Category Archives: Seasonal

New Year’s Resolutions

Synopsis : Often made, less often kept. How to improve your health, wealth and generosity … good habits for the season ahead, plus wildfires, bananas and XXXL beesuits. New Year’s Resolutions for beekeepers.

Introduction

Historically, the Babylonians used the start of their New Year as an opportunity to clear old debts, return a kindness or right a wrong. In 2000 BCE ¹ these New Year’s resolutions were retrospective, they did something measurable to ‘correct’ a past event.

At some point in the last 4000 years resolutions evolved to become prospective … and acquired increasingly religious connotations. The Romans made promises to their god Janus after whom the month of January is named. The change from a lunar calendar also shifted New Year, from the Babylonian springtime to its current location, shortly after all the mince pies are finished and the tree has shed the last of its needles onto the carpet.

Lots of people – perhaps 40-50% of the population ² make New Year’s resolutions and almost as many fail to keep them. In many cases this failure seems predestined; asked at New Year whether there’s an expectation that a resolution will be kept, only ~50% say they expect to achieve their goal.

In practice, that’s ambitious.

When asked one year later only 12% had managed to keep the resolution.

‘Close, but no cigar’ ³.

These days the once predominantly religious resolutions have, for many, been replaced by ‘self promises’ that can be broadly categorised as health (e.g. lose weight, quit smoking, get healthier), finance/career (e.g. save money, reduce stress) or generosity (e.g. be helpful, donate to charity).

New Year’s Resolutions for beekeepers

And, in a blatantly-contrived way, some of these resolutions are also relevant to beekeeping.

Like everyone else, beekeepers are just as capable of not keeping their resolutions, despite the clear benefits of doing so.

So, in no particular order, let’s have a look at a few beekeeping resolutions tailored to our obsession but still recognisable as generic or popular New Year’s Resolutions.

Quit smoking

Most beekeepers are smokers, or at least use smokers.

Smoker still life

In fact, the smoker is probably the most widely recognised tool of our trade. The smoke is used to calm the colony before inspections. It masks the alarm pheromones and so makes inspections a little easier. After smoking a colony and opening it up you will usually find a significant number of the bees gorging on open honey stores or nectar.

This probably accounts for the explanation that bees nesting in tree cavities have, over eons, evolved to respond to smoke from natural forest fires. This response includes gorging on stores so that the colony can abscond – a term used to describe the entire colony abandoning any brood and relocating – to set up home elsewhere.

This is almost certainly incorrect.

Abscond? What’s the point?

Firstly, bees exposed to wildfires do not abscond. Unfortunately they just get cooked, and almost certainly die from either heat or asphyxiation 🙁 . Or, if the nest survives the fire, they starve as there’s no forage in range. Secondly, if you assume it’s midseason and the queen is laying eggs like crazy, they probably cannot abscond as she will be too heavy to fly any distance.

What’s more, if you open a colony without using smoke there will still be bees gorging on honey stores … the disturbance alone is sufficient to make them do this.

Try it.

Mr Smoke-Too-Much

Just like the Monty Python character, you can smoke too much. If you do the bees get disorientated and distressed. On occasion I’ve had to smoke a colony heavily and it’s generally something to avoid (but they never abscond).

Many beekeepers probably rely on smoke rather more than they should. If you smoke a colony heavily at the hive entrance the bees will be driven up … to the exact region you want fewer bees when you manipulate the frames. A very gentle waft under the crownboard and the occasional very light puff to clear bees from the frame lugs should be sufficient.

There are alternatives to smoke. A plant mister with plain water works well for many colonies and is what I often use if I’m just inspecting nucs. There are also commercial smoke/smoker alternatives like Fabi-Spray or Apifuge.

One of the best ways to learn to use less smoke is to keep bees in a shed. If you are over-generous with the smoker you also end up getting ‘kippered’.

Kippered

I leave the smoker outside the door and only retrieve it when initially opening a colony and very rarely during inspections.

Of course, the best way to need to use less smoke is to select for calm, stable bees when you are queen rearing.

So … perhaps don’t quit smoking, but as Bounder-of-Adventure suggested to Mr Smoke-Too-Much in Monty Python’s Flying Circus, ’better cut down a little’ ⁴.

Reducing stress

The Oxford English Dictionary has at least 13 definitions for the term stress; although many automatically think of tension or anxiety, biologists also use the term to mean:

Disturbed physiological function occurring in an organism or cell in response to conditions, events, or factors that are deleterious or threatening.

Bees subjected to adverse conditions – like long-distance transport, temperature extremes or disease – show evidence of stress which can be quantified in changes to the levels of molecular markers such as pheromone receptors and immune responses. This ability to respond is important, but it can be at the expense of normal physiological activity; e.g. more fighting pathogens or keeping warm than following waggle dancing foragers or feeding developing larvae.

