Category Archives: Queen rearing

Picking winners, part 2

Synopsis : Some larvae are nutritionally deprived and may produce sub-optimal queens. Grafting may miss the ‘best’ larvae the colony would select for rearing as emergency queens.

Introduction

A fortnight ago I discussed the preference colonies show for heavy eggs – or more accurately for larvae reared from heavy eggs – when producing queens under the emergency response.

Why might this be interesting?

The longevity of the queen and the absolute dependence the colony has on her quality means that the choice of larvae they rear new queens from is of fundamental importance.

These are the larvae that develop to produce queens with the traits that benefit the colony – in fecundity, disease resistance and a range of other characteristics.

It cannot be random.

If they make the right choice the colony will flourish, swarm and their genes will be perpetuated.

That is a significant evolutionary selective pressure. Its application over the 90 million years or so since the evolution of eusociality has resulted in the honey bees we have today.

Now, these traits favoured by the bees might not all benefit our beekeeping, but some of them should. Longevity, fecundity and disease resistance are likely to be evolutionarily favourable traits, and will also be useful for beekeepers.

Defensiveness and swarminess … er, not so much 😉 .

But the bees have little time to select the best larvae. They have 6 days from the day the egg is laid until a larva is too old 1 to reliably develop into a queen.

In practice they select very young larvae (or even 3 day old eggs) so ensuring the resulting queen is fed for the maximum time with royal jelly, thereby producing a larger queen with more ovarioles.

So what do the bees choose?

Given the choice, which larvae are selected by the bees to rear new queens?

Artificial experiments and nepotism

The ‘heavy eggs’ experiment I discussed a fortnight ago was primarily designed to study kin selection and nepotism in honey bees. The study was conducted over a decade ago 2, but wasn’t published until 2021, though the results were known before then 3.

If you remember, nepotism in honey bees is a nice idea; particular patrilines of workers (fathered by the same drone) should favour larvae of the same patriline. However, there have been no convincing studies that actually support this, and there are compelling theoretical arguments why nepotism could actually be detrimental to the colony.

Parts of the study I’m going to discuss this week were also designed to test for nepotism. I’m going to ignore these 4 and instead focus on some more interesting results that I think have practical relevance for beekeeping.

In addition, the study this week uses methods that are more typical of those used by beekeepers and that avoid the artificiality of rearing larvae in vitro before reintroducing them to a queenless colony.

In this regard I’d argue that they more closely resemble what’s happening in a colony rearing emergency queens. Furthermore, they should be easier for beekeepers to understand, and to repeat … not for experimental purposes, but when rearing queens.

Sagili et al., (2018)

The majority of the studies I’m going to discuss are from Sagili et al., (2018). The title ’Honey bees consider larval nutritional status rather than genetic relatedness when selecting larvae for emergency queen rearing’ neatly summaries their conclusions, but some of the detail is worth discussing in a bit more detail.

It’s always interesting to know what goes on in the hive.

During inspections we see frames of brood – capped and open cells. Other than the larvae getting bigger as they get older they all look much of a muchness … but they’re not.

All larvae are equal, but some are more equal than others 😉 .

Hungry mouths

The queen lays an egg in an empty cell. Other than the egg, the cell remains empty for 3 days when the egg hatches to release the larva. Without prompt and regular feeding the larva will starve or suffer setbacks in development.

Unrealised potential … a frame with eggs and young larvae

For this reason the nurse bees make frequent visits to the occupied cells to determine their content and needs.

Is it an egg or a larva?

Is it hungry?

And these visits continue during the 5 days of larval development.

How many visits do they make, how often is a larva fed, and are all larvae treated equally?

Sagili and colleagues used observation hives and video cameras to record nurse bees visiting cells containing larvae of precise ages 5. They recorded visits over 4 hours to 2 day old larvae, and one hour observations of 5 day old larvae.

In four separate hives, 4-8% of the young (2 day old) larvae did not receive a visit from a nurse bee during the 4 hour period they were filmed.

Of the 5 day old larvae, again ~10% didn’t receive a visit during the observation period and, of those fed, the longest interval between feeds was ~36 minutes. However, over one hour, the older larvae that were being fed were visited very regularly; the median interval between feeds was a little under 4 minutes and they were fed for a total of ~7 minutes over one hour.

Clearly some larvae, for whatever reason, get little or no attention for extended periods, whereas those that are visited, are fed very frequently.

Nutritionally deprived and non-deprived larvae

Larvae that are infrequently visited are likely to be nutritionally deprived … or, using the technical jargon beloved of beekeepers and scientists alike, hungry 6.

Do nurse bees respond differently to nutritionally deprived and non-deprived larvae?

Which are visited first and fed first?

The scientists caged the queen on a frame and allowed her to lay eggs for 24 hours. They then removed the queen (caging her elsewhere in the hive) and waited for the eggs to hatch. 24 hours later the larvae were caged under either 13 mm mesh or 3 mm mesh. Workers can access the larvae through the 13 mm mesh, but cannot get through 3 mm mesh. Cages were left in place for four hours to create two populations of larvae on the same frame; nutritionally deprived and non-deprived.

Small and large mesh cages over day-old larvae

They then again used video recording of randomly selected larvae to record and quantify the attention and feed visits they received.

The purpose of this part of the study was to determine whether the nurse bees could discriminate between larvae that were nutritionally deprived and those that were not.

And they could …

Inspections and feeding visits to nutritionally deprived and non-deprived larvae

Deprived larvae were visited (inspected) sooner, the black bars in the graph above, and fed earlier. You can just about determine this from the graph; the stats are more convincing (but less comprehensible 😉 ).

In addition, deprived larvae received more frequent inspections, more frequent feeds and were fed for longer.

Acceptance of larvae for queen rearing

A colony rendered suddenly queenless will attempt to rear a replacement under what is called the emergency response. Suitable young larvae are selected, fed a diet rich in royal jelly and the cell is reshaped to be orientated vertically.

This vertical orientation is a major inducement for the workers to continue to feed the developing larva with royal jelly (She et al., 2011). This is exploited in queen rearing techniques that involve the grafting of young larvae into wax or plastic cups which are then placed, open end down, in a queenless colony.

Sagili et al., investigated whether nutritionally deprived and non-deprived larvae were favoured when queens were reared under the emergency response.

Interestingly, they did so using larvae in natural comb and following grafting into plastic queen cups.

Which were favoured for queen rearing? Grafted or natural, nutritionally deprived or non-deprived?

In both instances the larvae were presented to a queenless and broodless colony, using 6 recipient colonies in each case.

Larval acceptance for queen rearing using two different methods – grafted and in natural comb

In the case of grafting, 12 of each type of larvae were presented on a cell bar frame. When transferring comb (prepared as described before using caged larvae) the entire frame was introduced.

The recipient colony did not discriminate between the nutritionally deprived and non-deprived larvae when they were grafted, but they showed a marked preference for the non-deprived larvae in natural comb.

In addition, they reared significantly more queens from grafted larvae than they did from larvae in comb.

All larvae are equal, but some are more equal than others …

Since I’m enthusiastic about queen rearing, this last set of experiments was by far the most interesting part of the study.

There are two results that are particularly striking.

