Darwinian beekeeping

A fortnight ago I reviewed the first ten chapters of Thomas Seeley’s recent book The Lives of Bees. This is an excellent account of how honey bees survive in ‘the wild’ i.e. without help or intervention from beekeepers.

Seeley demonstrates an all-too-rare rare combination of good experimental science with exemplary communication skills.

It’s a book non-beekeepers could appreciate and in which beekeepers will find a wealth of entertaining and informative observations about their bees.

The final chapter, ‘Darwinian beekeeping’, includes an outline of practical beekeeping advice based around what Seeley (and others) understand about how colonies survive in the wild.


The chapter starts with a very brief review of about twenty differences between wild-living and managed colonies. These differences have already been introduced in the preceding chapters and so are just reiterated here to set the scene for what follows.

The differences defined by Seeley as distinguishing ‘wild’ and ‘beekeepers’ colonies cover everything from placement in the wider landscape (forage, insecticides), the immediate environment of the nest (volume, insulation), the management of the colony (none, invasive) and the parasites and pathogens to which the bees are exposed.

Some of the differences identified are somewhat contrived. For example, ‘wild’ colonies are defined fixed in a single location, whereas managed colonies may be moved to exploit alternative forage.

In reality I suspect the majority of beekeepers do not move their colonies. Whether this is right or not, Seeley presents moving colonies as a negative. He qualifies this with studies which showed reduced nectar gathering by colonies that are moved, presumably due to the bees having to learn about their new location.

However, the main reason beekeepers move colonies is to exploit abundant sources of nectar. Likewise, a static ‘wild’ colony may have to find alternative forage when a particularly good local source dries up.

If moving colonies to exploit a rich nectar source did not usually lead to increased nectar gathering it would be a pretty futile exercise.

Real differences

Of course, some of the differences are very real.

Beekeepers site colonies close together to facilitate their management. In contrast, wild colonies are naturally hundreds of metres apart 1. I’ve previously discussed the influence of colony separation and pathogen transmission 2; it’s clear that widely spaced colonies are less susceptible to drifting and robbing from adjacent hives, both processes being associated with mite and virus acquisition 3.

Abelo poly hives

50 metres? … I thought you said 50 centimetres. Can we use the next field as well?

The other very obvious difference is that wild colonies are not treated with miticides but managed colonies (generally) are. As a consequence – Seeley contends – beekeepers have interfered with the ‘arms race’ between the host and its parasites and pathogens. Effectively beekeepers have ‘weaken[ed] the natural selection for disease resistance’.

Whilst I don’t necessarily disagree with this general statement, I am not convinced that simply letting natural selection run its (usually rather brutal) course is a rational strategy.

But I’m getting ahead of myself … what is Darwinian beekeeping?

Darwinian beekeeping

Evolution is probably the most powerful force in nature. It has created all of the fantastic wealth of life forms on earth – from the tiniest viroid to to the largest living thing, Armillaria ostoyae 4. The general principles of Darwinian evolution are exquisitely simple – individuals of a species are not identical; traits are passed from generation to generation; more offspring are born than can survive; and only the survivors of the competition for resources will reproduce.

I emphasised ‘survivors of the competition’ as it’s particularly relevant to what is to follow. In terms of hosts and pathogens, you could extend this competition to include whether the host survives the pathogen (and so reproduces) or whether the pathogen replicates and spreads, but in doing so kills the host.

Remember that evolution is unpredictable and essentially directionless … we don’t know what it is likely to produce next.

Seeley doesn’t provide a precise definition of Darwinian beekeeping (which he also terms natural, apicentric or beefriendly beekeeping). However, it’s basically the management of colonies in a manner that more closely resembles how colonies live in the wild.

This is presumably unnnatural beekeeping

In doing so, he claims that colonies will have ‘less stressful and therefore more healthful’ lives.

I’ll come back to this point at the end. It’s an important one. But first, what does Darwinian mean in terms of practical beekeeping?

Practical Darwinian beekeeping

Having highlighted the differences between wild and managed colonies you won’t be surprised to learn that Darwinian beekeeping means some 5 or all of the following: 6

  • Keep locally adapted bees – eminently sensible and for which there is increasing evidence of the benefits.
  • Space colonies widely (30-50+ metres) – which presumably causes urban beekeepers significant problems.
  • Site colonies in an area with good natural forage that is not chemically treated – see above.
  • Use small hives with just one brood box and one super – although not explained, this will encourage swarming.
  • Consider locating hives high off the ground – in fairness Seeley doesn’t push this one strongly, but I could imagine beekeepers being considered for a Darwin Award if sufficient care wasn’t taken.
  • Allow lots of drone brood – this occurs naturally when using foundationless frames.
  • Use splits and the emergency queen response for queen rearing i.e. allow the colony to choose larvae for the preparation of new queens – I’ve discussed splits several times and have recently posted on the interesting observation that colonies choose very rare patrilines for queens.
  • Refrain from treating with miticides – this is the biggy. Do not treat colonies. Instead kill any colonies with very high mite levels to prevent them infesting other nearby colonies as they collapse and are robbed out.

Good and not so good advice

A lot of what Seeley recommends is very sound advice. Again, I’m not going to paraphrase his hard work – you should buy the book and make your own mind up.

Sourcing local bees, using splits to make increase, housing bees in well insulated hives etc. all works very well.

High altitude bait hive …

Some of the advice is probably impractical, like the siting of hives 50 metres apart. A full round of inspections in my research apiary already takes a long time without having to walk a kilometre to the furthest hive.

