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Mini-nucs: tips and tricks

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

Introduction

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

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

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

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

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

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

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

Painting and decorating

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

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

Hammerite Oxford blue, since you asked

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

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

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

Entrances and exits

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

But I will 😉

Entrance discs for mini-nucs

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

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

Crownboards

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

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

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

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

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

Feeder mods

The Kieler integral feeder has some good and bad points.

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

You win some, you lose some!

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

Feeder with queen excluder

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

Be thankful for small victories … 😉

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

Kieler frame feeders

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

Frames

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

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

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

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

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

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

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

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

Judging queen quality

You can’t … or at least I can’t.

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

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

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

Brood frame with a good laying pattern

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

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

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

Queen introduction

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

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

Checking for aggression

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

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

Rear some spares

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

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

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

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

Queen rearing diary; automagically populates days and events

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

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

Keeping things going

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

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

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

Mainly good organisation.

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

Scrub ‘caretaker’ queens

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

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

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

The end of the queen rearing season

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

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

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

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

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

Using mini-nuc brood frames

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

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

Overwintering mini-nucs

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

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

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

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

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

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

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

Gimme shelter

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

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

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

Tunnel entrances to overwintered mini-nucs

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

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

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

Finally

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

References

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

Measure twice, cut once

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Swear often 😉

I’ll return to cursing shortly … bear with me.

The autumn solstice is long gone and we’re fast approaching the end of British Summer Time 1. For most northern hemisphere beekeepers this means that there may be five months of ‘not beekeeping’ before we start all over again.

Of course, there are things we have to do with the bees in the intervening period.

The hive entrances must be kept clear so they can get out on the inoffensively named ‘cleansing flights’ when needed. There will be a winter miticide treatment to apply … probably long before midwinter. It is also important to keep an eye on the weight of the hive – particularly as brood rearing starts in earnest in late January and February – to ensure the bees do not starve.

But those three things aren’t going to fill anything like five months, so there is bound to be some time ‘spare’ over the coming months.

The elasticity of time

Although the year contains twelve about equal length months, those of us who keep bees in temperate northern countries experience a strangely warped calendar.

This is what it feels like … the beekeepers year

Apparently the months only vary in length by ±3 days. May and December contain the same number of days, but May disappears in the blink of an eye, whereas December can drag on interminably.

Weirdly there appears to be an inverse relationship between the available daylight to work in, and the amount of time it feels as though you have available to actually get the various beekeeping tasks completed.

This surely defies the laws of physics?

All of which means that beekeepers often have little free time in the summer and ample free time in the winter.

Some wise beekeepers have a busman’s holiday and go to New Zealand to tour apiaries (and – more to the point – vineyards).

Others catch up with all of the non-beekeeping activities that apparently ‘normal’ people do … like the decorating, or building model railways, or flamenco dancing 2.

Getting creative

But if you still want to dabble with a bit of beekeeping – in the broadest sense of the word –  through the cold, dark days of December and January 3 there are all sorts of things you can do. 

Many years ago I wrote an irregular column for my then beekeeping association on do-it-yourself (DIY) for beekeepers.

It was irregular because my use of punctuation has always, been suspect, and because it didn’t appear each month. 

That column eventually morphed into this website 4.

In fact, some of the very earliest articles were almost lifted verbatim from the beekeeping monthly newsletter.

I wrote about DIY because it was something that:

  • brought me a lot of satisfaction
  • saved me a few quid
  • improved my beekeeping

Now, a decade or more later, I still use the winter months to do the majority of my beekeeping-related DIY 5.

It’s only in the winter that I have the time to think things through properly before rummaging through the wood offcuts box and actually building something.

Measure twice, cut once

Which brings me back to the start of this post.

The motto for beekeeping DIY could be something like:

Measure twice, cut once, swear often 6

However, having identified a problem, there’s almost as much enjoyment to be gained from thinking it through to a workable solution than there is from the actual woodwork.

But Think lots, measure twice, cut once etc. doesn’t have quite the same flow.

