Host adaptations reduce the reproductive success of Varroa - a paper

Discussion in 'General Beekeeping' started by Adam Foster Collins, Sep 20, 2012.

  1. Adam Foster Collins

    Adam Foster Collins New Member

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    http://onlinelibrary.wiley.com/doi/10.1002/ece3.248/pdf

    I found this to be a very interesting and encouraging article about how a couple of isolated populations of feral honeybees have rapidly adapted to living with mites.

    Abstract
    Honey bee societies (Apis mellifera), the ectoparasitic mite Varroa destructor, and honey bee viruses that are vectored by the mite, form a complex system of host–parasite interactions. Coevolution by natural selection in this system has been hindered for European honey bee hosts since apicultural practices remove the mite and consequently the selective pressures required for such a process. An increasing mite population means increasing transmission opportunities for viruses that can quickly develop into severe infections, killing a bee colony. Remarkably, a few subpopulations in Europe have survived mite infestation for extended periods of
    over 10 years without management by beekeepers and offer the possibility to study their natural host–parasite coevolution. Our study shows that two of these "natural" honey bee populations, in Avignon, France and Gotland, Sweden, have in fact evolved resistant traits that reduce the fitness of the mite (measured as the reproductive success), thereby reducing the parasitic load within the colony to evade the development of overt viral infections. Mite reproductive success was reduced by about 30% in both populations. Detailed examinations of mite reproductive parameters suggest these geographically and genetically distinct populations favor different mechanisms of resistance, even though they have experienced similar selection pressures of mite infestation. Compared to unrelated control colonies in the same location, mites in the Avignon population had high levels of infertility while in Gotland there was a higher proportions of mites that delayed initiation of egg-laying. Possible explanations for the observed rapid coevolution are discussed.
     
  2. PerryBee

    PerryBee New Member

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    Hey Adam:

    Link isn't working for me. :???: :dontknow:

    Thanks (again). :mrgreen:

    Perry
     

  3. Adam Foster Collins

    Adam Foster Collins New Member

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    Weird. I just tried it again and it's fine. Anyone else having that problem?

    Perry, I sent you the paper via email.

    Adam
     
  4. DLMKA

    DLMKA New Member

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    makes me feel even better about my decision to not treat hives for varroa. If they die, they die. I can split hives that are able to manage the mites on their own.
     
  5. pturley

    pturley New Member

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    Having read this paper, I hope there is MUCH MORE to follow from this author about these populations. As with many observations, this leads to MANY more questions than it does in providing answers.

    The one theory proposed of a novel "pupal violatile compound" seems a bit far-fetched IMO. Well, certainly farther fetched than many other ideas that come to mind.
    Possible? Certainly... ...functional changes in chemistry occur with extremely minor differences in compositions.

    The simpleist theoretical mechanism I can think of could simply be the duration of larval development. The shorter the development time, the less chances for the mites to mature and breed in the brood cells. This was my impression in reading the observations. That these bees may simply be developing faster...

    NOTE: The paper assumed that "typical brood-ages" applied to these populations without doing the investigations needed to see if these "typical" values applied. In the interest of eliminiting this variable it would be interesting to see someone (original author or otherwise) do a follow-up study on these populations to track the actual ages of the larval samples.

    Good post... ...it has the "wheels turning" to be sure!
     
  6. Adam Foster Collins

    Adam Foster Collins New Member

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    Always more questions than answers.

    To my mind, this is the crux of the whole issue of mite resistance. The fact is, we just don't know that much about the mite/bee relationship and the ways in which the bee might respond if left alone long enough to do it.

    The paper suggests that the bee may be one of the rare creatures who can out-adapt its parasites. But as long as we keep throwing innumerable variables into the mix, the two are very unlikely to come to any balance.

    I'm very close to taking the leap, and quitting with all mite treatments. All of it. Simply because after a few years of really researching this subject as hard as I can, I really don't think we know very much about the affect we're having on the mite-bee relationship. It don't see much in the way of truly effective solutions. So why don't we just get out of the way?

    At least those of us who are not dependent on the bees for our livelihoods. I can understand economic pressures, but from what I can see, mite management has become its own industry. I have more faith in the bees' ability to adapt than I have in our ability to fix it with invention and intervention.

    I think we have to let her do her thing. I do not believe that she is dependent on humans to survive. I do not believe that she won't live and thrive if we get out of her way.

