Category Archives: Practice

Leave and let die

If you follow some of the online discussions on Varroa you’ll see numerous examples of amateur beekeepers choosing not to treat so as to ‘select for mite-resistant bees’.

For starters it’s worth looking at the ‘treatment-free’ forums on Beesource.

DWV symptoms

DWV symptoms

The principle is straightforward. It goes something like this:

  • Varroa is a relatively new 1 pathogen of honey bees who therefore naturally have no resistance to it (or the viruses it transmits).
  • Miticide treatment kills mites, so favouring the survival of bees.
  • Consequently, traits that confer partial or complete resistance to Varroa are not actively selected for (which would otherwise happen if an untreated colony died out).
  • Treatment is therefore detrimental, at the population level if not the individual level, to the development of Varroa-resistant bees.
  • Therefore, don’t treat and – with a bit of luck – a resistant strain of bees will appear.

A crude oversimplification?

Yes, I don’t deny it.

There are all sorts of subtleties here. These range from the open mating of queens, isolation of apiaries, desirable traits (with regards to both disease resistance and honey production 2), livestock management ethics, our responsibilities to other beekeepers and other pollinators. I could go on.

But won’t.

Instead I’ll discuss a short paper published in the Journal of Apicultural Research. It’s not particularly novel and the results are very much in the “No sh*t Sherlock” category. However, it neatly emphasises the futility of the ‘do nothing and expect evolution to find a solution’ approach.

But I’ll start with a simple question …

How many colonies have you got?

One? (in which case, get another)

Two?

Ten?

One hundred?

Eight-two thousand? 3

Numbers matters because evolution is a numbers game. The evolutionary processes that result in alteration of genes (the genotype of an organism) that confer different traits or characteristics (the phenotype of an organism) are rare.

For example, viruses are some of the fastest evolving organisms and, during their replication, mutations (errors) occur at a rate of about 1 in 104 at the genetic level 4.

This is why we treat ...

This is why we treat …

But so-called higher organisms (like humans or bees) have much more efficient replication machinery and make very many fewer errors. A conservative figure for bees might be about 10,000 times less than in these viruses (i.e. 1 in 108), though it could be as much as a million times less error-prone 5

There are lots of other evolutionary mechanisms in addition to mutation but the principle remains broadly the same. The chance changes that are acquired by copying or mixing up genetic material are very, very infrequent.

If they weren’t, most replication would result – literally – in a dead end.

OK, OK, enough numbers … what about my two colonies?

So, since the evolutionary mechanisms make small, infrequent changes, the chance of a beneficial change occurring is very small. If you start with small numbers of colonies and expect success you’re likely to be disappointed.

Where ‘likely to be’ means will be.

The chances of picking the Lotto jackpot is about 1 in 45 million for each ticket purchased. If you expect to win you will be disappointed.

It could be you … but it’s unlikely

If you buy two tickets (with different numbers!) your chances are doubled. But realistically, they’re still not great 6.

And so on.

Likewise, the more colonies you have, the more likely you’ll get one that might – by chance – acquire a beneficial mutation that confers some level of resistance to Varroa.

Of course, we don’t really know much about the genetic basis for resistance (or tolerance?) to Varroa in honey bees. We know that there are behavioural changes that increase survival. We also know that Apis cerana can cope with Varroa because it has a shorter duration replication cycle and exhibits social apoptosis.

There are certainly ‘hygienic’ and other traits in bees that may be beneficial, but at a genetic level I don’t think we know the number of genes that are altered to confer these, or how much each might contribute.

So we don’t know how many mutations will be needed … One? One hundred? One thousand?

If the benefit of an individual mutation is very subtle it might offer relatively little selective advantage, which brings us back to the numbers again.

Apologies. Let’s not go there.

Let’s cut to the chase …

Comparison of treated vs untreated colonies over 3 years

Miticides – whether hard chemicals like Amitraz or Apistan or organic acids like formic or oxalic acid – work by exhibiting differential toxicity to mites than to their host, the bee. They are not so specific that they only kill mites. They can harm other things as well … e.g. if you ingest enough oxalic acid (5 – 15g) it can kill you.

Amitraz

Amitraz …

Jerzy Wilde and colleagues published their study 7 comparing colonies treated or untreated over a three year period. The underlying question addressed in the paper is “What’s more damaging, treating with potentially toxic miticides or not treating at all?”

The study was straightforward. They started with 100 colonies, requeened them and divided them randomly into 4 groups of 25 colonies each. Three received treatment and one was a control.

The ‘condition’ of the colonies was measured in a variety of ways, including:

  • Colony size in Spring (number of combs occupied)
  • Nosema levels (quantified by numbers of spores)
  • Mite drop over the winter (dead mites per 100g of ‘hive debris’)
  • Colony size in autumn (post-treatment) and egg laying rate by the queen
  • Winter losses

The last one needs some explanation because in one group (guess which?) there were more winter losses than they started the experiment with.

Overwintering colony losses were made up from splits of colonies in the same group the following year, so that each year 25 colonies went into the winter i.e. surviving colonies were used to generate additional colonies for the same treatment group.

Treatment and seasonal variation

To add a little complexity to the study the authors compared three treatment regimes:

  1. Hard chemicals only – active ingredients amitraz or the pyrethroid flumethrin (the research group are Polish, so the particular formulations are those licensed in Poland – Apiwarol, Bayvarol and Biowar).
  2. Integrated Pest Management (IPM) – a range of treatments including Api Life Var (primarily a thymol-based treatment) in spring, drone brood removal early/mid season, hard chemical or formic acid in late summer/autumn and oxalic acid in midwinter.
  3. Organic (natural) treatments only – Api Life Var in spring, the same or formic acid in late summer and a midwinter oxalic acid treatment.

The fourth group were the untreated controls.

To avoid season-specific variation they conducted the experiment over three complete seasons (2010-2012).

The apiary in winter ...

The apiary in winter …

The results of the study are shown in a series of rather dense tables with standard deviation and statistic significance … so I’ll give a narrative account of the important ones.

Results …

The strength of surviving colonies in Spring was unaffected by prior treatment (or absence of treatment) but varied significantly between seasons. In contrast, late summer colony strength was significantly worse in the untreated control colonies. In addition, the number of post-treatment eggs laid by the queen was significantly lower (by ~30%) in untreated control colonies 8.

Remember that early autumn treatment is needed to reduce Varroa infestation and so protect the winter bees that are being reared at this time from the mite-transmitted viruses.

Out, damn'd mite ...

Out, damn’d mite …

The most dramatic effects were seen in winter losses and (unsurprisingly) mite counts.

Mites were counted in the hive debris falling through the open mesh floor during the winter. In the first year the treated and untreated controls had similar numbers of mites per 100g of debris (~12). In all treated colonies this remained about the same in each subsequent season. Conversely, untreated controls showed mite drop increasing to ~43 in the second year and ~114 in the final year of the study.

During the three years of the study 30 untreated colonies died. In contrast, a total of 37 colonies from the three treatment groups died.

The summary sentence of the abstract to the paper neatly sums up these results: 

Failing to apply varroa treatment results in the gradual and systematic decrease in the number of combs inhabited by bees and condition of bee colonies and consequently, in their death.

… and some additional observations

Other than oxalic acid, none of the treatments used significantly affected the late season egg laying by the queen. Api Life Var contains thymol and many beekeepers are aware that the thymol in Apiguard quite often stops the queen from laying. Interesting …

I commented last week on queen losses with MAQS. In this Polish study, 8 of 50 colonies treated with formic acid suffered queen losses.

In the third season (2012) 45% of the 100 colonies died. More than half of these lost colonies were in the untreated controls. In contrast, overall colony losses in the first two years were only 9% and 13%. Survival of untreated colonies for a year or two is expected, but once the Varroa levels increase significantly the colony is doomed.

Overall, colonies receiving integrated pest management or hard chemical treatment survived best.

Evolution …

March of Progress

Evolution …

Remind yourself where the colonies came from that were used to make up the losses in the treatment (or control) groups … they were splits from colonies within the same group. So, colonies that survived without treatment were used to produce more colonies to not be treated the following season.

Does this start to sound familiar?

Jerzy Wilde and colleagues started with 25 colonies in the untreated group. They lost 30 colonies over a 3 year period and ended up with just two colonies. Had they wanted to continue the study they would have been unable to recover their losses from these two remaining colonies.

If you don’t treat you must expect to lose colonies.

Lots of colonies.

Actually, almost all of them.

… takes time

This study lasted only three years. That’s not very long in evolutionary terms (unless you are a bacterium with a 20 minute replication cycle). 

It would be unrealistic to expect Varroa resistance to almost spontaneously appear. After all, there are about 91 million colonies worldwide, the majority of which are in countries with Varroa. Lots of these colonies will not be treated. If it was that easy it would have happened many times already.

What happens when you start with more colonies and allow more time to elapse?

Well, this ‘experiment’ has been done. There are a number of regions that have well-documented populations of feral honey bees that are living with, if not actually resistant to, Varroa.

One well known population are the bees in the Arnot Forest studied by Thomas Seeley. These bees have behavioural adaptations – small, swarmy colonies – that lessen the impact of Varroa on the colony 9.

Finally, returning to the title of this post, there is the so-called “Bond experiment” conducted on the island of Gotland in the Baltic Sea. Scientists established 150 colonies of mite-infested bees and let them get on with it with no intervention at all. Over the subsequent six years they followed the co-evolution of the mite and the bee 10.

It’s called the “Bond experiment” or the Live and Let Die study for very obvious reasons.