And, as we’ll see below, it doesn’t have to be woodwork.

So I can happily fill a few hours on a dark November evening thinking about improvements to a hive stand that could cope with 1500 mm of rain a year and very uneven ground 7, or how to best construct the removable slides for a Morris board.

And by best here, I mean for a lot less than the £30 charged for the commercial ones 8.

Morris board … that’s £8.25 please

Part of the thinking involves how to tackle the project with the limited range of tools I have. I don’t have the space or the skill 9 to own a bandsaw, or a thicknesser 10, or a router.

Almost everything I build uses a combination of Gorilla glue, Correx, hand tools, blood 11, wood offcuts and some really rich Anglo-Saxon phrases.

My DIY skills are legendary, and not in a good way, but the great thing is that the bees could not care less. 

Fat dummies

Most of the various things I build develop from ideas that occur during the ‘active’ beekeeping season.

If it’s needed urgently I’ll cobble something crudely together and use it there and then. However, it’s unlikely to have received much thought (or care in construction) and so I’m more than likely to ponder how it could be improved once I have a bit more time.

I learnt the basics of queen rearing from the late Terry Clare at a BBKA Annual Convention and couldn’t wait to have a go myself.

Fat dummies – mark 1

I used the Ben Harden queenright queen rearing approach. This needs an upper brood box with most of the space ‘dummied down’ to concentrate the bees on the grafted larvae. For this you need a couple of ‘fat dummies’ 12. I built my first fat dummies one afternoon using gaffer tape and Correx (see above) and later that April reared my first queens.

But that winter I had time to do a bit more research. Dave Cushman’s website described fat dummies with integral feeders.

Clever.

These would clearly be an improvement – unless there’s a strong nectar flow you often have to feed the colony – so I built some. 

Fat dummy with integral feeder

Fat dummy mark 2 … with integral feeder and insulation

Mine are still in use … and not just for queen rearing. They are packed with polystyrene insulation … an embellishment I thought up 13. I can use them to reduce ’empty’ space in a brood box occupied by an undersized colony. In fact, with two of them, I can overwinter a four-frame nuc over a strong colony to provide warmth from below.

Problem solving

As I said earlier, the problem solving is part of the fun. 

I use a lot of Correx. That’s the fluted polypropylene board that is used for political posters and For Sale signs.

Sourcing it is often not a problem if you’re prepared to do some homework.

It’s lightweight, strong, available in a range of cheery colours … but most importantly it is used for political posters and For Sale signs.

So, it’s often free.

And that’s a word all beekeepers like 😉

Wait for a general election and seek out a candidate who has suffered an ignominious and humiliating defeat. Ideally one in which they have both lost their deposit and and any remnants of support from the political party they were standing for … and ask politely.

And For Sale signs are even more easily obtained. Always ask … and remember that it’s bad form to remove them if the house has yet to be sold.

But there’s a problem with Correx. You cannot glue it with any normal glues. It’s got some sort of surface coating that prevents glue from adhering properly. 

Believe me, I’ve tried.

There are special glues, but at special prices 🙁

Roofs

I wanted to build some hive roofs from Correx but had to solve how to fold it ‘across’ the longitudinal flutes, and then how to stick it together in a way that would be weatherproof.

Pizza cutter

Pizza cutter … take care scoring the Correx

The folding bit was easy … it turns out that people who keep guinea pigs use this stuff to make the cages and runs for their cavies. And after an hour or two reading about someone else’s (weird) obsession I discovered that a pizza cutter was ideal for scoring Correx prior to folding it.

The glue I worked out for myself. I built a couple of dummy roofs and held the folded corners together with zip ties or regular gaffer tape, zip ties and regular gaffer tape, or some (claimed) waterproof tape.

Of these, the waterproof tape – specifically Unibond Extra Strong Power tape – worked really well. 

Sticky stuff ...

Sticky stuff …

And remains the only one I’ve found to work.