The prospect of inspecting hives situated at altitude is also not appealing. Negotiating stairs with heavy supers is bad enough. In my travels I’ve met beekeepers keeping hives on shed roofs, accessed by a wobbly step ladder. An accident waiting to happen?

And finally, I think the advice to use small hives and to cull mite-infested colonies is poor. I understand the logic behind both suggestions but, for different reasons, think they are likely to be to the significant detriment of bees, bee health and beekeeping.

Let’s deal with them individually.

Small hives – one brood and one super

When colonies run out of space for the queen to lay they are likely to swarm. The Darwinian beekeeping proposed by Seeley appears to exclude any form of swarm prevention strategy. Hive manipulation is minimal and queens are not clipped.

They’ll run out of space and swarm.

Even my darkest, least prolific colonies need more space than the ~60 litres offered by a brood and super.

Seeley doesn’t actually say ‘allow them to swarm’, but it’s an inevitability of the management and space available. Of course, the reason he encourages it is (partly – there are other reasons) to shed the 35% of mites and to give an enforced brood break to the original colony as it requeens.

These are untreated colonies. At least when starting the selection strategy implicit in Darwinian beekeeping these are likely to have a very significant level of mite infestation.

These mites, when the colony swarms, disappear over the fence with the swarm. If the swarm survives long enough to establish a new nest it will potentially act as a source of mites far and wide (through drifting and robbing, and possibly – though it’s unlikely as it will probably die – when it subsequently swarms).

A small swarm

A small swarm … possibly riddled with mites

Thanks a lot!

Lost swarms – and the assumption is that many are ‘lost’ – choose all sorts of awkward locations to establish a new nest site. Sure, some may end up in hollow trees, but many cause a nuisance to non-beekeepers and additional work for the beekeepers asked to recover them.

In my view allowing uncontrolled swarming of untreated colonies is irresponsible. It is to the detriment of the health of bees locally and to beekeepers and beekeeping.

Kill heavily mite infested colonies

How many beekeepers reading this have deliberately killed an entire colony? Probably not many. It’s a distressing thing to have to do for anyone who cares about bees.

The logic behind the suggestion goes like this. The colony is heavily mite infested because it has not developed resistance (or tolerance). If it is allowed to collapse it will be robbed out by neighbouring colonies, spreading the mites far and wide. Therefore, tough love is needed. Time for the petrol, soapy water, insecticide or whatever your choice of colony culling treatment.

In fairness to Seeley he also suggests that you could requeen with known mite-resistant/tolerant stock.

But most beekeepers tempted by Darwinian ‘treatment free’ natural beekeeping will not have a queen bank stuffed with known mite-resistant mated queens ‘ready to go’.

But they also won’t have the ‘courage’ to kill the colony.

They’ll procrastinate, they’ll prevaricate.

Eventually they’ll either decide that shaking the colony out is OK and a ‘kinder thing to do’ … or the colony will get robbed out before they act and carpet bomb every strong colony for a mile around.

Killing the colony, shaking it out or letting it get robbed out have the same overall impact on the mite-infested colony, but only slaying them prevents the mites from being spread far and wide.

And, believe me, killing a colony is a distressing thing to do if you care about bees.

In my view beefriendly beekeeping should not involve slaughtering the colony.

Less stress and better health

This is the goal of Darwinian beekeeping. It is a direct quote from final chapter of the book (pp286).

The suggestion is that unnatural beekeeping – swarm prevention and control, mite management, harvesting honey (or beekeeping as some people call it 😉 ) – stresses the bees.

And that this stress is detrimental for the health of the bees.

I’m not sure there’s any evidence that this is the case.

How do we measure stress in bees? Actually, there are suggested ways to measure stress in bees, but I’m not sure anyone has systematically developed these experimentally and compared the stress levels of wild-living and managed colonies.

I’ll explore this topic a bit more in the future.

I do know how to measure bee health … at least in terms of the parasites and pathogens they carry. I also know that there have been comparative studies of managed and feral colonies.

Unsurprisingly for an unapologetic unnatural beekeeper like me ( 😉 ), the feral colonies had higher levels of parasites and pathogens (Catherine Thompson’s PhD thesis [PDF] and Thompson et al., 2014 Parasite Pressures on Feral Honey Bees). By any measurable definition these feral colonies were less healthy.

Less stress and better health sounds good, but I’m not actually sure it’s particularly meaningful.

I’ll wrap up with two closing thoughts.

One of the characteristics of a healthy and unstressed population is that it is numerous, productive and reproduces well. These are all characteristics of strong and well-managed colonies.

Finally, persistently elevated levels of pathogens are detrimental to the individual and the population. It’s one of the reasons we vaccinate … which will be a big part of the post next week.



  1. Though this must at least partially be due to suitable nest site availability. I’m not aware that this has been studied.
  2. Though I appear not to have posted anything on related work by Seeley and Smith … an omission I’ll correct sometime in the future
  3. And brood diseases such as the foulbroods.
  4. Not the blue whale. Armillaria ostoyae is the Humungous Fungus. This is a type of honey fungus that grows in the Blue Mountains of Oregon where a single ‘individual’ (defined by genetic identity) has been measured as covering almost four square miles and was aged at between 1900 and 8600 years old.
  5. I say some as Seeley makes clear that what he proposes is a recipe in which not all of the ingredients are necessarily selected.
  6. I’m not going to list everything (buy the book, you won’t regret it) but I will highlight a few and add comments (in italics) of my own.