Almost all the colonies died.

Which is why the title of this post is more appropriate for those of us with only small numbers of colonies.


 

Midseason mite management

The Varroa mite and the potpourri of viruses it transmits are probably the greatest threat to our bees. The number of mites in the colony increases during the spring and summer, feeding and breeding on sealed brood.

Pupa (blue) and mite (red) numbers

In early/mid autumn mite levels reach their peak as the laying rate of the queen decreases. Consequently the number of mites per pupa increases significantly. The bees that are reared at this time of year are the overwintering workers, physiologically-adapted to get the colony through the winter.

The protection of these developing overwintering bees is critical and explains why an early autumn application of a suitable miticide is recommended … or usually essential.

And, although this might appear illogical, if you treat early enough to protect the winter bees you should also treat during a broodless period in midwinter. This is necessary because mite replication goes on into the autumn (while the colony continues to rear brood). If you omit the winter treatment the colony starts with a higher mite load the following season.

And you know what mites mean

Mites in midseason

Under certain circumstances mite levels can increase to dangerous levels 1 much earlier in the season than shown in the graph above.

What circumstances?

I can think of two major reasons 2. Firstly, if the colony starts the season with higher than desirable mite levels (this is why you treat midwinter). Secondly, if the mites are acquired by the colony from other colonies i.e. by infested bees drifting between colonies or by your bees robbing a mite infested colony.

Don’t underestimate the impact these events can have on mite levels. A strong colony robbing out a weak, heavily infested, collapsing colony can acquire dozens of mites a day.

The robbed colony may not be in your apiary. It could be a mile away across the fields in an apiary owned by a treatment-free 3 aficionado or from a pathogen-rich feral colony in the church tower.

How do you identify midseason mite problems?

You need to monitor mite levels, actively and/or passively. The latter includes periodic counts of mites that fall through an open mesh floor onto a Varroa board. The National Bee Unit has a handy – though not necessarily accurate – calculator to determine the total mite levels in the colony based on the Varroa drop.

Out, damn'd mite ...

Out, damn’d mite …

Don’t rely on the NBU calculator. A host of factors are likely to influence the natural Varroa drop. For example, if the laying rate of the queen is decreasing because there’s no nectar coming in there will be fewer larvae at the right stage to parasitise … consequently the natural drop (which originates from phoretic mites) will increase.

And vice versa.

Active monitoring includes uncapping drone brood or doing a sugar roll or alcohol wash to dislodge phoretic mites.

Overt disease

But in addition to looking for mites you should also keep a close eye on workers during routine inspections. If you see bees showing obvious signs of deformed wing virus (DWV) symptoms then you need to intervene to reduce mite levels.

High levels of DWV

High levels of DWV …

During our studies of DWV we have placed mite-free 4 colonies into a communal apiary. Infested drone cells were identified during routine uncapping within 2 weeks of our colony being introduced. Even more striking, symptomatic workers could be seen in the colony within 11 weeks.

Treatment options

Midseason mite management is more problematic than the late summer/early autumn and midwinter treatments.

Firstly, the colony will (or should) have good levels of sealed brood.

Secondly, there might be a nectar flow on and the colony is hopefully laden with supers.

The combination of these two factors is the issue.

If there is brood in the colony the majority (up to 90%) of mites will be hiding under the protective cappings feasting on sealed pupae.

Of course, exactly the same situation prevails in late summer/early autumn. This is why the majority of approved treatments – Apistan (don’t), Apivar, Apiguard etc. – need to be used for at least 4-6 weeks. This covers multiple brood cycles, so ensuring that the capped Varroa are released and (hopefully) slaughtered.

Which brings us to the second problem. All of those named treatments should not be used when there is a flow on or when there are supers on the hive. This is to avoid tainting (contaminating) the honey.

And, if you think about it, there’s unlikely to be a 4-6 week window between early May and late August during which there is not a nectar flow.

MAQS

The only high-efficacy miticide approved for use when supers are present is MAQS 5.

The active ingredient in MAQS is formic acid which is the only miticide capable of penetrating the cappings to kill Varroa in sealed brood 6. Because MAQS penetrates the cappings the treatment window is only 7 days long.

I have not used MAQS and so cannot comment on its use. The reason I’ve not used it is because of the problems many beekeepers have reported with queen losses or increased bee mortality. The Veterinary Medicines Directorate MAQS Summary of the product characteristics provides advice on how to avoid these problems.

Kill and cure isn’t the option I choose 😉 7

Of course, many beekeepers have used MAQS without problems.

So, what other strategies are available?

Oxalic acid Api-Bioxal

Many beekeepers these days – if you read the online forums – would recommend oxalic acid 8.

I’ve already discussed the oxalic acid-containing treatments extensively.

Importantly, these treatments only target phoretic mites, not those within capped cells.

Trickled oxalic acid is toxic to unsealed brood and so is a poor choice for a brood-rearing colony.

Varroa counts

In contrast, sublimated (vaporised) oxalic acid is tolerated well by the colony and does not harm open brood. Thomas Radetzki demonstrated it continued to be effective for about a week after administration, presumably due to its deposition on all internal surfaces of the hive. My daily mite counts of treated colonies support this conclusion.

Consequently beekeepers have empirically developed methods to treat brooding colonies multiple times with vaporised oxalic acid Api-Bioxal to kill mites released from capped cells.

The first method I’m aware of published for this was by Hivemaker on the Beekeeping Forum. There may well be earlier reports. Hivemaker recommended three or four doses at five day intervals if there is brood present.

This works well 9 but is it compatible with supers on the hive and a honey flow?

What do you mean by compatible?

The VMD Api-Bioxal Summary of product characteristics 10 specifically states “Don’t treat hives with super in position or during honey flow”.

That is about as definitive as possible.

Another one for the extractor ...

Another one for the extractor …

Some vapoholics (correctly) would argue that honey naturally contains oxalic acid. Untreated honey contains variable amounts of oxalic acid; 8-119 mg/kg in one study 11 or up to 400 mg/kg in a large sample of Italian honeys according to Franco Mutinelli 12.

It should be noted that these levels are significantly less than many vegetables.

In addition, Thomas Radetzki demonstrated that oxalic acid levels in spring honey from OA vaporised colonies (the previous autumn) were not different from those in untreated colonies. 

Therefore surely it’s OK to treat when the supers are present?

Absence of evidence is not evidence of absence

There are a few additional studies that have shown no marked rise in OA concentrations in honey post treatment. One of the problems with these studies is that the delay between treatment and honey testing is not clear and is often not stated 13.

Consider what the minimum potential delay between treatment and honey harvesting would be if it were allowed or recommended.

One day 14.

No one has (yet) tested OA concentrations in honey immediately following treatment, or the (presumable) decline in OA levels in the days, weeks and months after treatment. Is it linear over time? Does it flatline and then drop precipitously or does it drop precipitously and then remain at a very low (background) level?

Oxalic acid levels over time post treatment … it’s anyones guess

How does temperature influence this? What about colony strength and activity?

Frankly, without this information we’re just guessing.

Why risk it?

I try and produce the very best quality honey possible for friends, family and customers.

The last thing I would want to risk is inadvertently producing OA-contaminated honey.

Do I know what this tastes like? 15

No, and I’d prefer not to find out.

Formic acid and thymol have been shown to taint honey and my contention is that thorough studies to properly test this have yet to be conducted for oxalic acid.

Until they are – and unless they are statistically compelling – I will not treat colonies with supers present … and I think those that recommend you do are unwise.

What are the options?

Other than MAQS there are no treatments suitable for use when the honey supers are on. If there’s a good nectar flow and a mite-infested colony you have to make a judgement call.

Will the colony be seriously damaged if you delay treatment further?

Quite possibly.

Which is more valuable 16, the honey or the bees?

One option is to treat, hopefully save the colony and feed the honey back to the bees for winter (nothing wrong with this approach … make sure you label the supers clearly!).

Another approach might be to clear then remove the supers to another colony, then treat the original one.

However, if you choose to delay treatment consider the other colonies in your own or neighbouring apiaries. They are at risk as well.

Finally, prevention is better than cure. Timely application of an effective treatment in late summer and midwinter should be sufficient, particularly if all colonies in a geographic area are coordinately treated to minimise the impact of robbing and drifting.

I’ve got two more articles planned on midseason mite management for when the colony is broodless, or can be engineered to be broodless 17.


 

The hairdryer treatment

I must be missing a couple of fingers. When I wrote the last post on hive and queen numbering I counted off the days to the end of this week, scheduled the post and was then quite surprised when it appeared on Wednesday.

D’oh!

That Friday feeling

That’s spoilt the pattern a bit.

To get back on schedule here’s a note about the well-known trick to revitalise foundation 1.

Frames and foundation

It’s the time of the season when many beekeepers will be running out of frames as they try and keep up with splits and swarming.

It’s sometimes difficult to get new foundation precisely when you need it. The suppliers sell out or delivery takes a week and you need it that afternoon 2. I therefore usually buy in bulk and store it somewhere cool and flat.

If you look after it properly foundation lasts for ages. Don’t go piling things on top of the stack and try not to damage the fragile edges. However, over time it becomes brittle and develops a pale waxy bloom on the surface. It also loses that lovely ‘new foundation’ smell.

The bees draw out this old rather tired foundation appreciably less well than they do new fragrant sheets. In my experience this is particularly noticeable in supers.

However, a few seconds with a hairdryer on a medium setting quickly restores the foundation to its original state.