Firstly, more queens were reared from grafted larvae than were reared following the transfer of a frame of larvae. The difference was significant, with almost twice as many queens being produced following grafting. It’s also worth noting that the bees only had 24 grafted larvae to choose from, compared to a much larger number of larvae on the transferred natural comb.

More is better … right?

Secondly, the workers showed no preference between nutritionally deprived and non-deprived grafted larvae, but showed a strong preference for the well-fed larvae in natural comb.

So, what do these results mean?

Let’s have a quick recap:

  • developing larvae receive different amounts of ‘attention’ from nurse bees
  • about 10% of developing larvae received no (or only a limited number of) visits during an extended observation period. The presumption is that these larvae are likely to be nutritionally deprived (though this was not demonstrated)
  • nurse bees can readily distinguish between nutritionally deprived and non-deprived larvae; the former receive earlier inspections, are fed sooner and more frequently
  • when rearing emergency queens, workers preferentially select larvae in natural comb that are not nutritionally deprived. In contrast, they make no distinction between nutritionally deprived and non-deprived grafted larvae

We know from numerous studies that high quality queens must be well fed during larval development. The best queens are produced from very young larvae (or even 3 day old eggs) that are then fed for an extended period with copious amounts of royal jelly in a strong hive full of nurse bees.

Queens produced under these conditions are larger and have more ovarioles, so should lay more eggs for longer.

It makes sense that nurse bees can distinguish between ‘hungry’ and replete larvae … the former need feeding or they won’t develop properly. The former may already have been held back developmentally … not an ideal start for a new queen.

Since nurse bees can determine the nutritional status of very young larvae, logic would dictate that they would select those that are not nutritionally deprived to rear new queens from.

After all, the future of the colony, and any resulting swarms will depend on it.

So, why don’t they make a similar distinction when presented with grafted larvae?

Selection vs. maintenance of larvae for queen rearing

The key difference between the grafted larvae and those in natural comb was the orientation of the ‘cells’ in which the larvae were presented to the queenless and broodless colony.

Grafted larvae were presented in a vertically orientated plastic queen cup, whereas the cells in natural comb are horizontal 7.

Cell bar frame with vertically orientated plastic Nicot queen cups

The interpretation is that larvae in vertically orientated cells are not selected by the nurse bees, but are instead just maintained as developing queens.

In contrast, larvae in horizontal(ish) natural comb are selected as the starting material for new queens, and the resulting reshaping of the comb to form the queen cell leads to their maintenance as developing queens.

Significance for beekeeping and queen rearing

The increased number of queens reared from grafted larvae probably reflects this ‘maintenance’ response being triggered in the nurse bees. ’Any’ larva presented in a suitably orientated cell must have been preselected as suitable … so the bees feed them up with royal jelly.

The nurse bees don’t know that these grafted larvae were selected by the beekeeper, not on the basis of them being nutritionally replete, but more likely because they were visible, about the right size, and in an accessible part of the comb.

But … think back to the first experiment. This suggested that ~10% of all larvae are nutritionally deprived because they have received, at best, infrequent visits over the last few hours. If the beekeeper hadn’t picked them during grafting, it’s unlikely the bees would have selected them as being suitable for producing queens.

Are 10% of grafted queens sub-optimal? Remember, the differences may be subtle.

The other point I found interesting is that the bees reared fewer queens in natural comb than from grafted larvae.

Why?

Charged queen cell

One possibility is that the reshaping of the comb is a physical limitation and restricts queen production. Perhaps this is why so many are at the edge of combs? 8 

Another is that the bees only rear ’enough’ queens for their needs, but that they can only determine what ‘enough’ is using larvae in natural comb.

Whilst these are certainly possible I think there’s an intriguing alternative … only a small proportion, even of well fed larvae, are considered suitable by the colony for queen rearing and so selected by the nurse bees.

Yes, the bees favour larvae that are not nutritionally deprived, but perhaps there are additional characteristics that are also desirable (and that vary between larvae).

Quantity and quality

Grafting larvae is a well established method of producing large numbers of queens. If the donor colony is good quality there’s every reason to expect that the resulting queens will be good.

Most, if not all, commercially reared queens come from grafted larvae (where quantity is paramount and quality might be a secondary concern) … probably hundreds of thousands of queens a year are produced like this. It’s the method I’ve used for many years.

Queen cells from grafted larvae …

But this paper raises two or three interesting ideas:

  • about 10% of larvae selected at random for grafting are likely to be nutritionally deprived and so would not have been chosen by the nurse bees. The presumption is that these will produce sub-standard queens.
  • nurse bees might be a lot more selective in the larvae they choose for emergency queens, only favouring a subset of even those not nutritionally deprived.
  • queen rearing methods that present larvae in natural comb might produce fewer queens but those queens may have the desirable characteristics selected by the bees (potentially resulting in better quality but a smaller quantity).

If this last point is correct, it’s worth noting that queen rearing methods – like the Hopkins method – that use larvae in frames placed horizontally over the colony 9, may trigger the queen maintenance response rather than allowing the selection of larvae by the nurse bees.

It would be very interesting to determine whether the bees would discriminate between nutritionally deprived and non-deprived larvae presented on a horizontal frame.

Two final thoughts;

  1. Grafting works well, but that doesn’t mean it’s the best way to produce top-quality queens.
  2. The desirable characteristics nurse bees favour (for colony survival and reproduction) may not be beneficial for beekeeping.

But I’d be surprised if they weren’t 🙂


Note

I’ve not had a chance to discuss it, but Free et al., (1989) previously demonstrated that nutritionally deprived larvae received more attention from nurse bees. I’ll deal with how the workers detect the nutritional status of larvae in the future.

References

Free, J.B., Ferguson, A.W., and Simpkins, J.R. (1989) The Effect of Different Periods of Brood Isolation on Subsequent Brood-Cell Visits by Worker Honeybees (Apis Mellifera L.). Journal of Apicultural Research 28: 22–25 https://doi.org/10.1080/00218839.1989.11100815. Accessed November 22, 2022.
Sagili, R.R., Metz, B.N., Lucas, H.M., Chakrabarti, P., and Breece, C.R. (2018) Honey bees consider larval nutritional status rather than genetic relatedness when selecting larvae for emergency queen rearing. Sci Rep 8: 7679 https://www.nature.com/articles/s41598-018-25976-7. Accessed November 21, 2022.
Shi, Y.Y., Huang, Z.Y., Zeng, Z.J., Wang, Z.L., Wu, X.B., and Yan, W.Y. (2011) Diet and Cell Size Both Affect Queen-Worker Differentiation through DNA Methylation in Honey Bees (Apis mellifera, Apidae). PLOS ONE 6: e18808 https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0018808. Accessed November 22, 2022.

Picking winners, part 1

Synopsis : Queenless colonies prefer to rear new queens from heavy eggs. How was this determined and what are the implications for our queen rearing?

Introduction

Arguably the most important decision a colony will ever make is the selection of the eggs or larvae from which a new queen is raised. Other decisions are obviously important, such as the nest site a swarm occupies, but if the choice of ’starting material’ for the new queen is poor then the resulting colony is unlikely to thrive.

Actually, I suspect this isn’t arguable at all; whether it’s a replacement queen to take over after the colony swarms, or a supersedure queen to replace the ageing matriarch as she runs out of sperm or energy, a poorly chosen larva will – sooner or later – result in the demise of the colony.