Whilst I’m not aware of any studies of inspection-induced colony stress ⁵ I’ve no doubt it occurs … and that it’s at least transiently detrimental. The pheromone levels and gradients in the hive are disrupted, the brood nest is flooded with light, the location of bees in the nest are disturbed.

So, if you assume that that it is detrimental, try and minimise it. Only open the hive if needed, be gentle, use minimal smoke, be quick and calm and controlled … and try not to drop any frames 😉 .

The stressed beekeeper

The greater the disturbance you cause to the colony, the more defensive the bees become. They start pinging off your veil, burrowing into creases in your beesuit, stinging your gloves.

I love the smell of isoamyl acetate

You become aware of a feint but distinct whiff of ripe bananas … that’s the alarm pheromone produced from the Koschevnikov gland at the base of the sting.

Then things start going a bit Pete Tong.

Your stress levels rise, you use too much smoke, you try to work faster but consequently get clumsier, a bee gets inside your veil and you get even more stressed … and smoky … and clumsy … and stung.

If you are tense and anxious before even opening a hive the bees can probably sense it, and this may exacerbate things.

Beekeeping shouldn’t be like this.

To reduce your stress you need to:

have confidence in your protective clothing – buy a good quality beesuit and wear additional layers underneath when needed
wear gloves that enable good dexterity – thin nitriles rather than welding gauntlets
take care to cover areas of weakness – cuffs, ankles etc. (the bees will find them)
requeen defensive colonies as soon as practical from better quality stock
learn to inspect the colony quickly and calmly by practising (don’t avoid conducting inspections)
and, if you’re frightened of the sting reaction, take antihistamines in advance of apiary visits

Beekeeping is supposed to be an enthralling and relaxing pastime. If it’s a stressful battle – for you or the bees – then something is wrong.

Improved health

This is a huge topic and needs more than a few hundred words – here are three examples of good practice:

many diseases are always present in the colony but only become a problem under certain conditions. Deformed wing virus (DWV) isn’t an issue until Varroa levels rise, chalkbrood often ‘disappears’ by mid-season as the colony strengthens. Weak colonies are often more susceptible to disease and/or more likely to show symptoms. It therefore makes sense to maintain strong colonies. Take account of environmental conditions; don’t split them too hard and feed if necessary. Wasps and robbing bees aren’t ‘diseases’ but strong colonies are also better able to defend themselves.

DWV symptoms

ignore much of the nonsense you read in some surveys of colony losses. The biggest problem most beekeepers face is the toxic combination of DWV and Varroa. I would be amazed if these accounted for <75% of all annual colony losses. Isolation starvation? Nope … the winter bees died faster due to high levels of DWV and the little cluster froze to death. Monitor your Varroa levels a few times during the season and look out for overt DWV symptoms – much of either and you might need to intervene. Yes, there are other things to look out for, but mites and viruses are the biggest problem.

Varroa incursions and introductions in NSW, Australia, 19 December 2022

beekeepers are responsible for spreading many pests and pathogens between hives and apiaries. If the global distribution of Varroa doesn’t convince you of this, then the map of Varroa presence in New South Wales should. Similar data exists for foulbroods, where the only reasonable explanation for the presence of the same strain miles apart is hive movements or contaminated equipment. Practise good biosecurity and remember, ‘when you move bees, you move disease’.

Save money

Some beekeepers already have a bit of a reputation in this area … ‘deep pockets, short arms’ as they say ⁶. Even more beekeepers, whilst not actively mean, enjoy making savings wherever possible – if you want evidence of this just watch the stampeding hordes descend on the trade show sales at beekeeping conventions.

There are lots of ways to save money, at least after the initial expenditure on a hive (or two), beesuit, smoker etc.

Here’s one I started earlier … a Morris board under construction

Brood boxes and supers are probably best purchased as they are difficult/expensive to make without good tools, woodworking expertise and a source of high quality wood. Buy new cedar (even second quality) or poly boxes and they’ll last longer than you will. However, floors, roofs, crownboards and most of the things I consider as the horizontal components of the hive can be easily and inexpensively constructed.

Switching partly or totally to foundationless frames will save you a small fortune over the years.

Honey, honey

Of course, rather than reducing your outgoings, the other way to ‘save’ money is to raise your income.

Is your honey priced correctly? Beefarmers are talking about a glut after the good 2022 season, but I know plenty of places selling excellent local honey for £9-13 a jar (227 g or 340 g). The days when the milkman used to distribute and sell my honey for £4 a pound are long gone ⁷.

Do your homework, use attractive jars, think about your labelling and remember that well produced local honey is a unique premium product and should be priced accordingly.

Not local honey, but it might well be priced correctly

A final piece of advice on saving money. Omitting or skimping on Varroa treatments is false economy. I use Apivar and Api-Bioxal and spend less per hive per year than the cost of one 340 g jar of honey ⁸. That’s a small price to pay ⁹ and is a cost I more than recoup from increased honey production or reduced overwinter losses.