Revitalising foundation

Don’t overheat it. The sheet will bow slightly as it is warmed. Treat both sides to try and keep it as flat as possible. The foundation will become slightly translucent and regains that lovely ‘new foundation’ smell as oils are released from the warmed wax.

It’s easier to do this once the foundation is fitted in the frame. However, old, brittle foundation is less easy to work with when you’re making up frames in the first place.

Or you could use foundationless frames 😉

Your call.


Colophon

The phrase ‘hairdryer treatment’ is most often associated with the last but one, two, three, four 3 managers of Manchester United FC, Sir Alex Ferguson. The BBC’s Learning English website describes it very well … When Sir Alex Ferguson was angry with his players, he shouted at them with such force, it was like having a hairdryer switched on in their faces.

Since I’m interested in etymology 4 and not football I’ve no idea what prompted the rise in use of the term in May 2013, visualised below on Google Trends.

Hairdryer treatment – Google Trends

Perhaps the May 2013 peak wasn’t Fergie or football at all … perhaps it was a flurry of articles on restoring old wax foundation 😉

Keeping track

It’s mid-May and the beekeeping season in Fife has segued from the early spring ‘phoney war’, where there’s not enough to do, to an earlier-than-normal swarming season where there’s not enough time to do everything needed.

I’ve got more colonies than ever, spread across three apiaries. Work, home and the Naughty Corner 1.

Numbered nuc and production colonies.

I’ve previously written about that stage in a beekeepers ‘career’ when he or she makes the transition from struggling to keep one colony to struggling to keep up with all the bees they have.

Some never achieve this transition.

Most can with suitable help, support and perseverance.

Others are ‘naturals’ – what’s the equivalent of green-fingered for beekeeping? Sticky fingered (er, probably not) or perhaps propolis-fingered? Whatever, these new beginners smoothly progress to a level of competency well above the norm.

Struggling to keep

Beekeeping is easy in principle, but subtly nuanced in practice. The enthusiastic beginner can struggle. They lose their first colony in the first winter. They buy another, it swarms and throws off several casts and they end up queenless in mid-season. A new queen is purchased, but too late for the main nectar flow.

No honey again 🙁

And, it turns out, too late to build up the colony to get through the winter 🙁

Thoroughly demoralised now, they are resigned to more of the same or giving up altogether.

The overwintered nuc of fashionably dark native bees they ordered from Bob’s Craptastic Bees 2 fails to materialise 3.

As does the refund of the £35 deposit 🙁

The empty hive sits forlornly in a patch of weeds at the end of the garden, smelling faintly of propolis and unmet promises.

Smelling faintly of propolis and unmet promises

And, in mid-May, a huge prime swarm moves in 🙂

The beekeeper has never seen so many bees in their life 4. How on earth do all those bees manage to squeeze into that little box?

Following advice from their new mentor, the beekeeper gently slides 11 frames into the box and is encouraged to treat for Varroa before there is any sealed brood. Considering their previous experience things go surprisingly well, not least because the bees have a lovely temperament.

The bees ignore, or at least gracefully tolerate, the beekeeper’s novice fumblings. Instead they single-mindedly focus on drawing comb, rearing brood and collecting nectar.

Struggling to keep up with

The summer is long and warm, with just enough rain to keep the nectar flowing. The hive gets taller as supers are added. By autumn there’s enough honey for friends and family and a partially capped super to leave for the bees.

The bees are lovely to work with and the confidence and competence of the beekeeper improves further.

After overwintering well, the colony builds up strongly again and by mid-May of the following year the beekeeper has used the nucleus method for swarm control and now has two hives. The bees remain calm, steady on the comb, well tempered and prolific.

Very prolific.

By the end of this second ‘proper’ year the beekeeper has two full colonies and a nuc to overwinter.

Overwintering 5 frame poly nuc

Overwintering 5 frame poly nuc

And so it goes on.

With good bees, good weather, a determination to succeed and supportive training and mentoring the problem should be keeping up with the bees, not keeping them at all.

Stock improvement

Some bees are better than others. Once you have more than one colony – and you should always have at least two – you start to see differences in behaviour and performance.

Frugal colonies overwinter on minimum levels of stores and, if fed properly, don’t need a fondant topup in Spring.

Well behaved colonies are steady on the comb, only get protective when mishandled and don’t follow you around for 200 yards pinging off your veil.

Some bees are great at making more bees but promptly eat all their stores as soon as the weather takes a downturn. Others regularly need three supers per brood box 5.

These traits become apparent over the course of a season and, of course, are diligently recorded in your hive notes 😉

Primarily these characteristics are determined by the genetics of the bees.

Which means you can improve your stock by culling poor queens and uniting colonies and expanding – by splitting or queen rearing – your better bees.

Keeping track

And in between the swarming, splitting, uniting, moving and re-queening the overworked (but now hugely more experienced) beekeeper needs to keep track of everything.

Or, if not everything, then the things that matter.

Which bees are in which box, where that old but good queen was placed for safety while the hive requeened, which box did the overwintered nuc get moved to?

I’ve discussed the importance of record keeping a few years ago 6. I still score colonies by objective (e.g. levels of stores, frames of brood, number of supers added) and subjective (e.g. temper/defensiveness, steadiness on the frame, following) criteria.

This takes just a minute or so. I don’t write an essay, just a simple series of numbers or ticks, followed if necessary by a short statement “Skinny queen, laying rate ⇓, demaree’d” or “Nuc swarm ctrl. O charged QC on W • frame. Knock rest off in 7 days. Emergence ~24th”.

Objective and subjective notes

I still use pretty much the same hive record sheet for these notes (available here as a PDF) as it has served me well.

Numbering colonies, hives, boxes and queens

What hasn’t served me so well are the numbers painted on the side of some of my hives.

These were supposed to help me identify which colony was which when I’m reading my notes or in the apiary.

Trivial in the overall scheme of things I know, but as colony numbers have increase and my memory goes in the opposite direction I’ve realised that numbers painted on boxes can be limiting.

For example:

  • The colony expands from single to double brood. There are now two numbers on the hive. Which do you use?
  • You do a Bailey comb change, consequently changing one brood box for another. Do you record the changed number or continue to refer to it by the old number?
  • You use the nucleus method of swarm control. The nuc is numbered. All good. The nuc expands and has to be moved into a hive. It’s the same colony 7, does the number change? It has to if the numbers are painted on the boxes.
  • Some hives seem to have never been numbered (or the number has worn off) in the first place. These end up being named ‘The pale cedar box’ or ‘Glued Denrosa’. Distinctive, but not necessarily memorable.

And that’s before we’ve even considered keeping track of queens. For work (and for some aspects of practical beekeeping) queens are sometimes moved.

“Easy” some would say. The characteristics of the colony are primarily due to their genetics. These are determined by the queen. The hive number moves with the queen.

It’s easy to move a queen. It’s a bit more work to move the 60,000 bees she’s left behind to free up the numbered box to accompany her.

More work yes, but not impossible 8.

OK, what about a colony that goes queenless and then rears a new queen? If the logic of hive/colony=queen prevails then logically the requeened colony should be renumbered.

There has to be a better way to do this.

Numbered boxes and numbered queens

I purchased some waterproof plastic numbered cards and some small red engraved disks 9. Both are designed for identifying tables in pubs or restaurants.

Numbers for hives and queens

Numbers for hives and queens

I use the plastic card numbers to identify colonies. These accompany the bees and brood if they move from one apiary to another, or as colonies are split and/or united. It’s the colony I inspect, so this provides the relevant geographic reference and is the thing I’m writing about to when my notes state “Nuc swarm ctrl. O charged QC on W • frame. Knock rest off in 7 days. Emergence ~24th”.

I use the red numbers to identify the queen. A queenless colony will therefore have no red disk on it.

When a nuc is promoted to a full hive the number moves with it. If the colony swarms and  requeens, one red number is ‘retired’ and a new one is applied.

My notes carry both the colony number and the queen number. I have a separate record of queens, with some more generic comments about the performance of the colonies they head.

Colony and queen numbering

The numbers are sold in 50’s … I use them at random 10. About half of them are in use at the moment.

If queen rearing goes well, swarming goes badly or things get out of hand, numbers 51-100 and engraved black disks are also available 😉

Finally, to make life a little simpler I bought a box of stainless steel 11 map pins. These are easy to grip with a gloved hand and don’t need to be prised out with a hive tool. They have the additional advantage of being short enough to not project beyond the handhold recess on the sides of most hive boxes so they can be pushed together if they’re being moved.

I’ve got no excuse for mix-ups now… 😉


 

 

 

A tale of two swarms

Or … why it’s good practice to clip the wing of the queen.

After a cool start to May it’s now (s)warmed up nicely. Colonies are piling in nectar, mainly from the OSR, and building up really strongly.

It’s at times like these that vigilance is needed. A skipped inspection, a missed queen cell, and the season can go from boom to bust as 75% of your workforce departs in a swarm.

Not the entire season … but certainly the first half of it.

All beekeepers lose swarms … but should try not to

Natural comb

Natural comb …

All beekeepers lose swarms.

At least, all honest ones do 😉

However, I can think of at least four reasons why it’s pretty shoddy beekeeping practice to repeatedly lose swarms 1.