Let’s hope they’ve chosen a good ‘un (they will have!)

Conversely, a good larva, fed well by nurse bees, that mates with enough drones and evades marauding swallows on the return to the hive – and the clumsily wielded hive tool of the beekeeper – will end up heading a strong colony. This strong colony will collect a surfeit of pollen and nectar, so ensuring good overwintering survival. It will be better able to defend itself against wasps or other robbing bees, and will be less susceptible to disease 1.

Reproduction

A strong, healthy colony will build up well in the spring and produce one or more swarms 2. If these survive – undoubtedly also helped by having good genetics – the colony will have reproduced and can be considered successful.

A small swarm ...

Honey bee reproduction in action

This type of ’success’ is what evolution selects for, so you can be absolutely certain that the choice of eggs/larvae from which new queens are reared is not random.

Cooperation vs. nepotism

Rearing new queens involves cooperation. In fact, as eusocial insects, almost everything that happens in the colony is cooperative. Multiple nurse bees feed the developing queens, hundreds of scout bees survey the environment for new nest sites and thousands of related workers provision the hive with pollen and nectar.

It’s often stated that these workers are ‘half sisters’ … they share the same mother (the queen) but different fathers (drones).

And there are quite a lot of fathers … .

The queen mates with at least a dozen drones during the mating flights she takes. Some calculations suggest it’s significantly more than a dozen drones. Whatever the number, workers fathered by the same drone will be more related to each other than they will be to workers fathered by a different drone.

On average workers within a single patriline (i.e. fathered by the same drone) are supersisters and share 75% of their genes. In contrast, workers in different patrilines (i.e. different drones) only share 25% of their genes.

And this is potentially a problem for cooperation.

It might be expected that nurse bees would select their supersister larvae when rearing new queens. Doing so would help ensure the propagation of their genes in subsequent generations, rather than those of their half sisters.

This would be an example of nepotism; ’showing special favour or unfair preference to a relative’ 3.

Lots of studies have attempted – largely unsuccessfully – to demonstrate nepotism in social insects, but that doesn’t mean it’s not worth looking again.

Do worker honey bees exhibit nepotism when selecting larvae to rear new queens?

Nepotism vs. colony diversity

It’s easy to talk yourself out of an experiment.

You have a good idea, do a bit of reading, discuss it with your friends and collaborators and then – belatedly – consider the underlying theory.

At which point it all sort of falls apart and you find numerous reasons not to do the experiment in the first place.

It was a daft idea because of x, y and z.

Think of all the time and money you’ve saved … back to the drawing board.

And there are good theoretical reasons why nepotism is unlikely to be seen in social insects like honey bees.

The most compelling of these is that genetic diversity within the colony is beneficial.

And nepotism, by definition, reduces diversity.

A quick recap on the diversity story … colonies with limited genetic diversity e.g. those headed by poorly mated queens, are less ‘fit’ than colonies with extensive genetic diversity. Fitter colonies are bigger, stronger, healthier and more likely to reproduce. The seminal study on this was by Mattila and Seeley (2007) which I discussed briefly in Polyandry and colony fitness.

So, theoretically, nepotism is a ‘bad thing’ … don’t bother doing the experiment.

But hold on a second, we also know that different patrilines of workers ‘smell’ very different to each other because they produce distinct cuticular hydrocarbons (CHC).

If nepotism is such a ‘bad thing’ why retain the (evolutionarily ‘expensive’) genetic machinery to generate all these different CHC’s? Why not just make all workers from one queen distinct from those derived from a different queen?

Individual colonies need to have distinct CHC’s to prevent robbing, but why are different patrilines distinct in their CHC profile?

Maybe nepotism occurs after all?

Better do the experiment.

Nepotism and larval selection

The study I’m going to briefly discuss was recently published by AL-Kahtani and Bienefeld (2021). It’s interesting and reasonably definitive in my view. However, whilst it addresses the ”Do bees exhibit nepotism during larval selection?” question 4 I think there are features of the study that are somewhat artificial which might restrict the generality of the conclusions they reach.

More interestingly, and of relevance to practical beekeeping, they show that bees are highly selective in their choice of eggs/larvae.

Can beekeepers exploit this to produce better quality queens?

The experiment was very simple.

Simplified diagram of the experimental method (see text for details)

Unmated queens from diverse areas of Germany were instrumentally inseminated with sperm from 10 drones, each selected from different unrelated geographic areas.

Six colonies were established (only three shown above) which were subsequently split into a queenright egg-producing colony (EPC; presumably a nuc, though it’s not stated) and a queenless larvae-rearing colony (LRC).

Eggs laid within a 6 hour window were incubated for 48 hours in an incubator, weighed and then allowed to hatch. For the first 48 hours after hatching the larvae were artificially reared by feeding them a sugar/protein diet 5.

This artificial rearing was done to avoid any bias from non-genetic colony odours e.g. due to pollen/nectar.

After 48 hours, 30 larvae, 10 from the matched EPC and 10 from each of the unrelated EPC’s were grafted into plastic queen cups and presented to the LRC for rearing as queens.

The larvae selected were obvious as these were fed and wax was deposited to create the surrounding queen cell.

Did LRC’s preferentially select larvae from the matched EPC?

No.

This larval transfer was done several times to get statistically meaningful results, using six colonies, repeated either twice or three times in successive years. In total 450 grafted larvae were presented to the LRC’s.

Larval acceptance rates were ~48-60%, a figure often exceeded when grafting for queen rearing.

Capped queen cells

Capped queen cells produced using the Ben Harden queenright queen rearing system

I suspect this rather mediocre acceptance rate reflects the in vitro rearing of the larvae for the first 2 days, potentially compounded by the age of the larvae which – at 48 hours – are at least 30 hours older than optimal.

But the acceptance rate doesn’t really matter as it was similar whether the larvae were derived from the matched or unmatched EPC. This therefore ’contradicts the hypothesis that kinship plays a central role in the selection of larvae for queen breeding’ (to quote the authors verbatim).

Larval selection is not nepotistic.

But certain larvae were preferentially selected

Despite the fact that the bees didn’t appear to care whether the eggs were from a related colony or not, they did preferentially select larvae produced by certain queens.

And I’ve already given you a clue of the characteristic favoured by the workers … though the characteristic per se wasn’t directly selected by the workers bees.

The six different queens used in this study produced eggs that differed slightly in weight. On average, the heaviest and lightest eggs varied in weight by ~5%.

There was a significant and direct correlation between the average weight of eggs produced by a queen and the likelihood that the resulting larvae would be selected by the larval rearing workers.

Heavier eggs produced larvae that were favoured by the cell raising colony.

Relationship between average egg weight and whether they were accepted for queen rearing

Of course, the cell raising colony never saw the eggs … these were hatched in an incubator and fed for two days before grafting and introduction.

Nevertheless, there was something about heavy eggs that the larval rearing colony favoured.

A total of 248 virgin queens were produced from the 450 larvae grafted (55%). These virgins were weighed and subsequently naturally mated, resulting in 190 egg-laying queens (42% of grafts, or 77% of virgins). Of these, 147 came to a grisly end as they were dissected two months after they started laying to count the number of ovarioles (the sub compartments of the ovaries in which the developing oocytes are produced).

