Small cell size important in breeding Varroa resistance

After reading the blogpost ”Breakthrough?” an European PhD-Scientist wrote me an email with the following comment:

After reading your post I realized that you do have small cell size, but you’re not mentioning it in the actual post. To make sure that the reader’s get the full picture, the main components of your management system, this should be explained for them.

For instance, for me it’s a fact, that the cellsize used in a selection program is a factor incorporated in the population just like springfeeding appears to create a dependency of that feed to make bees start an explosive spring behavior.

As our bees are still wild animals, you can select whatever you like (or forget to see as selection-factor) to specialize your bees. Feel very good that your selection works.

But looking at the picture I have, some more ’vitality’ comes with better Varroa control. More or less ’Race’-independent. Question for me: ’slight inbreeding effect’?”

A valuable comment which gives food for thought. Thanks!

Small cell size (SC) is so natural for me, that it’s the normal thing. I forget it sometimes. Those small quick bees flying directly into the entrance are what I expect when looking at a bee colony.

It’s interesting Eric Erickson in Tucson when he started his breeding project for Varroa resistance found that many survivors that he used in his program were on 5.1 mm cell size. This was quite smaller than the most common 5.4 mm. http://www.elgon.es/diary/?p=457

Eric_EricksonF Eric Erickson when I and Hans-Otto Johnsen visited him and Lenard Hines about ten years ago talking Varroa resistance.

Erickson is said to have been forced to retire earlier than he should have. He died earlier this year (2016) well above his 70th year. There were nice obituaries, but I couldn’t find a word about his Varroa resistance program. Strange.

Every spring since I started to take my bees down to small cell size, when I took care of the dead outs after winter I saw that many combs were poorly drawn. The bees had many times failed to follow the 4.9-pattern and drawn patches of sometimes bigger worker cells and sometimes a lot of drone cells. Also when managing struggling colonies during the season the same observation was many times made. This year very little of this was seen. But I still have some colonies that can’t follow the 4.9 pattern when drawing their own combs (but they do well on already drawn small cell combs, especially colonies with heritage from queens from other beekeepers I have found interesting to try.

At the same time I’m aware that there are beekeepers that havn’t treated against Varroa for many years that still use large cell sizes. I draw he conclusion that it is possible to keep bees on large cell size and still be treatment free. But I see very little reason for not going down in cell size. The most important reason is that the bees themselves go smaller when given the chance. It must have something to do with their fitness and survival, not actually in first place in relation to Varroa.

Concerning the earlier blog post “Breakthrough?” and that I have used very little Thymol this year. Last year at the end of July I had used Thymol on about 70% of the colonies. This year at the same time of the year I have used Thymol on 2 colonies out of about 150 (I had about 150 last year too). I find it hard to believe that the only reason would be a successful breeder queen. I think better pollen availability this year has given a better immune system. And reinvasion I think is less problematic. With the latter in mind, I can imagine that adaptation to better control the mites is developing in the bees. And the absence of chemicals, in this case thymol, do not disturb this adaptation.

Another change in management is that I don’t move bees between apiaries. When making splits they stay in the same apiary. If there’s only one colony in a yard I split that colony and build up the apiary again this way (from now on). Some minor movements of bees have been done though.

17 thoughts on “Small cell size important in breeding Varroa resistance

  1. Erik, what do you consider the benefits of not moving bees between yards? Are you thinking some bees aren’t well adapted therefore they will dilute the positive effects in each yard?

    Richard

    • Good question Richard. To be honest I don’t know for sure. I do know though that bringing in colonies that aren’t adapted to your apiary’s situation in which your bees are fighting to adapt to control mites, can disturb that adaption. Take for example all you successful examples of not having treated for 10 years or more against the mite. You havn’t been bringing in colonies of bees. Though you have tried out queens from different sources. But those years you have had worst winter losses I’m convinced you have tried out too many the year before.
      After having wrote about you, Cory Steven and Darrel Jones. Thought about Olle Ohlsson in Munsala Finland and Hans-Otto Johnsen in Norway and a good friend in Germany. The most striking common thing is that you havn’t brought in colonies into your operation from outside. So after last year’s disappointing experience of so much of virus problems I knew I had to try different new approaches this year. One was taking this not bringing in “foreign” colonies down to the apiary level inside my own operation, to see if that would make any difference.
      Now this year is a better pollen year with better immune system. I see the results of a very good breeder. And probably also the effects of having to treat so much last year in that the varroa population will have longer time to reach a dangerous level again. But as I now also use the Bee shaker and can see the development of the varroa population in figures, at least I will do that in some apiaries, I can already see that the varroa population in at least some colonies has a negative development. That is very promising. How much impact the decision not to move colonies between apiaries have I don’t know, if any.
      I though think it has some positive effect, but realize that some movement of colonies isn’t too negative. My aim is to give the bees best possible environment to fully adapt to control mites, so good that they finally can stand quite som reinvasion. That I think is more of a learning and sharing knowledge process than genetic selection.
      Finally I think you can move colonies like you did before the mite arrived here. That’s my hypothesis. Anyway, the situation this season is very different from last year. We’ll see what happens later.