  1. Beekeepers like bees, but some of the general public do not. Some are frightened of bees and a few risk a severe (or even fatal) anaphylactic reaction if stung. Beekeepers have a responsibility not to frighten or possibly endanger non-beekeepers.
  2. Most swarms do not survive. Studies of ‘wild’ bees have shown that swarming is an inherently risky business 2. The swarm needs to find a suitable new home and then collect sufficient nectar to draw enough comb to build up the colony and store food for the  winter. The vagaries of the weather, forage availability and disease ensure that most swarms do not overwinter successfully.
  3. Swarms have a high Varroa load. The mites transfer a heady mix of unpleasant viruses within the colony, shortening the lives of the overwintering bees. With high virus and mite loads the swarm colony is likely to be robbed by nearby strong colonies. This effectively transfers the mites and viruses to nearby managed colonies, so risking their survival.
  4. The swarmed colony is left with a new virgin queen. She has to mate successfully to ensure the continued survival of the colony. Again, the vagaries of the weather mean that this isn’t certain.

And you get less honey 🙁

Regular inspections help prevent the loss of swarms. But it’s good to get all the help you can.

Here’s a brief account of two recent events that illustrate the differences between swarms from colonies with clipped queens or unclipped queens.

Swarm in an out apiary

I have an out apiary in a reasonably remote spot containing half a dozen colonies. I keep my poorly behaved bees there 🙂 There are other apiaries in the area as the forage is good.

I went to inspect the hives at the end of April. This was only the second inspection of the year. On arriving I found most colonies were very active, but one was suspiciously quiet.

Thirty metres away there was a swirling mass of bees settling in the low branches of a conifer.

My three initial thoughts were “Aren’t swarms a great sight?”“Dammit, they shouldn’t have swarmed!” and “Perfect timing, where’s the skep?”.

Skep and swarm

Skep and swarm

The skep was in the car. It usually lives there during the swarming season. The bees were spread over two or three branches, all drooping under the weight. After a bit of gardening I managed to drop the majority of the bees into the upturned skep 3.

I inverted the skep over a white sheet laid out on the grass and propped one side up using a bit of wood.

The air was full of bees. While I busied myself inspecting the lively (in more ways than one 😉 ) colonies, the swarm gradually started to settle into the skep.

Skep and swarm

Skep and swarm

There were lots of bees exposing the Nasonov’s gland at the end of the abdomen, fanning frantically at the entrance to the upturned skep. This is a pretty certain indication that I’d managed to get the queen into the skep.

Fanning bees

Fanning bees

An hour later I’d finished all but one inspection – the quiet colony – it was beginning to get cool and the light was fading.

I could no longer see eggs, not because there weren’t any but because I’m not an owl.

The swarm still needed to be hived so I left the quiet colony until the following day, wrapped the skep in the sheet and took it to another apiary.

Brrrr!

And then the temperature plummeted. For the following week the daytime highs barely reached double figures. Nighttime temperatures were low single digit Centigrade.

The swarm would likely have perished and had a virgin queen emerged in the ‘quiet hive’ she’d have not got out to mate.

I didn’t look in another hive until the 7th, but when I did I got a surprise.

The ‘quiet hive’ contained a marked laying queen. I’d requeened this colony late in 2018 and my notes were a little, er, shambolic 🙁

I’d not recorded whether the queen was clipped and marked (the usual situation), marked only (not entirely unusual) or clipped only (not unknown!).

Whatever, they hadn’t swarmed after all 🙂

They were quiet because they had a high Varroa load with overt signs of DWV infection. Mite and virus levels in late September had been checked and confirmed to be very low. Presumably the mites had been acquired by drifting or robbing late in the season 4.

The hived swarm contained an unmarked laying queen and are lovely calm bees 🙂

A swarm in my home apiary

Fewer photos for this one as I didn’t have a camera with me …

I arrange my hives with the frames oriented ‘warm way’ 5 and inspect them standing behind the hive to avoid returning foragers.

Number 29, your time is up.

Number 29, your time is up.

Earlier this week I noticed a few bees flying under the DIY open mesh floor (OMF) from behind one hive. It’s not unusual to have bees at knee height during inspections but since all I was doing was dropping a nuc off in the apiary I didn’t give it much more thought.

Later in the week I returned to do the weekly inspection.

There were more bees going underneath the hive.

With a bit of effort I peered under the floor to find a 5cm deep slab of bees almost entirely filling the space under the OMF.

Better notes means you know what to expect

My notes were much more comprehensive this time 😉

I knew that the colony had a 2018 white marked and clipped queen.

I removed the supers (which were reassuringly heavy) and quickly inspected the brood box.

Lots of bees, lots of sealed brood, some late-stage larvae but no eggs.

In addition I could see two queen cells … one sealed and one about 3-4 days old, unsealed and with a fat larva sitting in a thick bed of Royal Jelly.

Don’t panic

It was pretty obvious what had happened.

The colony had swarmed 6 but the clipped queen, being unable to fly, had crashed to the ground in a very unregal manner, climbed back up the hive stand and sheltered under the OMF. The swarm had then clustered around her.

They had probably been there for a few days.

Another swarm hived

I placed a new floor and brood box next to the swarmed colony, with the entrance facing the ‘back’. I removed the swarmed brood box and, with a sharp shake, dumped the entire slab of swarmed bees from underneath the OMF into the new hive.

Before adding back all the brood frames I peered into the box as a tsunami of bees started moving from the floor up the side walls.

There! A white marked clipped queen 🙂

White clipped and marked queen returning to the colony

You’ll now have a better chance of finding and keeping her if they swarm.

It’s always reassuring to know where the queen is … and to have good enough notes to know what to look for 😉

I assembled and closed up the new hive and put the swarmed hive back in its place. I then carefully went through every frame checking for queen cells again.

There were only two. I destroyed the sealed cell. I didn’t know how old it was and couldn’t be certain it contained a developing queen.

In contrast, I could ‘age’ the unsealed cell (3-4 days) and knew it contained a larva and copious amounts of food.

I prefer to know when a queen emerges rather than save a few days by leaving the sealed cell. I only generally leave one cell to prevent casts being lost.

There were very young larvae in the colony. It is therefore possible the bees could generate more queen cells in the next day or so. Since I know when the queen will emerge I can check the colony before then and destroy any further cells they generate.

Two swarms, the same outcome … lessons learned

As far as this beekeeper (and I hope the bees 7) is concerned both swarms had a satisfactory outcome.

A number of lessons can be learned from events like these:

  • All beekeepers ‘lose’ swarms. Weather, work, emergencies and life generally can conspire to interrupt the 7 day inspection cycle. Sod’s Law dictates that when it does, the colony will swarm. I’m reasonably conscientious about inspections but I completely missed the signs the home apiary colony was about to swarm.
  • The weather can change suddenly. The swarm in the conifer would have probably perished from the cold in early May. If the weather had stayed warm the scout bees would have found a welcoming church tower or roof space to occupy in a day or so. In both cases the swarm would have been truly lost.
  • It’s always good to carry equipment to capture a swarm. A sheet and a skep, or a large nuc box. Secateurs make ‘gardening’ easier (mine are no longer AWOL). Spare equipment (hives) is essential during the swarm season.
  • An obviously smaller-than-expected colony and a nearby swarm may well be completely unrelated. Check why the colony is weak and take remedial action if needed (mine has Apivar strips in now).
  • Colonies near my out apiary appear to have high mite levels. Since that’s where the conifer swarm came from this also now has Apivar strips in.
  • When is a lost swarm not lost? When the queen is clipped. The queen cannot go far so neither can the swarm. If she returns to the hive stand or the underside of the floor, so will the swarm. If she perishes for some reason the swarm usually returns to the original hive.
  • You can keep bees without knowing where the queen is, but it’s easier if you do. Marking her helps find her, clipping her wing helps keep her there 8.
  • Similarly, knowing when the queen will emerge allows you to predict when she will be mated and start laying. You can avoid interrupting her returning from her mating flight and – before then – you can remove other queen cells to prevent the loss of a cast from a strong colony.
  • Good notes help. Keep them 😉

It’s relatively easy to find unmarked queens in smallish colonies early in the season. It’s a lot harder to find them in a strong colony in mid-May.

Mid-May ... 45,000 bees, 17 frames of brood, one queen ... now marked

Mid-May … 45,000 bees, 17 frames of brood, one queen … now marked and clipped

But it’s worth finding her, marking her and clipping one wing.

If you don’t the swarm you lose might really be lost 😉


 

 

Queen marking

You don’t need to see the queen during your weekly inspection of the colony. There are clues that are usually enough to tell you the colony is queenright. These include the general temper and demeanour of the colony, the presence of ‘polished’ cells ready for the queen to lay eggs in and, of course, the presence of eggs.

Of these, temper can be influenced by weather or forage availability 1 so might be less trustworthy.

Queenright?

Queenright?

And, of course, eggs only tell you the queen was present when they were laid … so sometime in the last three days.

Seeing is believing

If you really want to be certain there is a queen present – for example, because you need to put her in a specific place for swarm control using a Pagden artificial swarm or the nucleus method – then you need to find the queen.

I’ve discussed this before so won’t cover the subject again.

Having found her, how can you make it easier to find her again?

The obvious (pun intended) thing to do it to mark her in a way that makes her distinctive. She will therefore be easy to see amongst the thousands of her daughters running around the hive.

Marked queen surrounded by a retinue of workers.

Her majesty …

There are additional advantages to marking the queen.

The presence of a blob of paint also provides some temporal information.

If you find an unmarked queen in a hive that you know was previously occupied by a marked queen then:

  • the colony has swarmed and requeened itself … and your inspections are too infrequent!
  • the marked queen has been superceded 2. It’s not unusual to find an unmarked queen in a hive at the first inspection of the season, suggesting that the colony superceded the queen late in the previous year, or …
  • the paint has worn away 😉

If you use different coloured markings for different years you can even determine the age of the queen.