    I know that many of you disagree, and I empathize. I empathize with the pressures of money, and the risk of losing on investment. I empathize with the urge to do everything you can to help them, and the urgent need to assist the bees with fighting the mites.

    But I just don't think it's working.

    I respect all of the different perspectives on this, and I do not claim to 'know' any more answers than you do.

    But I'm going to try this. I'm not treating for mites at all anymore. I decided this earlier in the year, when after oxalic acid, EO's and whatnot, I opened my first drone combs this spring to find them teeming - I mean TEEMING with mites.
    That's a treadmill I just can't deal with. I have wavered recently, I will admit, as winter approaches. I do have the urge to initiate some form of treatment 'just to be safe". I love my bees, and I hate to think of losing them. But I think we're on the wrong path collectively with all this mite-fighting.

    I think we're breeding stronger mites and weaker bees. I think the bees have the genetic ability to adapt to this pest rapidly if we get out of her way. Getting out of her way is, admittedly a tough pill to swallow, but I think it's the only way we'll ever see a bee able to live without a crutch in our lifetime. I realize that's only my opinion, but it's the one I've come to.

    I'm jumping.

    Wish me luck. I'll keep you posted.

    Adam
     
  7. Crofter

    Crofter New Member

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    Adam, I hope you are right and certainly wish you luck. I wish we could do separate controlled studies, large enough to be definitive and separate enough that each endeavor did not defeat or affect the other but that is hard to do. I have a feeling of reluctance to risk the entire species by now refusing to experiment with alternative treatments: we engineered the problem by removing geographical isolation and incurred cross species adaptation of a pest. The Asian bee swarms ten times a year and makes only a few pounds of honey but they co exist happily with the mites. That is not an adaptation we want unless we frame it only as a solution to pollination requirements. Man has been treating for thousands of years, mites, mange, and many other pests of animals he has brought under his control. Left to their own devises animal populations are usually adequately sparse to limit most of their pests. If we want to raise them in artificial conditions (population density) it is not going to be near as easy to get adaptation that must also fulfull our preconditions. That it be pleasing to the eye of man is not one of Mothers concerns. Nature is very adaptive but man are we putting hobbles on it with our demands!
     
  8. PerryBee

    PerryBee New Member

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    Adam:

    Good news! We've just been accepted as the East Coast Distributors for Baye..............Oh,........................never mind! :lol:

    Seriously buddy, I know in our many conversations that you have been struggling to come to grips with how you wanted to keep bees.
    Now that you have made your decision I will always be willing and able to support you in any way I can. It's what keeps do! :wink:
     
  9. efmesch

    efmesch Active Member

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    Possibly, the most effective way of meeting the needs of beekeeepers and the bees would be:
    1. To continue helping our hives overcome the ravages of varroa (by whatever method the beek chooses) and
    2. keeping hives from long term trap-outs/cutouts untreated.

    Instead of looking at the trap-out/cutout hives as a quick means of increase, use them as a source of possibly modified genetics that have managed, unassisted by man, to overcome destruction by varroa. Don't treat them, just raise them as you would any hive and, if they prove to be "resistant", use them for queen raising. If we do enough of this, long enough, we should be helping to encourage the distribution of varroa resistant strains of bees.
     
  10. Adam Foster Collins

    Adam Foster Collins New Member

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    Yes. Believe me, my mind is already wandering to that queen bee Perry removed from that old house last week... ;)
     
  11. heinleinfan

    heinleinfan New Member

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    Hey Adam,

    I don't treat for mites myself, not chemically anyway. I believe, like you, that chemical treatments will only build stronger mites, not stronger bees. (Not using chemicals whenever possible, in all aspects of my life, is something my husband and I believe in personally, so it just translated over to the bees.)

    I do use sugar dusting along with screened bottom boards, and I do counts periodically with sticky boards. I have mites, but I've not ever had numbers that made me feel I had a problem with mites. I do this because I don't believe bees that are kept can be completely left to their own devices.

    Yes, they've survived for thousands of years on their own. But, we're putting them into an artificial environment when we keep them. We are choosing the hive locations, we are forcing them to build comb where we want it (even with foundationless keeping) and for most of us, we force them to drastically overproduce honey every year, so that we can harvest the excess. Because of this, I don't believe kept hives could be left completely alone and still thrive.

    I almost think of beekeeping as like...tiny wildlife preserves. People who care for preserves try to mimic natural habitats for animals and plants as best they can and reach a balance of giving *just enough* human intervention for the plants and animals to thrive.