You need to lightly sand the surface of the Correx and ideally degrease it with some solvent. I still have roofs built 8 years ago with the original tape holding them together. They cost me £1.50 each to build as I had to buy 14 the Correx as the only For Sale signs I had were too small.

Here’s one I made earlier

Most of the things I’ve made have been through one or two iterations of ‘improvement’ before I’ve ended up with something I’m satisfied with.

The Kewl floors I almost exclusively use these days were an improvement of the original design I built, but have also had a couple of additional modifications. 

My honey warming cabinet – one of the first things I ever built – was modified after a few years by the addition of a fan to better circulate the warmed air. This significantly improved it.

The things I’ve discussed above are all good examples of why it’s worth spending some time in the winter doing some creative thinking and DIY 15 :

  • commercial Morris boards are expensive and (I think) have entrances that are too large
  • I’m not aware of any commercially available fat dummies … please correct me if I’m wrong
  • no one sells hive roofs (or super carrying trays) for £1.50
  • my floors are ideal for the beekeeping I do and significantly less expensive than anything similar available commercially
  • my honey warming cabinet is used to warm supers before extraction, to melt set honey and – because the temperature control and heat distribution is good enough – has even been used as a queen cell incubator

Electrickery

This winter I have three projects to entertain me.

The first project is the second iteration of my DIY portable queen cell incubator. The first of these was cobbled together earlier this year. Although it worked – more or less – it was far from satisfactory.

Mark 2 is currently being stress tested.

It is being tested.

I am getting stressed.

Queen cell incubator – mark 2 … a work in progress

I’ve managed to achieve really good temperature control. However, I’m currently struggling with uneven temperatures at different areas within the box. They barely fluctuate, but they’re not the same.

Great temperature control at a range of (different) temperatures

Grrrr.

I’m pretty sure this is solvable 16 and that it will be possible to build something better than is available commercially for about 10-15% of the price 17.

But, almost more important than that, it will be a problem I’ve solved 18 that suits me, my bees and my beekeeping … which will be very satisfying.

The second project is a set of hive scales. Lots of others have tackled this problem and there are some really clever and complicated solutions out there.

The plan is for mine to be the exact opposite.

Simple, and not very clever at all.

Testing is ongoing 😉

Software, not hardware

And the final project is software, not hardware.

All my honey jars have unique batch numbers. These allow the individual apiary (and bucket) to be identified. The batch number is generated by some PHP or perl scripts and used to print a QR code onto a Dymo label affixed to the back of the jar.

QR code containing a batch number

But that monochrome pointillist pattern contains a hidden web address as well. The purchaser will be able to point a mobile phone at the code and get more information about the honey 19. 

Having sold honey ‘from the door’ for years I’m unsurprised when buyers want to know more about local bees and the available forage … and with these labels they can (and do).

I’ve written the scripts to handle label creation and logging/redirecting ‘views’. I now have to write the programs that create the customised web pages with the local information lifted from the backend database.

And, with only ~165 days until I next expect to open a hive, I think I’m going to have my work cut out to complete any of these projects.

 

DIY queen cell incubator

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NOTE: This post is now redundant as I have designed, built and tested version 2 of my portable queen cell incubator. I’m leaving this post here for those who wanted to read some of the background information.

You can please some of the people all of the time, you can please all of the people some of the time, but you can’t please all of the people all of the time … so said John Lydgate (1370-1450).

And he wasn’t wrong.

This is something I’m particularly aware of writing a weekly post on beekeeping. Much like my talks to beekeeping associations, the ‘audience’ (in this case the readership) ranges from the outright beginner to those with way more experience than me.

An article, like the one last week, on transporting your first nuc home and transferring it to a new hive, is unlikely to be of much interest to an experienced beekeeper.

Conversely, a post on something esoteric – like Royal patrilines and hyperpolyandry – is probably going to be given a wide berth by someone who has recently started beekeeping 1.

There’s no way I can write something relevant, interesting and topical for the entire breadth of experience of the readers 2. 