Queen weight and ovariole number have previously been considered as markers of queen quality. Perhaps disappointingly, there were no significant differences in terms of virgin queen weight, ovariole number or the delay in onset of egg laying between queens produced from heavy or light eggs.

Crude criteria of what’s best

I’m not unduly concerned that the crude criteria we use to judge the quality of these queens (weight and ovariole number) failed to demonstrate significant differences. These criteria may not be the same as the ones selected by the bees 6. The fact that we cannot measure differences in the resulting queens does not mean that there were not qualitative differences in queens reared from heavy eggs that would benefit the colony.

Or would have been if they hadn’t been dissected 🙁 .

Where have all my young girls gone?

Bigger AND better … or just bigger?

It just means we were probably not measuring the right things.

However, extending this experiment from the relatively straightforward ‘heavy eggs are favoured’ observation is not trivial. If the scientists cannot see a difference in the queens then they might have to look at colony performance over time, or in adverse years, or when swarming, or in hard winters etc. Each of these may directly or indirectly act as a selective pressure on the queen quality, and hence the choice the bees make in the initial eggs or larvae that are selected for queen rearing.

Caveats

The relationship between egg weight and larval acceptance shown above is based upon the average egg weight produced by each of the 6 queens used in the study.

These average weights varied by about 5% (154.9 to 162.7 micrograms). That’s not a lot, and is narrower than the range of egg weights produced by an individual queen. Unfortunately, this data isn’t presented, but it can be inferred from the standard deviation of the mean egg weight.

For example, the average weight of the heaviest eggs was 162.7 micrograms with a standard deviation of 22.2 micrograms. With some basic assumptions of the distribution of weights, that means that 68% of the eggs were between 140.5 and 184.9 micrograms, but the remaining 32% were heavier or lighter.

Clearly, queens produce eggs that vary considerably in weight … and this has also been shown in previous studies (e.g. AL-Kahtani et al., 2013).

I would have liked to see a graph of the weight of individual eggs and an indication of whether or not the resulting larva was accepted as starting material for a new queen.

Secondly, there are methodological problems – acknowledged by the authors – in the relationship between queen quality and egg weight. So few queens were reared from lightweight eggs that it was difficult to determine if these produced poor quality flyweight queens with low numbers of ovarioles.

You can only work with what’s available.

Emergency response and egg/larval selection

The other two caveats I have are to do with the experimental design. The study involved rearing queens under the emergency response; larvae were presented to queenless and broodless colonies. For survival, they had to rear queens from the material presented (but still exhibited a preference).

However, I’d suggest that the vast majority of queens reared by honey bees – over the millions of years that have shaped the evolutionary choices we are now testing – are produced under either the swarming or supersedure responses.

Is egg/larval choice under the emergency response the same?

We don’t know 7.

The non-random construction of queen cells.

Finally, it has been shown that colonies prefer to rear queens from 3 day old eggs rather than 48 hour old larvae. I understand why the authors reared the eggs in vitro, but it does rather ignore the known preferences of the colony (see The bees know best for more on this topic).

Yes … they had no option other than to choose between the offered 48 hour old larvae … but would they have made the same choice if they had been given the eggs in the first place?

Why are heavier eggs preferred … ?

This is where we get to speculation and I’m going to save the discussion for after a follow-up post 8 in the next fortnight or so.

The bottom line is we don’t really know, but we have some pretty good ideas (though some are extrapolated from other social insects).

However, there’s a related question; ”How are the heavier eggs/larvae selected?” … and I think it’s fair to say this remains unclear 9.

… and is this relevant to our queen rearing?

When I rear queens I select larvae from a colony that shows some or all of the traits that I favour in my bees.

I’m a simple beekeeper and I have very simple needs … I want my bees to be calm, well-tempered, steady on the comb and frugal in winter. The best colonies that exhibit these traits are used as a source for grafting larvae when queen rearing.

Nice bees and a nice queen

In contrast, colonies that exhibit lots of chalkbrood, have poor temper, run about the comb or – worst of all – ‘follow’ are never used for queen rearing. Nor are they allowed to replace their queen during swarm control. Instead, these are requeened (as early as practical) from better stock.

I’ve described before my ‘rule of thirds’. When comparing the sum total of the various traits I care about, the best third are used for queen rearing. These queens are used to requeen the worst third and – if there are spares – the intermediate quality third as well.

However, if I run out of queens I’m reasonably happy to let the middle third requeen themselves (for example, during swarm control).

You’d be surprised how quickly the average quality of your bees improves using a strategy like this.

Grafting larvae vs. letting the bees choose

But the ‘best third’ are defined solely by my criteria.

I ignore any preferences the bees might have by choosing the larvae when grafting.

Assuming the queens that head these top third ‘good’ colonies produce a range of egg sizes (which they will), the bees would preferentially select the larvae from the largest eggs.

I just pick the larvae of the right age that I can see 10 and transfer them to a Nicot plastic queen cup.

Eggs and young larvae

Eggs and young larvae

Not the same thing at all.

Perhaps it doesn’t matter? After all, thousands of apparently satisfactory queens are reared by grafting every season.

Perhaps the characteristics the bees select for – whatever they are – are irrelevant for beekeeping? We don’t know, but I’d bet that some of the criteria that benefit the bees – and are evolutionarily selected – might well benefit beekeeping.

Poor ‘take’

Sometimes I get 100% ‘take’ i.e. all the grafted larvae accepted and reared as queens 11.

Sometimes it’s less, a few times it’s almost none 🙁 .

Cell bar frame with three day old queen cells, The Apiarist.

3 day old queen cells …

In the latter instance I usually assume that the cell raising colony is not sufficiently ‘receptive’ but perhaps I’ve chosen undersized larvae (for their age), or perhaps the donor queen only produces undersized larvae (again, for their age)?

In the best tradition of “If at first you don’t succeed, try, try and try again” I usually just have another go. Almost always, I have another go in exactly the same way.

Perhaps if I used larvae from a different (but still good) colony the take would be improved?

Or perhaps if I presented the larvae in a manner that allowed the bees to select those to be developed into queens I might get improved acceptance? 12

I could end up with more queens and – potentially – better queens.

It’s blowing a hoolie tonight

And, as another autumn storm winds itself up to come barreling in from the Atlantic, dreaming about balmy May afternoons in the apiary and improved ways to produce better queens is about as close as I can get to beekeeping 😉 .


References

AL-Kahtani, S.N. and Bienefeld, K. (2021) ‘Strength surpasses relatedness–queen larva selection in honeybees’, PLOS ONE, 16(8), p. e0255151. Available at: https://doi.org/10.1371/journal.pone.0255151.
Al-Kahtani, S.N., Wegener, J. and Bienefeld, K. (2013) ‘Variability of Prenatal Maternal Investment in the Honey Bee (Apis mellifera)’, Journal of Entomology, 10(1), pp. 35–42. Available at: https://doi.org/10.3923/je.2013.35.42.
Mattila, H.R. and Seeley, T.D. (2007) ‘Genetic Diversity in Honey Bee Colonies Enhances Productivity and Fitness’, Science, 317(5836), pp. 362–364. Available at: https://doi.org/10.1126/science.1143046.

