the super were pretty lethargic. I’ve seen this before and am not concerned. I don’t know whether these are bees gorged with stores, having a kip or perhaps young bees that don’t know their way about yet. However, it does mean that any bees dropped while removing the bag tend to wander aimlessly around on the ground.

I’d prefer they were in the hive, out of the way of my size 10’s.

If you look at many of the frames in the hive they will be partially or completely filled with stores. The outer frames are likely to be capped already. 

An outer frame of capped stores

These frames of stores are heavy. There’s no need to look through the entire box. I simply judge the weight of each frame and inspect any that are lighter than a full frame of stores.

Closer to the brood nest you’ll probably find a frame or two stuffed, wall-to-wall, with pollen. Again, a good sign of a healthy hive with the provisions it needs to rear the winter bees and make it to spring.

Disease

The only sign of disease I saw was a small amount of chalkbrood in one or two colonies. This is a perennial situation (it’s not really a problem) with some of my bees. Quite a few of my stocks have some (or a lot of) native Apis mellifera mellifera genes and these often have a bit of chalkbrood.

I also look for signs of overt deformed wing virus (DWV) damage to recently emerged workers. This is the most likely time of the year to see it as mite levels have been building all season and brood levels are decreasing fast. Therefore, developing brood is more likely to become infested and consequently develop symptoms.

Fortunately I didn’t see any signs of DWV damage and the initial impression following the first week or so of miticide treatment is that mite levels are very low this season. I’ll return to this topic once I’ve had a chance to do some proper counts after treating for at least 8-10 weeks (I use Apivar and, since my colonies all have medium to good levels of brood, the strips need to be present for more than the minimum recommended 6 weeks).

Closing up

Although these were the last hive inspections, they weren’t the last time I’ll be rummaging about in the brood box.

At some point during the period of miticide treatment I’ll reposition the strips (adjacent to the ever-shrinking brood nest) having scraped them to maximise their effectiveness.

Apivar scratch and sniff repositioning studies

However, all that will happen in a month or so when I can be reasonably sure the weather will be a lot less benign. Far better to get the inspections out of the way now, just in case.

So, having added the additional fondant (typically half a block) I closed the hives, strapped them up securely and let them get on with making their preparations for the coming winter.

Goodbye and thanks for the memories

There’s a poignancy about the last hive inspections of the season.

The weather was lovely, the colonies were strong and flying well, and the bees were wonderfully placid. It’s been a great season for honey, disease levels are low to negligible and queen rearing has gone well 11.

But it’s all over so soon 🙁 .

Hive #5 (pictured somewhere above … with the empty bag of fondant) was from a swarm control nuc made up on the last day of May (i.e. a 2021 queen). It was promoted to a full hive in mid-June. At the same time, while the hive they came from (#28) was requeening I’d taken more than 20 kg of spring honey from it. The requeening of #28 took longer than expected as the first was almost immediately superseded. Nevertheless, the two hives also produced almost 4 full supers (conservatively at least 40 kg) of summer honey.

Good times 🙂 .

My notes – for once – are comprehensive. Over the long, dark months ahead I’ll be able to sift through them to try and understand better 12 what went wrong.

That’s because – despite what I said in the opening paragraph of this section – there were inevitably any number of minor calamities and a couple of major snafu’s.

Or ’learning opportunities’ as I prefer to call them.

Last light over Rum and Eigg … not a bad view when visiting an out apiary

But that’s all for the future.

For the moment I have a sore back and aching fingers from extracting for days and the memory of a near-perfect final day of proper beekeeping.

It’s probably time I started building some frames 🙁


 

Intangible benefits

Synopsis : Some end of season thoughts on the intangible benefits of beekeeping. What does it provide other than honey and wax? 

Introduction

Central and Eastern Scotland were bathed in warm sunshine as I drove to Fife last Sunday. It was near-perfect weather for adding clearers to the hives in preparation for removing the last of the honey supers for extraction. Warm, but not too hot, breezy enough to keep any midges at bay but not so windy the bees would be flustered.

Lifting the supers was hard work, but it was lovely to be in the apiary, the bees were really mellow, there weren’t many wasps and it was a very enjoyable afternoon.