Going by the popularity of certain posts it’s clear that many readers are relatively inexperienced beekeepers.

The post entitled Queen cells … don’t panic! contains little someone who has kept bees for five years doesn’t or shouldn’t already know 3. Nevertheless, it is one of the most popular pages over the last couple of years. It has already been read more times this year than all previous years 4.

I suspect the majority of these thousands of viewings are from new(ish) beekeepers.

If you’re in this group then I suggest you look away now 😉 5

I’m going to discuss a pretty focused and specialised topic of relevance to perhaps a fraction of 10% of all beekeepers

The 10%

When I started beekeeping I was certain I would never be interested in queen rearing.

In fact I was so certain that, when repeatedly re-reading Ted Hooper’s book Bees and Honey, I’d skip the chapter on queen rearing all together. 

By ‘queen rearing’ I mean larval selection, grafting, cell raisers, cell finishers, mini-nucs, drone flooding etc. 

Queen cells from grafted larvae … what a palaver!

What a palaver!

All I wanted was a few jars of honey.

Oh yes, and slightly better tempered bees.

And perhaps a nuc to overwinter ‘just in case’.

What about a queen or two ‘spare’ for those swarms I miss?

A year or two later I had the opportunity – through the generosity of the late Terry Clare – to learn the basics of queen rearing and grafting. 

A week later I had a go on my own.

Amazingly (though not if you consider the tuition) it worked 🙂 . I successfully reared queens from larvae I’d selected, transferred, produced as capped cells and eventually got mated.

It was probably the single most significant event in my experience as a beekeeper. I got my nuc to overwinter and I’ve gradually improved my bees through selecting from the best and requeening the worst. I know how to produce ‘spare’ queens, though need them less frequently as my swarm control has also improved 😉  6

I don’t know what proportion of beekeepers ‘actively’ rear their own queens. I suspect it’s 10% or less.

But even that select group aren’t the target audience for this post.

The target audience are queen rearers who need to incubate queens or queen cells for protracted periods (hours to days) without constant access to mains electricity.

Let me explain

The peripatetic beekeeper

I live on the remote west coast of Scotland 7 but keep the majority of my bees in Fife. 

My apiaries in Fife are 30-40 minutes apart, and I drive past one on my way to my main apiary (in St Andrews). If I need a ‘spare’ queen in an out apiary (and have one in St Andrews) it adds over an hour to what is already a four hour beekeeping commute.

That’s an hour of my life I’ll never get back and something I’d really like to avoid 8.

On the west coast beekeepers and bees are very thin on the ground. I’ve just started queen rearing here and (again) have a 45 minute commute between apiaries 9. I’m working with another beekeeper and larvae are sourced from one and the cells are raised in another.

You can move frames of larvae about if you keep them warm and humid – a damp tea towel works well – at least if the times/distances are not too great.

But there’s an added complication … this area is Varroa free and I don’t want to be moving potentially mite-infested frames into the area. Nor do I want to deplete any of the donor colonies of brood frames.

All I want to move are a few larvae … but they’re a lot more fragile and sensitive.

So … two slightly unusual situations.

It seemed to me that my life would be a lot easier if I had some sort of portable queen and queen cell incubator.

My trusty honey warming cabinet

More than most events in beekeeping, the timing of the various stages of queen rearing is very clearly defined. You graft day old larvae and use the cells 10 days later. This timing currently defines the dates of my trips … except that sometimes there are diary clashes.

If my apiary with the cell raising colony was a mile away I could just go later in the day. 

But it’s not … 🙁

Before I started this (temporary) life as a travelling beekeeper I’d sometimes needed to incubate queen cells that were near to emergence. Once the cell is capped you can put it in an incubator, either until you use it as a capped cell, or until the virgin queen emerges. You then requeen a colony using the recently emerged virgin queen.

This was clearly another option to make the diary clashes less of an issue – raise the cells and then incubate them (outside the hive) until emergence, and then use the queens.