Winter projects

Synopsis : Now is the time to make plans for the long winter ahead; frame building, winter projects, some light reading or an escape to somewhere warmer and with better wine?

Introduction

The good late summer September weather 1 has been replaced with the first of the equinoctial gales. Actually, more of a 30-40 mph stiff breeze with an inch or two of rain than a real gale. Nevertheless, wet and windy enough to preclude any outdoor jobs, and instead make my thoughts turn to winter projects.

The more northerly (or southerly) the latitude, the longer the winter is. Here in north west Scotland there’s virtually no practical beekeeping to be done between the start of October and early/mid April i.e. over 6 months of the year.

Some beekeepers fill these empty months by taking a busman’s holiday … disappearing to Chile or New Zealand or somewhere equally warm and pleasant, where they can talk beekeeping – or even do some beekeeping – and, coincidentally 2 enjoy some excellent wines.

Santiago bee graffiti

Santiago, Chile, bee graffiti …

Others ignore bees and beekeeping for the entire winter and think (and do) something completely different. They build model railways, or practise their ju-jitsu or – if really desperate – catch up on all the household chores that were abandoned during the bee season.

They then start the following season relatively unprepared. Almost certainly, next season will be similar to last season. They’ll make similar mistakes, run out of frames mid-season and lose more swarms than they’d like.

Rinse and repeat.

Alternatively, with a little thought, some reading, a bit of effort and some pleasant afternoons in the shed/garage/lounge, they can both plan for the season ahead and prepare some of the kit that they might need.

As Benjamin Franklin said ”By failing to prepare, you are preparing to fail.”

Looking back to look forward

I’ve discussed beekeeping records previously (and should probably revisit the topic). My records in the early years were terse, patchy, illegible and of little real use, perhaps other than in the few days that separated colony inspections.

Better than nothing

Better than nothing … just.

My records now are equally terse, but up-to-date and reasonably informative. I’ve got a numbering system for my colonies and queens that means they can be tracked through the season. The records are dated (rather than ’last Friday’) so I can calculate when important events – like queen emergence or mating – are due.

They’re also legible, which makes a huge difference. I could just about read my old scrawled pencil notes a few days after an inspection, but would have had no chance 5 months later.

By which time I’d have lost the little notebook anyway.

So, at some point over the next few months – sooner rather than later – I’ll look through my records, update the ‘queen pedigree’ table 3 and summarise things for the season ahead.

In the spring I’ll update a new sheet of records with a short note on overwintering strength/success and then we’ll be ready to go.

But, in reviewing the records I’ll remind myself about the things I ran out of, the timing of swarm control (when there’s the maximum pressure on available kit) and ideas I might have noted down on how things could have been done better 4.

Reading and listening

The winter is a great time to catch up on a bit of theory. Some beekeepers do exam after exam, pouring over Yates’s Study Notes until they can recite chapters verbatim.

I’ve done enough exams in my lifetime for … a lifetime, and have no intention of doing any more.

However, I’m always happy to do a bit of reading. I’ve currently got The Native Irish Honey Bee and Joe Conti’s The Hopkins Method … (which I’ll return to shortly) by my desk. I’m also partially successfully at keeping up with some of the relevant scientific literature 5.

A larger and more enthusiastic audience than usually seen at a beekeeping talk

There are also numerous winter talks available. Some are through local associations, others are available more widely. I ‘virtually’ attended one this evening where there were questions from as far apart as Orkney and Tasmania.

Of particular relevance to Scottish beekeepers, it’s worth noting that our association membership fees are usually significantly less than south of the border (probably because your SBA membership is separate), so you can inexpensively belong to a couple of associations and benefit from their talks programmes and – if you’re lucky – Co-Op purchasing schemes 😉

My attendance at these talks is less good than it should be, largely because I give a lot of talks each winter, but I instead benefit from the Q&A sessions which can be both entertaining and informative.

OK … enough theory

Theory is all well and good, but beekeeping is a practical pastime and just because it’s dark, cold, wet and windy, doesn’t mean there isn’t practical stuff you could be doing.

Competitive beekeepers will use the time to prepare the perfect wax block or bottle of mead for their – local or national – annual honey show.

I’m not competitive, and my wax is pretty shonky but I’ve had fun making (and more fun testing) mead 😉

But there are lots of other things to do …

The known knowns

By reading your comprehensive notes you will know that you ended the season with 5 colonies, that swarming started in mid-May but was over by early July, and that you’ve got one really stellar queen you’d like to raise 2-3 nucs from.

All of which means you are going to need a minimum of 60 new frames next season. These need to be ready before swarming starts.

Bamboo foundationless frames

Bamboo foundationless frames

How did I get to 60?

About a third of brood frames should be rotated out and replaced each season (~20). The nucleus method of swarm control uses the fewest frames, but you’re likely to have to use swarm control for all your colonies (~25). Then there’s a further 15 frames for the 3 additional nucs you want to prepare. Of course, if you’ve got lots of stored drawn comb 6 or you use double brood boxes, or Pagden’s artificial swarm method these numbers will be different.

The point is, you will need extra frames next season.

I’m ending this season with about 20 colonies and so expect to need over 200 frames next year, possibly more if queen rearing goes well. Some frames will be recycled foundationless frames but others will contain normal wired foundation.

And what about supers? 2022 was a good year for honey. If you had enough supers and super frames you’ll probably be OK in an average year.

Whether it’s average or not, it’s always easier to build the frames – well-fortified with tea and cake – in the winter, rather than in a rush as you prepare to go to the apiary.

Exactly the same type of arguments apply to any other routine piece of kit – broods, supers, crownboards, roofs, clearers. Buy or assemble and prepare them in the winter.

After Tim Toady try something new

A few weeks ago I introduced the Tim Toady concept. For just about any beekeeping activity, there are numerous ways that it can be completed. There must be dozens of different methods for swarm control or queen rearing, perhaps more.

Of course, however many methods there are, all – at least all the effective ones – are based upon the basic timings of brood development and of the viable fractions of the colony. These things don’t change.

The biology of the honey bee is effectively unvarying.

Queens take 16 days to develop, drones take 32 days (from the egg) to reach sexual maturity. A queen and the flying bees are a viable fraction, as are the nurse bees and young brood etc.

Despite being based around these invariant 7 biological facts, not all swarm control or queen rearing methods are equal. Certainly, the end results might be similar, but some methods are easier, use less equipment, need less apiary visits or whatever i.e. some methods probably suit your beekeeping better than others.

My advice about this plethora of different methods to achieve the same ends remains exactly what it was a month ago … learn one method really, really well. Understand it. Become so familiar with it that you don’t need to worry about its success 8.

And then, after a bit of winter theory, plan to try something different.

And the winter is the ideal time to build any new things you might need to try this alternative method next season.

Here are a couple of my past and current winter projects.

Morris boards

Probably 90% of my queens are produced using the Ben Harden approach. It was the method I first learnt, and remains the method I’m most confident with. I’ve found it a reliable small scale method for rearing queens.