Doubly so because there were more weighty supers than expected and by the second apiary it was clear 2022 was looking like a bumper season.

Of course, I ran out of clearers … 🙁 .

Where do they go?

I checked the TARDIS-like shed but couldn’t find any spares so had to leave the last couple of hives to be cleared ‘manually’ i.e. shaking the bees off every frame.

Not the end of the world and – in good weather – something that doesn’t agitate the bees too much.

Somewhere in here are some spare clearers …

However, Monday dawned with leaden skies and almost no wind. Whatever weather was here was going to be staying.

By the time I got to the first apiary it was raining gently … but steadily.

By the time I had suited up, lit the smoker and arranged the Correx roofs to stack the supers in and under, it was still raining steadily … but much harder.

And by the time I’d retrieved and stacked the supers from the first few hives I was soaked.

It continued raining for several hours.

Have you noticed how heavy a beesuit gets when it’s all soggy?

And how slowly a sodden beesuit dries?

Real and intangible benefits

It was a really tough day.

I finished in the last apiary at about 4 pm, changed into the only dry things I had and set off on the five hour return journey back home.

As I was eating up the miles (and my belated lunch) on the A9 I got to think about why I keep bees.

It can’t just be because I like honey. There are excellent local honey’s sold in fancy organic cafe’s or up-market farm shops, or kilograms of mass-produced sweet stuff (labelled as honey) available from any supermarket you choose 1.

I estimate it costs well over £500 to start beekeeping. And by the time you’ve bought a few more hives, an extractor, a creamer, and a bottling machine you might have spent 40-times that amount.

You can buy a lot of lovely ‘artisan’ honey for £20,000.

So there has to be something other than just ‘liking honey’.

12ox hex jar with clear (runny) honey. The Apiarist

12ox hex jar …

There’s the pleasure of producing something high quality and desirable. It gives me a real sense of achievement. There are very few beekeepers who forget their first ever honey crop.

As a biologist, I find bees fascinating. And, as a virologist studying honey bee pathogens, I’m able to mix business and pleasure.

But I was beekeeping long before I started studying their diseases. The honey and the ‘beekeeping at work’ are tangible benefits.

As the miles piled up behind me I began to think instead of the intangible benefits of beekeeping.

What else have I gained from this engrossing pastime?

Other than the honey and smelling a bit foisty?

Does my bum look big in this?

As a callow youth I was probably less fashion-conscious than many of my contemporaries. I didn’t have the platform shoes, flares or a double-breasted frock coat 2. However, I was still acutely aware when I didn’t fit in, when I looked incongruous or when I was wearing something I thought others would ridicule.

Would I really have fitted in better wearing these?

Of course, being (a bit) older and (a little bit) wiser I realise now that it doesn’t really matter what others think. What’s more, other than the callow (or the shallow), most other people rarely notice, and certainly don’t care, what I wear.

Which, when you think about the amount of time I spend in a beesuit, is probably fortunate.

Saggy and baggy

It’s doubly-fortunate when you consider how profoundly unflattering a beesuit is. Shapeless and voluminous. They aren’t form-fitting 3 for obvious reasons … a sting might penetrate the cotton weave when stretched over the underlying soft tissue, but does no harm if there’s a billowing excess of material in the way.

Cold, clammy, heavy and baggy … a wet bee suit

I’ve just had my ‘best’ beesuit repaired. I bought it secondhand and it’s had well over a decade’s hard use. The veil had bee-sized holes in it, two of the pockets were torn, one zip pull was broken and all the cuff and ankle elastics were perished. For about £70 4 it’s now as good as new.

’As good as new’ but still profoundly unflattering 😉 .

But I simply don’t care.

I wear it when driving between apiaries, when I nip into a shop for a takeaway coffee or when I fill the car with petrol.

Unfortunately, on Monday my beesuit was soaked, so I drove home in my pyjamas. Yes, there were some odd looks at the filling station, but I’m a beekeeper … looking odd goes with the territory and I’ve learned not to care.

The physique of a Greek God

As I segue effortlessly from callow youth to early middle age I’m aware that I’m a little bit less like Charles Atlas and a little bit more like Charles Hawtrey.