39 thoughts on “Darwinian beekeeping

  1. Janet Wilson

    Thankyou for that lucid examination of “Darwinian” beekeeping. With your permission I will link that from my own web page on the subject! We have so many good alternatives now for ameliorating bee stressors, and many more appearing over the horizon. Letting bees die from Varroasis is neither necessary nor wise: here in Canada we think the feral honey bees are all gone, unable to weather our winters when carrying Varroa and Varroa-vectored viruses: colony health is dependent on bees having an informed and effective beekeeper. Letting Nature take her course would likely result in no honey bee culture at all in cold winter climates, and only Africanized stock in warm winter areas: a recipe for beekeeping and food supply system disaster. I am sure Dr. Seeley means well, but his observations are not solutions.

    1. David Post author

      Hello Janet

      Happy for you to link to it, of course. There will be a couple of follow up posts, though perhaps not consecutive.


  2. James

    I think that one of the main benefits of limiting the size of the hive is that once the bees have filled their cavity with stores they will be free to carry out other jobs within the hive, such as grooming mites, gathering propolis and who knows what else.

    I’m afraid that I have a problem with all of your points on swarming. Resistant bees are not going to spread many mites when they swarm because they won’t have many mites….they’re resistant bees. Equally resistant bees are not going to suffer if there are other colonies in the area with high mite loads beacause…they’re resistant bees. Seeing as plenty of people near me (Oxon) are already claiming to have mite resistant colonies, I don’t think coming across some resistant bees should be too difficult. I myself have been treatment free for 2 years and have lost 1 colony out of 5 – fairly normal, but maybe they will all die this season from their persistently elevated levels of pathogens. I shouldn’t joke actually should I – I think the third year is meant to be the crunch point? Either way life goes on.

    Further, the idea that swarms are a nuscience to other people is not true in my experience. Last summer we had 4 swarms in the village where I live, not from my hives (I do actually manage to prevent swarming, mainly for the honey crop though) or from any other beekeepers (there are none). Nobody complained about it; people I spoke to were interested, and felt excited and intrigued – lucky even – to see a swarm, one man was quite happy having a swarm in his garden and saw not reason so have them removed (by me). No idea where they ended up, but hopefully hopefully they’re living happily somewhere in peace like they have been doing to thousands of years…

    1. David Post author

      Hello James

      There may be other benefits from a small volume hive, but it’s clear from the studies conducted by Thomas Seeley that the prime ‘gain’ is limiting colony size (hence pathogen levels) and precipitating swarming.

      Of course, if everyone had ‘resistant’ bees none of what I’ve described would be needed and swarming colonies would not transmit mites far and wide. The problem is that they don’t and the resistant bees may well have high viral and mite loads. The oft-quoted ‘resistant’ bees maintained by Ron Hoskins in Swindon have DWV levels of 10^7 – 10^8 per bee. That’s about 10,000 times higher than my research colonies which are maintained using two standard mite treatments per season (and therefore achievable by all beekeepers). We start seeing symptomatic bees with DWV only slightly higher than Swindon bees carry. There have been no published tests of things like longevity, learning, foraging efficiency etc., all of which are known to be negatively affected by high DWV levels. There have been no tests of other markers of colony stress.

      The Darwinian beekeeping proposed by Seeley inevitably involves – at least at the beginning of the ‘selection’ process – the loss of mite infested swarms and the active or passive culling of colonies. The large-scale ‘leave and let die‘ experiments give an idea of the scale of colony losses necessary.

      Do we even know whether the resulting small and swarmy colonies would be able to meet the levels of honey production or pollination that bees currently deliver? I suspect not.

      Year 3 is the big one in many studies of treatment free beekeeping … assuming mite levels started at a very low level. By year 3 mite levels are likely to have approached dangerously high levels. I hope yours survive. Post an update when you know …

      Swarms hanging in trees are rarely an issue. Perhaps instead ask homeowners who have had to have soffits ripped out during a ‘cutout’ what they think about beekeepers deliberately not conducting swarm prevention. As you say, you’ve no idea where they ended up. I’ve seen cutouts from roof spaces, colonies established 3 storeys up in a chimney of a hall of residence, classrooms closed because bees were falling out of the light fittings. None of the property owners were pleased to have bees in residence … I’d say that was their loss as bees are fascinating and generally harmless creatures.


    2. Janet Wilson

      James: in my 12 years of beekeeping no one has demonstrated meaningfully Varroa resistant bees. Meaningful is: you can reduce or end your treatments, the colonies are robust, healthy and productive (they make honey and increase). I’d be happy if there were meaningfully resistant bees, but so far all claims fall woefully short. There is also no discussion of the tragic mismatch between the bee reproduction rate and strategy and the mites’. Allowing bees to handle Varroa sans treatment is itself an application of a strong selective pressure: do we really think the mite genome will not respond to that pressure? Mite populations are (genetically speaking) nimble for a host of reasons, but principally their advantage lies in turning over their population many times in the life of any one bee queen…and we also have to remember that bee reproduction is based on mixing up the gene pool, not preserving single advantages like mite resistance. The drive to not treat bees pending an enduring solution to the Varroa problem makes no sense now that we have non toxic miticides like the organic acids. I think current research holds a real promise of eradicating mites from the honey bee population: let’s wait a bit on the live and let die strategy until it is literally the only option left.