Tipp-Ex, Humbrol or Posca

You mark the queen by placing a contrasting spot of coloured paint on the top of her thorax.

Tipp-Ex (typing correction fluid) works perfectly well though the usual applicator brush is a bit too broad. It dries rapidly and the aliphatic hydrocarbon solvents it contains do not appear to adversely affect the odour of the queen.

Tipp-Ex is only available in white. Contrasting certainly, but this gives no opportunity to indicate the year the queen was reared.

As an alternative you can use one of the ~180 Humbrol Enamel paints. These are used by model makers to paint their locomotives, toy soldiers or Airfix kits and so are available in a wide range of not very useful shades like Dark Camouflage Grey or RAF Blue.

Fortunately they are also sold in some rather strident yellows, reds and greens that should be visible in the hive.

Humbrol Enamel paints are sold in small, rather fiddly little tins. Not ideal when you’re wearing gloves and a beesuit. They need shaking/mixing before use, open easily with the thin blade of a hive tool and can be applied with the end of a matchstick.

Despite the solvent base of Humbrol Enamel paint, it doesn’t dry particularly fast. I’ve only used it a few times and abandoned it in favour of …

Posca are water-based art pens. Their model PC-5M has a bullet tip ~2.5mm in diameter and so combines paint and applicator in one easy-to-use package. These pens also come in a wide range of colours.

Shock news! Beekeepers in agreement.

Beekeepers use different colours to indicate the year a particular queen was reared. Since queens rarely live more than 3 years a total of 5 different colours are sufficient to age-mark queens without confusion.

Amazingly 3, as far as I’m aware all beekeepers use the same queen marking colour scheme.

Colour Use in Year ending
White 1 or 6
Yellow 2 or 7
Red 3 or 8
Green 4 or 9
Blue 5 or 0

Queens reared this year (2019) should therefore be marked green.

Any colour as long as it’s white

Or blue.

I’m red-green colourblind. This means I struggle to discriminate between some reds and greens. It also means that I ‘trust’ colours (or my ability to distinguish between them) less. Subtle differences are often ignored 4.

A bright yellow dot on the thorax of a queen is easy to see … except in a colony that is piling in lots of OSR pollen, when every fifth worker is loaded down with bright yellow corbiculae.

I therefore only mark my queens white or blue.

These are both colours that I find easy to see, that are rarely present in pollen baskets or elsewhere in the hive, and so are very distinctive.

I used to alternate odd and even years until my blue Posca pen stopped working 🙁

Failing Posca queen marking pen

My white Posca pen has just starting playing up. If you search you can find them for about £5 for three and they last for years.

Easier said than done

I started an earlier section with the words “You mark the queen by placing a contrasting spot of coloured paint on the top of her thorax”.

Beginners can find this a daunting task.

After all, isn’t the queen the most important and precious member of the hive?

What if you squash her by accident? Or the other bees don’t like the smell of the paint and attack her? What if she flies away?

OK, the first of these is a disaster 5, but is relatively easily avoided using one of the methods described below. The second is unlikely if you let the paint dry properly and very unlikely if you use a water-based Posca pen.

The third is also unlikely … (mated) queens are generally reluctant to fly and, if they do, they fly poorly. You can generally pick her up from the grass near your feet 6. If you lose sight of her, close up the hive and carefully leave the area (watch where you step). She will usually return to the hive.

So, although it is easier said than done, marking queens is not that difficult and is a very useful skill to become competent and confident at 7.

To mark the queen she must be immobilised. There are essentially three ways to do this:

  1. On the frame, using a press in cage. Also called a crown of thorns (or crown of thorne’s, depending where you purchased it 😉 ) cage.
  2. Off the frame in a handheld queen marking cage.
  3. Off the frame simply holding her between your thumb and forefinger.

Crown of thorns or press in cage

Press in cage

Press in cage

The press in cage is a wood, plastic or metal ring with spikes protruding from one side. Over the top is a thread (or plastic in cheaper versions) mesh. You find the queen on the frame, place the press in cage over her without spearing her, or her retinue, push down gently to immobilise her and then apply a dab of paint to her thorax.

This is easier said than done.

Firstly, there are usually lots of bees on the frame the queen is on. Isolating her from her daughters can be tricky. The more you chase her around the frame the faster she runs … and then she disappears around the side bar and you have to start all over again.

You need three hands. You cannot hold the frame, the cage and the pen. The cage needs to be held when you use the pen. You therefore must place the frame down horizontally (usually on the top bars of the other frames) and the bees on the underside may not appreciate this.

As soon as you’ve isolated her the workers clamber on top of the press in cage, obscuring your view of the queen.

Your view isn’t good anyhow as you are hunched over the frame, almost certainly blocking the light and making everything more difficult to see.

Is it obvious I’m not a big fan of the press in cage?

I know I still carry one as I periodically stick the spikes through my fingers when rummaging around in my bee bag. However, I’ve not used it for years and far prefer to use a handheld queen marking cage.

Handheld queen marking cage

The simplest of these consist of a cylinder with one end covered in a thin open mesh made of thread and a foam-topped plunger.

Alternatively, and my favourite, the thread mesh is replaced with a series of horizontal plastic bars that are too narrow for the queen to crawl between.

Handheld queen marking cage

Handheld queen marking cage

You pick the queen off the frame, drop her into the cylinder, insert the plunger, immobilise her gently against the mesh/bars and apply the paint to her thorax.

Hold on.

Wait a minute.

You pick the queen off the frame?

That’s the easy part. Queen bees are naturally equipped with two convenient handles.

The wings.

The thumb and forefinger of an ungloved or thinly gloved hand are fabulously dextrous. It is easy to pick up the queen by one or both wings, move her away from the frame, put the frame down, pick up the queen marking cage and drop her in.

From frame to cage in a few seconds

I’m right-handed and this description is for right-handers.

Hold the frame (usually by the lug) with the queen on it in your left hand. Gently rotate the frame so the face is well-lit 8. Wait for the queen to be away from the edge of the frame. Wait until she’s walking towards you. Gently clench your third, fourth and fifth fingers, extending you ‘pincer-like’ thumb and forefinger. Slowly approach the queen from behind with this hand as she calmly walks across the frame 9.

Without grabbing or snatching calmly grasp her by the wing (or wings) and lift her from the frame. If you miss and just nudge her or she turns away at the last moment don’t harry her across the frame trying repeatedly.

Let her calm down.

Get your breath back.

Try again.

Gently put the frame down. Ideally, place it protruding at an angle in between the frames of the brood box. Take your time. Don’t drop the frame or allow it to tip over. If you balance it nicely with the lug wedged inside the box edge and the bottom bar balanced on the runner you’ll easily be able to reintroduce the queen after marking her.

Once your left hand is free pick up the cylinder of the queen marking cage. Drop the queen in. Cover it with two fingers (holding it between your thumb and fourth and fifth fingers). Pick up the plunger with your right hand and, after gently shaking the queen to the bottom of the cage, insert the plunger. Invert the cage, gently push the plunger up to trap the queen – thorax uppermost – and hold the plunger in place between your fourth and fifth fingers and palm, while holding the cage cylinder between thumb and forefinger (see the image further up the page).

There she goes ...

There she goes …

You can then use your right hand to apply the paint.

Handheld

Once you have learnt to pick the queen off the frame it’s an easy transition to do away with the queen marking cage and simply hold her on the back of your left forefinger, trapping her legs – so immobilising her – with your thumb and third finger. Ted Hooper’s book Guide to Bees and Honey has a good description of this 10.

This is easier without gloves. Even very thin nitrile gloves makes holding the queen immobile more difficult 11. Since I always wear gloves to reduce propolis staining and potential pathogen transmission I use a handheld queen marking cage.

Final comments on handling the queen

Picking the queen up with gloves on is straightforward if the gloves are thin enough. It’s easy with nitrile gloves and possible with Marigold-type washing up gloves.

Don’t try it with the large leather ‘beekeeping gauntlets’ as they give you hands like feet as a PhD student once said of the dexterity of my laboratory skills 🙁

If you hold the queen by both wings she will wave her legs in the air and curl her abdomen, but be unable to do much else.

If you pick her up by one wing she usually manages to swivel round and grab your thumb with her feet. Don’t worry, you won’t pull her wing off.

But thinking that will might make you lessen your grip … at which point she will calmly (or not so calmly) walk up your thumb. Don’t panic. She won’t sting and is very unlikely to take flight.

Queen marking

However you immobilise her the actual marking is straightforward. The goal is to place a small dab of paint on the top of her thorax.

Not on her head, her abdomen or her wings.

Small means 2-3 mm across. Don’t overload whatever you are using to apply the paint.

If it’s a matchstick just touch the surface of the paint (or Tipp-Ex).

If it’s a Posca pen, press the nib a couple of times against a firm surface (hive lid, thumb etc) to load the pen, check that it delivers the right amount with a light touch and then mark the queen.

I like to step away from the hive to mark the queen, perhaps to a corner of the apiary in light shade. This separates me from the flying bees and so I can focus on the job, literally, in hand 12.

Releasing the queen

Allow the paint to dry for a few minutes before releasing the queen.

If you’re holding the queen you’ll have to stay holding her while this happens (or put her in a matchbox). Enjoy your time with her … she’s going to be working hard for you 🙂

With a handheld queen marking cage I move the plunger down an inch or so and place her in the shade while I get on with something else for a couple of minutes.