Beekeeping is hard physical work.

I removed about 30 supers on Monday. If you assume that the average weight of a super is about 18 kg 5 the lifting, sorting, stacking and packing the car probably involved shifting a cumulative two metric tonnes of boxes.

Full super ready for extraction

Heavy, heavy, heavy

That’s a lot of lifting.

Many of the individual frames still contained a few stragglers which had to be shaken off. I simply hold one lug and bash the top bar sharply with the other hand. This requires a reasonable amount of finger strength … and leaves the heel of my hand rather bruised and battered after a long day of clearing supers.

As an aside, it’s always worth waiting for most of the honey to be capped (see the post last week), as frames of capped honey retain far fewer stragglers than frames of uncapped stores. As previously noted, a queenless hive’s supers hadn’t cleared overnight.

Beekeeper’s back is a very real problem and one that is well worth avoiding. I tripped carrying three full supers a couple of seasons ago and was in considerable pain for many weeks.

Good lifting technique, coupled with reasonable upper body strength from regular lifting, helps a lot.

So does not leaving stuff lying around the apiary to trip over 🙁 .

Naturally, my beesuit is so ill-fitting and shapeless that you can’t tell that I have the physique of a Greek God, but I can assure you that this is another of those intangible benefits of being an apiarist.

MAMIL 6

On a more serious note, the physical nature of beekeeping – in moderation and with appropriate technique – must be good for you. I’d much prefer to maintain or improve my back, arm and hand strength with weekly colony inspections than by going to the gym.

I prefer to do my weightlifting in the apiary

Not least because the Lycra outfits I’d have to wear to “fit in” at the gym would make my ‘Charles Hawtrey not Charles Atlas’ physique all too apparent 😉 .

Though, being a beekeeper, I probably wouldn’t care – see above.

‘Mainly dry’ 7

As a beekeeper living in Scotland I’ve become a little bit obsessive about climate and weather.

The climate has a fundamental impact on beekeeping. It influences the availability of natural forage and the time when it yields nectar. It determines when the season starts, how fast the colonies expand and when – like now – it’s effectively ’all over bar the shouting’.

The day-to-day weather influences when and if my queens get mated, how hot it will get in the bee shed and how wet I’ll get removing supers full of the ‘summer’ honey 🙁 .

Climate varies with latitude and longitude.

Weather can be a lot more localised.

By searching Weather Underground and similar sites for data uploaded from hobbyist weather stations 8 it’s usually possible to find a very local weather report.

19-26 August 2022 temperatures within a mile or so of my Fife apiary

I’m interested in conditions needed for queen mating in the sometimes iffy Scottish summers. By checking the weather records once queens start laying it’s very clear that the – usually quoted – ’sunny, over 20°C and light winds’ is a load of nonsense.

19-26 August 2022 temperatures in my west coast apiary

I currently live so remotely that I installed my own weather station to get a record of the actual local conditions. This close to the Atlantic they can vary wildly in just a few hours – we had heavy rain this morning 9, but lovely ‘softy Southern queen mating’ weather all afternoon 😉 .

Getting out and about

Some of these peripheral interests will have tangible benefits for my beekeeping. However, and of more relevance to this post, I’m consequently a lot more in tune with what the weather is likely to do over the next 12-24 hours.

The BBC might claim it’s going to be ‘wet with strong westerlies all day’ in north west Scotland (a region that stretches at least 200 miles from Durness to Oban), but I now know it will probably blow through by late morning and be fine in the afternoon.

I could open some hives, but I might instead go walking or cycling.

Sanna beach

Inevitably, living somewhere that gets 1-2 metres of rain a year, we see a lot of clouds. My more-than-passing interest in the weather has expanded into an appreciation of clouds and cloud formations. As I drove west along Glen Tarbert at the beginning of the month, in a car laden down with squeaking poly supers 10, the clouds merged and folded into one another above me.

Clouds, Glen Tarbert … mammatus?

At least, that’s what it looked like.

Beekeeping, other than in a bee shed I suppose, is of necessity an outdoor activity. By trying to understand how the climate and weather helps or hinders my bees I’ve learnt how to take advantage of unexpected – or at least not forecasted – good weather for other interests.