Be more helpful

One of the best ways to learn is to teach.

If you’ve got a year or two of beekeeping experience why not volunteer to act as a mentor for beginners? By sharing the responsibility for an additional hive or two you will get more beekeeping experience than if you just manage your own. These additional colonies will make the distinction between ‘good’ bees and ‘poor’ bees much easier, particularly if they share a similar environment.

Mentoring and training … the best way to learn

The inevitable questions from your mentee will challenge your understanding of the bees;

Is this a queen cell or a play cup? What’s the difference between them anyway?
Does this queen look inbred? Is there another explanation for a pepper-pot brood pattern?
How do I cut out a queen cell overlaying a foundation wire?

As good as the training course was that I attended, and despite my attentiveness during my subsequent solo blunderings ¹⁰, I’ve learnt much more from mentoring since I started.

Try it, you won’t regret it. You already know more than you think you know, and – if you’re anything like me – you’re only just realising how much else there is to learn.

Donate more to charity

I am aware of two charities that promote beekeeping in communities, supporting “sustainable beekeeping to combat poverty, build resilient livelihoods and benefit biodiversity” and who “mentor and train in local beekeeping best practices, business skills, and protecting the environment” ¹¹ :

Both do really valuable work, primarily in Africa, but in other countries as well.

You can donate directly or purchase anti-tamper labels for jars that also help promote the work of the charity to the purchaser/consumers of your honey. Gift Aid donations if you can.

Lose weight

No, no, no … I don’t think so.

This one is the exception.

Other than during the self-flagellation exercise that is honey extraction, in particular shifting full supers from hives to the the store and then to the extractor, I don’t think there are any circumstances when beekeepers want less weight.

I want my supers to be bloated with honey and I want them stacked head high.
Colonies going into winter should be stuffed with stores and correspondingly heavy.
I want the heaviest swarms possible to conveniently make their way to my bait hives. Bring it on, the more the merrier. They’ll get established faster and may even yield a good crop of honey (see 1, above).

There may be things I’m overlooking and my basic politeness means I have no intention of discussing anything to do with XXXL beesuits.

Does my bum look big in this?

Bargain basement

NHBS ¹² currently have a special offer (£13.99 rather than £23.99) on Thomas Seeley’s The Lives of Bees. Although I’m not a fan of his Darwinian Beekeeping ideas, the book is an outstanding account of the biology of free-living honey bees. It is not a book about beekeeping but it explains loads of things about their behaviour which will help you understand why they’re doing what they’re doing.

The Apiarist in 2022

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Synopsis : A review of the year on The Apiarist; top of the posts, weirdo searches, clickbait titles and coffee. Don’t expect anything erudite. Happy New Year!

Introduction

And another year ends.

After 51 posts, ~160,000 words, 999 comments and ~62,000 spam ‘adverts’ for fake sunglasses, casinos, ivermectin ¹ and goodness-only-knows-what (in Russian) later, this is the last post of the 2022.

Assuming this appears before midnight on the 30^th I’ll have ² managed to meet my self-imposed deadline of posting every Friday afternoon this year. This is my annual review of what happened on the website during the year, which were the most popular posts, where did visitors come from or go to etc.

Warmer days

Overall, the ~510 posts on the site were read ~20,000 more times than last year. This is a fractional increase over last year, despite the fact that readers increased by ~7.5%. I assume this might be due to the articles being longer (and therefore more self-contained ³ ), though there may be other reasons to do with changes I’ve made to the server that runs the site (and the accuracy with which I count ‘real’ visitors).

The first posts on The Apiarist – on Paynes poly nucs and clearer boards – were made in 2013, so this year marks the end of a decade of writing.

During the last year, what have visitors been reading?

What does this ‘top ten’ tell me?

Seven of the top ten posts are about swarming, its prevention or control. This is not because the majority of the posts on this site are about swarm prevention or control. Instead I think that this is an aspect of beekeeping that many people – I assume particularly beginners – struggle with.

However, whilst swarming might result in the loss of a swarm ⁸, it rarely results in the loss of the complete colony.

It feels like a disaster, but isn’t.

Drone comb built under a super frame in a brood box

In contrast, poor management of Varroa will regularly result in the loss of the colony, but it’s not until the 14^th most popular post this year that the first post on mite control appears.

I suspect this reflects a couple of things:

swarm control is needed during the summer months (May – July) when readership of this site is the highest. There are about 2-3 times the number of readers in June as December.
there’s something more ‘immediate’ about the need for swarm control, whereas many beekeepers think that miticide treatments – as long as they’re applied sometime – are less time-sensitive. I’m not at all convinced that this is correct; swarm control is clearly time-sensitive, but I’d argue that winter mite treatment with oxalic acid can be almost as time-critical.

