Synopsis : Foundation is getting more expensive. Try foundationless frames; save money and reduce miticide contamination in your hives.
Introduction
While preparing some minor updates for a talk this week 1 I had cause to look up the price of foundation.
Flippin’ heck!
Foundation is one of the beekeeping basics. It’s effectively a consumable item that you periodically have to replace … or more correctly you replace the frames containing new sheets of foundation. It is recommended that brood frames are replaced every three years; this means you should expect to replace 3-4 frames per season in a National hive.
Like other basics, such as eggs and pasta, the price of foundation is rising inexorably. The last stuff I bought – premium National wired worker deep – was about £13 from Thorne’s. I bought ~15 packets and it hurt.
It’s now £15.60 a packet (for 10 sheets) 2. If it goes up much more I’ll have to trade in a kidney before visiting Brian at Thorne’s of Newburgh.
Synopsis : Getting good answers involves asking good questions. But remember that the bees have no concept of what is ‘best’, or of the calendar.
Introduction
If you’re just starting beekeeping it’s likely you will have a never-ending list of questions about the somewhat arcane and often perplexing hobby you are embarking on.
And if you’ve been beekeeping for years (or even decades) you might have the same number of questions, albeit somewhat more specialised or esoteric 1. You’ll also probably be involved in answering some of the questions from less experienced beekeepers.
Hive tools … which is the best?
Getting good quality and appropriate answers broadly depends upon three things:
who (or what) the question is directed at,
the wording of the question, and
whether the answer is simply factual or involves a subjective assessment
Let’s take a simple example …
Q. What is the scientific name of a bee? A. The scientific name for the order of bees is Hymenoptera, but this encompasses many different species of bees, not just a single type of bee. To specify a particular species, a scientific name would be necessary, for example, the scientific name for a honey bee is Apis Mellifera.
… so, let’s be more specific …
Q. What is the scientific name of a honey bee? A. The scientific name for a honey bee is Apis Mellifera.
By asking a more specific question you have received a better answer.
Unfortunately, it’s still not completely correct.
There is a convention on the capitalisation of scientific names; the name of the genus (in this case Apis) is always capitalised, but the name of the particular species (mellifera; meaning honey-bearing) should start with a lowercase letter.
The correct answer should therefore be Apis mellifera.
Or what?
You may have noticed the who (or what) in the list above. The ‘or what’ was deliberate because, increasingly these types of questions will be answered, not by humans or beekeepers 2, but by a machine.
In fact, the two questions and answers shown above were answered by a machine … in this case one called ChatGPT. In this post, ChatGPT responses are shown in red text. The only reason you may not have heard of ChatGPT 3, released just 2 months ago, was because you’ve been living as a hermit in the Tora Bora cave complex for the last few years.
If ChatGPT is new to you then you’re going to have ample opportunity to experience it – or its successors – in the next few months and years. ChatGPT is described as a chatbot which has been trained through supervised and reinforcement learning. It can do a range of things that are a lot more impressive than not quite getting the scientific name of honey bees correct … it can compose music, write computer code and pass written exams for medicine. It can produce essays and it is causing considerable concern in education, where students are already using it for homework 4.
Perhaps I’ll save myself some late night writing by asking ChatGPT to do my homework …
Write a 500 word article for beekeepers about hive tools and Taranov swarm control, remembering to include a handful of poor quality puns and some truly shocking, punctuation.
I asked it to do this … it generates the answer in less than a minute. I’ve added the answer as a separate page as I don’t want to get even more distracted from the topic of the post today.
Factual inaccuracies
ChatGPT does OK on the poor puns (beeeing, buzz-worthy etc.) but less well on the shoddy punctuation, unless you count the Oxford comma.
It does much less well on Taranov swarm control. Indeed, I had started by asking it to “Describe how to conduct swarm control using the Taranov method” and received the following answer:
The Taranov method is a technique used for swarm control in beekeeping that involves manipulating the hive to prevent swarming. The process begins by identifying a colony that is likely to swarm and removing any queen cells, which are the cells that contain developing queen bees. Next, the beekeeper will divide the colony by removing a section of comb with eggs and young larvae, and placing it in a new hive box. This creates a population imbalance in the original hive, which triggers the bees to start raising new queen bees. Finally, the beekeeper will monitor the hive to ensure that no new queen cells are forming, and will continue to remove them as they appear. This method aims to reduce the likelihood of swarming, by keeping the colony balanced and preventing the development of new queen bees.
Which is almost completely wrong. I’m not going to describe Taranov swarm control, but it’s not that. If you want to know (and it is an intriguing method, though not one I have used) I suggest you ask an experienced beekeeper, not a machine. It requires a simple, correct, factual answer.
Subjective or qualified answers
The other thing ChatGPT is not good at is answering questions that require some experience and/or may be subjective. For example …
Q. What is the best type of beehive for a beginner? A. For a beginner, the Langstroth beehive is considered the best option due to its standardized dimensions, ease of management, and wide availability of equipment and accessories. Additionally, it is commonly used by many beekeepers and has a strong community of support and resources available.
… OK, what about something even more important?
Q. What is the best type of hive tool for beekeeping? A. A J-shaped hive tool is widely considered as one of the best for beekeeping. It is versatile, durable and can be used for a variety of tasks such as prying apart beehive boxes, scraping propolis and wax, and removing frames.
The first answer actually isn’t bad, particularly if you are in the US. However, the justification is a little odd and could equally well be applied to a National, Dadant 5 or Layens hive.
The ‘best hive’-type question is one commonly asked by beginners and one where a better question improves the answer. If you instead ask ChatGPT for the best beehive for a beginner in the UK it recommends a National hive (justified by compatibility).
However, the answer ChatGPT gives to the ‘best hive tool’ question is clearly wrong.
Simply the best … no contest!
Anyone with even passing experience of opening a hive knows that the claw-type hive tool is by far and away the most practical, comfortable and good looking 😉 .