Of course, I don’t always get it right … I spent an hour in a remote bus shelter during a violent thunderstorm last week. It would have been spectacular had I not been so concerned that the bus shelter was largely made of metal …

Phenology

I’ve discussed phenology – ‘the timing of periodic biological phenomena in relation to climatic conditions’recently. This is much more interesting than the weather per se.

There are tangible benefits for beekeeping. If you realise the migrant birds are late to arrive you shouldn’t be surprised if the colonies are less well developed when you conduct the early spring inspections.

But the intangible benefits outweigh these.

Just having an appreciation of how the year builds, the flowering of the plants and trees, the arrival of animals and the onset of the breeding season, is intensely rewarding. I expect the sand martins by late March, but am disappointed if I’ve not seen a swift by the 8th of May. I look forward to their arrival. The siskins will disappear for a couple of months at the end of the year to feed on pine cones in the forests … but they’ll be back in January.

Siskin

I spent the best part of three decades sitting in cramped offices, reading or writing papers and grant applications. Long weeks and weekends of work often left me isolated from the natural environment.

Although I was always interested in natural history, beekeeping has raised my awareness of the cyclical annual events in the ’rhythm of the seasons’.

That’s enough cod-philosophy … almost time to move on.

Be observant because it will help your beekeeping, but be observant because it will reward you in many other ways as well.

Organisation and patience

When I first started thinking about the topic of intangible benefits I considered including a commentary on how waiting for queens to get mated has instilled a Zen-like patience to the rest of my life.

Likewise, I planned to discuss how the organisation needed to manage the roofs, boxes, boards, frames, food, miticides etc for 30 colonies – many on the other side of the country – had brought order to my shambolic logistical skills.

However, doing either of these would have made this post a work of fiction 🙁 .

I dare say my organisational skills have improved, but I still ran out of clearers last week. I also used a clearer on a suspected queenless colony. Had I thought about this – and been a little more organised – I’d have not bothered with a clearer on that colony as it wasn’t going to clear anyway.

So, my beekeeping-related organisational skills still need honing, and there’s little-to-no evidence of any improvement in the rest of my life.

Chaos? What chaos?

Although I am a lot better at patiently waiting for queens to mate and start laying, there’s unfortunately been no noticeable improvement (I’m regularly reminded) in anything else.

Everyone is interested in bees 11

If you walk around for long enough wearing a beesuit you’ll get asked about bees and honey.

This can lead to all sorts of interesting or surreal conversations about honey bees vs. bumble bees. There’s a lot of confusion out there. I’ve been asked about waspkeeping, and candle making and lots about tree bumblebees (Bombus hypnorum – very interesting … these arrived in the UK in 2001 and have now spread as far north as southern Scotland).

Of course, few are interested in the arrival and spread of tree bumblebees, but they do want to know why there is a ‘swarm’ of bees around their bird box (these are males waiting for the virgin queens to emerge).

Although some of the conversations might start from an ill-informed position, there is real interest in bees. It’s a good opportunity to emphasise that, although honey bees aren’t threatened with extinction, some bees are.

Plant native wild flowers, stop using pesticides in the garden, don’t believe all the ’beewash’ you read in the supermarket … and don’t ‘sponsor a hive’.

Of course, some of these conversations lead to honey sales 🙂 .

A fifteen minute conversation might only result in the sale of a single jar of honey. The intangible benefits are the conversation, the people I meet and the new things I learn.

So much easier sold by the bucket

Or you might hit the jackpot and sell a complete bucket. That of course is a real financial benefit … and think of all that jarring and labelling you don’t need to do 😉 .

Hay fever

Probably half the conversations I have about bees and honey involve a discussion of the benefits of local honey for hay fever sufferers. Although I try and correct this pseudo-science I don’t do so with sufficient force to impact honey sales.

And a final hint for the uninitiated about selling honey … carry a jar or two of honey in the car. A casual request for one jar might lead to a regular monthly order for a gross.

Just sayin’ 😉 .

Gifts

Not everyone likes honey, but everyone knows someone who likes honey.