And – since you asked – the least popular post was a 2017 article on the need (or otherwise) for midsummer colony inspections which attracted an underwhelming total of just 9 viewers 🙁 .

I think all this really tells me is that the search facility is used rather infrequently … and the indexing is not as good as it could be.

Where from and where to?

About 50% of readers reach the site from Google searches which account for ~90% of all the search engine traffic that leads here. I’ve stopped bothering looking through the search terms (other than for this annual post) as they’re generally a combination of obvious beekeeping terms (swarm, queenright, Varroa) and glaring typos (swam, denaree, fundationless).

However, now and again there are searches that could make for entertaining future posts:

how to calculate items in a jar ⁹
what colour are queen cells ¹⁰
コンタクトキラー　柔術 ¹¹
little drama ¹²
have flour water honey salt what can i make ¹³
profit per hive beekeeping ¹⁴

Readers leave the site via the outgoing links I embed in the posts. Of these, links to the equipment supplier E.H. Thorne’s were the most commonly clicked (perhaps I should ask for a lucrative sponsorship deal? ¹⁵ ), with Wikipedia a close second. I’m a big fan of Wikipedia, particularly for recent cultural references, and donate to support it.

Hives and a nuc

Thorne’s and Wikipedia were followed by the Welsh BKA (for articles by Wally Shaw), the National Bee Unit and Dave Cushman’s website (now maintained by Roger Patterson), though these three lagged well behind the first two.

Behind the scenes

The site is self-hosted on a virtual machine in the cloud.

I’ve no idea what that means either 😉 .

Not this sort of cloud (at least, I don’t think so)

However I do know that it involves a reasonable amount of maintenance to ensure the site is secure, that the firewall lets bona fide visitors in whilst excluding ‘script kiddies’ and the majority of bots, and that software is kept updated to minimise vulnerabilities.

All this takes more time that I would like and, because of my limited abilities, a lot more time than it should.

However, it also gives me a bit more control over things. After a major site upgrade in September I now want to introduce a few more changes over the next few months.

Comments

The commenting system is, frankly, a bit primitive. It’s the one that comes packaged with the software that runs the site, but it lacks certain features I think would be beneficial. I’ve tested a number of alternatives and hope to switch to another system soon. It should make comment approvals (for me) easier and will facilitate better threaded comments, and ‘upvoting’ helpful comments. For the terminally shy it should also allow anonymous commenting, with certain provisos.

I’d like to thank everyone who took the time to comment on posts this season. These help clarify errors I’ve made, or suggest alternative interpretations or conclusions.

Social media

New posts to this site appear on Friday afternoons (at the moment … goodness knows what’ll happen in the future). They are automagically announced on Facebook and Twitter.

Social media

Or were … 🙁 .

This ‘free’ feature of the software that runs the site will very soon become a ‘premium’ feature for which they’ll try and charge me over £100 a year extra. It’s this sort of ‘feature creep’ (the wrong term, but I can’t think of the right one at the moment ¹⁶ ) that takes either time or money to fix.

I don’t have much of either.

Of the two, Facebook generates a bit more traffic. However, I’m not a Facebook user and I find it an abomination to use interactively. Therefore … if you rely on Facebook for new post announcements then please consider signing up for email announcements instead. The Facebook linking may well disappear altogether.

You might have noticed that Twitter is a little chaotic these days. Adverts and hate speech are increasing on a daily basis and it’s becoming a much less pleasant environment. I barely use it, and I get the impression that others are using it less. Follower numbers are all over the place and it’s less ‘fun’.

At the current rate Twitter may well go bankrupt before I decide to stop posting new post announcements there. In the meantime, those of you who have switched to Mastodon can find me at https://mastodon.scot/@theapiarist. I will endeavour to make new post announcements to Mastadon and Instagram (the latter is a relatively new account, but is altogether better than either Facebook – who own it – or Twitter).

There isn’t one.

But I would like to replace the current email system (and possibly some of the social media stuff listed above) with an emailed newsletter. If so it will be ‘opt in’ and you’ll need to sign up separately for it.

Watch this space.

Coffee

The ~160,000 words of beekeeping ~~wisdom~~ verbiage this year were generally written late at night, aided by an unhealthily large – but nevertheless deliciously invigorating – number of cappuccino’s and flat white’s. I think the latest I stopped was 3:15 am, a time unreachable without copious quantities of coffee.

I’m therefore very grateful to supporters who ’Bought me a coffee’ in 2022, and particularly grateful to those of you who are repeat supporters.

Lovely

This support not only stops me slumping semi-conscious over the keyboard in the wee hours of the morning, snoring stentorianly, but also helps offset the costs of the server and the associated software needed to run the site ¹⁷.

Thank you 🙂 .

Even Buy Me a Coffee has suffered from ‘feature creep’ in 2022 and stopped taking Paypal payments. I know this caused some supporters a problem. If you’d like to support The Apiarist but want to use Paypal you can now do so via Ko-fi ¹⁸.