I’d already used my trusty honey warming cabinet to incubate queen cells. When I built this I used an Ecostat chicken egg incubator element rather than a 100 W incandescent bulb. The Ecostat heaters are thermostatically controlled and do a pretty good job of maintaining a stable temperature, anywhere between the high 20’s (°C) and about 55°C.

A day in the life of my honey warming cabinet (click for explanation of fluctuations)

There were two minor issues … the incubator needed a 240 V mains supply and was about the size of my car 10.

Honey warming cabinet. The Apiarist

Honey warming cabinet …

However, it’s perfect if you need to incubate 800 queen cells at once 😉

What I needed was a smaller, more portable, ‘battery’ – or at least 12V – powered version … 11

Beekeepers have short arms and deep pockets

One obvious solutions was to use a commercially available hen egg incubator. Brinsea are one of the market leaders and I know several beekeepers who use them as queen cell incubators. 

Although they are usually mains powered, they actually have an integral transformer and run at 12V, so could be powered from a car cigarette lighter socket. Temperature and humidity are controlled. They start at about £80 and would need modifying to accommodate queen cells, or Nicot cages containing queens.

The beekeeping-specific commercial solution is the Carricell.

Carricell queen cell incubator

These are manufactured in New Zealand in three sizes – for 40, 70 or 144 queen cells. Swienty (and presumably others) sell the 70 cell variant 12 over here for €636 13.

Excluding VAT 🙁

Beekeepers are notoriously commendably parsimonious. Since I have an alter ego named Dr. Bodgit, it seemed logical to try and build my own.

For a little less that €636 …

And ideally less than £80 😉

But first I needed to know more about the influence of temperature on queen cell development.

Temperature and development

The usual temperature quoted for the broodnest is about 35°C. Numerous studies have shown that, although the temperature is never constant, it is always in the range 33-36°C 14. 

It is reasonably well known that temperature can influence the development time of honey bees. At lower temperatures, development takes a little bit longer.

More significantly, Jürgen Tautz and colleagues showed almost two decades ago that honey bee workers reared (as pupae) at low temperatures have behavioural deficiencies 15.

For example, workers reared at 32°C showed reduced waggle dance activity when compared to bees reared at 36°C. Not only were they less likely to dance to advertise a particular nectar source, but they would dance less enthusiastically, performing fewer dance circuits.

In tests of learning and memory – for example associating smells with syrup rewards – bees reared as pupae at 32°C were also impaired when compared to bees reared at 36°C.

Tautz also demonstrated that bees reared at the lower temperature were more likely to go ‘missing in action’. They disappeared at a faster rate from the hive than the bees reared at the higher temperature. This strongly suggests their compromised memory or learning also had a negative influence on their survival. For example, in predator evasion, flight duration or the ability to find the hive.

OK … so temperature is really rather important for worker development.

Perhaps very accurate thermostatic control will be needed?

But what about queens?

There are good reasons to think that queen development might not be quite as sensitive to lower temperatures.

Queen cells are relatively rarely found in the centre of the broodnest. Those that are are often considered to be ‘supersedure cells‘, though location alone is probably not definitive.

Where are queen cells more usually found?

At the periphery of the broodnest, decorating the lower edges of the frame and even protruding down into the space below the bottom of the comb.

Queen cells

Queen cells …

Logic suggests that these might well experience lower temperatures simply by being at or near the edge of the mass of bees in the cluster. 

Perhaps queen development is less temperature sensitive?

Fortunately, I don’t need to rely on (my usually deeply flawed) logic or informed guesses … the experiment has been done 16.

Chuda-Mickiewicz and Samborski incubated queen cells at 32°C and 34.5°C. Those incubated at the lower temperature took ~27 hours longer to emerge than those at 34.5°C (which emerged at 16 days and 1 hour after egg laying).

However, of the variables measured, this was the only significant difference observed between the two groups. Body weights at emergence were similar, as were the spermathecal volume and ovariole number.

In both temperature groups ~90% of (instrumentally) inseminated queens started laying eggs.