I think this is the reason why honey makes such a great gift. If you’re saying thank you for the invitation to dinner, or for looking after the dog, or for that large bag of runner beans, there is nothing to beat a jar or two of honey.

It’s a handmade gift, it’s beautifully presented, it is exceptionally high quality and – other than the jars that came from the same bucket – totally unique.

In these regards it is a much better present than a bottle of wine … though wine and honey is also a winning combination.

A winning combination

The gift of a jar of honey is more personal, more thoughtful and much more likely lead to a conversation … ”Wow, thank you, is this honey from your own bees?”.

How many times have you been asked whether the bottle of merlot came from your own vineyard? In fact, how many times is the bottle of wine accepted without comment and then immediately put aside?

It doesn’t have to be honey of course – it could be candles (if they’re better than mine) or beeswax wraps or propolis tincture.

It’s the fact that it’s homemade, unique and high quality that counts.

I think this was the first of the intangible benefits I became aware of when I started beekeeping. Managing the colonies, rearing the queens and harvesting the honey is very rewarding … but it’s great that the honey brings pleasure to nearly everyone.


 

Mini-nucs: tips and tricks

Synopsis : More discussion of modifying and maintaining mini-nucs for queen mating; judging queen quality, repeat queen mating, season’s end and overwintering mini-nucs.

Introduction

A couple of weeks ago I described some of the basics of using mini-nucs for queen mating. I’ll try and avoid overlaps with that post in the following discussion of ‘tips and tricks’, effectively a rag-bag collection of stuff I failed to cover last time, interspersed with some typical problems that might be encountered.

Inevitably some of the discussion will be about specific modifications to the particular mini-nucs I use (Kieler or Warnholz polystyrene mating nucs). I settled on these because I needed a dozen one season, I had zero experience in using any so had nothing to compare and I couldn’t afford Apidea’s.

Kieler mini-nucs: four topbar frames and an integral feeder

Overall I’ve been reasonably satisfied with the choice my younger, poorer 1 and (even more) ill-informed self made. Over a decade later I’m using the same mini-nucs and I’ve not been tempted to try anything else 2.

Nevertheless, despite a Kieler-centric flavour to some of the comments below, most still apply directly (or with a little finagling) to other makes of mini-nuc.

Finally, I’ll repeat the point I made last time … mini-nucs are ’high maintenance’. They are not ’fit and forget’ beekeeping. Unless placed in the shade they may well abscond on a lovely day 3. Late in the season, without care and attention, they can get robbed out by wasps in hours. If there’s no nectar flow they will need feeding.

But, looked after carefully, they can be an efficient way to get queens mated .

Painting and decorating

Any poly hive needs painting to protect it from UV degradation. Most of my mini-nucs were first painted with el cheapo masonry paint. This has a matt finish and has been reasonably hard wearing.

More recently, I’ve started painting – or overpainting – them with Hammerite garage door paint. This is an oil or solvent based gloss paint. It causes the surface of the polystyrene to melt (very slightly) and therefore bonds extremely well. The Swienty brood boxes I painted several years ago look as good now as they did then. The Hammerite paint comes in a range of colours, including a rather nice green or blue.

Hammerite Oxford blue, since you asked

Successful queen mating needs reasonable weather (and patience). However, it also needs the returning mated queen to successfully find the mini-nuc she set out from. It therefore makes sense to either place the mini-nucs in separate and distinctive locations, or (perhaps that should be and/or) to paint them in distinctive colours.

Red ‘Wilko’ masonry paint and ‘bin end’ yellow gloss

I tend to place mine in pairs and so often have a plain and coloured one on the same stand, facing in opposite directions to further help the queen discriminate between entrances.

Entrances and exits

Kieler-type mini-nucs have a rotatable entrance with three or four options – blanked off, ventilation, a queen excluder or fully open. I shouldn’t need to mention that, if there’s a virgin queen in the hive (that you want mated), the entrance must be fully open.

But I will 😉

Entrance discs for mini-nucs

You can purchase replacement entrance disks like those in the photo above from a range of suppliers (or eBay, which is significantly less expensive). Using these may help queens return to the correct mini-nuc after orientation or mating flights.