Praise and abuse

Someone presumably not on the supporters list is ‘RG’ ¹⁹ who posted a comment on April 1^st:

Who are you??? What is your connection to the bee world.? Are you a credible writer and have the expertise to make statements about bees and bee able to back it up? Are you an expert bee person? Where do you get the information you post?

I receive a lot of similar sounding generic comments which usually contain links to other websites i.e. adverts of one form or another. I therefore assumed it was one of these or an ‘April Fool’, albeit not a particularly good one, and banned RG.

However, I also did a little research and discovered a beefarmer of the same (unusual) name in Iowa. I’ve no idea if it was one and the same person. Whether he was or wasn’t, he ensured the ban was permanent by sending me an even less polite follow-up email.

Fortunately, the majority of the communications I receive – in comments on individual posts, direct emails or accompanying coffee contributions – are very much more supportive and appreciative.

Thank you again for this support. It goes a long way to offsetting the few negative comments from RG and the like.

The Apiarist is retiring

Actually, The Apiarist has retired.

I always thought that 32 was too early to retire ²⁰, but it’s going great so far 🙂 .

Whilst I still have bees on the east coast of Scotland, that’s unlikely to continue much beyond the start of the 2024 beekeeping season. I now live permanently on the remote west coast and have other plans and priorities.

These other plans and priorities (obviously) include a significant amount of beekeeping. However, not exclusively … assuming the weather is better than the shocker we had this year I’ll be doing more walking, cycling, sailing, canoeing, birdwatching, photography and (a lot more) lounging around looking at the view.

Laptop, binoculars, coffee … my summer ‘office’

I’ll also be doing more writing, though not more here.

Three thousand word posts are probably too long for the majority of readers. The average this year is about 3,100 words. The tens of thousands who read Queen cells … don’t panic – a mere 1500 words long – were probably looking for a quick answer.

I’ve found X … what must I do next?

They don’t have time to learn about why they’ve found X, what the colony was doing before X appeared, or what it would normally do next with X.

Despite the fact that knowing these things would almost certainly help them know exactly what to do when X appeared 😉 .

Conversely, 3,000 words is too few to do the really big and important topics in beekeeping justice.

Environmental competition, climate change, neonicotinoids, fake honey, treatment-free strategies and lots of the science would benefit from more in-depth coverage. Even some of the more ‘anecdoty’ (that isn’t a word, but should be … OED tells me that anecdotal would be better) posts would benefit from more space.

I’m looking at alternatives.

Coming next

If there are topics I’ve not covered, but should, then email me with suggestions. I’ve written almost 800,000 words on beekeeping since 2013 so do a quick search first to check it’s not already been covered.

I’m not keen to simply rehash stuff that’s already written. There are only so many ways that you can describe Pagden’s artificial swarm and it gets boring just shuffling the words into a slightly different order.

However, remember that I’ll only cover topics I feel qualified (and competent) to write about, so you won’t find much here about candlemaking or mead. I’ve done both, and although I might be qualified I’m a long way from competent.

But … I can’t promise I’ll write a post on any particular topic … at all, or any time soon ²¹. I need to know something about the topic and be interested in it. Both of these (particularly the first) are major limitations.

Much of the reward of writing these posts is furthering my own knowledge of the honey bee and beekeeping topics that fascinate me. That’s why I’ve written several posts recently on larval selection for queen rearing; it’s clear that the ways the bees do it and the way beekeepers do it are fundamentally different.

Is this relevant to beekeeping and queen rearing?

Possibly … I don’t yet know enough.

A new beekeeping year

I’m writing this is the dying days of 2022, a year which will be notable (in the UK) for political chaos ²², the end of Covid ²³ and climate change; we started with storms Eunice, Dudley and Franklin and ended it being the warmest year on record ²⁴.

As I discuss in my talk on Planning for the season ahead, at a first approximation it’s reasonable to expect that next year will be much the same as this year, or the average of the last few years, at least when considering the weather.

You’ve therefore got a pretty good idea what to expect and when to expect it.

Now is the time to start making your preparations … and perhaps your resolutions for the season ahead.

Whatever 2023 brings, may your supers be heavy, your queens fecund, your bees well-tempered and your swarms … from someone else 😉

Happy New Year

2022 in retrospect

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Synopsis : A brief look back over the season just finishing. Climate is what we expect, weather is what we get ¹. And we got a lot of it.

Introduction

The winter solstice last Wednesday seems an appropriate time for a brief overview of the season that has just finished. The 21^st of December is the shortest day of the year. Perhaps surprisingly, because of the equation of time (the difference between solar clocks and our clocks) it is not the day with the latest sunrise and earliest sunset. For my location, these are on the 29^th and 14^th of December respectively.

Not only is it the 21^st the shortest day of the year, it’s also – ironic considering the freezing weather the UK had last week – only the beginning of astronomical winter, which lasts until the 20^th of March.