With a press in cage just leave it a couple of minutes before gently lifting it off. This is the easiest and least traumatic way to release the queen (and one of the only advantages of this marking method). The queen is already on the frame and surrounded by bees, so there are no shocks or surprises.

The important thing to avoid when releasing the queen is to suddenly drop her onto the top bars or into the hive. There’s a possibility the the workers will ball and kill her.

Gently offer her to a gap between the top bars, or to the face of the frame you left protruding from the top of the hive. With the handheld cage it’s easy to just rest it on the top bars and watch.

She will usually calmly walk in and disappear from sight.

Calmly walks in …

Job done.


 

 

And they’re off …

I posted last week on the relative lateness of the start of the beekeeping season here in Scotland 1. Having been away for a few days I was both surprised and disconcerted to find this waiting for me when I arrived at the apiary to conduct the first inspections of the year.

When is a swarm not a swarm?

When is a swarm not a swarm?

Surprised because I’d missed all the seasonal clues that indicated swarming might be imminent.

Disconcerted because, in the interests of full disclosure, I’d have to admit to it 😉

The colony behind the near-invisible one inch entrance hole through the bee shed wall is a double brood colony in an Abelo poly hive. It was headed by a 2018 queen (or had been 🙁 ) and had a nice temperament and good manners.

The queen was marked blue and one wing was clipped to prevent her flying off.

But it wouldn’t have stopped her trying to fly off. Instead she would have ignominiously spiralled to the ground 2.

Usually what then happens is she attempts to climb back up and the swarm gathers around her. In a standard hive this is often this is underneath the hive stand.

My guess was that she’d made it up to the landing board and stopped or got stuck there.

I had a gentle prod about in the beard of well-tempered bees but could see no sign of her.

With about 20 more hives to inspect I quickly decided to walk them into a fresh hive … I’d let them do this while I got on with other colonies in the apiary.

Don’t think, do

Walk this way

Walk this way

I put together a new floor and a brood box of mostly foundationless frames. I put one or two frames of drawn comb in and gently dislodged a couple of clumps of bees into the box.

Within a very short time more bees were marching down the wall of the shed and clustering between the frames of drawn comb in the brood box.

What started as a trickle became – if not a torrent – then certainly a determined stream of bees taking up residence in the new box.

To encourage them I balanced a split board across the tops of the frames to provide a welcoming dark ‘cavity’ for them to occupy. Very soon you could see bees fanning strongly at the opening between the split board and the shed wall.

Fanning workers

Fanning workers

I interpreted this as meaning the queen had entered the box and the workers were encouraging others to join her.

After an hour or so I moved the hive a few inches away from the shed wall, placed a crownboard and roof on and carried on inspecting other hives in the apiary. By this time about 75% of the bees had left the ‘swarm’ and entered the brood box.

Not so fast

And that’s when everything ground to a halt.

There were no bees fanning at the hive entrance. No more bees entered the box through the entrance. Instead they started leaving in dribs and drabs.

I’ve hived swarms like this before, or done the classic ‘walk them up a sheet’ having dumped them from a skep outside a hive. Other than this being a real spectacle, one of the striking features is that what starts as a mass of bees ends being an absence of bees … they all enter the hive.

'Walking' a swarm into a hive

‘Walking’ a swarm into a hive

Clearly something was wrong and I was beginning to suspect that there wasn’t a queen in the ‘swarm’ at all.

So I did what I should have done in the first place. I had a look in the original hive.

Hello there!

Blue skinny queen

Blue skinny queen

I smoked the double brood box gently from the bottom, intending to encourage the queen (if she was there) into the upper box.

The box was busy but not packed with bees 3, there were good amounts of sealed brood (and a really nice tight laying pattern on many frames).

There were quite a few ‘play cups’ and a few had eggs in them. This is one of the early signs of swarming.

I found the queen on the 19th of 22 frames.

Perhaps I was too gentle with the smoke 🙄

She was the queen I was expecting. Marked blue, though the paint was beginning to rub off a bit, and with the left wing clipped.

She looked like she had lost a bit of weight.

Big fat queens in full laying mode (which they should be getting to by late April) aren’t very aerodynamic so workers slim the queen down before swarming to improve her flying ability.

This queen looked to me like she’d been on the F-plan diet (but remember I’d not seen her since last August). In addition, the number of eggs in the colony was relatively low. This would also be expected if the colony had been preparing to swarm as queens reduce their laying rate in the few days before swarming.

What else could be seen?

Stores and pollen levels were good.

The notable absence from the hive was of well developed, sealed or unsealed queen cells.

A colony will normally swarm once developing queen cells are capped. A colony with a clipped queen often delays swarming for a few more days. It’s therefore usual to find sealed queen cells in a swarmed colony. There may also be unsealed cells as well.

~3 day old queen cell ...

~3 day old queen cell …

There wasn’t anything close to a sealed queen cell in the colony 4. The best developed were, at the very most, a couple of days old.

So what happened?

Other than the absence of well developed queen cells the colony looked as though it had swarmed.

If it walks like a duck etc.

Since the queen was clipped she had eventually clambered back to the hive and re-entered, leaving many of the workers who had left with her clustered around the hive entrance.

That’s currently my best guess 5.

If that was the case, notwithstanding the current lack of well-developed queen cells, they’d be trying again as soon as the weather was good enough. I therefore decided to preempt them by doing a classic artificial swarm.

I moved the queen on a frame with a small patch of brood into the box I’d used to try and ‘walk’ the swarm into. I then moved the – now queenless – double brood box a couple of metres off to one side in the shed. Finally I placed the queenright box in the place the original colony had occupied.

And what will happen?

Full details are in the description of Pagden’s artificial swarm. The flying bees from the double brood box will return to the box with the queen. The hive bees in the double brood box will start to rear one or more new queens.

And at that point I’ll intervene.

The double brood box has lots of brood and stores spread across 21 frames. The bees are well tempered, stable on the comb and have no significant signs of chalkbrood or other diseases (and Varroa and virus levels are exceptionally low – I’d measured both 6).

They are a good stock to make increase from.

I’ll check them in a  few days and see how queen cells are developing. Once there are good sealed cells I’ll split the colony into several 3-5 frame nucleus colonies. The final number will depend upon the number of good queen cells and the number of bees left in the colony.

It should be possible to generate half a dozen good nucleus colonies from a suitable double brood colony without too much of a problem.

First inspection summary

I got through all my colonies (eventually). With a reasonable number to compare it’s easy to define the good, the bad and the indifferent ones.

It’s much easier to do this once the season is properly underway, which is a good reason not to inspect too soon in the year. Some colonies are very early-starters, others lag bit. If you inspect too early you might consider the slow ones are dud or failed queens.

I was pleased to see that most were good or at least indifferent, with only a couple clearly exhibiting undesirable personality traits – aggression, laziness, running, following – or, in one case, disease (rather too much chalkbrood). These will be destined for prompt requeening and drone brood will be removed to reduce their contribution to the gene pool.

My overwintered 5 frame nucs looked excellent, with a couple needing re-hiving immediately.

Here's one I prepared earlier

Here’s one I prepared earlier

The first inspection is really little more than a check that things are all OK. It doesn’t matter whether I see the queen. If there are eggs present I’m happy.

Eggs? Overt disease? Stores? Brood? Space? … next please!

Overwintering losses

I lost 10% of my colonies this winter – two from 20. This includes both full colonies and overwintered 5 frame nucs.

One colony drowned. The lid and crownboard blew away in a severe storm and they were subjected to a three-day deluge over a long weekend when I was away.

Mea culpa. I should have had more bricks on the roof.

Spot the drone laying queen

Spot the drone laying queen

In the second colony the queen failed and turned into a drone laying queen (DLQ). This had been my worst-tempered colony last year and was scheduled for requeening. However, the queen I found wasn’t the clipped and marked one I’d left there in August. Clearly there had been a late-season supercedure and the replacement queen was poorly mated.

Although she was a bee I didn’t keep it is great to be beekeeping again 🙂


Colophon

And they’re off! is the phrase used by horse racing commentators at the start of a race. It is also the title of a song composed by William Finn from the musical A New Brain. The song is about the damage gambling does to families. There’s a good cover version by Philip Quast on YouTube.

Natural vs. artificial swarms

I’ve now covered four of the most frequently used swarm control strategies. These are:

  • Pagden’s artificial swarm – the horizontal splitting of the colony
  • The vertical split – an equipment-frugal variant of the above involving a vertical separation of the colony
  • The nucleus method – in which the queen is removed with sufficient workers to make up a small (nuc) colony, leaving the original colony to rear another queen
  • The Demaree method – which, at its simplest, relocates the queen from the brood and associated nurse bees, but does not physically split the colony

If conducted correctly all should prevent loss of a swarm. However, the individual methods – even the first three which involve the physical separation of the bees in the hive – are not the same.

In addition, these swarm control methods do not recapitulate the separation of bees that occurs when a hive naturally swarms.

The purpose of this post is to contrast the original and new colony composition of the split-based methods of swarm control (i.e. Pagden and vertical) with natural swarms.

Temporal polyethism

I introduced this term when discussing the honey bee colony as a superorganism. It means that adult worker bees have different roles depending upon their age. For the first two and a bit weeks they have duties inside the hive such as cell cleaning, brood rearing and wax production.

They then transition through a period of being guard bees before becoming foragers, flying from the hive and collecting water, nectar and pollen.

For convenience I’ll refer to these two groups of bees as young, nurse or hive bees and flying bees.

Vertical and horizontal splits

The classic Pagden artificial swarm and the vertical split are fundamentally the same process.