But, as they say, ’familiarity breeds attempt’ (at something new) and I’ve always liked the elegance of the Cloake board. This is a split board with an integral queen excluder and a horizontal slide. You place it between the boxes in a strong double-brood colony. By inserting the slide, opening upper front and lower rear entrances and simultaneously closing the front lower hive entrance you render the top box temporarily queenless and enable it to get stuffed with all the returning foragers 9. The queenless upper box is now in an ideal state for starting new queen cells from added grafts.

Morris board

But most of my west coast bees don’t end up as booming double brooders … the standard Cloake board needs too many bees for my location.

Parallel Cloake boards 

Which is where the Morris board comes in. It’s effectively two parallel Cloake boards. Paired with a ‘twinstock-type’ divided upper brood box (or two cedar nuc boxes) it works in the same way as the Cloake board, but only needs sufficient bees to pack a 5-frame nuc so is better suited to my native bees.

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

You can buy Morris boards … or you can easily build them. This was one of my winter projects in ’20/’21. I’ve used them for the last two years successfully and have been pleased with the results.

I don’t think I understand their use as well as the Ben Harden system … but I will. In particular, I have yet to crack the sequential use of one side, then the other to rear a succession of queens.

Portable queen cell incubator

This was my one big project last winter. Unfortunately, we had a shocker 10 of a summer on the west coast and it was rarely used. I did put a few queen cells through it successfully, but queen rearing generally was hit and miss (mainly miss) so it’s yet to prove its full worth.

Portable queen cell incubator version 2

This is version 2 of the incubator. I’m gradually compiling a list of opponents for version 3 11 that should correct a few things that could be improved – capacity, level of insulation, heat distribution – though the current incarnation is probably more than adequate.

Building – and testing, which actually took a lot more time – the queen cell incubator was a lot of fun. I discovered (and created 🙁 ) a series of problems that needed to be solved and, relatively inexpensively 12, enjoyed sorting them all out. I could work in my warm, well-lit workroom, drink gallons of tea, and dabble with 12V electrickery without endangering my life.

I’ve used it this season powered by a 12V transformer indoors, from an adapter in the car or from a battery with solar backup in the apiary.

However, to use it properly I need to rear more queens … which brings me to … 

Queen rearing without grafting

Both the Ben Harden and Cloake/Morris board methods of rearing queens use a suitably-prepared colony in which young larvae are presented. Typically 13 these larvae are grafted from a suitable donor colony.

Grafting is perceived by some as a ‘dark art’ – though perhaps not exactly malicious – involving a combination of sorcery, spells, fabulous eyesight and rock-steady hands 14.

It isn’t, but this perception certainly dissuades many from attempting queen rearing.

Capped queen cells

Capped queen cells produced using the Ben Harden queenright queen rearing system

I find grafting relatively easy and routinely expect 80-90% ‘take’ of the grafted larvae. My sorcery and spells are clearly OK. However, in the future, my eyesight and manual steadiness/dexterity are likely to decline as I get older 15.

I’ve also been reading some papers on how the colony selects larvae to develop into queens. Their strategy isn’t based upon what they can see and pick up with a 000 sable paintbrush … funny that.

I’m therefore going to try one of the graft-free methods of rearing queen cells, and the approach I intend to use is the Hopkins method. Hence the part-read copy of Joe Conti’s book mentioned earlier.

The Hopkins method of queen rearing

This method involves the presentation of a frame of suitably-aged eggs and larvae horizontally over a brood box packed with young bees. Importantly I mentioned both eggs and larvae as, under the emergency response colonies preferentially rear new queens from 3 day old eggs.

The resulting queen cells are cut from the frame and used to prime nucs or mini-nucs.

Even with my presbyopia and ’hands like feet’ I should be able to manage that 😉

The intention is to couple the Hopkins method with a 12-frame double-brood queenless nuc box which is subsequently split into several nucs for mating the new queens. And, if that wasn’t enough, I’m hoping I can integrate this with some swarm prevention for the donor colonies … time will tell.

All of that means I need some new kit 🙂

Before butchery photo … an eke being adapted for the Hopkins method of queen rearing

I purchased some Maisie’s poly nuc boxes, floors, feeders and ekes in the summer sales. In the winter I’ll spend some time butchering them with my (t)rusty Dremel ‘multi-tool’ to accommodate the horizontal brood or super frames (and a cell bar with grafts for good measure) before painting them a snazzy British racing green or Oxford blue 16.

More poly hive butchering

I’ve already done a little poly hive butchering this winter.

I’ve got about 20 Everynucs from Thorne’s. These are a thick-walled, well made nuc with a couple of glaring design flaws. However, I’m prepared to overlook these as, a) they’re relatively easy to fix, and b) they cost me a chunk of money and I’m loathe to spend at least the same amount again to replace them.

In addition, bees overwinter fantastically well in them.

Here's one I prepared earlier

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

I’ve also got a few compatible feeders which are really designed for feeding syrup. You can add fondant, but the bees then need to follow a rather convoluted path to access it.

Everynuc feeder ...

Everynuc feeder …

I decided to modify the feeders to allow both by fitting a syrup-proof dam about half way along the feeder and drilling some 3-4 cm holes through the resulting ‘dry’ side of the feeder 17 .

Wooden syrup-proof dam and holes in an Everynuc feeder

Fondant, ideally in a transparent/translucent plastic food container 18 is inverted over the holes and the bees have direct access to it, even in the very coldest weather.

Munchity crunchity … direct access to the fondant

The Ashforth-type syrup feeder still works if needed and I no longer need 8 gallons just to top up each nuc 19. Typically my nucs won’t need feeding in midwinter, but if they do I should be able to position the fondant directly over the cluster allowing them the best chance of reaching it.

Winter weight

This is a practical project carried over from last year. I’m interested in the changing weight of the hive as the colony segues from ‘maintenance’ mode to early season brood rearing. I’ve drawn some cartoon graphs where there’s a clearly visible inflection point, with the hive weight dropping much faster once brood rearing starts.

Hive scales

I’m keen to have some real data rather than just my crummy cartoons. I already have the tools for the job, my no expense spared made hive scales. Tests last year showed that these were pretty accurate; I was about 8% shy of the actual weight (which doesn’t matter a jot, it’s the percentage change in weight that’s critical) and, more importantly, produced readings that were reproducible within a percent or two.

However, last year I was thwarted by bad weather, a lack of Gore-tex and an unexpected delay in evolving gills. I’ve now bought a sou’wester and, in the name of science, am preparing to brave the elements every week or so to weigh half a dozen hives.

And in between all that lot I’ll be building frames 🙂 20


Note

The other winter project already part-completed is moving this site to a new server. Frankly this has been a bit of a palaver, but I think it’s now sorted.

If you had problems connecting over the last few evenings, apologies. If things still seem odd, slow, broken or unresponsive drop me a note in the comments or by email. Of course, if you can’t connect at all you’ll never read this postscript 🙁 .

The changes I’ve made will enable some new things to be incorporated over the next few months, once I’ve got a bit of spare time and have built all of those frames 😉

Mini-nucs: tips and tricks

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

Introduction

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

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

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

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

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

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

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

Painting and decorating

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

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

Hammerite Oxford blue, since you asked

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

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

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

Entrances and exits

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

But I will 😉

Entrance discs for mini-nucs

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

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

Crownboards

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

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

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

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

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

Feeder mods

The Kieler integral feeder has some good and bad points.