      1. David Post author

        Thanks for that comprehensive response Janet. I remain to be convinced that we could eradicate mites totally – the feral colonies alone are likely to prevent that – but agree that a lot of ‘resistance’ really isn’t. I’m aware of some resistant bees that, moved away from the relatively isolated location they (and the associated parasites and pathogens) were selected in succumb just as fast to incoming mites and viruses. That isn’t resistance … or even tolerance.

        That doesn’t mean that some traits that confer various levels of reduced susceptibility to mites cannot occur. However, if they were as good as some suggest they’d start to dominate the feral populations. They don’t.


        1. Janet Wilson

          I am confident that we will eventually excise the Varroa from our honey bee population…alas that may not happen in my beekeeping lifetime…but I do believe in 20 years this will all be a blip on the history screen. Meanwhile area-wide suppression of mite numbers along with switching from imported bees to local bees is one way to lessen the impact of Varroa.

          And as an aside, I have had to euthanize colonies for AFB. After observing how quickly bees die in alcohol washes done for mite counts, I tested using rubbing alchohol as a euthanizing agent. It works very quickly and efficiently…as humane a method as I have found. It is readily available, inexpensive, and less gruesome than the other methods. No one likes killing colonies, but when you have to, at least this offers a quick and merciful end.

          1. David Post author

            Hi Janet

            I’m a big fan of area-wide suppression of mite numbers and we’ve been doing experiments on this for the last couple of years in a closed (island) environment. There’s also clear evidence that local bees are better. Unfortunately there’s a shortage of local bees and a lot of new beekeepers desperate to start every season who simply “buy in” because they haven’t the patience to wait … 🙁

            Thanks for the tip on killing colonies. In the lab we use carbon dioxide and freezing, but that’s not practical on a hive scale.


  3. Emily

    As someone who has ended up with bees in my chimney (not from my own hives), I’m not a fan of leaving bees to swarm either.

    1. David Post author

      Hi Emily

      Just because I like bees doesn’t mean everyone does (though I find this hard to understand!). Every spring the BBKA ‘swarm line’ and beekeeping associations are inundated with calls to collect swarms. The vast majority of these have been ‘lost’ from managed colonies. If the general public all wanted bees in their eaves (or wherever) there would presumably be far fewer calls to ‘just get rid of them please’.


      1. Emily

        Yes, and getting rid of them is not always cheap/easy. I’ve been quoted £4,000+ for live bee removal. Meanwhile, as I wait and keep hoping they’ll die out naturally, we can’t use our fire so that room is too cold to use half the year… would do it myself but balancing on a roof and clearing out a chimney is not in my skill set!

        1. David Post author

          Very wise … but that’s exactly what beekeepers are expected to do (usually for free because they’re “helping save the bees”). I was asked to retrieve a colony coming through a fireplace three floors up a five storey building … without taking the walls down. Fat chance.

          I don’t do any cutouts (there are insurance implications as well – BDI insurance has a 3 metre cutoff for ‘working at a height’ if I remember correctly) but instead set out bait hives. Each colony that appears there is one less going into someone’s loft space. Sometimes the bees are good, sometimes less so. If the former they’re kept, if the latter the swarm is united with another colony.

          After eradicating the mites and checking for signs of other diseases of course 🙂


  4. Julia

    As I read your write-up of Seeley’s assertions, one particular thought keeps recurring in my mind: Even if correct about the Darwinian approach being the best way to deal with mites overall, this approach can never work if not adopted by virtually ALL beekeepers. Otherwise, all that is likely to happen is that those who take the Seeley approach get to replace their bees every year.

    Also…does he discuss what is likely to happen to the food supply, and ensuing social and economic effects of it being decimated for a few years until pollinating stock is able to recover?

    1. David Post author

      Hi Julia

      Both very valid points and both will be covered in a future post. I’m pretty certain that the resulting colonies – in size, productivity and pollination activity – would be unsuitable to meet (the already unmet) demand for honey or to pollinate agricultural and environmental plants.

      The irony of ‘saving the bees’ and potential food shortages is an interesting one 😉


  5. Alan Schenk

    Very interesting analysis, thankyou. One realisation suddenly struck me after reading your article (being new to beekeeping) is that at some point, a hobby beekeeper, perhaps keeping 3-4 hives maximum, will inevitably, if his/her bees are healthy, have to create splits to prevent swarming and will have the responsibility of doing something with these splits. One wonders how many members of a local association (mine is Oxford) have the capacity to take on other member’s splits and how many splits is that likely to be on an annual basis. Surely at some point, a limit is reached, then what?

    1. David Post author

      Hello Alan

      I’ve written about topics related to this previously. The first thing to remember is that losses on average in UK and US beekeepers appear to be ~25 – 30% per year. The figures are a bit like Amazon reviews – the beekeepers who tend to complete the surveys are probably those that have either very high or very low losses. However, for the sake of argument, let’s assume that that 25% of colonies are lost (usually overwinter) every year. These shortages need to be made up or overall colony numbers would fall (they’re not).

      Particularly early in the season there will always be a market for healthy overwintered colonies.

      The second point is that splits can always be united back to the original hive, having removed the older queen. It’s not unusual to split a colony, rear a new queen, see how she performs and then (if good enough) cull the old queen and unite them back together again. In this way the overall colony numbers don’t increase. Some beekeepers don’t even intervene in getting rid of the old queen, they simply unite and let them sort it out amongst themselves.

      If you do vertical splits you can perform this entire process using just a single hive stand and roof, with two boxes and a split board.