The ’widely considered’ in ChatGPT’s answer is the giveaway. It’s (obviously) never used a hive tool and so cannot speak from experience.
Flame wars
The examples above are trivial but they do show both the abilities and shortcomings of ChatGPT. But it will get better – more accurate, more factually correct, better at providing qualified subjective answers (and hiding the fact that it has no direct experience of any of the things it is comparing).
You’d better get used to it as it will revolutionise our interactions – direct or indirect – with computers; websites, discussion forums, computer programming, teaching, student assessment and – increasingly – creative work as well.
It’s going to put a lot of people out of work 🙁 .
I’m already out of work, so I don’t feel too threatened, but perhaps it’s also going to eventually replace the beekeeping blogger.
As an aside, I thought a ChatGPT-powered ‘user’ on a beekeeping discussion forum like Beesource in the US, or the BeekeepingForum here in the UK would be – at least briefly – entertaining. Some of the discussion threads on these can get really out of hand, even with strict moderation (a thankless task).
ChatGPT can already interact conversationally, its command of the subject and of English (and, of course, a range of other languages) is already better than many readers/contributors, and it would be a whole lot more persistent in an online argument (though it is currently not particularly creative when it comes to insults).
It’s going to render many of these discussion forums worthless and is already banned from some of the computing forums. The scientific journal Nature has established ground rules for its use – it cannot ‘share’ authorship (!), its use in data analysis must be documented etc.
I already find many discussion forums unrewarding … they might get a lot worse, at least in the short term. Since many beginners use them a lot, I thought it was worth mentioning.
Better answers
Although I’ve been wandering some way off topic there are some important points embedded in the first half of this post.
The question you ask influences the answer you get.
In beekeeping, your local environment and your latitude are particularly influential in the lives of your bees.
I gave a talk this evening on queen rearing. One of the questions was ‘How early in the season can I start?’
That’s a perfectly good and valid question, but answering it requires knowing something about the local climate and colony development.
It also varies from year to year … for example, a cold spring delays things.
Some might simply answer ‘mid-May’ or ‘late-April’ … indeed, questions like that may be asked by someone wanting a calendar-based answer.
Unfortunately, beekeeping isn’t that simple. Beekeepers on the UK south coast can often start queen rearing two months before I can here in north west Scotland.
My answer involved something about drone availability. A drone takes 24 days to develop and a few days after that to become sexually mature. Studies have shown that the peak of drone brood production occurs about one month before swarming (Page and Erickson, 1988), though production starts earlier.
And the correct answer is …
So a better answer is to keep an eye on your colonies, observe drone brood production increasing and – 3-4 weeks later (or perhaps a little before 6 ) – start your queen rearing with every expectation the bees will have got the timing about right.
One of many …
In a cold spring they’ll start producing drones later, at a more southerly latitude they’ll produce drones much earlier than they will in northern Scotland.
Yes, the answer is more difficult to understand than ‘the 19th of April’, but it’s much more likely to be correct because it is based on an understanding of the biology of the bees.
It’s also likely to be correct most years. You can test this by keeping notes. You’ll then have something to refer back to next year and the one after that, and you’ll be able to answer, with compelling authority, anyone who asks you the same question 😉 .
In about 30 years you’ll be able to review your notes – of drone production and queen rearing successes – and see whether the timing needs revising 🙂 .
In doing that you’ll have completed the transition from seeking a calendar-based response, to understanding the drivers that determine colony development and reproduction, and end up with an answer that is generically applicable, qualified and based upon personal experience.
Expect biased answers
My preference for a particular type of hive tool is based upon personal experience (and unrelated to the fact that I bought 20 of them very cheaply a decade ago). Do not underestimate the importance of personal experience in answering beekeeping questions … or its ability to generate biased, unqualified or even completely incorrect answers.
Ask three experienced beekeepers a question and you’ll get five answers … one will be completely wrong, another will involve ‘brood and a half’ (also wrong … obviously), a third will answer a different question altogether and the final two will express diametrically opposing views about whether the J-shaped or claw-shaped hive tool is ‘best’.
The answer you get is based upon the experience of whoever you ask … and how willing they are to answer.
Be warned, it’s not unusual for the most (usefully) experienced and the most vociferous beekeepers to be different individuals. In fact, it’s not unusual for the most vociferous to be much less experienced than they sound.
For a subject as practical as beekeeping, practical experience is far, far more valuable than ‘knowledge’ gleaned from the internet (after all, you might have been reading something written by ChatGPT).
I know the difference between the Miller and Hopkins methods for queen rearing. I’ve not used either (yet) so I don’t know which is better – either outright, or in particular circumstances.
This can all be a bit overwhelming as a beginner … use your judgement, listen, check some of the answers in a good book 7 or a reputable online source, ask a follow-up question.
Nobody knows all the answers and it sometimes feels as though the more knowledge you acquire, the more questions appear.
Answer your own questions; observation and understanding
There is no ‘best’ hive, or 8 hive tool. The bees don’t care and – through experience – you’ll find what suits your beekeeping.
It’s likely that the ‘best’ anything in beekeeping – bee, hive tool, hive, smoker, forage, honey, hive stand, extractor, queen excluder etc. – is a meaningless concept.
It’s an irrelevant question as far as bees are concerned. There may be good ones and bad ones, but it’s surprising how tolerant and accommodating the bees – and a beekeeper – can be.
I’d strongly recommend that anyone starting beekeeping ignores articles with the word ‘best’ in them – except perhaps this one.
Ask meaningful questions and look for insightful answers.
The ‘when to start queen rearing?’ is a good – albeit incomplete – question and I suggested how I would (or did) answer it above.
In that example it is really by observing and understanding the bees that you answer the question. I think those are two of the most important skills to acquire as a beekeeper; doing so will always help you get better answers, not least because they help answer them yourself.