      • I’m not sure how the separation of beeyards effects the colonies’ adaption. Three of my outyards are far enough from the others to be isolated from their influence. Some years I do have more losses in these isolated yards than the ones in closer proximity to each other. I do restock the losses in these yards from my main nuc yard which is the physical epicenter of most of my yards and my queenrearing/nuc making yard. But it is hard for me to say exactly why the isolated yards don’t do quite as well. Next year one of the isolated yards will get a neighboring yard of my bees in the same valley so maybe results there will improve. There may be so many other variables, such as weather, that it is hard to know for sure.

        Our weather this past year may impact the bees health in more ways than usual. Our winter was very mild, April was record setting warm, and May was cool and wet. One result was colonies built up very quickly, and about one month early, only to stay in the hives much of May when we get our main nectar flow. How does this effect mite populations? One of our years of largest losses coming out of winter followed a year with a very mild winter and early spring. I point this out only because of all the things effecting our bees, the weather may have the largest impact some years. Sorry if this got off track from moving hives.

        • You are right, don’t be sorry, there are many causes of problems for bees. Weather is one. It wouldn’t surprise me if the outyard will benefit from a new apiary of yours not far from it. Originally the post was about small cells when selecting breeders, but I’m happy with every interesting comment. They add to my understanding.
          I have had one outyard gone down to just one colony. I split that one this year. No treatment there, and the split looks fine as well. Another yard went down to two. I split the best colony there this year. The other shifted its queen. All three looks fine with no treatment so far. A third outyard had four colonies last year. One of these was the leftover from the chosen breeder last year. I brought home the breeder by splitting the colony. It had virtually no mites. The other three had to be treated last year, they were splits except one that had its queen shifted due to too many mites. This year the split of the breeder attempted to shift its queen too early and ended up as nothing, such happens. The other three had an infestation level of 0.3% in June. Next year I will split the best in that apiary.
          I don’t know why this development is taking place now among my bees, but I don’t complain. We’ll see later on what happens.

  2. Eric, I see similar issues in our bees. All 90 treatment-free colonies are raised on small cell in brood chambers and the honey super frames are foundationless. The majority of the colonies have mostly adapted to pulling small cell combs in brood area, so I have now started using some foundationless frames in brood area as well. Some colonies have trouble following small cell and override the foundation provided, but overall I have become pleased with the progress of regression. Our winter/spring losses this year were about 20%. One important aspect to mention is that the sightings of deformed wings has gone down considerably over the last 5 years. Its becoming more rare that I find them inside the colonies, but still an occasional worker is sighted crawling on the ground indicating there is still some transition happening in our stationery apiary. All colonies are in deep 10 frame boxes, which I also feel is a better environment for the colony to have the largest sheets of comb that can be easily provided. This observation is based on the longevity conditions of the feral bees that I have removed that have been consistently existing in places for 5 or more years.

    One thing I do is bring in dozens of retrieved swarms and removal bees for evaluation and rehabilitation. This mixing, I feel, has helped to increase the genetic composition of our entire apiary, and largely no negative issues. Our area is highly supportive of the apiary immune system by providing abundant nectar and pollen sources throughout the growing season, especially in September. This late season pollen and nectar flow is short but very strong. The colonies become very productive for the month of Sepetember rearing the winter bees on this late season bloom, long after golden rod which has already started blooming here. I try to make sure all the colonies have a benefit to the entire apiary. 90% of my colonies are within 1 mile area. I run the entire operation in Baltimore, Maryland in an urban environment. The rural county farm area is a toxic place for bees here in this state.