So perhaps development temperature is not so critical (for queens after all).

The cheque queen is in the post

Finally, I expected my bodged incubator would also be used to transport mated queens. There’s good evidence that these are very robust 17. After all, you can get them sent in the post 18. 

Again, the experiment has been done 🙂

Survival of adult drones, queens and workers at 25°C, 38°C and 42°C

Jeff Pettis and colleagues investigated the influence of temperature on queen fertility 19 and concluded that incubation within the range 15-38°C are safe with a tolerance threshold of 11.5% loss of sperm viability 20. 

In addition, Pettis looked at the influence of high or low temperatures on adult viability (see graph above). Queens and workers survived for at least 6 hours at 25°C or 42°C. In contrast drones, particularly at high temperatures, ‘dropped like flies’ 21.

Stand back … inventor at work

Version 1 of the incubator was built and has been used successfully.

Queen cell incubator – exterior view (nothing to see here)

It consists of a polystyrene box housing a USB-powered vivarium heating mat. This claims to offer three heating levels – 20-25°C, 25-30°C and 30-35°C – though these are not when confined in a well-insulated box where it can reach higher temperatures. I’m not sure I believe the amperage/wattage information provided and don’t have the equipment to check it.

I run it from a 2.1A car USB socket, or a similar one that plugs into the mains.

The battery pack in the picture above runs the Raspberry Pi computer that is monitoring the temperature 22. It’s important to have accurate temperature monitoring and to do some trial runs to understand how quickly the box warms/cools. In due course all this wiring can either be omitted or built in … but it wouldn’t be a proper invention unless it looked cobbled together 😉

Not a lot to see here either …

Inside the box is a lot of closed cell foam – some crudely butchered to accommodate Nicot queen cages – sitting on top of a large ‘freezer block’. This acts as a hot water bottle. There’s also a plastic tray holding some soggy kitchen towel to raise the humidity.

Define ‘success’

The box has been used for the following:

  • transfer grafted larvae from an out apiary to a cell raising colony an hour away. Success defined by getting the grafted larvae accepted by the cell raiser.
  • transport queen cells up to 7 hours by car 23. Success defined by requeening colonies with the cells.
  • transport and maintain virgin queens for 7-10 days. These emerged in the incubator and then accompanied me back and forth before being used. All are now in hives and out for mating.

While powered – either in the house or the car – the box is easy to maintain at an acceptable temperature for extended periods, though it takes some time to reach the operating temperature.

An afternoon collecting and distributing queen cells to an out apiary

Even when opening the lid as queen cells are added/removed the temperature fluctuates by no more than 2-3°C. The graph above was generated from temperature readings taking queen cells from one apiary to another.

I’ll describe maintaining queens for extended periods in an incubator (with no attendant bees) in a future post.

The future

This really is a bodged solution.

At the moment the temperature has to be changed manually to keep it within the 32-35°C range. This might only be every few hours, depending upon how frequently the box is opened.

The combination of the insulation and the ‘hot water bottle’ freezer block means it can be left unattended overnight.

However, it really needs to have automatic temperature control. This should be trivial to add but will require more time than I have at the moment and for the box to be empty. It’s accompanying me on an exotic holiday to Glenrothes for the next three days 24 and will be in use for much of July as I start to make up nucs for overwintering.

So … as promised, an inelegant but working solution for a fraction of the 10% of beekeepers who rear queens. 

At a fraction of the price of a commercial one 🙂

STOP PRESS – update 7th September ’21

I now have a working solution with proper thermostatic temperature control. It’s currently going through a final series of tests. I strongly suggest you don’t follow the botch-up design described above, but wait for another post on this subject sometime this winter. It’s possibly to build a queen cell incubator with fully automatic temperature control of ±0.5°C that will work at home or in a vehicle for about £60.