      It’s certainly possible to have too many bees … it’s a rite of passage to being a good beekeeper.

      Remember, overwintered colonies are worth considerably more than a late-season split 😉


      PS Just re-read your post … I’ve never known the limit reached. There is always a market for bees.

  6. Ann Chilcott

    Thank you for your carefully thought through blog, David. Natural selection will not work well in most parts of the UK due to the density of managed colonies, and the points that you presented. I don’t think that Professor Seeley is advocating that we adopt all of the guidelines. Do you not think that we could do a lot better for our bees though if we took on board some of these suggested changes?

    1. David Post author

      Hello Ann

      I’m doing some calculations at the moment about hive densities and will write something on this in the future. I’ve previously noted that keeping bees with low Varroa levels is much easier in Fife than it was in Warwickshire. I bet this is partly due to colony density.

      I don’t think it’s clear from the book whether he’s advising all or some. Certainly the latter is hinted at, but the not treating, the uncontrolled swarming and the culling of colonies are likely to have the greatest impact. I suspect the other things alone, or in combination, may not be sufficient.

      I do think some of the things proposed are likely to be beneficial. Even for those who treat. Again, I’m planning to cover this sometime in the future (and in a post, rather than a very long comment that will not be read by many). I’m interested in the rough hive interiors amongst other things. I’ve got some ideas about using insect mesh netting stuck to the inside walls (thinner than the QE he used) to see how it works.

      Not a particularly informative answer I’m afraid, but it’s late and I’m just back from talking at Edinburgh & Midlothian BKA.


  7. Alex

    Kill heavily mite infested colonies – how about this instead; treat the colony to reduce the mite numbers and then unite the colony with another whilst also dispatching the queen from the mite infested colony. At least you get the benefit of strengthening another colony for winter… that is assuming that the pathogen load of the workers from the mite infested colony is not overly detrimental to colony they are being united with. What do you think? A good idea or not?

    1. David Post author

      That would work (and in fairness to Thomas Seeley, he did suggest ways to avoid killing the colony). To ensure that the pathogens from the mite-infested colony weren’t transferred to the queenright one I’d want the latter to have a very low Varroa level as well. If you don’t the vector will still be present to transmit the high DWV levels across the the ‘clean’ bees.

      And, much better than killing bees 🙂


  8. Alasdair

    I’ve read quite a bit of Thomas S work and applied a lot of it to my beekeeping. I keep bees in 10 to 15 gallons hollowed out logs. I won’t have clear results until Spring 2020. But I definitely encourage swarming as that is how it works in the wild. Here is a video of what I’m doing. https://youtu.be/9JzyiaHnBV8

    I’m donating hollowed out logs for free if anybody is interested.

    The logs provide excellent thermals and I’m hoping assist in mite control. Any help is appreciated.

    Alasdair Mackenzie

    1. David Post author

      Hello Alasdair

      Post an update when you know how it went … but it needs to be 2-3 years with no treatment at least. Most colonies will die by then if the mites (and viruses) get them.

      What do the local beekeepers think of the swarms shed into the environment which could have catastrophically high mite levels?


  9. Jackie Elliott

    I have to question some of your Darwinian beekeeping post. You state that the Darwinian concepts Tom Seeley proposes are likely to be to the detriment of bees. This would be true only if this words were taken out of context, let me give two examples.

    When he speaks about moving hives we have to allow that he writes from his experience in the USA. The majority of hives are owned by bee farmers who need the pollination contracts to make a profit each year. As we all know their hives travel 1000s of miles every year. He’s not talking about the hobbyist beekeeper that takes a few hives to the heather.

    You made another point that really troubled me. I would worry that some of Seeley’s disciples would follow the incomplete advice you quoted. Under “Practical Darwinian Beekeeping” , with reference to Varroa you quote from Seeley:
    “Refrain from treating with miticides – this is the biggy. Do not treat colonies. Instead kill any colonies with very high mite levels to prevent them infesting other nearby colonies as they collapse and are robbed out.”

    Tom Seeley also says about the above point:
    ”I strongly advise, however, that you adopt this suggestion …….only if you can do so as part of a program of extremely diligent beekeeping”.

    Most of us don’t have the number of hives or dedication required to take on such a programme so he definitely does not endorse not treating for Varroa for the average beekeeper.

    n.b. “this is the biggy” are your (The Apiarist’s) words which isn’t clear in your post.

    Keep on blogging, best read of the week. 😊

    1. David Post author

      Hello Jackie

      I think one of the problems with the proposals is there is no context – in terms of who it might apply to – provided. Seeley doesn’t say “commercials should to this, but hobbyists do that”.

      You’re absolutely right about his qualification regarding not treating only if you are following a program of extremely diligent beekeeping. However, I think the majority of beekeepers would think that they’re diligent or – my larger worry – that beginners with no experience start with the best intentions without realising the commitment involved (I’ve written about this under Principles and Practice). No beginner thinks that she/he isn’t going to be diligent.

      Without culling mite-infested colonies there’s a very major risk of environmental contamination. If you treat there’s no selection. He can’t have it both ways. If you somehow exclude the loss (through deliberate culling or disease) of mite infested colonies the remaining parts of the proposal are unlikely to result in mite-resistance. They could well benefit the bees e.g. more propolis in the hives (and see also the comment from Janet shortly), but they won’t deliver the much-wanted Varroa-resistance.