    • Feral swarms I think are less problematic as they have less problems than managed bees, especially compared to package bees from commercial sources. yes, you are lucky with such a good late pollen and nectar flow. And that you are not situated in a highly agricultural area.

  3. I think the viral background is important and bee movement affects this.

    In a natural setting, exposure to new viral sub types would be relatively low compared to situations where large numbers of bees are moved interregionally. The adaptive landscape would be more stable and large episodic losses would lessened if less bees were moved especially over long distances.

    • This may well be an explanation Leroy and a clue. I do think also that when our bees have been able to develop and fine tune their mite control mechanisms, which they do in the abscense of as much alien chemicals as possible, they will be able to cope also with these more difficult situations. These viruses are following mites and with less and less impact of mites where bees are quick to remove them, from themselves and from brood, viruses will cause less and less problems. But until we are there I suspect little of movements is beneficial to help our bees to survive and fine tune their resistance.

  4. I´m still a little shy posting here being a newcomer so please don´t take me as a loudmouth. (3 years beekeeping)
    Last year the colonies I bought ( not treated for some years) were thoroughly harvested.
    They came to me with the claim to be on small cells but I now measured the combs I sorted out and they were mostly 5.1.
    I have my own press 4.9 foundation so I started to regress them.
    They still have some problems to draw correctly but now I think the most important fact to health is leaving them their own honey and pollen.

    Which is a serious problem to professional beekeepers who depend on honey harvest.

    My bees are about to change their attitude.
    I talk about the Carniolans, the AMM I have are acting like ferals but they are not adapted to the climate, they breed like crazy and but have no stores the mother coming from the canary island. That will change with the hybrids.
    Formerly the Carniolans`s social life was lived on the entrance boards. They fought robbers, feeded their own, rested after foraging and so on.
    Now they live behind the entrance and if you see them they start like rockets and go in immediately.
    They have a feral aura now. They are very small and don`t fall prey so much to predators any more.
    I harvested 40kg of honey out of 3 queenless splits. I used 3 kg to feed back into the mother hives. Those struggled. Because I did the splits with mostly capped brood they had all the mites.
    All my hives (14) do the VSH if necessary. But the mother splits struggled. I donated the honey and they recovered.
    I will not split like that again. I will divide in half using the same amount of capped brood and open brood in every split. Foragers will drift. I will do only strong splits with 6-8 brood combs Dadant. I will leave them all honey except surplus.

    Now I think the most important facts are nutrition and beekeeping methods. More than small cells.
    Do not think small cells are not important to me. But in my climate zone bees draw 5.0 naturally.
    I live in a very crowed area. Many small beekeepers. It`s hard to keep bees without treatments. I´m not much isolated.
    You need a strategy. With every location you need your own strategy.
    A beekeeper who owns 200 to 300 hives is dominant in his area. I´m not.
    I need another strategy.
    For the time being I believe I will not be able to have production hives. Maybe never. So I will try to have splits so strong they are able to produce some surplus.
    I love bees. I have to be humble. No flow, no honey.

    • Thanks for sharing your experiences and thoughts Sibylle. It’s hard to say which management detail is most important or if any is more importantant than another. Actually I think it’s enough to understand which are important. And the degree of importance may differ in differnt situtions and phases of in this case the adapation process in becoming Varroa resistant.
      Leaving honey for winter food I find an investement for future strength and health of the colony and thus making it possible for bigger early crops. If you have bees that don’t breed when they sholdn’t. I would love to be able to leave let’s say 25 kg of hony on every colony. I do where I can. It’s as easy for a commercialbeekeeper as for a small scale one.

  5. Two thoughts from my site:
    To safely judge on increase on mite resistance of your bees by the amount of thymol used or number of colonies treated, you can look on a longer run – several years, instead of just comparing 2 years. The overall trend should tell.

    Second thought is more a question; you anticipate that low pollen availability had a big impact last year on resistance behaviour, resulting in increased treatment, which is a very plausible explanation. What would be countermeasures? Do you think that if the hives would have had bigger pollen stores the situation would be better? Or do they need fresh pollen anyway?