If unsealed queen cells are found during a colony inspection the queen, with a frame of emerging brood, is moved to a new box. This box is placed on the site of the original hive.

The remaining bees and brood are moved, either to one side in the case of the Pagden or on top of the queen-containing box (separated by a split board) in a vertical split.

Split board ...

Split board …

Critically, the new box with the brood and bees is provided with a new hive entrance, located off to one side or on the opposite side of the original hive 1.

Flying home

Over the following day or two the flying bees leave the relocated brood box with the new entrance and return to the queen-containing brood box in the original location.

As a consequence of their excellent homing navigational skill, the hive manipulation results in the separation of the bees into two populations:

  1. The flying bees i.e. those over ~3 weeks of age that had orientated to the original hive location, which are now located with the queen.
  2. The nurse bees i.e. those less than 3 weeks old, which remain in the relocated brood box, together with the brood in all stages (eggs, larvae and pupae).
Artificial swarm separation of the colony

Artificial swarm separation of the colony

How does the artificial swarm compare with the age distribution of bees in a real swarm?

Real swarms

I’ve previously discussed prime swarms and casts. The former contain a mated queen. In contrast, casts are produced from very strong colonies after the prime swarm has left. Casts are headed by a virgin queen. These are sometimes called after swarms and are usually smaller than prime swarms.

What about the workers in the swarm? What might be expected?

Perhaps they’re primarily the older flying bees? After all, these are the bees that have finished their hive duties and are now routinely foraging outside the hive. It’s the natural place for them.

Swarm of bees

Swarm of bees

Alternatively, remember that swarms have no ‘homing’ instinct for a day or two after emerging. They can be readily moved and you can safely ignore the less than three feet or more than three miles rule. Perhaps this means that they’re primarily young bees that have yet to go on their orientation flights?

Real experiments and contradictory results

Enough speculation … how do you determine this experimentally?

There have been numerous studies of the age distribution of bees in natural swarms. However, the data tends to be rather contradictory though the methods used are often broadly similar.

How do you determine the age composition of workers in a swarm?

Essentially you ‘spike’ the colony with a set number of marked bees of a known age over about 8 weeks. This is easy to do, but tedious.

Workers are allowed to emerge in an incubator. On the day of emergence (0 days old) they are marked with a colour that distinguishes them from older or younger bees. Every three days 100 identically marked i.e. same age, bees are added to the study hive(s). Over the period May to July this will accumulate red, then yellow, then blue, then mauve, then cyan, then pink etc. cohorts of workers, each representing a known age class.

It must be a nightmare spotting the queen in these hives 😉

The colony is allowed to swarm, the swarm collected and the number of bees of the different age cohorts in the swarm counted.

I missed a step out there. Have you ever tried counting the bees in a swarm? It’s much easier if they don’t move.

1002, 1003, 1004, 1005, er, where was I? Damn!

1002, 1003, 1004, 1005, er, where was I? Damn!

Perhaps it’s best that I missed that step out 🙁

What you end up with is a count of the total number of bees in the swarm and the numbers of bees of each 3 day cohort over the last several weeks. You can therefore determine the age distribution of the workers in the swarm.

Is it as simple as that?

I’ve actually oversimplified things a bit. There’s a possibility that different age cohorts of bees die within the hive at different rates, perhaps depending upon forage availability or weather or something else.

Think about it. Assume there was a dearth of nectar in late May and the blue and red labelled cohorts added during that period were underfed and died prematurely.

If there were very low numbers of blue and red bees in the swarm you might assume that these ages were ‘left behind’ by the swarm … when actually they weren’t able to swarm at all.

The real question is therefore whether the age distribution of bees in the swarm is similar to that in the parental hive.

OK, OK … is it?

No.

Swarms do contain bees of all ages.

However there are significantly more young bees and many fewer old bees than would be expected from the age distribution of workers in the parental colony.

Age distribution of bees in swarms

Age distribution of bees in swarms

The o and e in the graph above represents the position of the observed and expected median age class for the expected distributions. So, in swarm C the observed median age is ~10 days old, whereas the originating hive median age was ~19 days.

The graph above comes from a 1998 study by David Gilley 2 and supports earlier work 3 by Colin Butler 4 which is often cited as one of the definitive studies on the ages of bees in a swarm.

Additional considerations

Is it surprising that young bees predominate in natural swarms?

Swarms usually emerge from the hive late morning or early afternoon on warm, sunny days. In fact, at exactly the time most older bees aren’t in the hive anyway because they’re out and about foraging.

Remember also that swarming is a precarious activity for the colony. Most swarms do not survive 5. Natural selection will have resulted in swarm populations that maximise their chance of survival.

Once bees start foraging their life expectancy is pretty short. It has been estimated that they experience about 10% mortality per day. If only old bees left in the swarm with the queen the newly established colony would very rapidly dwindle in size, perhaps before significant numbers of new brood emerged (which takes 21 days from the first egg being laid). This would likely limit the chances of survival of the new colony.

What has this got to do with artificial swarms?

As beekeepers (or at least as responsible beekeepers) we spend May and June rushing about like headless chickens trying to control swarming in our bees.

Many of us achieve this using a variety of methods which are generically referred to as artificial swarms. I suspect that many beekeepers think that the artificiality is because of our interventions.

Where have all my young girls gone?

Where have all my young girls gone?

It is … but it’s worth remembering that the artificial swarms we generate are very different in composition to natural swarms. Our artificial swarms predominantly leave the older bees associating with the queen, with the young bees remaining with the brood.

These old bees have to draw new comb and rear the new brood. These are activities they last did weeks ago (a long time in the life of a bee).

Final thoughts

There are artificial swarm control methods that were developed to better replicate the age distribution of bees in a natural swarm. One example of these is use of a Taranov board. I’ll cover this in a future post.

It’s also worth noting that the bees of different ages in a natural swarm have different roles even before they occupy a new location. The older bees form a mantle around the bivouacked swarm that protects it from inclement weather (amongst other things) and the oldest bees are the scouts responsible for finding a new nest site.

Again, both topics for another post … I’ve got bait hives to set out 🙂


 

Demaree swarm control

I’ve covered three swarm control methods in previous posts. These are the classic Pagden artificial swarm, the vertical split that is directly comparable but requires less equipment and more lifting, and the nucleus method.

As described on this site, if successful, all achieve the same two things:

  • They prevent a swarm being lost. Don’t underestimate how important this is in terms of not irritating your neighbours, in helping your honey production and in giving you a quiet sense of satisfaction 🙂
  • They result in the generation of a second colony headed by a newly mated queen.

This doubling in colony number, or – more generally – the managed reproduction of colony numbers, is termed making increase.

Managed reproduction

Making increase is of fundamental importance in beekeeping.

Without deliberately splitting colonies, unless you buy in nucs every year (kerrching!), collect swarms or steal hives 1 your colony numbers would never increase.

Making increase is therefore critical if you want more colonies. However, it’s just as important (and a darn sight less expensive than buying nucs) if you want to make up any overwintering colony losses, thereby keeping the same number of colonies overall 2.

Not making increase

Once you’ve got bees, with good management, you can always have bees. However, at some point you reach that sweet spot where you have enough bees and don’t want more colonies.

The Goldilocks Principle is the concept of having just the right amount. Not so few colonies that a really harsh winter causes problems, and not so many that you cannot enjoy your beekeeping at the peak of the season.

When you reach that point you no longer need to make increase, you just want to keep the same number of colonies.

Which means that the swarm control methods that essentially reproduce the colony may not be ideal.

Of course, you can unite colonies having removed the unwanted queen from one of them, but this is additional work. Not a huge amount of work admittedly, but work nevertheless 3.

This is where the Demaree method of swarm control comes in useful. As practised, Demaree swarm control prevents the loss of the swarm without increasing colony numbers.

It has the additional significant advantages of keeping the entire foraging force of the colony together (even better for honey production than not losing a swarm) and needing no specialised equipment.

Demaree swarm control – in principle

George Demaree

George Demaree

The principle of the method is very straightforward.

When queen cells are found during an inspection you conduct a form of a vertical split, separating the original queen and flying bees from the nurse bees and sealed brood. You place the latter above a queen excluder.

A few days later you return and remove any new queen cells from the top box, so preventing swarming. Finally you leave all the brood to emerge from the top box.

Demaree swarm control – in practice

A cartoon diagram of the process is shown below. The only additional equipment required is a brood box with 11 frames of drawn comb or foundation and a queen excluder.

That’s it.

Demaree swarm control

Demaree swarm control

Here’s a bit more detail:

  1. If you find queen cells during an inspection gently remove the brood box and place it on an upturned roof off to one side 4.
  2. Place the new brood box on the original floor. Add 9 frames of drawn comb or foundation, leaving a gap in the middle of the box.
  3. Using minimal smoke, go through the original box and find the queen.
  4. Place the frame with the queen in the middle of the new brood box on the original floor. This frame must contain no queen cells.
  5. Push the frames in the new brood box together and add in the eleventh frame.
  6. Add a queen excluder.
  7. Add the supers above the queen excluder. If there were no supers on the original hive then it’s worth adding a couple of supers now. It will provide better separation of the new and old brood boxes and it will encourage the bees to store nectar in supers rather than the top brood box.
  8. Add a second queen excluder.
  9. Place the original brood box on top of the queen excluder.
  10. Go through the upper brood box and remove every queen cell. Shake the bees off the frames to do this. Push the frames together and add one additional frame. Add the crownboard and roof.