      My comment about ‘to the detriment of the bees’ reflects the total absence of studies on health of untreated colonies. Health in the widest context – resistance to disease, non-overt pathogen loads (and long-term consequences like worker longevity, learning defects, foraging problems), resistance to other stressors like pollen/nectar shortages. Are these bees fit and healthy or are they actually living with persistent disease? We don’t know because no one has looked.

      If the colonies are smaller their nectar-gathering will be less. Are they able to overwinter as well as large mite-treated colonies? We know with the latter that size counts – big colonies are better at overwintering than small ones.

      What about pollination services? Are smaller colonies able to deliver what is needed? Would untreated ‘mite resistant’ colonies be able to pollinate the $5bn almond crop?

      The biggy remains … to make selection work there have to be losses. Lots of them. That’s what selection is.

      I want to be convinced that what we select is capable of delivering the thousands of tons of honey needed and the billions of plants pollinated. If it yields small, swarmy, disease-prone (for example, increased susceptibility to diseases other than those transmitted by Varroa) colonies then we have a problem.


  10. Janet Wilson

    Two points in response to this most interesting discussion:

    1. The bee research unit in Canada found some years ago now, and entirely by accident (some hives built for a study were made by mistake with rough wood interiors) that bees will propolize the walls of their hive if the walls are roughened, and the upshot was that in those hives, disease rates were lower than in un-propolized-walled hives. So we have been advocating, thanks to the ingenuity of my fellow beekeeper Michael Jaross of Bellingham, WA, USA, the use of a “Paper Tiger” on interior hive walls in the course of routine maintenance. The Paper Tiger is a round tool that fits in your hand and has three toothed wheels. It is made to perforate wallpaper such that it is more easily steamed and removed. That propolis will not, alas, save your bees from a potent nearby infective source of disease but it may help and won’t hurt.

    2. Alas “that is how it works in the wild” is not how it works any longer. Here in Canada swarms do not often survive in the wild (although they used to) thanks largely to mite pressure. Bees no longer live in the world in which they evolved, we have altered the environment too much. Where I live, the health of colonies is almost entirely dependent on the care, attention and expertise of a beekeeper…principally in achieving good mite control. And in any case, not all the wild is suited to honey bees. Here we have only one big nectar flow (in June), so bees must be fed through the late summer dearth to get to winter weight. I am betting when this area was truly wild, pre-Contact, honey bees were thin on the landscape.

    1. David Post author

      Hello Janet

      Very interesting.

      1. I’m going to look into the propolis envelope ‘thing’ in more detail this year. There’s nothing wrong with providing minor benefits where we can – lots to be gained and no downside. Here’s a link to a Paper Tiger (which I had to look up).
      2. The survival of swarms has never been good. Again, Seeley has done lots of the work on this if I remember correctly. Swarming is a risky business – they set off with ~3 days of honey in their bellies and the hope of finding somewhere suitable to live. If it doesn’t work out they try and survive where they are … and this happens.

      Epic fail

      I live part of the time on the wet and windy west coast of Scotland. It’s an area that a friend used to keep a lot of bees in. Perhaps my friend never lost a swarm 😉 , but there’s no evidence for any feral colonies in the area. I’ve never seen a honey bee there. I know the ‘local’ beekeepers live at least 5 miles away. I suspect that area is on the very edge of what can be tolerated and that the bees will need support at some points of the season to survive. I’m currently planting pollen-bearing trees by the dozen to improve the environment for when I get bees. It’s a Varroa-free area which makes the absence of feral colonies all the more disappointing.


      1. Janet Wilson

        This has been a great discussion David…thanks for hosting! Since reading the Canadian research (which was presented at the BCHPA some years ago) I take any blobs of propolis I find in summer and smear it across the landing board, in front of the reducer opening in particular. I figure it may work as a nice foot-wipe/hand-wash station for incoming bees. Might help, doesn’t hurt.

  11. Bill

    I keep half a dozen Warré hives on a London rooftop, and the swarm emigration control I practise is providing alternative, alluring, available, local accommodation that is better than any nearby chimney or soffit. Bait hives don’t need to be perfect – the Australian wisdom that you don’t have to be the fastest swimmer on the beach to escape the shark, just faster than the slowest, holds good – but its actually quite easy to tick most of the boxes the scouts are prioritising.

    I’ve only ever “lost” one swarm (when two hives swarmed simultaneously), and none of the swarms that chose to move into my bait hives has ever formed a cluster prior – it seems the scouts had always informed the decision before the swarm left home. On one occasion they barely even flew – crawling down the front of my house into a bait hive like bee treacle.

    For many years, with guidance from Tom Seeley, I performed an N=1 experiment: offering swarms two bait hives, six feet apart, identical in every respect save that one was uninsulated (US customary R1) the other insulated (R11) in an attempt emulate a thicker-walled tree cavity. Even though I randomly swapped them around, the swarms always chose the insulated over the uninsulated. Every time. So now all my bait hives are insulated.

    Derek Mitchells paper on hive insulation: https://www.researchgate.net/publication/281541406_Ratios_of_colony_mass_to_thermal_conductance_of_tree_and_man-made_nest_enclosures_of_Apis_mellifera_implications_for_survival_clustering_humidity_regulation_and_Varroa_destructor

    refers to a 1997 study on the effect of high hive humidity on varroa:

    https://www.researchgate.net/publication/226918364_High_Humidity_in_the_Honey_Bee_Apis_mellifera_L_Brood_Nest_Limits_Reproduction_of_the_Parasitic_Mite_Varroa_jacobsoni_Oud which noted that varroa struggle in the tropics.