Asking an experienced beekeeper gets you part way there but it doesn’t come close to working something out yourself.
Do an experiment
I used the word ‘arcane’ in one of the opening sentences. It means mysterious, obscure or little understood. Despite sounding a little like the word archaic – meaning old fashioned or belonging to an earlier period – it has a totally different etymology. Arcane is derived from the Latin arcānus meaning ‘closed or shut up’, whereas archaic is from the Greek ἀρχαϊκός for ‘ancient’.
Nevertheless, bits of beekeeping are both arcane and archaic.
Sometimes they’re ‘old fashioned’ because experience has shown that a particular method works reliably well, so is promoted and becomes widely used. However, sometimes it’s because ”it’s always been done like that” and everyone unquestioningly follows the approach without asking whether there are other – perhaps better – ways of achieving something.
A foundationless frame is a frame containing no foundation (helpfully, the clue is in the name) . Every foundationless frame you use saves you about £1.40 based upon the current price of foundation. What’s more, because commercial foundation contains miticide residues, every frame you use reduces traces of miticides in your hive.
And, if you read online about making foundationless frames you’ll find lots of descriptions, many of which include instructions to provide a wax, or waxed, starter strip attached under the top bar for the bees to start drawing comb from.
When I started using foundationless frames I – unquestioningly – followed these instructions, cutting 2 cm strips of commercial foundation and nailing them in place in my frames.
Foundationless frame
And they often fell out … which prompted me to ask a question I should have done in the first place, and to do an experiment.
Ask the bees
Where do bees naturally start drawing comb?
Wherever the swarm ends up. If it’s in a previously unoccupied tree hole, or loft space, there are no convenient strips of wax foundation to be used as guides. The cavity may be completely empty.
Clearly they don’t need a starter strip to work from.
However, the beekeeper does not want the bees to build comb totally haphazardly. We want them to stick within the confines of the frame or it becomes impossible to manipulate. It’s therefore useful to provide them with ‘guides’ on where to start … they might not follow them, but they almost always do.
So, by understanding what the bees do naturally, qualified by our own selfish interests in managing the colony, we can ask the bees what suits them … a strip of wax foundation, a waxed wooden guide or a lollipop stick.
And, having worked out which the bees prefer, we can make a decision based upon what also suits us.
Take your pick …
I therefore did a simple experiment. I built a dozen or so foundationless frames, each containing three randomly positioned starter strips under the top bar – one third wax foundation, one third waxed wood and one third plain wooden lollipop stick (or ‘tongue depressors’).
Over the course of a season I used these in a variety of colonies and observed which of the starter strips was preferred … indicated by which the bees chose first, or which they avoided.
And the results are in …
It made no difference at all. There was no correlation between the type of starter strip and use by the bees.
They just don’t care.
So I only now use plain wooden starter strips. They are quicker and easier to prepare, impervious to the steam wax extractor and much more robust. I use them in full hives and in my mini-nucs for queen mating, simply gluing the wood in place.
Kieler mini-nuc topbar frames – no need for foundation or waxing
A little understanding of what the bees do, coupled with a little experimentation and some observation, allowed me work out the answer to the question ’What is the best material for starter strips’9.
I should note that many other have reached exactly the same conclusion independently. I’m not claiming to have discovered this first, but I did formally test what the bees preferred.
Some ChatGPT creativity to end with
To finish I thought I’d ask ChatGPT to do something creative.
Rather than eliciting incorrect answers about Taranov swarm control I asked it for a poem, in the form of a haiku 10, about honey bee swarms;
Golden bees swarm forth Honeyed scent on the breeze Nature’s sweet bounty.
Not bad 🙂
References
Page, R.E., and E. H. Erickson, Jr. (1988) Reproduction by Worker Honey Bees (Apis mellifera L.). Behavioral Ecology and Sociobiology 23: 117–126 https://www.jstor.org/stable/4600197. Accessed February 3, 2023. Note: this might not be accessible online, so you could try this instead – Page, R.E. Jr (1982) The seasonal occurrence of honey bee swarms in north-central California. American Bee Journal 121:266-272.
Synopsis : Queen rearing is enjoyable and educational. Don’t let the experts put you off. You don’t need to graft day-old larvae to rear queens.
Introduction
A long time ago 1 I bought, read and re-read Ted Hooper’s excellent book Guide to Bees and Honey. Every time I read it I’d find something I’d missed the last time and, even now, there are nuanced comments I think I am only now beginning to understand.
I’m exaggerating slightly when I say ’read and re-read’ as there was one chapter I pretty-much skipped over each time.
That was the chapter on queen rearing.
What put me off?
It was probably his description of opening queen cells with the tip of a penknife to check how far development had progressed, re-sealing the cell and returning the frame to the hive.
She’s gone …
I knew enough about bees to know that the future success of the hive depended upon it successfully requeening after swarming.
But I didn’t know enough to stop them swarming 😉 .
I’d also already had to ‘borrow’ a frame of cells from a friend to rescue a terminally queenless colony of mine. ’Enthusiastically clumsy’ defined my beekeeping skillset, and was probably the comment the 2 examiner made in his notes during my BBKA Basic assessment.
The prospect of meddling with developing queens, with something so precious, seemed like total madness.
Surely it’s better to let them get on with it?
For the first couple of years of beekeeping, I thought of queens as an exquisitely fragile – and by implication valuable – resource. The prospect of rearing them, handling them, putting them in little boxes or – surely not? – prising a cell open to see if they’d developed sufficiently, was an anathema to me.
Consequently, I repeatedly skipped the chapter on queen rearing.
Too difficult … not for me … nope, not interested.
The BBKA Annual Convention
Before they moved the event to Harper Adams, the BBKA used to hold its spring convention at the Royal Agricultural showground just outside Warwick. My (then) local association provided stewards for the event and I was asked – or volunteered – to help the late Terry Clare run the queen rearing course one year.