STOP PRESS – update 26th November ’21

Full details of version 2 have now been published and this page is left here for historical reasons only … 

Let there be light

Our new bee shed provides a protective environment for hives, allowing inspections in most weather conditions if needed. The only exception is during extended cold periods when the colonies remain clustered. The shed is south facing and gets whatever sunlight is available from early/mid morning depending upon the season. This warms the shed nicely and, because of the seven 50 x 50cm windows along the side 1, provides light to work the colonies.

A typical sunny day ...

A typical sunny day …

But – believe it or not – the East coast of Scotland is not always sunny. Although it is one of the sunniest places in Scotland, with an average of ~1500 hours of sunshine a year 2, it is not always bright when I need to inspect the colonies.

And if it is grey and overcast outside it can be really murky in the bee shed.

This was the only significant drawback of the original bee shed which – due to its orientation – got no direct sunlight through the windows from early/mid-afternoon. Consequently, late afternoon inspections on gloomy days could be a bit testing. There was enough light to find the queen and observe the general state of the colony, but finding eggs or distinguishing the age of larvae – something critical for our research – was very hit and miss. It was usually necessary to take frames to the open door to see things better.

Which, of course, was not ideal if it’s chucking it down or windy outside, the very conditions that justify using a bee shed in the first place.

LED lighting systems

Therefore, in addition to orientating the new bee shed to maximise light throughout the day, I’ve also installed a 12V LED lighting system. These are available in kit form or you can easily purchase the necessary components – battery, solar panel, charge controller, cable, lamps and a switch – individually 3.

For convenience I used a Geo 4 Solar Lighting Kit from the Solar Centre. It’s not the cheapest way to get started, but at least all the components should be compatible and there are some (rather perfunctory) instructions provided. There’s also a useful YouTube video linked from the suppliers website.

The kit includes a single 30W solar panel and six 40W-equivalent LED bulbs. The latter seemed unlikely to be bright enough to help see eggs and developing larvae so I’ve replaced them with 9W LEDs, equivalent to about 120W incandescent bulbs 4.

Battery

The Solar Centre also sell suitable batteries for solar power systems … but at daft prices. I therefore sourced one elsewhere, ending up with a 100Ah leisure battery 5. This is probably overkill for lighting the shed … my back-of-the-envelope calculations suggest this battery will run the six 9W LED lamps for over 20 hours from a full charge 6. However, there are additional things I want power for in the shed including some hive monitoring equipment, so the excess capacity will come in useful.

The battery is hidden away in the corner of the shed inside a battery box. This includes USB and 12V outlets, enabling additional things to be hooked up in due course.

Installation

This was pretty straightforward. It was simply a case of rigidly adhering to red = positive and black = negative cabling, connecting all the bulb holders together, wiring up the switch and the charge controller, hooking up the solar panel and screwing in the bulbs.

The solar panel was fitted to the shed roof. This caused a few problems. Firstly, the roof is at an angle of ~25°. This appeared to be less than optimal for a solar panel at the latitude (56° N) of the shed. The usual way to determine the panel angle is to add 15° to the latitude in winter, or subtract 15° from the latitude in summer – the difference to take account of the angle of the sun in high summer or midwinter.

Since the lighting will be used mostly in summer – during inspections – I sketched a few possible bracket designs to angle the solar panel at about 40°. However, I ran out of time and enthusiasm, so ended up fitting the panel directly to the roof.

Solar panel installation ...

Solar panel installation …

I subsequently discovered an alternative way of calculating the optimal angle for a solar panel – multiply the latitude by 0.9 and subtract 23.5 i.e. (56 * 0.9) – 23.5 = 26.9°, which isn’t significantly different from the angle of the roof in the first place  😀

Switches

The lighting system has a standard on-off switch. However, I’d wanted to install a simple time switch which would automatically turn the lights off after a fixed period, for example one hour. This would avoid draining the battery should the system be left on inadvertently. The 12V timer I bought came with no comprehendible instructions and I’ve so far failed to get it to do what I want.