    The authors didn’t create a chart of their results in their paper, but it’s visually arresting:


    Now that’s what I’d call effective birth control. Mitchell elaborates on how tree-cavity-like insulation facilitates the maintenance of high hive humidity. Of course the bees could theoretically choose to disregard humidity and just go with ambient. But since we know that increased humidity increases bee egg viability, it very hard to imagine that the bees don’t know this too – and will regulate humidity accordingly to better nurture their young. Insulating hives to emulate the insulation of a tree cavity not only allows bees’ temperature control mechanisms to be applied in the kind of environment where these mechanisms evolved their exquisite sensitivity – providing stable brood temperature in environments across the planet – it would also allow their similarly tuned humidity regulation to work at its best.

    When people ask me if I treat for varroa, I say yes – by insulating my hives I’m tipping the balance against the mite and in favour of the bee, 24/7, 365, and for no effort or intervention after installation. Side effects – mostly beneficial. Accidental overdosing – almost impossible – in one of the trees in Seeley’s Arnot Forest study, successful bees had to crawl through 29 inches of wood to get from entrance to cavity.

    All the above is elaborated at even greater length in the book I recently published. Tom Seeley kindly gave this quote to the publisher:

    “THE IDLE BEEKEEPER” is a beautifully written and wonderfully informative book on how to be a hobby beekeeper who is deeply respectful of his or her bees. The author, Bill Anderson, describes in detail how he succeeds as a hive keeper, not a beekeeper, for he knows that the bees keep themselves far better than he would ever do. The “idle” in its title refers not to laziness, but to the need to go into each hive on just two days each year, to add and remove a comb honey super. This is the book that I will recommend to novice backyard (or rooftop) bee enthusiasts.
    –Thomas D. Seeley, author of The Lives of Bees, Cornell University.

    1. David Post author

      Hello Bill

      Very interesting. I’ve left the links in for the benefit of others.

      How do you propose that a hundred or so scout bees quantify the insulation of a bait hive? They generate insufficient heat to warm the cavity and don’t stay overnight to measure loss of heat from the cavity. Prior to being occupied, during the time scouts are visiting, I’d expect the inside and outside temperature to be similar.

      I’m not questioning your observation, just wondering how it is determined by the bees.


      PS Other comments made in response to Archie McLellan also apply here – pathogen levels, measures of colony fitness etc.

      1. Bill

        Hello David.

        We know from Tom Seeley’s work that he details in HONEYBEE DEMOCRACY that individual scout bees make repeated visits to potential new homes. Why?

        Before ushering in your swarm it’s obviously useful to check that a promising space is still available, and hasn’t been occupied by other bees. But the volume of the space, the aperture and orientation of the entrance, and the height off the ground are all unlikely to have changed since the last visit – a waste of effort for an individual scout to reconfirm such pertinent features. I propose that one of the benefits of scouts revisiting at different times of day is to establish the level of insulation a candidate for a new home would offer.

        An uninsulated bait hive with 1inch thin walls is approximately (US) R1. On a sunny day in June, a scout flying inside such an unshaded, uninsulated hive at 9am would notice little difference in temperature between inside and out. But if that scout bee returned in the continued sunshine at 3pm, it would feel a massive difference between inside and out. R1 is not far off the insulation provided by a canvas tent – any camper will tell you what has happened at 3pm to the bar of chocolate they safely left in the tent at 9am – and the bees sensitivity to temperature is exquisitely more accurate than ours

        If our human camper had instead left his bar of chocolate in a log cabin the same size as the tent but with 6 inch thick walls and roof, its greater insulation would have made little difference to their bar of chocolate at 9am. But it would give the chocolate more chance of not being liquid at 3pm on that sunny June day. A scout flying into a similarly insulated tree cavity or bait hive at 3pm that day would notice significantly less difference between inside and outside temperatures compared to that uninsulated bait hive.

        Clearly there will be a less dramatic difference on a shady June day, but the difference between ambient and bait hive interior temperature will still pertain between the insulated and uninsulated hives – the second law of thermodynamics determines that heat energy will flow into and out of the hive as ambient temperature outside rises and falls, above and below interior. Nothing can be done to stop this adherence to the law, but insulation will slow the flow. Over the course of the day, the insulation will buffer temperature change inside the hive relative to outside, and the bees can measure this reduced difference by simply flying in from outside at different times of day. They can then compare the relative insulation of different potential sites.

        Offered a choice, all the swarms that moved into my bait hives chose R11 over R1.



        1. David Post author

          Very interesting … I also wonder how it might be tested properly. Bees might visit to simply reinforce the good impression they had the first time, a bit like potential house buyers making return trips to view a property. The vigour with which they dance and recruit other scouts depends upon them “remembering” the potential nest site and I suspect this might require reinforcement. I seem to remember that other dancing tails off over time …

          One potential thing to start with would be to formally demonstrate that the same scout does visit at different times of day when there is a temperature differential.

          I suspect a lot of swarms will be lost this season if things continue as they are … perhaps the ideal time to think about how this might be tested.

          By chance, most of my bait hives are poly as I usually build them out of two old and disliked Paradise Hives supers. However, I’ve never made side-by-side comparisons of attractiveness.