I’d never done any queen rearing … and still hadn’t completely read that chapter in Hooper’s book.
I’d like to take this opportunity to apologise to those who paid to attend the course … at least those who received any ‘help’ from me, though everything else about the course was very good.
Checking grafted larvae
After an introductory lecture from Terry, we spent a warm afternoon in a poorly lit room practising grafting larvae. A thin cloud of disorientated bees circled our heads before being ushered out through the windows. Most of the larvae on the frames were visible from across the room 3 but at least they didn’t turn to mush with our neophyte fumblings as we transferred them from comb to plastic queen cups.
Terry moved from table to table, checking progress. He explained things well. Very well. The preparation and procedures seemed a whole lot more accessible than they had in Hooper’s book.
I’m a reasonably quick learner and that afternoon convinced me I should, and could, at least try it on my own.
The session ended with a wrap-up lecture in which Terry encouraged us all to ‘have a go’, and not be put off by an initial lack of success.
He assured us it would be worthwhile and enjoyable.
We dispersed into the late afternoon sun, talking of bees and queens and our plans for the season ahead.
Balmy April weather
There was an early spring that year, colonies had overwintered well and were strong. The Convention was held in early April if I remember and the good weather continued for at least another 2-3 weeks.
Well before the end of the month I had my first successfully grafted larvae being reared as queens.
Success!
It wasn’t an overwhelming success.
I probably grafted a dozen, got half accepted, lost more during development 4 and ended with just two virgins. I don’t have notes from those days, but I’m pretty sure only one got successfully mated.
So, success in a very limited way, but still success 🙂 .
It still makes me smile.
Terry’s presentation had clarified the mechanics of the process. It no longer seemed like witchcraft. It was all very logical. He’d made it clear that the little specialised equipment needed was either ’as cheap as chips’5 or could easily be built at home by someone as cack-handed as I was am 6.
The practical session had given me confidence I could see and manipulate huge fat larvae that were far too old to be reared as queens larvae. Even with my ’hands like feet’ moving a delicate larva from comb to plastic queen cup seemed possible, if not entirely natural.
JzBz plastic queen cups
I scrounged some JzBz cups from someone/somewhere, built a cell bar frame and some fat dummies7 the week after the Convention and used one of my colonies as a cell raiser and the other as the source of larvae.
And, at a first approximation, everything sort of worked.
I could rear queens from larvae I had selected 🙂 .
Try, try and try again
I repeated it again the following month. I was more successful. The nucs I produced were either overwintered or built up strongly enough to be moved into full hives.
I think one went to my mentee. My association encouraged relative newcomers to mentor, probably one of the best ways to improve your beekeeping (other than queen rearing).
Within a year I had 6-8 colonies or nucs and twice than number the year after that.
Almost all were headed by queens I had reared … ‘almost’ as my swarm control skills were still developing 😉 .
Now, over a decade later, my swarm control skills have improved considerably … as has my queen rearing.
I remain resolutely cack-handed but I’m now a lot more confident in my hamfistedness.
I still mainly use the same technique Terry Clare taught on that course in Stoneleigh, though I’ve now also used a number of other approaches and successfully reared queens using most of them. Even the cell bar frame I built is still in use, though I’ve built some fancier fat dummies.
Fat dummy … with integral feeder and insulation
Queen rearing has taught me more about keeping bees than any other aspect of the hobby … more about judging the state of the colony, the quality of the bees, the suitability of the environment, the weather, the forage etc.
Queen rearing has improved the quality of my bees, year upon year, so that they suit my environment and colony management.
But – more importantly and perhaps a little selfishly – queen rearing has given me more enjoyment than any other aspect of beekeeping.
I’d prefer to rear queens than get a bumper honey crop … but because I rear queens that suit me and the environment, I do pretty well for honey as well.
10%
I give 20-30 talks a season to beekeeping associations. When I’m talking about queen rearing I usually ask the organisers about the number in their association that actively rear queens.
By actively I mean that do more than simply allow colonies to requeen themselves during swarm control. Don’t get me wrong, I’m not denigrating this essential aspect of beekeeping. We all (have to) do it.
To me ‘active’ queen rearing doesn’t necessarily mean grafting larvae, incubators, mini-nucs and all that palaver. But it does mean:
preparing a colony to be in a suitable state to rear new queens 8.
rearing queens from larvae selected (though not necessarily individually selected) from a colony with desirable characteristics e.g. good temper, productivity, frugality.
rearing more than one queen at a time, with the excess used for making increase, for sale, for ’just in case’ situations etc.
There’s perhaps a slightly grey area where you split a hive (with desirable characteristics) that’s making swarm preparations into multiple nucs, each of which gets an immature queen cell.
But, let’s not get bogged down in definitions … that’s not the point of this post (which, although it might not be obvious yet, is to encourage you to ’have a go’).
And, when I ask 9, I’m regularly told that only a small number, perhaps ~10%, of association members actively rear queens.
Why so few?
Enjoyable, educational, useful … choose any three
Of course, there’s no requirement that a beekeeper gets involved in queen rearing. You can keep bees for years without rearing queens, other than during swarm control and by making up splits. I know a few beekeepers who have been keeping bees like this for decades … by many criteria they are skilled and successful beekeepers.
But sometimes, which might mean ‘often’, being able to rear queens and having some of those ‘spare’ queens available is extremely useful.
Spare queens, heading nucs in the apiary, can be overwintered to make up losses. These can be sold or donated in Spring to meet the enormous10 demand for bees early in the season. The availability of a queen can ‘fix’ an aggressive colony, can rescue an otherwise doomed colony, or can effectively ‘gain’ a month of brood rearing and nectar collection should the old queen fail.
And that extra month of brood might make the difference between successful overwintering or not.
In my view, once you can rear your own queens you are pretty-much self-sufficient … there are very few situations that cannot be rescued.