Oops, almost forgot … bees have a tendency to nibble away at the polystyrene around the entrance of these Kieler nucs (or at the ‘under entrance’ which I’ve never used) while confined. It’s therefore worth painting the entrance tunnel as well as the outside.

Crownboards

Apidea’s and several other mini-nucs I’ve looked at are sold with clear semi-rigid plastic crownboards. Some have integral flaps for adding the queen cell or feeding the mini-nuc without letting clouds of bees escape (admittedly small clouds, as they’re only primed with a few hundred millilitres of bees).

Kieler’s are sold without a crownboard. Don’t let that put you off. A thick piece of clear plastic works just fine as a crownboard and you can easily engineer (i.e. cut) a small flap to add the queen cell between the topbar frames. I use a small piece of tape to hold in down.

Plastic crownboard. Note flaps for adding the queen cell and (above the feeder) adding syrup

You can put an additional small flap above the feeder that allows you to add syrup without any bees escaping. This only needs to be a few millimetres square and doesn’t need taping down. Even if you don’t think you’ll be feeding syrup – which you do using a small funnel – this modification takes seconds and won’t be in the way (but you’ll be glad it is there if you need it).

Hold the crownboard in place with drawing pins. That way there’s less chance it will blow away should you open the box on a windy day. It also means the crownboard stays stuck to the brood body, rather than being removed with the tightly-fitting roof.

Feeder mods

The Kieler integral feeder has some good and bad points.

It’s a good size, so reducing the chance of the mini-nuc starving if left for an extended period. However, this inevitably cuts into the space available for bees and brood, meaning that retention of the feeder can lead to rapid overcrowding.

You win some, you lose some!

The feeder is easy to remove and only fits in one orientation. Irritatingly it is too deep to fit into the ‘second storey’ extension (see below). It also has no cover or queen excluder and the queen can sometimes end up in the feeder, particularly if the bees build comb there.

Feeder with queen excluder

I therefore usually fit a small rectangle of plastic queen excluder, balanced on map pins stuck into the inner walls of the feeder. This stops the queen entering the feeder, but doesn’t necessarily stop the bees building comb there.

Be thankful for small victories … 😉

If you need more brood space you can easily replace the integral feeder with a homemade frame feeder designed to feed fondant. I build these shorter than the integral feeder so that they can be used interchangeably in the ‘second storey’ extension.

Kieler frame feeders

These work well, cost pennies to make and can be quickly exchanged when needed. When I’ve overwintered queens in these mini-nucs I’ve always used these fondant frame feeders in the upper storey, with frames filling the entire lower level. This reduces disturbance when you need to feed them.

Frames

The Kieler is a mini-topbar hive. Each topbar has a longitudinal slot cut into its underside designed to take a strip of foundation. They also have a ‘pinched’ central area, so that a queen cell can be easily inserted between two adjacent bars.

The bars themselves are just 15 x 8 mm softwood. Purchased separately they cost 36 p each (Yikes! … and those don’t even appear to have the central pinched indent).

If you need more (and you will … to replace losses and for the the upper storey should you buy one) just make your own with some wood from the store, a metal ruler, a Stanley knife and some antiseptic cream and Elastoplast.

And, while you’re at it, don’t go fiddling about with little strips of foundation held in place with melted wax. I did this for years. They work perfectly well, but they are fragile. The foundation in unused topbar frames will get bent or broken, and then you’ll have to start all over again.

Instead, eat as many Fruit Splits, Rocket lollies or Twister’s as you can stomach 4 and keep the sticks. Split these lengthwise and glue them into the longitudinal slot in the Kieler topbar using normal wood glue and 5 never re-wax them again.

Kieler mini-nuc topbar frames – no need for foundation or waxing

And, no, you don’t need to cover them in melted wax or anything else. All the bees need is a guide to help them draw the comb in the right place.

I’m sure there’s stuff I’ve forgotten about, but that lot will do for the moment. Let’s move on to four specific practical aspects of using mini-nucs.

Judging queen quality

You can’t … or at least I can’t.

I don’t think you can meaningfully determine the quality of the queen in a mini-nuc. The time between when she starts laying and when she runs out of comb is sometimes too short to even check whether she’s producing worker brood.

