I really work for getting bees that can handel the varroa mite themselves. You get results when you do, but it’s extra work and sometimes it’s difficult to interpret what you see. And you loose some bad bees. And some not so bad bees don’t give any honey – and you shift the queen in those. That’s the two most important results from such a work.
I got a good report in the discussion forum of VSHbreeders.org. That’s encouraging.
http://vshbreeders.org/forum/showthread.php?tid=211
Efforts for resistant bees give results
Dear Eric,
I have read with interest your post about VSH trait. Especially the VSH test seems to be a very good quantitative method. With the lenses you describe, you might even analyse stocks in the field….I personally like your observation, that varroa mites move more slowly in stocks that show VSH, which might itself contribute to varroa resistance beside the outake of pupae.
The first thing I’d like to ask is, no other factors like epigenetic induction or hive management have been discussed as well, but also might impact VSH trait.
For instance; if VSH trait is genetically existing but induction of VSH alleles might only be accomplished when having a critical concentration of a certain trigger (these trigger might correlate to degree of might infestation but also to bee population size). With other words big stock might show VSH trait but not small stocks, although genetic is the same. (This would be a different potential explanation to the one you give, when you refer to a critical amount of worker bees in a population that must show VSH behaviour.)
Another example would be hive management. Some people (e.g. Lusby) argue that nearly every bee is able to react on varroa, you have to establish natural living conditions, which take away all/most burdens/stresses. As stresses are differentially hierarchized/prioritized, bees will react first on stresses that are higher prioritised like for example honey take in (e.g. when too much honey is harvested by bee keeper at once) and don’t “take care” on inducing the VSH trait adequately, when mite pressure is relevant. VSH trait might be first induced when higher prioritized stresses are relieved or mite pressure becomes too high that it is too late, to react. Consequently, bees with the same genetic might only come across the mite attack, when hive management is appropriate.
Breeding on VSH might be therefore, increasing the priority of VSH against other traits or reducing the concentration of the trigger that causes epigenetic induction. However, a strong VSH prioritzation might compromise brood development and honey intake.
Best regards,
Rüdiger
Those readers that want to rake part of posts on this blog about VSH can go to ‘Categories’ on the right and click on ‘VSH’. Or click here: http://www.elgon.es/diary/?cat=26
Field work with reading lense (about 2x) (and reading glasses, about 2.5x):
Yes, that’s possible and I think it’s good to use ‘cold’ (LED) light to be able to see well into the cells. So sitting in the shade and using a lens with LED lamp around the lens (they exist) and a good battery would be a good choice.
Epigenetics:
Epigenetics is more and more discussed. It’s understood to be behind much adaption rather than classic selection, which many times is slow. Selection for example could never explain how the African bees could develop resistance in 5 years both in South America and in South Africa. Only epigenetics can. But not much is truly known about epigenetics, though research in this area is increasing. Epigenetics: how DNA is read and expressed thus determining which proteins are produced and how much, which lies behind all traits. Chemicals resulting from environment impact results in epigentic changes which are inherited to next generations until environment changes again.
Management:
Yes, of course management is important. Bees are always under stress in nature. But we can give them much additional stress, or little additional stress. Of course it’s easier for them to deal with life and stay healthy if we give them as little additional stress as possible. Let them work without too much disruption, don’t rob them too much, try to let them come in contact with as little alien chemicals as possible, miticides and agro chemicals for example.
Breeding strongly for VSH:
I find no negative effects of that, if the population of bee colonies involved are ‘big’. Thus avoiding inbreeding. This means it’s made a little differently compared to how Harris and Harbo did it. They made it quick, in three years! With the result you describe as much inbreeding was involved. But when outcrossing again vitality was gained back and VSH alleles were introduced in higher concentration in the stock crossed with. I have been doing a breeding project now since 1989 when I introduced Monticola bees from East African Mountains. Then sending queens to places where Varroa was present. Regressing my bees to small cell size. Then Varroa attacked severely in 2008-09 (it came of course some years earlier to my apiaries). I had hoped the bees should be able to handle the mite immediately almost without problems. That was just a dream. They needed time for the epigenetics to work, and some selection of course. During this time Varroa population has to be big enough for adaption and selection to be able to take place. But hadn’t I used some alien chemicals I had lost all my bees, which would have been a disaster in many ways. I still use some thymol, but very little compared to recommended amount. Also the number of hives not needing any thymol are growing. Honey production is high in healthy colonies. This year when I learnt how to test for VSH by John Harbo, I found some of my bees having high VSH values. The best one I haven’t described yet. I will in a later post.
Dear Eric,
thanks for your quick reply! I will have a look for the lenses with the cold LED light.
Africanized bees
I didn’t know that African bees weren’t able to cope with Varroa in the beginning. I just thought they were able to do so from the beginning of infestation. That means they needed some time to “react” on varroa as well. Did we know something about varroa resistance mechanisms of African bees that make them more successful than e.g. European bees? Probably VSH as well; shorter developing times of worker bees and drones? Is there something else?