And all of those benefits are before you even consider the two other things I mentioned above:
that successful queen rearing will inevitably improve your more general skills as a beekeeper, and
you will get a lot of satisfaction and enjoyment from doing it … literally ’the most fun you can have in a beesuit’11.
Why so few?
Beekeeping, like many other hobbies, can appear an esoteric pastime. Weird terminology, hierarchical organisation 12, specialised equipment, unusual costumes and a tendency to still use arcane practises.
And queen rearing – probably like candle making or the production of excellent mead 13 – is a specialised niche within what is already a rather niche activity.
It has its own terminology, equipment and methods.
To the uninitiated – even to another beekeeper, like me reading Ted Hooper’s book – it can appear fiendishly difficult.
And, unfortunately, some practitioners make it sound esoteric, specialised and difficult.
It’s a sort of one-upmanship.
They promote methods that may not suit the beginner, that require lots of resources, or that involve techniques that sound exceptionally skilful, even when they’re not. Not deliberately perhaps, but that’s what happens.
All of which means that:
people are dissuaded from trying it in the first place
those that do try (with trepidation because, you know, ”it’s difficult”) and that achieve only limited success, have their initial impression reinforced and are unlikely to try again
It’s very easy to talk yourself out of trying something you think will be difficult and/or you are unlikely to succeed at.
Actually, it’s not only easy, it’s also entirely understandable.
Why go to all that trouble if it’s unlikely to work?
After all, you can usually buy queens ‘next day delivery’ for £50 … surely that would be easier?
Perhaps … if they’re available when you want them. Really early in the season? Think again. During the peak swarming season when everyone else wants to requeen their colonies they accidentally destroyed all the queen cells in. Nope.
But, as Terry Clare so ably instructed … it is not that difficult to rear your own.
There’s more than one way to do it
I’ve written an entire post on this topic and it applies as much to queen rearing as it does to other aspects of our hobby.
If not more.
There are many different ways of successfully achieving the three key components of the process:
preparing the colony to receive larvae
presenting the larvae
getting the resulting virgin queens mated
Today’s post isn’t an introduction to queen rearing … it’s meant instead as an encouragment to try queen rearing.
If you’ve got a year or two of beekeeping experience and one, or preferably two, colonies you have the essentials you need to start. It’s what I started with … and look how that ended 😉 .
Over the next three months I’ll write two or three more posts on the basics, in good time for you to ’have a go’ in 2023.
Preliminary setup for Ben Harden queen rearing
If you’re impatient to read more, I’ve already written about two methods I have used extensively – the Ben Harden system and queen rearing with a Cloake board.
However, throughout these descriptions I’ve emphasised the use of individualgrafted larvae.
Grafting is the transfer of larvae from the comb where the egg hatched to a wax or plastic queen queen cup. For best results the larvae should no more than ~18 hours old.
A suitable larva may well be no bigger than the egg it hatched from.
Already I can feel beginners switching off … “Too difficult … not for me … nope, not interested.”
Although grafting is an easily learned and reasonably straightforward technique it can appear very daunting to the beginner.
Perhaps I’m therefore also guilty of making queen rearing sound ‘esoteric, specialised and difficult’.
Am I guilty as well?
Indubitably, m’lud.
But … in my defence please consider the two recent posts on ’Picking winners’.
The purpose of those posts was to highlight – for people (like me) that already routinely use grafting as part of their queen rearing – that the bees may choose different larvae to rear as queens than the beekeeper might choose.
The beekeeper is essentially non-selective, whereas the bees are very selective.
I think this is interesting and it’s got me wondering about the qualities the bees select and whether they’d be beneficial for my beekeeping.
But there’s another equally important ‘take home message’ from these two posts. This is relevant to beekeepers who do not already rear queens (but who would like to) but that are put off by the thought of grafting.
And that is that you can easily produce excellent quality queen cells without grafting or ‘handling’ larvae at all.
If you refer back to that three point list above, point 2 ( ‘presenting the larvae’) can be as straightforward as simply adding a frame of eggs and larvae to a suitably prepared hive.
That’s it.
What could be easier?
No magnifying glasses, no headtorch, no treble ‘0’ sable paintbrush, no JzBz plastic cups, no cell bar frame, no ’do I or don’t I prime the cups with royal jelly?’, no desperate searching around the frame for larvae of the right size, no worries about larvae getting chilled, or drying out …
Pick a frame, any frame
As long as it has eggs and young larvae … and comes from a donor colony that has the characteristics you like in your bees.
Eggs and young larvae
There’s little point in rearing queens from poor quality bees.
For starters I’d suggest you select a frame from a colony of calm, well behaved bees.
If none of your colonies are dependably calm and well behaved you definitely need to learn to rear queens, but you should ask a friend or mentor 14 for a frame of eggs and larvae from a good colony.
Bees are very good at picking larvae suitable for rearing into queens. Let them do the ‘heavy lifting’. Once the queen cells are ready you cut them out of the frame and use them in the same way as you would use cells from grafted larvae.
So, having hopefully convinced you that you don’t need to graft larvae to produce queen cells, that seems like a logical place to end this post.
In future posts I’ll discuss points 1 and 3 in that numbered list above.
You already know almost everything you now need to know about point 2 😉 .
Synopsis : Does repeated oxalic acid vaporisation of colonies rearing brood work sufficiently well? Is it as useful a strategy as many beekeepers claim?
Introduction
Oxalic acid is a simple chemical. A dicarboxylic acid that forms a white crystalline solid which dissolves readily in water to form a colourless solution. It was originally extracted from wood-sorrels, plants of the genus Oxalis, hence the name. In addition to the wood-sorrels it is present in a wide range of other plants including rhubarb leaves (0.5% oxalic acid 1 ), the berries and sap of Virginia creeper and some fruits, such as starfruit. Additionally, fungi excrete oxalic acid to increase the availability of soil nutrients.