December sunrise

However, for beekeepers, the 21^st is significant for two reasons; increasing amounts of daylight and the fact that many colonies are likely to now have started rearing brood for the coming season. Longer, warmer ², days will make foraging possible – both in terms of there being forage available and it being warm enough for the bees to fly.

And, to survive next winter – as well as hopefully reproduce (swarm) next summer – the colony needs to start rearing brood now.

It takes bees to make bees. A colony cannot collect sufficient nectar and pollen to rear large amounts of brood, or keep large amounts of brood warm, unless there are lots of bees already in the colony. Therefore, a small ³ broodless colony will restart brood rearing slowly, ramping brood production up as more bees – and pollen and nectar – become available.

A gentle reminder

Most of my colonies have been broodless from about the second week of November but the majority are now brood rearing again. ‘Most’ and ’the majority’ as there are a few hives that appear to have never stopped, going by the debris that has fallen through the open mesh floor onto the Varroa tray.

There are others that appear to have not yet have restarted.

When the colony is either completely broodless (or has the minimum level of brood) the proportion of the total number of Varroa mites in the hive that are phoretic are at a maximum. That is the time to treat with dribbled or vaporised oxalic acid … not at some convenient time in mid-January when you belatedly remember.

My colonies were treated with oxalic acid on the 13^th of November and, after an initial mite drop that confirmed that the treatment had worked, during recent monitoring have not dropped another mite in the last 21 days.

Look! No mites! 1/12/22 to 21/12/22

The fewer mites in the colony when brood rearing starts, the lower the peak mite level will be later in the season (all other things being equal i.e. brood breaks, swarming, rate of brood rearing etc.). If the levels remain reasonably low it will not be necessary to intervene until late summer, after the honey harvest occurs and before the bulk of the winter bees are being reared. This is why I treat in the winter.

The alternative is you start the season with high mite levels and end up with damagingly high mite levels before or during the summer nectar flow, all of which makes everything more complicated than it needs to be.

But enough thinking about next season, how did this season go?

Pretty well 🙂 .

Latitude and longitude

I’ve got bees on either side of Scotland. They are at about the same latitude and the closest east and west coast apiaries are only separated by 110 miles as the bee flies. Nevertheless, the season is completely different on opposite coasts.

I think this is due to three interacting factors:

climate; the west coast is generally warm(ish) and wet ⁴ whereas the east coast is much drier and generally has colder winter temperatures and hotter summer temperatures. For comparison, at the time of writing, Fife had a fraction under 1 metre of rain for the year with minimum and maximums of -10°C and 30°C, in contrast on the west coast we’ve had 2 metres of rain and temperatures of -3°C and 25°C. However, as will become clearer when I discuss queen rearing, these basic facts obscure some significant differences in climate, and have consequences for beekeeping.
forage; the east coast is rich agricultural land and there’s usually oil seed rape available early in the season. This gives the bees a huge boost. In contrast, the west coast has scrubby woodland and hedgerows with natural forage but almost no farming and precious few gardens (and the deer eat everything anyway 🙁 ). The main honey-producing forage on the west coast is heather.
bees; my Fife bees are homegrown ’Heinz’ local mongrels ⁵ with a little bit of native black bees in their dim and distant past. On the west coast the bees are native Apis mellifera mellifera. These are much more frugal, build up more slowly in Spring, swarm much later and will continue to forage in miserable weather.

Winter

I do almost no practical beekeeping during astronomical winter (reminder … 21^st December to 20^th March). My colonies are treated for Varroa before winter starts (see above) and colony inspections don’t start until after winter ends.

East coast

I checked colony weights periodically – about once a month – by hefting the hive. Where needed I added additional blocks of fondant. I don’t bother messing about adding 250 g at a time but just place 2 kg blocks in a food container inverted over the top bars. The weather is too cold for regular foraging and you don’t want a break in rearing the important early season brood.

Mid-March and fondant blocks being replaced

I added Varroa trays for a month from late January and the Varroa drop was (reassuringly) exceedingly low., and non-existent in the best hives. Remember, these were treated with oxalic acid three months earlier and brood rearing was building up strongly. Towards the end of this winter period colonies were foraging freely and building brace comb up into the inverted food trays, now emptied of fondant.

West coast

My west coast bees have no Varroa. I still periodically add a tray under the hives to see what falls through and to monitor brood rearing. Other than adding a block of fondant to a couple of hives I did nothing at all with them until well into April.

Spring

Spring felt as though it started later than usual. Cuckoos were a week or so later than normal in arriving, as were house martins and swallows. Unusually, grasshopper warblers didn’t arrive at all on the west coast. However, although these phenological signs suggested a late spring, the bees had been busy.

East coast

Most of my colonies are in single National boxes. It suits the bees and it suits me. Most consequently need swarm control, but that’s OK. It’s an opportunity to requeen them, it allows the production of a spare nuc or two and – timed correctly ⁶ – the queenless ‘half’ collects a good surplus of honey.