As an interim measure I’ve fitted a kitchen cupboard “on when open” circuit breaker in series with the main switch. The lights only turn on when the shed door is open. When working in the shed the door is almost always left open with the smoker left on the step outside. If this isn’t done there’s a tendency to end up getting ‘kippered’ as the shed fills with smoke 😉 

Kitchen cupboard switch ...

Kitchen cupboard switch …

The wiring is spectacularly bad – in true Dr. Bodgit style – but it works just fine. 

Bulb holders and reflectors

The bulb holders were fixed to the shed roof, more or less directly above the position of the hives. Due to the angle of the roof this places them above head height – so little chance of hitting them with your head – but it does mean they are rather dazzling.

Welcome ...

Welcome …

It’s no use fixing them down the centre of the roof as the light is then behind you when conducting inspections, so negating most of the benefits of installing the lighting system in the first place.

Therefore, to avoid retinal burns (!) I’m investigating simple white Correx ‘reflectors’ nailed to the roof battens near the lamps. These should angle the light better into the hives.

Finally, to allow future changes to the lamp holder positions should they be needed, I allowed additional cable between them, all held in place using lots of cable clamps.

There should be bees in the shed by the time this is posted. However, we’ll need to wait a few weeks until it’s warm enough for routine inspections before we can be sure the lighting system is optimal.

Colophon

Let there be light is a Biblical phrase from the third verse of the Book of Genesis. Many academic or educational institutions use the phrase in Latin, Fiat lux, as a motto.

Inevitably the phrase is also used as the basis for a large number of quotes, including my particular favourite (from the actress and comedian Ellen DeGeneres) “In the beginning there was nothing. God said, ‘Let there be light!’ And there was light. There was still nothing, but you could see it a whole lot better.“

Even kewler floors

So-called kewl floors have underfloor entrances that are pretty-much rodent proof (so you don’t need mouseguards in winter) and are easy to seal when needed for transporting hives or administering vaporised oxalic acid. They are very easy and inexpensive to build. The last batch I built were all fitted with a Correx landing board that protruded a centimetre or so. It turned out that the ‘design’ (a rather grand word for the bodged solution I came up with at the time) was not ideal so I’m gradually replacing them with a modified version that corrects the worst of the faults of the original.

New Correx landing board ...

New Correx landing board …

The problem

  1. The protruding landing board inevitably got a bit bashed about when transporting colonies
  2. The gap underneath the landing board disorientated bees who climbed up the hive stand or otherwise undershot. This was particularly noticeable when reversing colonies during vertical splits. I’d previously fitted a plastic ‘skirt’ to some hives to fix this (see pic below).
  3. The ‘edge’ of the Correx provided a narrow and slippery target for heavily-laded foragers returning to the colony. Many lost their grip and fell off into the grass before having a second or third attempt at entering the hive.

The solution

An L-shaped piece of Correx (of course), though this time not protruding, with a rough textured integral ‘skirt’ to block the gap below the hive entrance works well. To make an acute bend in Correx you need to make two parallel cuts through one skin and remove the intervening ‘rib’. This takes longer to write than to do. After stapling† the Correx in place I spray paint it and sprinkle sand onto the wet paint. You can use different colours to help orientate bees and minimise drifting. Alternatively, use multi-coloured ‘repurposed’ estate agent signs and a clear spray varnish of some type.

Other improvements?

The final change I’d intended to make to these floors was to add a second entrance on the opposing side. Some hive manipulations involve turning the colony 180° on the stand – these include vertical splits and using a Cloake board for queen rearing. Rather than manhandling the entire colony it would be much easier to seal off the front of the hive and open a hinged entrance at the rear (much like opening and closing the gates on a Snelgrove board). Unfortunately, this batch of floors were over-engineered, with the upper upper rim glued and screwed in place, so this modification will have to be introduced when (or if) I next build floors.

New landing board in action …

† The original landing board was held in place with gimp pins. Inevitably these had rusted which made removing them a bit of a pain. When replacing them I used stainless steel staples (like these from Arrow) with the hope that this will make future removal of the landing board easier.