Oxalic acid is inexpensive to produce by a variety of processes and was possibly the first synthesised natural product. About 120,000 tonnes are produced annually and it is mainly used for bleaching wood (and often sold as ‘wood bleach’) and cleaning products – including teeth. It chelates iron and so is used for rust removal and is used as a dye fixative (or mordant 2 ).
Oxalic acid and API-Bioxal … the same but different
It is also, when used properly, devastatingly effective against the ectoparasitic mite Varroa destructor.
And, even more importantly, when used properly it is extremely well-tolerated by honey bees.
Great!
Not so fast …
Unfortunately for beekeepers, some of the commercially available i.e. licensed and approved, oxalic acid-containing treatments either contain unnecessary additives and/or have limitations in their approved modes of administration that reduces their efficiency and use in real world beekeeping situations.
Oxalic acid-containing miticides and their use
A quick search of the UK’s 3 Veterinary Medicines Directorate snappily titled Product Information Database for ‘target species = bees’ and ‘active ingredient = oxalic acid’ yields three products :
Varromed (BeeVital GmbH) which is a solution containing formic acid and oxalic acid
Oxybee (DANY Bienenwohl GmbH) which is an oxalic acid solution PLUS a separate powder containing essential oils and sugar. As far as I can tell, Oxybee looks to be the same product as Dany’s BienenWohl powder and solution, which – although listed and licensed – I cannot find for sale 4 in the UK
API-Bioxal (Chemicals Laif S.P.A) which is purchased as a powder composed of 88% oxalic acid dihydrate together with silica and glucose
I’m going to largely ignore Varromed and Oxybee for the rest of this post. I’m sure they’re perfectly good products but I’ve not used either of them so cannot comment from personal experience.
Keeping your powder dry
More relevant to this post, Oxybee and Varromed are both liquids, and this post is about vaporising (aka sublimating) oxalic acid.
And vaporisation involves using the powdered form of oxalic acid.
Which neatly brings me to the methods of application of oxalic acid-containing treatments to kill mites.
I’m sure there are some weird and wonderful ones, but I’ll be limiting any comments to just three which – from my reading of the instructions – are the only ones approved (and then not for all of the products listed above) : 5
Spraying a solution onto the surface of the bee-covered frames
Dribbling or trickling a solution onto each seam of bees between the frames
Vaporisation or sublimation of powdered oxalic acid by heating it in a metal pan to convert it to a gas. This permeates the hive, settling on all the surfaces – woodwork, comb, bees – and remains active against mites for a period after administration
Broodless is best
Oxalic acid, however it is administered, does not penetrate brood cappings. Therefore all of the approved products are recommended for use when the colony is broodless.
Typically – though not exclusively – this happens in the winter, but the beekeeper can engineer it at other times of the season.
If the colony is broodless you can expect any oxalic acid-containing miticide to reduce the mite population by 90% or more. There are numerous studies that support this level of efficacy and it’s what you should be aiming for to give the colony the best start to the season.
I discussed at length how to determine whether a winter colony is broodless a fortnight ago in Broodless?
This post is a more extensive response to several comments (made to that Broodless? article) that recommended repeated vaporisation of oxalic acid at, either 4, 5 or 7 day intervals.
The idea is that this kills the phoretic mites present when the colony is first treated and the mites subsequently released as brood emerges.
How many repeats?
I’ve seen anything from two to seven recommended online.
I’ll discuss this further below, but I’d note that the very fact that there’s such variation in the recommended repeat treatments – perhaps anything from two, fours days apart to seven at weekly intervals (i.e. spanning anything from 8 days to 49 days) – suggests to me that we don’t know the optimal treatment schedule.
Which is a little weird as, a) Varroa is a globally-distributed problem for beekeepers and is more or less invariant (as is the brood cycle of the host honey bee), and b) repeated treatment regimes have been used for over 20 years.
Which brings me back to a crude comparison of vaporisation vs dribbling, or …
Sublimation vs. trickling
A hive can be sublimated with oxalic acid without opening the hive. The vaporiser alone is introduced through the hive entrance or – in the case of certain models – the vapour is squirted through a hole in the floor, brood box or eke. In contrast, trickling oxalic acid requires the removal of the crownboard.
In the video above I’m using a Sublimox vaporiser. The hive entrance is sealed with foam and the open mesh floor is covered with a tightly fitting slide-in tray. As you can see, very little vapour escapes.
Although oxalic acid is well tolerated by bees, and it has no effect upon sealed brood, a solution of oxalic acid is detrimental to open brood. Therefore, trickled oxalic acid weakens the colony – because the acidity kills some or all of the open brood – and repeated trickling of oxalic acid is likely to compound this (see Al Toufailia et al., 2015). In contrast, repeated oxalic acid vaporisations appear not to be detrimental to the colony (caveat … I’m not aware of any long-term studies of this, or for the impact on the queen).
API-Bioxal approved methods of administration
The instructions for API-Bioxal clearly state that only a single treatment by vaporisation is approved per year. The exact wording is:
Maximal dose 2.3g per hive as a single administration. One treatment per year.
In contrast, when used as a solution for trickling the instructions state:
Up to two treatments per year (winter and/or spring-summer season in brood-free colonies).
This seems nonsensical to me considering what we now know about oxalic acid – remember, API-Bioxal was licensed in the same year (2015) that Al Toufailia et al., demonstrated it was detrimental to open brood, and I’m reasonably sure this had been shown previously (but can’t currently find the reference).
But, it gets worse …
API-Bioxal contains oxalic acid with powdered silica and glucose. I presume the silica is to keep it free-running. I’m not aware that powdered silica kills mites and I’m damned certain that glucose has no miticidal activity 😉 .
Neither of these two additives – which I’ve previously called cutting agents – are there to increase the activity of the oxalic acid … and the presence of the glucose is a real problem when vaporising.