I usually leave her in the box until there’s some capped worker brood present and then – ideally – move her to a 2-5 frame nucleus colony. At the same time I clip and mark her. As long as she’s laying one egg per cell (and she sometimes starts laying more than this, but should slow down after a day or so) and the brood develops into worker brood then things should be OK.

However, it’s not until she’s laid a full frame or three of brood that you can judge the laying pattern (remembering that the laying pattern may also depend upon the bees in the box with her).

Brood frame with a good laying pattern

Furthermore, to properly judge her you need to observe the behaviour of the bees that develop from the eggs she lays.

Are they well tempered? Are they steady on the comb? Do they have the other traits you are keen to promote? Frugality? Good pollinators? Preferential collection of avocado nectar (Afik et al., 2010).

OK, perhaps not the last of those, but you’d be surprised about the traits some beekeepers favour.

Queen introduction

I remove the mated queen from the mini-nuc, place her in a JzBz cage without attendants and introduce her in the usual way to a queenless full-frame nucleus colony; I leave the sealed cage hanging between frames overnight and – assuming there are no signs of aggression to the caged queen – I remove the plastic cap and leave the workers to eat their way in through the fondant-plugged entrance/exit tube.

If there are signs of aggression, leave it another 24 hours.

Checking for aggression

A well designed introduction cage has some protection for the queen so she can avoid aggressive workers that can otherwise damage her feet. I’ve had considerable success with the JzBz cages (and happen to have inherited a bucket full and so don’t use anything else 😉 ).

I’ve inadvertently left a queen trapped in one of these cages for 6 days with no ill effects. Don’t rush things.

Rear some spares

What do you think happens with commercially reared queens, many or most of which are mated from mini-nucs?

Exactly … nothing, other than being popped into a shipping cage and having a £40 price tag attached.

In contrast, you have the opportunity to check your queens more thoroughly.

Rear a few more than you need, check out their performance, keep the best and donate the unwanted to one of the many, many beekeepers clamouring for queens – particularly late in the season. Even the also-rans are likely to be OK 6. Not necessarily great, but more than good enough to get the colony through to the next season 7.

Queen rearing diary; automagically populates days and events

And finally, make sure you keep good records. The first couple of times you do this you’ll think you will be able to remember the key points the following year; the dates of emergence, the time it took to have mated queens, the origin of the queen cell used to prime the mini-nuc etc.

But you probably won’t. The notes will be very useful for planning your queen rearing the following season.

Keeping things going

Populating mini-nucs early in the season is often a thankless and unpleasant task. The weather is cool, the bees are tetchy and – as described a fortnight ago – you may have had to shake through the colony twice to get the young workers.

That’s not the sort of task I like to repeat if I can possibly avoid it.

If you’re rearing queens all through the summer you can simply remove one mated queen and, shortly afterwards (within a few hours), add a new mature queen cell. This is the ideal situation and, with good organisation, good weather and good mating success, you can get three or four queens out of a single mini-nuc in one season.

Mainly good organisation.

You need to ensure you have a succession of mature queen cells ready at the about right time, remembering that queen mating often takes longer than expected (or wanted).

Scrub ‘caretaker’ queens

If that’s not possible, or if you want (or have) to interrupt queen cell production (e.g. your queenright cell starter swarms or a round of grafting fails) you can remove the mated queen from the mini-nuc and allow the bees to rear a ‘scrub’ queen.

A well populated mini-nuc will readily do this. The resulting queen is usually a bit on the small side, but she will keep the worker population ticking over and ready to accept a new mature queen cell in due course. In addition, the enforced brood break while they rear the scrub queen helps prevent the mini-nuc from getting too overcrowded.

These ‘caretaker’ queens are reared under the emergency response and – assuming there are suitable eggs in the little colony – emerge about 15 days after you remove the mated queen (remember, the bees preferentially choose 3 day old eggs to rear queens under the emergency response). A fortnight or so later the queen should be mated and laying. This approach therefore means you can take 4-6 weeks off if needed.

The end of the queen rearing season

What do you do with the contents of the mini-nuc after you’ve taken the last of the mated queens out? The little hive may well be bursting with bees, with all 4-6 combs containing brood.