    • That’s what I have intended. I have though realized that it might take many years to continue with that approach and see progress. That’s because I keep treating only those having virus problems and not those that soon after will get problems, and thusthose later one will be agents giding the newly treated ones new mites very soon. Thus keeping a high mite and virus level in the colonies. That’s why I have tried to change strategy. I have tried somewhat different ideas. I will share the experiences and thoughs a little later on when work has slowed down a bit.

      • I’m looking forward to share you insights in your selection strategy!
        Besides, you mentioned that you keep treating only those with virus problems in former times, hence showing signs of DWV, but not those that soon after will get problem. I’m not entirely sure, what do you mean by the second ones. I suppose these are hives that have a high virus tolerance and therefore have high mite levels but no bees with DWV sign and crush later on, as too many worker brood is heavily affected and the colony becomes weaker or die? Is this the reason you concentrate on bee shaker as well in the recent past?

        One more comment to your point with the high mite level, that you find a bit negative…. In principle you can watch this from different perspectives. From the perspective of honey, of course you want not so much struggling, weak or even dieing colonies. However, from a perspective of resistance breeding a significant mite level is not too bad, as this tells you which colonies are able to cope with that challenge and which not. Secondly, the colonies that can’t cope in the beginning with the mite levels other hives of the yard can, might be helped with capped brood level removal to be able to manage the challenge after a while and keeping the mite level on a let’s call it reactive level. Because to me it seems plausible when the mite levels are too low, these stock will not gain let’s call it epigenetic burst or learning by crisis, as the mite acceptance level might be too low, to react and to become better in resistance terms.

        A short third question: You said that you have on two yards one or some more survivors, that you are going to make nucs from. I suppose you stop treatment there and follow a strict selective system similar to nature. Can you tell what was the original number of stock in that yards?

        • When those colonies that didn’t show DWV bees when others did and was treated later on came up with crippled winged bees they did get treated. That was the strategy, as soon as they showed wingless bees, or rather at least two of them on the hard board in front of the hive and/or on a brood comb and the brood combs looked spotty and the strength of the bee colony was shrinking I treated.
          But what has happened it seems is that with this higher mite level in the apiaries, also the virus level has been increasing, so that the bees come up with crippled winged bees at lower mite levels. That can be held as bad or good. But to get the virus levels going higher and higher in you bees I don’t like. Therefore i think, if you should treat, that treat when mite levels goes above a certain level, like 3 %, or so. That is a way low, but today it’s unfortunately very common that bees show virus effects at that mite level.
          If you don’t treat, all those bees that are weakened by mites and viruses will die and that will stop the steadily increasing levels of viruses. That’s why I think, if choose to treat, that treat when the mites is above a certain level.
          Today our bees need our help to avoid reinfection of mites to be able to develop resistance traits without making it difficult developing this by using chemicals in the hive. There are plenty of mite hives to get reinvasion from easily to train them further when time is ready for that. I don’t hink you have to worry about that. there re plenty of mite hives around, not too far from you and me.
          Have I stopped treating from those yards you mention. yes, as long as the mite level is so low. I have recently checked them. The mite level is well below 3 %. The original number of stocks in those yards? The one ended up with one (and now two with the split) was 10. Another one was 8 which then was two (and now three with a split). This later one is actually only 500 meters from another beekeepers yard, which though has Elgon bees. But he doesn’t treat as I do and his bees are not as resistant as mine as he have got them from a friend that hasn’t selection continuously as I have. I suspect this yard of mine is at risk sometimes of the year to be somewhat reinvaded. And one of the two original hives this year had suddenly almost a mite level of 11% after a spring with 1%. The other colony 1% spring and now. The split I didn’t check. The 11% colony didn’t show any wingless bees to my surprise, but they got thymol at once. It’s one of the very few colonies that have bee treated this year, so far.

  6. Mites can be the carrier of a virulent virus or not.
    When mutation of virus takes place it`s possible an apiary, which had much mite infestation but no DWV wings so far ,suddenly experiences an outbreak of new sickness until the host (bee) is able to cope with this.
    If the bees are already able to cope with DWV they maybe have problems with CPV, as it was with one of mine.
    I would like to know if it`s true small cell bees are not infested so much because having tergits that are narrow or is the advantage of small cells only the lower development of mites?
    To strengthen the immune system of the bees is one of the main standards to have mite tolerant bees I think.
    This can be done by us or by nature.
    The microfauna, developing in non treated hives in wax not cleaned away is one of the factors, or the food left.
    The microfauna is killed by treatments.