Caramel coated Sublimox vaporiser pan
When glucose is heated to 160°-230°C it caramelises (actually, this happens at 150°C 6 ), coating the inside of the vaporising pan. This needs to be cleaned out afterwards 7. The instructions state:
Cool down and clean the vaporizer after use to remove possible residue (max 6%, around 0.140 g).
However, I don’t want to focus on what I consider to be a very effective but decidedly sub-optimal product … instead I want to discuss whether repeat treatment with oxalic acid actually works when there is brood present.
Why is repeat treatment recommended?
Remember, it’s not recommended or approved by the manufacturers of API-Bioxal or the Veterinary Medicines Directorate. I really should have titled this section ’Why is repeat treatment recommended by those who advocate it?’
But that wouldn’t fit on a single line 😉 .
When you sublimate oxalic acid, the gas cools and the oxalic acid crystals settle out on every surface within the hive – the walls, the frames, the comb, the bees etc.. For this reason, I prefer to vaporise oxalic acid when the colony is not tightly clustered. I want everything to be coated with oxalic acid, and I particularly want every bee to be coated because that’s where most of the mites are.
Unless they’re in capped cells 🙁 .
And if they’re in capped cells, the only way the Varroa (released when the brood emerges) will come into contact with oxalic acid is if it remains present and active within the hive. Unfortunately, it’s unclear to me exactly how long the oxalic acid does remain active, or what accounts for a drop in its activity.
But it does drop.
If you treat a colony with brood present and count the mites that appear on the Varroa tray every day it looks something like this:
Mite drop per day before and after treatment
’Something like’ because it depends upon the phoretic mite levels and the amount and rate of brood uncapping. For example, you often see higher mite drops from 24-48 hours than 0-24 hours after treatment.
I know not why.
The drop in the first 48 hours – presumably almost all phoretic mites – can be very much higher than the drop from day three onwards 8.
The duration of activity after vaporisation
Some studies claim oxalic acid remains active for 2-3 weeks after administration. I’m a little sceptical that it’s effective for that long and my own rather crude observations of post-treatment mite drop (of brooding colonies) suggests it returns to background levels within 5-7 days.
I could rabbit on about this for paragraphs as I’ve given it a reasonable amount of thought, but fortunately the late Pete Little did the experiment and showed that:
The recommended dose for colonies with brood is three or four doses seven days apart, however I found out that this is not effective enough, and treated 7, 6, 5 4, 3, 2 days apart to find out the most effective which is 5.
It therefore makes sense that three treatments at five day intervals should be sufficient. This period comfortably covers a complete capped brood cycle (assuming there is no drone brood in the colony) which is 12 days long.
If there is drone brood present you would theoretically need four treatments at 5 day intervals to be sure of covering the 15 day capped brood cycle of drones.
But it turns out there are some additional complications to consider.
Dosage
In the UK the recommended i.e. approved, maximum dose of API-Bioxal is 2.3 g by vaporisation. Remember my comments about the other rubbish stuff API-Bioxal contains, 2.3 g of API-Bioxal actually contains a fraction over 2 g of oxalic acid dihydrate.
This is the active ingredient.
When comparing different experiments where some have used ‘plain’ oxalic acid dihydrate and others have used – or will use – API-Bioxal, it’s important to consider the amount of the active ingredient only 9 .
In the US, oxalic acid was registered as an approved treatment for Varroa in 2015. By vaporisation, the approved dosage is 1 g of oxalic acid dihydrate per brood box i.e. half that approved in the UK.
Remember also that a deep Langstroth is 5% larger (by volume) than a National brood box.
And Jennifer Berry and colleagues in the University of Georgia have recently determined whether repeated administration of vaporised oxalic acid to a colony rearing brood is an effective way of controlling and reducing Varroa infestations (Berry et al., 2021).
And the answer is … decidedly underwhelming
Here are the experimental details.
The paper doesn’t state 10when the experiment was done but they measured honey production in the treated colonies and were definitely brood rearing, so I’m assuming late summer.
Colonies were treated with 1 g / box (double Langstroth deeps) vaporised oxalic acid every five days for a total of 35 days i.e. 7 applications. Mite infestation levels (percent of workers carrying phoretic mites) were measured before and after treatment. Almost 100 colonies were used in the experiment, in three apiaries, randomly split into treated and control groups.
Let’s get the easy bit out of the way first … there was no difference in brood levels, adult bees or food stores at the end of the study. The treated hives were not disadvantaged by being treated … but they didn’t gain an advantage either 🙁 .
Mite levels after treatment normalised to pre-treatment levels (dotted line = no change)
During the experiment the percent mite infestation (PMI) levels in the untreated control colonies increased (as expected) by ~4.4. This is an average and there was quite a bit of variation, but it means that an initial mite infestation level of 4 (average) increased to 8.4 i.e. over 8 mites on every 100 adult workers in the hive.
3% is often considered the cutoff above which treatment is necessary.
Overall, the PMI of treated colonies reduced over the duration of the experiment … but only by 0.7.
From a colony health perspective this is a meaningless reduction.
Seven treatments with the recommended (in the US) dose of oxalic acid stopped the mite levels increasing, but did not reduce them.
Repeated administration of the US-approved oxalic acid dose by vaporisation does not reduce mite levels in a way that seems likely to significantly benefit the colony.
🙁
Dosage, again
I’m not sure the primary data used to justify the US approved 1 g / box dosage. Early studies by Thomas Radetzki (PDF) showed a 95% reduction in mite levels using a dose of 1.4 g. This was a large study involving ~1500 colonies and a dose of 2.8 g was not significantly more effective. I’m quoting the figures for broodless colonies 11.
The Berry results were similar to two smaller previous studies by Jamie Ellis and colleagues (Jack et al., 2020, 2021) who demonstrated that 1 g oxalic acid vaporised three times at weekly intervals was ineffective in controlling mite levels.
However Jack et al., (2021) also applied a similar treatment schedule using different doses of oxalic acid.