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

You win some, you lose some!

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

Feeder with queen excluder

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

Be thankful for small victories … 😉

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

Kieler frame feeders

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

Frames

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

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

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

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

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

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

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

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

Judging queen quality

You can’t … or at least I can’t.

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

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

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

Brood frame with a good laying pattern

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

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

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

Queen introduction

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

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

Checking for aggression

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

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

Rear some spares

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

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

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

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

Queen rearing diary; automagically populates days and events

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

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

Keeping things going

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

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

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

Mainly good organisation.

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

Scrub ‘caretaker’ queens

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

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

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

The end of the queen rearing season

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

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

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

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

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

Using mini-nuc brood frames

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

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

Overwintering mini-nucs

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

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

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

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

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

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

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

Gimme shelter

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

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

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

Tunnel entrances to overwintered mini-nucs

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

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

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

Finally

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


References

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

Mini-nucs: the basics

Synopsis : Mini-nucs are a good way to get queens mated. They are inexpensive, use few resources and are relatively straightforward to use. This post describes the basic features and use of mini-nucs for mating in miniature.

Introduction

Mini-nucs are the small hives some beekeepers use for queen mating.

Pedantically, queen rearing could be considered the generation of queen cells with – in due course – the production of virgin queens. However, it’s a rather pointless exercise if it’s not also followed – in pretty short order – by queen mating.

A queen needs the support (and probably encouragement!) of a colony of some sort while she becomes sexually mature, goes on her orientation and mating flights, packs her spermathecae and then starts laying eggs.

The hive can be anything from a full-sized double-brood colony, possibly containing over 40,000 bees, to a container no larger than two egg boxes primed with 300 ml (perhaps no more than 1000) of bees.

Kieler mini-nuc

Clearly, dedicating a full colony for queen mating (unless she is destined to stay in the same box of course) is resource-intensive and impractical. For this reason most beekeepers who rear more than a very few queens will use smaller hives for queen mating.

Even using 4-6 frame nucleus colonies for queen mating is very demanding of resources; each needs to be started with a frame or two of emerging brood and the adhering bees and a frame of stores, possibly with some additional bees shaken in on top. Getting half a dozen queens mated in these ‘full-sized’ nucs might requires ‘gutting’ two complete colonies 1.

But you don’t need to use a full-sized nuc … with care you can scale things down … a lot.

How mini is a mini-nuc?

When I started beekeeping the hive choice for queen mating was either a ‘full-size’ 5 frame nuc or the mini-nucs manufactured by Apidea or Kieler (the latter are sometimes sold as Warnholz mating hives).

Apidea mini-nuc

I’ve used Kieler’s for years. They are the only type I own … largely because they were appreciably cheaper than Apidea’s. Were and are … a Kieler costs about £22 and the Apidea is £36 2.

Since I started (which wasn’t that long ago) the choices have proliferated. There are now a plethora of plastic or polystyrene equivalents to Apidea’s or Kieler’s. Some may be better, some may be worse. Many are less expensive (at least than an Apidea).

I’m sure all can be made to work and the general principles I discuss below probably apply to the majority of these true mini-nucs (and any number of homemade equivalents). Note that both Kieler’s and Apidea’s can be extended by the addition of a second story which are really needed for overwintering queens in these small boxes. If you aspire to try that, make sure whatever make you choose is extendable.

Kieler with ‘upper storey’ added … not so mini now

In addition to these mini-nucs there are now hives that take frames about 15 cm square, or homemade versions using half-size super frames in a super divided four ways. None of these are really mini-nucs. I’ve no real experience of them and so can’t talk about their pros and cons. Friends who have them tend to rave about how good they are, but I’ve too much incompatible equipment already and can’t justify their additional cost (they can be three times the price of a Kieler).

A love-hate relationship

I have a love-hate relationship with my mini-nucs.

I love …

  • the limited resources needed to set them up. A cup full of bees, a lump of fondant and a mature queen cell gets you started.
  • their value for money. A Kieler costs less than a pretty cheap commercial queen and you can produce 2-3 mated queens in a single Kieler in one season. If you buy (or sell) queens they pay for themselves within a season.
  • the speed with which queens get mated and start laying. In my experience this is significantly less time than a 5 frame nuc, and less still than a full hive.

However, it’s not all good news. There’s a lot to dislike about mini-nucs as well, this includes …

  • the work involved in setting them up properly. I’ll discuss this further below.
  • their size and my fat fingers. The clue is in the name. Mini-nuc. Finding the queen is easy, but manipulating the frames can be a little awkward.
  • the maintenance they need. Mini-nucs are high maintenance. If you’re not careful, during a dearth of nectar they will starve, during a glut they will pack the box completely, during a cold spell they will freeze and during a heatwave they will abscond. And, if none of these things happen, they’ll get robbed out by wasps 3.

When I lecture or teach queen rearing for beginners I recommend using 5 frame nucs until you can produce good queen cells reproducibly and as needed. Then try some mini-nucs …

General principles

Whatever the make, all mini-nucs are used in broadly the same way.

The empty box contains 3-4 frames, often just consisting of a topbar and a starter strip, and a compartment for food. You can fill the latter with syrup or fondant (or damp granulated sugar). It’s worth noting that some manipulations of these little boxes may require them to be inverted at the start, so you either need to add syrup later or use fondant.

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

A cup full (perhaps 250 ml to 300 ml) of bees is added to the mini-nuc and left for a few hours (at least) so that the bees realise they are terminally queenless. You then add a near-to-emergence queen cell, or run a virgin queen in through the entrance.

The mini-nuc needs to be placed in the mating apiary, not too close to queenright hives (or you can lose some of the bees added to the box). These hives are very poor at thermoregulating – there aren’t enough bees present – and they readily overheat. Therefore, place the mini-nuc in dappled shade or somewhere it doesn’t get the full strength of the sun.

Gimme shelter … an Apidea mini-nuc ‘catching a few rays’ … a recipe for absconding

The entrance is opened and 7-10 days after the queen emerges she should be mated and laying. You remove the mated queen and add another near-to-emergence queen cell … ad infinitum, or at least until the end of the season.

After removing the last mated queen of the year you shake the bees out and store the mini-nuc in the shed for the winter months.

What could be easier?

Of course, it’s not quite that straightforward …

Stocking mini-nucs

Ideally you stock a mini-nuc with young worker bees. Older workers are more likely to disappear back to the hive they came from (unless you move the mini-nuc a few miles away) and will be less good at drawing comb. Young bees are also likely to survive for long enough to rear the new brood once the queen is mated and laying.

Note that I also stated worker bees … you should avoid including drones, firstly because they contribute nothing to the functioning of the little colony, and secondly because you probably want the queen to mate with drones from outside the apiary 4.

There are lots of ways of achieving this, some more complicated than others. The best description I’ve read is by ModernBeekeeping in the instructions 5 they provided with Kieler hives.

In brief, this involves:

  • finding the queen in a strong hive and placing her somewhere safe (on a frame in a two-frame nuc, or in a cage in your pocket … she’ll be fine in either for a few hours).
  • moving the brood box to one side and placing an empty brood box on the hive floor.
  • shaking all the bees from the brood frames into the empty brood box. Work fast. The bees will try and clamber out. Give them a few sprays of water from a plant mister to help contain them 6.
  • placing a queen excluder over the bee-filled-but-otherwise-empty brood box, then putting the brood box and brood-filled frames on top of this.
  • retiring for a well-earned cup of tea.