    I try to give *just enough* human intervention to my bees to have them thrive in this unnatural environment I keep them in, but leave them to their own devices otherwise, because they know far better than I what is best for them.

    Does that make sense?
     
  12. Adam Foster Collins

    Adam Foster Collins New Member

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    It does.

    But I believe we can go all the way to not treating at all. I'm working with top bar hives, narrow frames in 8 frame hives, a mix of small cell and natural comb (moving more and more to natural comb - foundationless). I am not focused on honey production. My interest is in the bees.

    Now that's just what I am doing, and I am completely aware that there is no 'right' way, but rather thousands of "my ways". Each one suits an individual relationship between a person and their bees in a particular time and place.

    From my own present perspective, I am just choosing a direction to explore. Once I have experience on that path, I might be more prepared to tout it's degree of value. For now, I can only say what I intend to do and why I'm choosing to do it.

    It's just for all the attention the mites have gotten over the last 20 years; for all that we've thrown at them in an attempt to annihilate them - they've only gotten stronger, and more common.

    That makes me want to try something else.

    Now some of you may have given an honest try to treatment free and failed. If so, then I don't blame you for believing that it won't work. But given so many conflicting opinions on just about everything, it seems that one has to try most things for one's self, in one's own regions, before you can know.

    I haven't yet really given it a go. So I guess it's time.

    Adam
     
  13. Gypsi

    Gypsi Super Moderator Staff Member

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    Adam,

    I'm with you. But happily, I have very few mites and an area relatively isolated from both feral bees and other beekeepers bees. I took up beekeeping because of a total lack of pollinators. Which means I have a relatively controlled population - whatever bees I bring home.

    I bought my nucs from Flyman, who has been breeding survivor stock in to varroa sensitive hygenics. And I have a swarm and a cutout. Don't know if the swarm had mites, but the broodbreak when I killed their queen helped a lot. The cutout I accidentally caused a broodbreak on. And when the inspector and I went through 4 out of 5 hives, we found 2 mites. One in a sugar roll, one in a drone larva. I took 32 larva out of the 5th hive, and found 1 varroa mite total after opening all 32. (at the kitchen sink.)

    So yes, it can be done. I did some powdered sugar dusting on my bees last year and had them cleared up of mites before they were killed off by robbers. And weekly thorough dusting, with sbb's, causes brood break but does not necessarily produce hygenic bees that will remove mites. Sbb's I think are necessary, with oil stickies in my case. Without the oil stickies in the nucs the flyman brought.

    I'm thrilled at the moment.
    Gypsi
     
  14. Adam Foster Collins

    Adam Foster Collins New Member

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    One could add other perspectives, such as this paper, entitled Characterization of the Active Microbiotas Associated with Honey Bees Reveals Healthier and Broader Communities when Colonies are Genetically Diverse

    "Colonies with genetically diverse populations of workers, a result of the highly promiscuous mating behavior of queens, benefited from greater microbial diversity, reduced pathogen loads, and increased abundance of putatively helpful bacteria, particularly species from the potentially probiotic genus Bifidobacterium...Our findings illuminate the importance of honey bee-bacteria symbioses and examine their intersection with nutrition, pathogen load, and genetic diversity, factors that are considered key to understanding honey bee decline."


    Studies like this make me question the wider effects of our treatments, aimed at the destruction of varroa. What does the addition of say, thymol do to microbes in the bee's gut? What domino effect does that have on other aspects of bee health, such as their ability to deal with pathogens?

    This line of questioning is what leads me to be quickly overwhelmed with a sense that the number of variables, and the number of ways in which our interference could be causing more harm than good quickly spiral beyond our potential to keep track of them. The systems are simply to complex for most of us to fathom.

    In the face of that complexity, I feel the most reliable solution might be in letting the bees adaptive abilities take their course.

    Perhaps our collective focus, and our efforts should come to bear on just how best to "get out of the way." And that alone should become our attempt at "treatment".

    Adam
     
  15. Gypsi

    Gypsi Super Moderator Staff Member

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    What does the clorox I add to my sugar syrup do? Raises pH, prevents fungus. Bees drink from swimming pools all the time, so I don't think the sodium hypochlorite hurts them. But that could be a treatment in and of itself. I mainly add it when the syrup will be out there for a week, and to prevent fermentation of stored syrup.

    But I'm going "monkey see - monkey do" in adding it, I have no idea what that does to the bacteria in their gut either.