          1. Bill

            Agree. There are many beneficial reasons for scouts to revisit and insulation measuring is likely one of them, and a feasible explanation of why they consistently chose my insulated bait hives over uninsulated

    2. Janet Wilson

      I am happy to read the book, but goodness. If beekeepers in my area only went into their hives twice a year, their bees would be crawling with Varroa, full of viral disease, would starve in the late summer dearth, be left to swarm and vulnerable to EFB, which is common locally. And once again, may I object to Dr. Seeley’s insinuation that if you don’t do things as he suggests then you are disrespectful of your bees? I am reminded of Mark Winston’s infamous “Manifesto”, which in sly language laced with “maybe’s” chided beekeepers for not thinking about the obvious.

      1. David Post author

        Hello Janet

        You make three very good points. Being ‘disrespectful’ could equally be applied to beekeepers who let disease go unchecked (both to the bees and to other local beekeepers). I’m also uncomfortable with similar comments about happy bees or stress-free bees. I don’t believe either is measured and it’s simply anthropomorphic.

        Mark Winston’s Manifesto can be found on here on his website. In re-reading it I was reminded he made the point that most of the benefits of leave-alone or treatment free beekeepers are anecdotal. This doesn’t mean there aren’t benefits, just that they have not been properly presented for scrutiny (as I said somewhere earlier in the comments, are bees with 100,000,000 copies of DWV likely to be as fit – or long-lived – as those with 1 to 10 thousand?). Winston suggested that “Perhaps research should rigorously analyze these “perhaps” ideas” … but I’m not aware that this research has happened. Quantifying simple measurables like colony build-up, foraging activity, nectar gathering, viral loads etc. is relatively straightforward. You’d need to do a side-by-side comparison with managed colonies in a similar environment. I’m not sure who’d be willing to fund such a study (and it would need to be funded). I suspect the results would be very interesting.

        Finally, as you say, two inspections a year are a recipe for near-certain disaster. If they don’t starve they’ll swarm … if they’re strong enough with the pathogen load they’ll be carrying.


    3. Daniel

      Thanks for you book! I’ve just read it. It’s awesome. I’ve started building 8cm ICB (expanded cork boards) hives after reading both your and Thomas book. From my calculations they would provide around R12. I’m in Portugal so we have lots of cork. It’s also rough inside so should be good for propolis coating!

      1. Bill Anderson

        Thanks Daniel! I think that even though I currently insulate with wool, cork will be the most ecological way to provide bees with the level of insulation they’re used to in hives we can lift! I’d be very interested to hear how you get on with the two issues I know are still potentially challenging cork devotees – weather proofing the exterior in general and the junctions between boxes in particular. I wonder if it might be possible to created variably expanded cork hive boxes – so that the surfaces of their walls are relative dense (strong but poor insulators) while the interior of the walls is fully expanded (more crumbly but much better insulating)?
        Insulation’s contribution to hive humidity control may be just as important as temperature – very interesting research article here on it’s role as an indirect treatment for varroa: https://royalsocietypublishing.org/doi/10.1098/rsif.2019.0048

        1. David Post author

          Interesting to see the water absorption of cork hives. You could have a hive that turns into a block of ice when the temperature plummets. Also worth noting that Derek’s study is theoretical … going by by small entrance poly hives in my bee shed the hive humidity is very high.

          Water in Abelo frame rebate

          Water sometimes collects in the rebates of the frame rests. Less ecologically friendly than cork … but a damn sight easier to sterilise if needed 😉


  12. Bill Anderson

    I suspect less water would be absorbed by cork exposed to rain running off vertical hive walls than cork immersed or being boiled in a lab! These architects calculated that cork boards were effectively water resistant for exterior walls:

    I wonder if the natural cork resin that is released by heat in the expansion process to bind the expanded cork could be more densely concentrated on the outside – rather like the crust of a very crusty loaf of bread – to provide even better weather proofing and water resistance to the leavened cork within? Half inch thick timber hive boxes with such a cork “loaf” baked onto their exterior might be a useful and durable hybrid.

    Mitchell’s paper is theoretical, but much of the data he draws on from others isn’t. The observed number I find particularly interesting as a tipping point in hive humidity is around 4.2kPa – above this level bee larvae thrive, but varroa fecundity falls. Anything we can do to help the bees maintain a healthy hive humidity greater than 4.2kPa is concomitant varroa control. Insulating our hives to the level of tree cavities – which the bees took for granted as they evolved their complex and sophisticated temperature and humidity control mechanisms – is a good start.

    It’s interesting that although your poly hives are much better insulated than wooden, water sometimes collects in the rebates of the frame rests. Not only are these rebates a horizontal surface to collect pools of water, they are also at the thinnest and least insulated part of the hive box. Even though poly hive humidity may seem high, it would be even higher if the water in those cooler rebates hadn’t condensed there and was still held in the hive air.

    1. David Post author

      Hi Bill

      Apologies, missed this reply. The photo of the poly hive was in my bee shed. There’s still a good thickness of poly ‘outside’ (it’s an Abelo box) and all my hives have a 50mm block of Celotex/Kingspan on top at all times, so it was probably reasonably well insulated. I use a lot of perspex crownboards and get very little condensation on them.

      I’m in the process of finishing a new bee shed and it will have some homemade hive monitoring equipment installed – primarily temperature and humidity if I can get the sensors working properly. My interest is in brood rearing and the rational control of Varroa … i.e. applying a “midwinter” treatment when the colony is really broodless, rather than simply applying it in the holiday period between Christmas and New Year.

      Perhaps if the humidity is high enough no treatment will be needed? We’ll see 🙂


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