Data from Jack et al., 2021 using different repeat doses of oxalic acid
Ignore the intermediate values in panel A, just look at the pretreatment and ‘3 weeks’ mite infestation values.
Mite levels increased in untreated controls and decreased in all treated colonies. However, there was a clear dose response where the more oxalic acid used the greater the impact on the mite levels.
Four grams of oxalic acid reduced the mite infestation rate significantly … from ~5% to ~2% (I’ll return to this). However, the intermediate levels of oxalic acid, whilst reducing mite levels, did not do so significantly from the next closest amount of oxalic acid. For example, 1 g wasn’t significantly more effective than no treatment (as already stated), 2 g was not significantly more effective than 1 g and 4 g was not significantly more effective than 2 g.
But wait … there’s more
I’m familiar with two other studies that look at dose and/or repetition and efficacy (there are more, but this isn’t meant to be an exhaustive review, more a ”Do we know enough?” overview).
Gregoric et al., (2016) published a 12 study that appeared to use combinations of treatments in multiple apiaries. The abstract claims 97% reduction using three 1 g vaporisations, though these are spread over a 57 day period (!) stretching from mid-August to late-November. Mite drop in November following treatment was ~75% (presumably broodless) , but only 10-20% in August. Interestingly I can’t find the figure 97% anywhere in the results …
Finally, Al Toufailia et al., (2015) investigated the dose response to vaporised oxalic acid, showing an 80% reduction in infestation at 0.56 g and 93-98% who using 1.125, 2.25 and 4 g of oxalic acid. All of these studies were determined using broodless colonies.
The Al Toufailia and Jack studies – as well as the Berry study – also reported on adverse effects on the colony. With certain exceptions vaporisation was well tolerated. Some colonies went queenless. Where the queen was caged in late summer to render it broodless (Jack et al.,) some colonies subsequently failed to overwinter successfully (though, look on the bright side, mite levels were reduced 😉 ).
Don’t do that at home … I presume they impacted the production of winter bees.
confused.com
I’m not sure there’s a compelling, peer-reviewed study that definitively shows that repeat treatments of vaporised oxalic acid administered to a brood rearing colony reduces mite levels sufficiently.
Yes, the Jack et al., (2020) showed a significant reduction in the infestation rate (using 4 g three times at seven day intervals), but it was still around 2%.
In late summer, with 20-30,000 bees in the box and 6 frames of brood, that’s still ~600 mites (and potentially more in the capped brood).
In midwinter with about 10,000 workers and much smaller amounts of brood in the hive a 2% infestation rate is still 200 mites.
That’s still a lot of mites for a nearly broodless colony … I treat my colonies when broodless (and assume I’m killing ~90% of the mites present) and am disappointed if there are 45 mites on the Varroa tray. 50 mites on 10,000 workers is an infestation rate of 0.5%.
I’ve waffled on for too long.
All those advocating – or using – repeated oxalic acid vaporisation on brood rearing colonies in late autumn/winter need to think about:
dosage … 1 g is clearly too little (at a 5-7 day interval, but what if it was at a 4 day interval?), 2 g is better and 4 g is well-tolerated and certainly more effective
frequency … which I suspect is related to dosage. The goal must be to repeat sufficiently frequently that there is never a period when oxalic acid levels fall below a certain amount (and I don’t know what that amount is). 1 g on a daily basis might work well … who knows?
duration … you must cover a full capped brood cycle with the repeats
adverse effects … inevitable, but can be minimised with a rational treatment schedule
Broodless is best
It really is.
But, if your colonies are never broodless 13 then I wouldn’t be confident that repeat treatment was controlling Varroa levels sufficiently.
I have treated repeatedly with oxalic acid. In the good old days before API-Bioxal appeared. It certainly reduced Varroa levels, but not as well as my chosen Apivar does these days.
Repeated oxalic acid vaporisation is regularly proposed as the solution to Varroa but I’m certainly not confident that the data is there to support this claim.
Take care out there 😉
Notes
In a future post I’ll revisit this … I’ve got a pretty clear idea of how I’d go about demonstrating whether repeated oxalic acid treatments are effective in meaningfully reducing mite levels i.e. sufficient to protect the colony overwinter and through to the following late summer.
References
Al Toufailia, H., Scandian, L. and Ratnieks, F.L.W. (2015) ‘Towards integrated control of varroa: 2) comparing application methods and doses of oxalic acid on the mortality of phoretic Varroa destructor mites and their honey bee hosts’, Journal of Apicultural Research, 54(2), pp. 108–120. Available at: https://doi.org/10.1080/00218839.2015.1106777.
Berry, J.A. et al. (2022) ‘Assessing Repeated Oxalic Acid Vaporization in Honey Bee (Hymenoptera: Apidae) Colonies for Control of the Ectoparasitic Mite Varroa destructor’, Journal of Insect Science, 22(1), p. 15. Available at: https://doi.org/10.1093/jisesa/ieab089.
Gregorc, A. et al. (2016) ‘Integrated varroa control in honey bee (Apis mellifera carnica) colonies with or without brood’, Journal of Apicultural Research, 55(3), pp. 253–258. Available at: https://doi.org/10.1080/00218839.2016.1222700.
Jack, C.J., van Santen, E. and Ellis, J.D. (2020) ‘Evaluating the Efficacy of Oxalic Acid Vaporization and Brood Interruption in Controlling the Honey Bee Pest Varroa destructor (Acari: Varroidae)’, Journal of Economic Entomology, 113(2), pp. 582–588. Available at: https://doi.org/10.1093/jee/toz358.
Jack, C.J., van Santen, E. and Ellis, J.D. (2021) ‘Determining the dose of oxalic acid applied via vaporization needed for the control of the honey bee (Apis mellifera) pest Varroa destructor’, Journal of Apicultural Research, 60(3), pp. 414–420. Available at: https://doi.org/10.1080/00218839.2021.1877447.
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.
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 …