About three hours later …

While you were drinking tea the young bees moved up through the queen excluder to tend the brood. The drones will remain below the queen excluder and a lot of the foragers should be out foraging. You’ve effectively isolated the young bees and so can now harvest them.

Each fully-covered frame has 2500-3000 bees on it … you’ll need about 1000 for each mini-nuc.

Getting them from the frames in the brood box to the mini-nuc involves the following:

  • shaking the bees off the frame into a deep, smooth sided container with curved internal corners/joints. A washing up bowl is suitable, a picnic cooler is better.
  • periodically misting the bees in the container with water. Don’t drown them. Just spray them enough to stop them crawling up the sides too much. It helps to give the container a sharp bash onto the ground every now and then to shake the bees down to the bottom again. But remember … you need live bees in your mini-nuc so treat them as gently as possible.
  • scooping up 300 ml of bees into a flexible, clear measuring container. I use a cut-down 2 litre drink bottle; prepare it in advance by adding 300 ml of water and marking where the meniscus is. That’s the volume of bees you need.

Mister and bee-measuring-scoop

  • quickly pouring the damp bees into the mini-nuc. If you’re using Kielers you do this by adding them through the removable floor with the hive inverted on the ground or table. It’s easier doing it like that than trying to add the roof – one handed, after adding the topbar frames, with bees clambering out everywhere (which can be carnage). Take my advice, fill the feeder with fondant and add the bees to an inverted Kieler.

Kieler’s ready for stocking with bees

Tidying up

The more bees you harvest from the donor hive, the less able it will be to look after the brood it contains 7. Therefore, if you’re filling several mini-nucs you will probably need to harvest the bees from multiple hives. All can be added to the same washing up bowl/picnic cooler before distributing them to the mini-nucs.

Once you have harvested sufficient young bees and populated the mini-nucs:

  • reassemble the donor hives and add back the queen. If you’ve harvested nurse bees from more than one donor, make sure you add the correct queen back to each hive! 8
  • place the mini-nucs somewhere cool and dark. I put them in the garage. Leave them closed up for 24-72 hours and mist them with water twice a day through the mesh floor panel.

Mini-nucs … populated, terminally queenless and panicking in Garrison Kieler (sorry)

Adding the queen cell and relocating to the apiary

  • add the queen cell 1-2 days before the queen is due to emerge. Apidea’s have a neat ‘port’ in the plastic crownboard through which the cell can be added. I do the same thing with a sheet of polythene on Kielers. If you’re doing this indoors (where escaping bees might be an issue for non-beekeeping members of the family) then do it at night with a red head torch. Bee can’t see red light and so won’t fly 9.
  • the following day, place the mini-nuc out in the apiary, open the entrance and let the bees fly. I tend to do this late in the afternoon.

Mini-nucs – note entrances facing in opposing directions

  • check the queen has emerged by recovering the opened queen cell a day or two later. There’s no need to look for the queen.
  • cross your fingers and wait 😉
And they're off

And they’re off …

It’s as easy as that?

Yes, in theory.

In reality though …

As with so many things to do with queen rearing, timing is very important. Typically you need to use the queen cells 10-11 days after grafting. Therefore the mini-nucs should be made up 2-3 days before that. When I lived in the Midlands, for the first round of queen rearing, this might have been in the third week of April.

Remember the proverb ‘March winds and April showers bring forth May flowers’?

In particular the ’April showers’ bit … 😉

In my experience, populating mini-nucs in the rain is probably the worst task in beekeeping.

All the bees are in the box.

They’re not happy being disturbed.

They are particularly unhappy about being unceremoniously shaken into a new box.

And, if it continues raining, they’ll be extremely resentful about being disturbed again when you return from drinking tea (and topping up your anti-histamines) to shake through the box again.

But, the queen cells will not wait.

Queen cells ready to ‘rock and roll’

If you’re going to do this for the first time, choose a really good flying day, ideally when there’s a nice flow on. The bees still won’t like being messed about with, but it will be a whole lot easier for you.

All sorts of other things can go wrong, and sometimes do. I’ve had misters block (having previously been used for syrup), I’ve tipped the picnic cooler over, I’ve put two queens back into one hive … I could go on.

It gets easier with experience and the effort is worthwhile. You’re setting up tiny little hives from which your precious queens will fly and get mated. And once established, they can be used several times without all the palaver involved in stocking them in the first place 🙂

Queen mating

It is my impression that queens tend to get mated faster from mini-nucs than they do from 5-framers, or full hives. Of course, I’ve never done a side-by-side comparison of the two 10, but I have talked to a number of experienced beekeepers who have expressed the same opinion.

Why should this be?

The consensus was that the small boxes give the queen fewer opportunities to hide, meaning that the workers can more easily chivvy her out on orientation and mating flights.

However, while re-reading Gilles Fert’s Raising Honeybee Queens (Fert, 2020) I found a comment that contradicts my experience:

American breeders have noted that queens in very small mini-nucs mate later than those from larger colonies, and with a success rate of just 60% to 70%. They found that tripling the volume of these mini-nucs boosted the success rate to 92%!

I’ll try and track the original source down … and determine whether the ’no space to hide’ and ’chivvied out by the workers’ have any basis in fact or are just the sort of daft ideas beekeepers share when stuck indoors on a wet day.

I’ve certainly not noticed a lower queen mating success using mini-nucs but, statistically, I’ve not used them enough to observe the difference between 70% and 92%.

A queen about to go on an orientation flight

Once you know the queen has emerged just leave the bees to get on with things, other than checking stores and space periodically. On good flying days, or potential queen mating days (which can be worse than you might imagine – it was 14.5°C when the photo above was taken), it’s important not to disturb the colony in case you interrupt an orientation or mating flight.

And, once you have your mated queen, you can use her for whatever you want … requeening production colonies, making up nucs for overwintering, selling or donating.

That’s all folks …

Of course, that’s nothing like all.

When I decided to write about mini-nucs I jotted down a list of interesting things to cover. Almost none of them are in the preceding 2,700 words 🙁

Typical.

That’s because I can’t cover some of the more interesting aspects of mini-nucs without covering the basics first. I’ll therefore return shortly – perhaps even next week – to this topic and waffle on about:

  • DIY modifications/improvements to Kieler’s
  • How to judge the quality of the queen
  • Repeat queen mating and ‘caretaker’ scrub queens
  • Overwintering mini-nucs
  • Emptying mini-nucs at the end of the season
  • And anything else I can think of in the intervening period.

Note

Mating in miniature is the title of a book by Bernard Möbus on queen mating in mini-nucs. It looks a little dated now (it was first published in 1983) but is an interesting read and, although the equipment has changed in the last 40 years, the principles remain much the same. I think it was published by BIBBA, but they no longer list it (and nor do Northern Bee Books). Try eBay?

References 11 

Fert, G. (2020) Raising Honeybee Queens: An illustrated guide. Deep Snow Press. ISBN 978-0-9842873-8-3