Leave the colony for one week. At the next inspection you should only need to check the top brood box (i.e. the original one).

  1. Carefully inspect every frame and remove every queen cell. Again, you should shake the bees off the frames to do this. If you miss any queen cells there’s a good chance the colony will swarm.
  2. Close up the hive and leave the brood in the top box to emerge.
  3. About 25 days after conducting the first inspection (1 above, where you first found QC’s) you can remove the upper brood box from which all brood will have now emerged.

Explanatory notes

If you have a reasonable understanding of the development cycle of queen and worker bees you will understand how the Demaree Method simultaneously prevents swarming and keeps the entire colony together.

Honey bee development

Honey bee development

  • By splitting the colony you separate the queen and the flying bees from the nurse bees and the brood. The queen in the new (now bottom) box has ample space to lay, particularly if you provide her with some drawn comb to use.
  • The bottom box will now be less crowded and the swarming urge will therefore be much reduced.
  • You destroy all of the queen cells in the original (now top) box when you rearrange the hive. This is to stop any new queens emerging in this box in the following week.
  • However, this top box still contains eggs and young larvae. Since it is now located a long way from the queenright box the level of queen pheromone is very low. Consequently, in the week following the hive rearrangement, the bees will create new emergency queen cells in the top box.
  • When you return a week later all the eggs in the top box will have hatched and the youngest larvae left will be about four days old i.e. too old to be reared as new queens. Therefore, when you destroy all the new queen cells in the top box, you prevent the colony swarming.
  • You can remove the top brood box as soon as all the brood has emerged i.e. 25 days after first rearranging the hive 5.

Demaree pros and cons

Pros

  • An effective method of swarm control
  • Relatively simple procedure to implement and understand
  • Only requires a single brood box, frames and a queen excluder
  • Generates big, strong colonies and keeps the entire foraging force together
  • Modifications of the process can be used for queen rearing 6

Cons

  • Necessary to find the queen
  • Critical to remove all queen cells at the start and after one week
  • Generates tall stacked boxes, so some heavy lifting may be involved
  • Drones in the top box get trapped by the queen excluder 7
  • In a strong flow the bees can backfill the top box with nectar. Add sufficient supers when you first rearrange the hive
Framed wire QE ...

Framed wire QE …

Historical notes

George Whitfield Demaree (1832–1915) was a lawyer in Kentucky, USA, and a pioneer in swarm control methods. His eponymous method was published in the American Bee Journal in 1892. The original method was subtly different from that described above:

Demaree method

Demaree method

In his description he emphasises the need to keep the colony together to maximise honey production.

I suspect Demaree used a single sized box (as broods and supers) as he describes placing brood frames above the queen excluder in the centre of the super flanked by empty frames. As described, he doesn’t mention returning after one week to destroy queen cells above the queen excluder. Don’t forget to do this!

I particularly like Demaree’s comment that any swarm prevention method that “require a divided condition of the colony, using two or more hives, is not worthy of a thought”.


 

Bait hive guide

Spring this year is developing well. Even here on the chilly east coast of Scotland colonies are looking good and flying strongly when the sun is out. Large amounts of pollen are being taken in and there’s every sign that the hives are queenright and rearing lots of brood 1.

It’s too soon 2 to open the colonies but it’s not too soon to be thinking about the consequences of the inevitable continued expansion over the next few weeks.

Most healthy colonies will make preparations to swarm, often between late April and mid-June. The timing varies depending upon a host of factors including colony strength, climate, weather, forage, build up and beekeeper interventions.

Swarm prevention and control

You, like all responsible beekeepers, will use appropriate swarm prevention methods. Supers added early, ensure the brood box has space for laying etc.

In due course, once the colony gets bigger and stronger, you’ll notice queen cells and immediately deploy your chosen swarm control method e.g. the classic Pagden artificial swarm, the nucleus method I described last week, Demaree, vertical splits or – if you’re feeling ambitious – a Taranov board 3.

Which will of course be totally successful 😉

But just in case it isn’t …

… and just in case the beekeeper a couple of fields away is forgetful, unobservant, clumsy, on holiday, in prison or has some other half-baked excuse, be prepared for swarms.

As an aside, other than just walking around the fields, you can easily find hives near you by searching on Google maps and you can get an idea of the local beekeeper density 4 using the National Bee Unit’s Beebase.

You might think you know all the local beekeepers through your association, but it’s surprising the number who just ‘do their own thing’.

Swarms

This isn’t the place to discuss swarms in much detail. Here’s a quick reminder:

  1. The colony ‘decides’ to swarm and starts to make queen cells.
  2. Almost certainly, scout bees start to check out likely sites the swarm could occupy in the future 5.
  3. The swarm leaves the hive on the first calm, warm, sunny day, usually early in the afternoon, once the queen cells are capped. The prime swarm contains the mated, laying queen and about 75% of the worker bees 6.
  4. The swarm gathers around the queen and sets up a bivouac hanging from a convenient spot (tree, gatepost, bush, fence etc.) near to the hive. They rarely move more than 50 metres. It’s worth emphasising here that the spot they choose is convenient to the bees, but may be at the top of a 60 foot cypress. It may not be particularly convenient for the beekeeper 😉
  5. Scout bees continue to check out likely final sites to establish the new colony, returning to the swarm and ‘persuading’ other scouts (by doing a version of the waggle dance) so that, finally, a consensus is reached. This consensus is essentially based upon the suitability of the sites being surveyed.
  6. The scout bees lead the swarm to the new location, they move in and establish a new colony.

If you’re lucky you will be able to recapture the swarm if the spot they choose for their bivouac is within reach, not above a stream, in a huge thorny bush or on an electricity pylon.

A small swarm ...

A small swarm …

I say ‘recapture’ because, since the bivouac is usually near the issuing hive, it’s probably come from one of your own hives (unless you are snooping around your neighbouring apiaries 7).

But what if you miss the bivouacked swarm? Or if your neighbour misses it?

Those bees are going to look for a suitable location to set up home.

If you provide a suitable location, you can get them to hive themselves without the grief of falling off a ladder, toppling into a stream, getting lacerated with thorns or electrocution

This is where the bait hive comes in. Leave a couple in suitable locations and you can lure your own and other swarms to them.

Freebees 🙂

What do scouts look for?

The scout bees look for the following:

  1. A dark empty void with a volume of about 40 litres.
  2. Ideally located reasonably high up.
  3. A solid floor.
  4. A small entrance of about 10cm2, at the bottom of the void, ideally south facing.
  5. Something that ‘smells’ of bees.

What I’ve just described is … a used beehive 8.

More specifically, it’s a single National brood box (or two stacked supers) with a solid floor and a roof, containing one old dark frame of drawn comb pushed up against the back wall.

No stores, no pollen 9, just a manky old dark comb. The sort of thing you should be turning into firelighters.

That’s all you need.

However, you can improve things by giving the bees somewhere to start drawing comb and siting the hive in a location that makes your beekeeping easier.

Des Res

The first thing swarms do when they move in is start drawing comb. You can populate the bait hive with a few foundationless frames so they’ve got somewhere to start.

Bait hive ...

Bait hive …

In my view foundationless frames are much better than frames with foundation for bait hives. The scout bees measure the size of the void by flying around randomly inside 10. If you have sheets of foundation they’ll crash into it frequently, effectively giving them the impression that the void is smaller than it really is. And therefore making it less attractive to the scouts.

You can improve the smell of the hive by adding a little lemongrass oil to the top bar of one of the frames. Don’t overdo it. A drop or two every 7-10 days is more than ample.

If you do use foundationless frames make sure the hive is level. If you don’t the comb will be drawn at an angle to the frames which makes everything harder work later in the season. Your smartphone probably contains a spirit level function that makes levelling the bait hive very easy.

Location

But not if it’s above head height, or you’re teetering on top of a ladder …

It was Tom Seeley who worked out most things about scout bees and swarms (see his excellent book Honeybee Democracy). This included the observations that they favoured bait hives situated high up.

Believe me, it’s a whole lot easier if the bait hive is on a standard hive stand. It’s easier to level, it’s easier to check and it’s easier – in due course – to retrieve.

Bait hive

Bait hive

I’ve previously discussed how far swarms prefer to move from their original hive. Contrary to popular opinion (and perhaps illogically) they tend to prefer to move shorter distances i.e. 20m >> 200m >> 400m. However, there are also studies that show swarms moving a kilometre or more.

Don’t get hung up on this detail. Stick out a bait hive or two and, if there are swarming colonies in range, they’ll find it.

I always leave a bait hive in my apiaries and one or two in odd corners of the garden. In the last few years I’ve never failed to attract swarms to the bait hives, and know for certain that some have moved in from over a mile away as the bee flies (thanks Emma 😉 ).

Mites and swarms

Assuming you don’t have the luxury of living in Varroa-free areas of the UK (or anywhere in Australia) then the incoming swarm will contain mites. Studies have shown that ~35% of the mite population of a colony leaves with the swarm.

But, for about the first week after the swarm sets up home in your bait hive, what’s missing from the new arrivals is sealed brood. Therefore the mites are all phoretic.

Do not delay. Treat the swarm with an appropriate miticide to knock back the mite population by ~95%. An oxalic acid-containing treatment is ideal. Single dose, relatively inexpensive, easy to administer (trickled or vaporised) and well tolerated by the bees.

Varroa treatment ...

Varroa treatment …

You have eight days from the swarm arriving to there being sealed brood in the colony

Far better to slaughter the mites now. In a few months their numbers will have increased exponentially and the majority will be in capped cells and more difficult to treat.