But, one or two are in double brood boxes.

I tend to rotate these as a means of controlling swarming, or at least attempting to. The queen tends to work in the upper brood box so, once this is more or less packed, I switch it with the lower box. Inevitably this breaks the brood nest which many consider a poor beekeeping practice.

Reversing brood boxes

However, the queen moves up again, filling the empty space ‘above’ her. By the time the upper box is full of brood, much of the lower box has emerged and I can rotate the boxes again.

Neither of the colonies I did this with this season needed additional swarm control ⁷. Both ended the year with the same queen they’d started with.

Interestingly – at least it is to me – one of these queens had been destined for replacement very early in the season. In the first 2-3 inspections I’d noted some followers and overly-defensive behaviour.

On the 1^st of May I’d scribbled ”Not nice bees – requeen ASAP” in my notes. However, the box switching distracted me (and her), made inspections quick and easy, and I had no spare queens anyway. By June the colony was no longer defensive and they remained calm and pleasant bees for the rest of the season.

If there is a lesson to this anecdote I’m not sure what it is 😉 .

West coast

After a fantastic March and April the weather took a turn for the worse. It rained on all but 5 days of May and the average temperature never exceeded 18°C. Much of the early season forage – primarily a variety of willows and abundant gorse – had finished and most colonies needed feeding. To encourage brood rearing I fed thin syrup and – for some colonies – pollen sub patties.

Early season – pollen pattie and brace comb

I’ve got a lot to learn about keeping bees here on the west coast. Both the climate and the available forage – at least until the heather flowers – are less good than on the other side of the country.

As a consequence, and in contrast to Fife, I only started swarm control on the west coast in the last couple days of astronomical spring (which ends on the summer solstice).

The busy part of the season was still ahead.

Summer

Astronomical summer runs from the 21^st of June until the 23^rd of September. This is the period with the second honey crop on the east coast and the heather crop (what little there was of it) on the west.

East coast

The majority of new east coast queens got mated, clipped and marked in late June and early July. Looking through my notes while preparing this post I see that a couple are still recorded as ‘NN’ … this means that, for whatever reason, I’ve found a laying queen (or know one is present) but have yet to get around to marking her.

At this time of the season the boxes are bursting with bees and, with a new queen and the risk of swarming much diminished (to say nothing of the heavy supers and high temperatures) my enthusiasm to scrabble through the box looking for her is ~~non-existent~~ less than it should be.

I can always hear a little voice saying ”She’ll be much easier to find next April …” 😉 .

The summer honey crop was exceptionally good. Unusually I had a couple of hives with 5 supers and one – in the shed – barely fitted under the rafters.

A tight squeeze

For the first time I had one of my clearer boards blocked with bees from the supers. This is clearly something I’ll have to look out for in the future, though I’m still not really sure why this particular hive got blocked. The board had only been in for about 18 hours, there was a deep lower rim to the clearer and no more than four supers.

Blocked clearer

Honey extraction was the usual tedious and messy process. Other than the sheer quantity, the only thing notable was that, considering the relatively dry summer on the east coast, the water content of the honey was – at about 18% or so for many buckets – higher than expected.

Or perhaps my refractometer is poorly calibrated 🙁 .

West coast

Until late August the weather on the west coast was very poor. Rearing queens was tricky; several rounds of cells were torn down, presumably because the colony was thinking ”Are you daft? Nothing is further from our mind than new queens … have you any more syrup?”

Cells that did reach maturity were placed in mini-nucs for mating, or used for requeening splits from other colonies.

And that’s when the problems started.

Summer 2022 rainfall

Although I had reasonable numbers of drones, helped by most colonies having a frame of drone foundation added back in April, queen mating was a protracted and fraught process. The weather in July was terrible with a lot of rain (~150 mm for the month, about 25% of what I’d expect for the year on the east coast) and only 3-4 days when the temperature exceeded 20°C.

West coast July temperatures

All my queens did eventually get mated but, by golly, they took their time. A couple that emerged on the 15^th of July were laying by the 26^th of August … but had no sealed brood yet. This wasn’t unusual. These were getting worryingly close to the age at which they were too old to mate.

In one colony, the day I discovered the mated queen there was also evidence of a small amount of laying workers with widely scattered drone brood in worker cells. Fortunately, her brood rearing soon suppressed laying worker activity ⁸ and the colony ‘survived’. However, it will be next season before I can tell how well these queens were mated and I remain concerned that some may fail overwinter.

The heather honey crop eventually arrived in the three weeks of good weather before mid-September which pretty-much rescued the season.

Autumn

I usually do more beekeeping in September and early October than I do in August. The preparation for winter (which still seems a long way off, particularly if the weather is good) is critical and cannot be delayed.