Many beekeepers shake the bees out in front of a strong hive. The majority of the workers will be accepted, but the brood is wasted.

To avoid this I’ve used ‘zip’ ties to secure two Kieler topbar frames into a standard brood frame. At the very least these can be placed into a full sized hive for the brood to emerge. Usually, by the time of year I get round to this the bees have stopped drawing comb. Once the brood has emerged I move the frame to the side of the brood box and remove it.

Dave Cushman has details of some clever frame modifications that allow Kieler-type (he calls them Kirchhain mating hives) frames to be drawn at the beginning of the season and used to accommodate brood-filled frames at the end.

Unsurprisingly, when I’ve done this it’s been a lot more ’Heath Robinson’. The Kieler topbar frames are a little too long to fit end-to-end in a National frame. I therefore built some with a scrap 8 mm thick spacer (shown in black below) tacked under one side of the frame. I then use zip ties to hold everything more or less in place.

Using mini-nuc brood frames

Despite being a total bodge this has generally worked well. I’m pleased not to waste the brood.

Now I know the air freshener trick (described in this 2020 post) I’d probably just add the frames as shown in the diagram above together with the adhering bees, and give them and the recipient colony a quick blast of ’Sea breeze’ before uniting them.

Overwintering mini-nucs

Alternatively, with a little care you can overwinter queens in mini-nucs. This saves you the faff of emptying them at the end of the season, and means they are ready for queen cells the following year (after removing the queen of course) 8.

I’ve overwintered queens successfully quite a few times but certainly don’t consider myself an expert at it. There’s quite a high attrition rate. Remember how small these colonies are, how limited the space is for stores and the relatively small population of bees present to stop the colony freezing in the winter.

I think every mini-nuc I’ve overwintered successfully has been a double-decker, with the standard Kieler brood box underneath an additional extension brood body. These almost double the volume of the mini-nuc.

The mini-nuc needs to be strong in mid/late autumn, almost certainly boosted by combining the contents of two separate mini-nucs. You can unite them over paper in the same way you’d treat a full sized hive.

Unfortunately, the upper and lower brood boxes have different depths, so comb drawn in the bottom box needs to be trimmed to fit in the upper box. A messy and irritating task.

I replace the lower integral feeder with additional brood frames and place one or two fondant frame feeders in the upper chamber – usually one at either end to ensure the mini-cluster is near to one of them.

Place the box somewhere sheltered, leave the entrance open to allow the bees to fly for cleansing flights and cross your fingers …

Gimme shelter

I’ve not overwintered mini-nucs since returning to Scotland, though I know several beekeepers here who do this successfully. In the Midlands we often had quite harsh winter weather – certainly much colder than we usually get here on the north-west coast of Scotland.

Two double decker mini-nucs overwintered successfully in an unheated greenhouse

A decade ago, well before my bee shed experiments, I was successfully overwintering mini-nucs in an unheated greenhouse with entrance tunnels from the hive to the outside. These worked surprisingly well and got queens through some really hard weather (note the snow in the picture above – late March 2013).

Tunnel entrances to overwintered mini-nucs

If the winter was particularly severe I would cover the mini-nucs with a thick layer of bubble wrap to try and retain as much warmth as possible. The levels of stores needs to be checked regularly, particularly once brood rearing starts in earnest. These little colonies can starve surprisingly quickly 🙁 . It takes seconds and causes minimal disruption to swap out those fondant frame feeders.

With a little luck and the normal amount of good judgement it was sometimes possible to remove the overwintered queen to make up a nuc in mid/late April, replacing her with a queen cell from the first round of grafting.

Of course, it rarely worked quite as smoothly as that … 😉 9

Finally

The one thing I would not recommend you try is allow the mini-nuc to build up to a full-sized nuc without supplementing it with additional brood and bees. A mini-nuc is too small and it will take too long rearing a few hundred bees at a time to make even a five frame nuc. I’ve tried and it’s a waste of effort.


References

Afik, O. et al. (2010) ‘Selection and breeding of honey bees for higher or lower collection of avocado nectar’, Journal of Economic Entomology, 103(2), pp. 228–233. Available at: https://doi.org/10.1603/ec09235.