    Or stress the bees while working them. Change order of broodnest, for example or the making of too small colonies which will put all their energy in growing but not in fighting disease and parasites.

    • In our environment where many have used a lot of treatments I think we will have problems finding mites which are not carrying any viruses. I think we have to count on that as soon as we have mites we have viruses in lesser or bigger degrees, mostly bigger. When Varroa first were discovered in Sweden they could find 10 000 mites in a colony and no virus effects. Very soon after they began treating mites with formic acid a colony was found having no more than 500 mites. It was full of “pedestrians” as the beekeeper called them.
      Yes, there are for sure different degrees of virus resistance among our bees. And the resistance will develop due to virus pressure. But if the pressure get too high too quick the colony will die before it has been able to develop the resistance enough, through epigenetic and genetic changes. And viruses can be “helped” by bad management by the beekeeper, stressing factors as you describe and not enough nutrition.
      When the microfauna is working as it should in kind of an ecological system, fungi, bacteria and viruses and other things are doing good. But the system is delicate and gets easily disrupted, by chemicals for example. Sometimes though there are difficult choices, letting colonies die or save them and killing microfauna. If the microfauna is better in old black combs I don’t know. I guess it could be bad as well if the colony has had big disease problems.
      There’s very little studies done concerning why small cell size is beneficial and how beneficial it is. Almost the only type of tests done are on development of the mite population during a quite short period of time. Mostly these studies are not very good designed and gives doubts on the results, or rather lack of results, that is no statistical significant differences. Which you don’t if the tests do not take in account the important details governing population dynamics. You might even don’t know all these details when putting up a test.
      The first thing to take in consideration is that bees themselves choose smaller sizes in the broodnest, if given the time to naturally build their own combs.Why do they do that. Because they get more fit and survive better and can reproduce better. That’s the reason nature “choose” what it does. In what way then does small cells give this result? We don’t know for sure, but there discussions of course. You mention smaller body parts. Yes, mites are more often found on other parts of the body than in between abdomen tergits. What effect this has is discussed. A good immune system has effect on different pathogens, which is important. Smaller bees, whether they are born in smaller cells or not have got other composition and smaller amount of food, from the nurse bees. Smaller nurse bees may produce different food than bigger nurse bees. I can’t confirm that smaller cell size gives shorter development time of the brood.
      The most important traits to get rid of mites are hygienic behaviors, hygienic behavior of different kinds and degrees against mites in brood, and hygienic behavior against mites on their own bodies and on the bodies on other bees, what is called grooming. Also hostility against bees with mites on them coming to enter the colony, which is also kind of hygienic behavior.

  7. I would like to quote Kirk Webster on this:

    > In the long run it’s always the same: now and then we might get a little help from the USDA or other agency, but to succeed farmers need to create their own systems, their own reality, and do their own research. In my case I tried to do this by taking the Russian bees and applying to them the techniques I had learned from my mentors, my experience and especially from the tracheal mites. My apiary today is not perfect by any means, but I have been able to make a living from bees without using any treatments since 2002. Despite assurances from “authorities” and “experts” that there is now such thing as commercial beekeeping without mite treatments, a few of us have discovered that Sir Albert Howard’s idea that pests and diseases should be viewed as friends and allies, helping us to restore health and balance, is true even in this extreme case. The time- and worry-intensive methods of beekeeping promoted by the scientific beekeeping community–with constant mite treatments and laborious testing for specific traits in colonies that never get a chance to show their real potential–can all be done away with by simply using a stock that has a history of non-treatment and survival; allowing the mites to select the best and strongest colonies; and by rapidly propagating the survivors to replace the initial losses, and then to increase the apiary size. The mites are doing a much better job of testing the bees than any number of lab coats, clip boards and computer programs can do, and after the initial collapse-and-recovery cycle, at a very low cost. Beekeepers who tried to avoid this collapse-and-recovery cycle by continuous treatments are now suffering from contamination of their combs, and experiencing losses the same or worse than untreated apiaries..extreme case<, which means threat by varroa sickness, is still here after all this years, it`s even stronger because we have weakened the bees with our managements.
    Everyone has his own approach to have resistant bees, but in the end I like the idea of mites being our "friends" to help us along.
    Sibylle

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