East coast

Apivar strips went into all the Fife colonies on the same day that I started winter feeding and removed the honey supers (which this year was the last few days of August). Over the next 2-3 weeks I monitor the Varroa drop to get an idea of the infestation level.

Gone are the days when I count every mite … it’s now usually a case of few/some/lots. However, I also photograph the trays, clean them and replace them ready for the next visit. I then look again at the photos on a big monitor in the lengthening evenings with a large glass of shiraz, so have a pretty fair idea the numbers associated with my few/some/lots categories.

I’m well aware of the numbers of bees that drift between colonies, and equally aware how these distribute mites and the viruses they carry. However, even hives as ‘cheek by jowl’ as those in my bee shed showed markedly different infestation levels.

Fortunately, very few colonies exhibited high mite drops during treatment. However, I think the gross discrepancies in mite levels (I’m assuming the %age of mites killed per colony as similar) tell me two things:

the principle of just monitoring one sentinel colony per apiary is flawed. If your sentinel has a low mite load you could be missing colonies with dangerously high mite levels. Conversely, you could ‘over-treat’ colonies – intervening when it’s not needed – if your sentinel colony had a high mite load.
these colonies with high mite loads, presumably exposed to similar levels of drifting etc., may not have desirable genetics (as far as mite control is concerned) and should probably be excluded from future queen rearing.

Fondant was finished by early October and – other than the November OA treatment – it was all over for the year.

West coast

There’s even less to do in the autumn on the west coast. These bees don’t have Varroa so no miticides are needed. The majority of the hives and nucs were packed with stores from the heather (so explaining the small amounts of honey I extracted 🙁 ) but still received a few kilograms of fondant to top them up for the long winter ahead.

As an aside, the heather honey wasn’t extracted (via the even messier crush and strain method) until late November and the water content was a very respectable 14-15%. Or perhaps my refractometer is poorly calibrated 🙁 .

At the last colony checks (late September) most colonies still had good levels of brood. The good late season weather and the heather has given them a real boost and they looked very good going into the winter.

Since then they’ve been out foraging on late season pollen. Unusually the weather was mild and dry enough for them to forage on the ivy and they were very busy through the warm first half of November.

But since then it’s all gone very quiet. Other than check the straps are secure for the inevitable winter gales, there’s now nothing to do until at least late March (or probably April).

Season’s Greetings

It was Oscar Wilde who said that ”Conversation about the weather is the last refuge of the unimaginative” so I’ll stop there 😉 .

For beekeepers in northern latitudes, it’s not quite ‘all or nothing’, but the difference between the busy summer season and the quiet of the winter is very marked. But there are still things to do.

I’ll be spending the next few weeks:

building stuff for the season ahead.
making some interesting blended honeys … both as a way to reduce the high water content of some of the honey from this season, and to eke out some of the limited amounts of heather honey I got this year.
having another (likely abortive) attempt at making palatable mead.
drinking coffee, spending time with family and friends, and doing all sorts of non-beekeeping things to keep me busy until the weather warms and it all starts again next year 🙂 .

Wherever you are, and whatever you’re doing, Season’s Greetings …

Broodless?

30 Replies

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 …

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

50 Replies

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 … 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 the ’diutinus’ 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.

Introduction

New Year’s Resolutions for beekeepers

Quit smoking

Mr Smoke-Too-Much

Reducing stress

The stressed beekeeper

Improved health

Save money

Honey, honey

Be more helpful

Donate more to charity

Lose weight

Bargain basement

Introduction

Top of the Posts

10 – Swarm prevention

9 – Queen cells … quantity and quality

8 – The nucleus method

7 – Pagden’s artificial swarm

6 – Vertical splits and making increase

5 – The ultimate hive stand? (2022)

4 – Demaree swarm control

3 – Winter covers and colony survival (2022)

2 – Mad honey

1 – Queen cells … don’t panic

What does this ‘top ten’ tell me?

Where from and where to?

Behind the scenes

Comments

Social media

Newsletter

Coffee

Praise and abuse

The Apiarist is retiring

Coming next

A new beekeeping year

Introduction

A gentle reminder

Latitude and longitude

Winter

East coast

West coast

Spring

East coast

West coast

Summer

East coast

West coast

Autumn

East coast

West coast

Season’s Greetings

Introduction

What is the opportunity?

Discard your calendar

Don’t wait until Christmas

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

How to detect the absence of brood

A quick peek

Hive debris

Open mesh floors and Correx boards

Reading the runes

Not so fast!

The cessation of brood rearing

But my bees are never broodless in the winter

This isn’t an exact science

Introduction

Bees don’t hibernate

Cedar and poly hives

Temperature anomalies

Hive covers reduce food consumption and colony mortality

(Un)acceptable losses

Hive covers

Kingspan

Two variables … and woodpeckers

Solar gain and tar paper

Winter losses

Varroa

If I’m right …

Let’s briefly revisit hive temperatures