Epigenetics
Epigenetic regulation determines the response of an organism, based on their genetic (are relevant genes present?) and environmental situation (is the stimulus strong enough and are other traits higher priorized based on resource situation?). So genes might be there like e.g. VSH genes but not expressed, hence no VSH behaviour visible.
That epigenetic regulation reflects their evolutionary history and apparently allows organisms to react flexible on different situations (e.g. mite infestation) and save costs by not expressing genes, when they are not needed. The price is -once the e.g. infestation is happening – a lag of time which is needed until the response of an organism (bee) is expressed.
(I have to apologize – I worked 10 years ago in the field of ecology with model plants (Arabidopsis) and investigated the trade-off of resource allocation in regard to resistance, reproduction and growth in dependence of stresses like drought, salt and so on. The bottom line was there: The higher the other stresses become, the less was invested in defense, even enemy pressure was there. This points to an elastic adaptation outbalancing different requirements and situations and in the end of the day in a bigger survival rate, as environment can quickly change.)
Although, I don’t exactly know whether this is the same in bees, I would suppose basics might be similar. At least it helps me understanding the different observations made from different people at this topic.
Management:
And on the other hand the, let’s call it “resource allocation model”, is in line with the observations of beekeepers like Ed and Dee Lusby or Stephan Braun, who tell you that you can/should take any local bee (a little bit exaggerated, as the VSH genes must at least be present, as you can’t regulate what isn’t there) and if you follow organic bee keeping principles (release the artificial stresses) followed by strong induction (crisis of the hive) they can induce their VSH genes against mites as they have enough resources to do so and don’t need any varroa treatment. (little bit simplified…)
Breeding strongly for VSH
As our European bees haven’t seen the varroa before, inducing the VSH genes is probably on a very low urgency level in their epigenetic regulation program as it has been no big need so far. Hence, breeding for varroa resistance might “put” the priority of relevant genes more up, at least so much that bees are able to cope with the varroa, when the selection system is strong enough. Hence, the expectation would be epigenetic regulation occurs probably much earlier compared to other strains (or even constitutively??), which we might observe as outtake of pupae at an early stage of mite infestation or even then, when resources might be limited and other comparable strains don’t induce VSH trait.
As you state – keeping bees without treatment is still a challenge and take years – if you do not want to compromise on honey crop, behaviour etc. So I’m looking forward to see your post regarding your newest high potential queens and learn more about this interesting topic!
Best regards,
Rüdiger
In South America when Varroa came, the infestation degree was many times 50%, that is a mite on every second bee. In South Africa one extreme observation was 50,000 mites in one colony without it dying, at least when the observation was done. Not many colonies died in these places during the adaption period in about 5 years. The infestation degree was coming down so much the bees were called resistant after about 5 years. Soon enough infestation degrees was found to be around 5%.
The difference with European bees is that genetic variation was and is much bigger among African bees than European bees. In Europe isolated mating stations have been used for many years. Cellsize was natural – 4.8-5.0 among Africans, enlarged to 5.3-5.7 among Europeans. More chemicals of different kinds among Europeans, etc.
The 2 VSH genese were found by Harris and Harbo when using large cellsize. They and others found that VSH didn’t work on drone brood, only worker brood. Though I and others who have bees on small cellsize see VSH-like trait quite a lot as well in drone brood.
Today the cooperation among genes is sometimes simplified by saying that “all” genes are involved in forming most or “all” traits, but mostly only a few very much influence specific traits looked upon. So the game is quite complicated. Conclusion is that more genes can be involved than these predominately 2, specifically under different circumstances. And probably epigenetics doesn’t stop work just because some effects has been achieved. And ordinary selection of course is working as well. In this process I strongly suspect also learning how to handle mites by the bees is involved. That is, not only the queens and drones spreading the genome is involved but also how this genome (selected and epigentically changed) is expressed also through the phenotypes of the individuals. And learned behaviour is passed on directly to other individuals. Conclusion is that you don’t get all the effects of an adaption by sending queens to another beekeeper, it might help enough, but best by sending a nuc or small colony.
Ok, this colony I talked about seems, in the midst of colonies I had to treat a little, to have eradicated the mites, anyway I couldn’t find one single mite in the brood after some years without treatment.
I have to reply to my reply to Rüdiger Dietrich on Dec 13 2013.
I wrote: “The 2 VSH genese were found by Harris and Harbo when using large cellsize. They and others found that VSH didn’t work on drone brood, only worker brood.”
I have found a work by Jeffrey Harris that do show VSH on drone brood, but not as much as on worker brood. I know I’ve read of a work in which no hygienic behaviour was seen on drone brood. But Harris did show that it is present in VSH bees but at a lower intensity than on worker brood.