Genetic Purity vs. Hybrid Vigor

[NeilV]

The discussion about Russian bees and their breeding got me to wondering.

On the one hand, I understand the idea that hybrid vigor results from mixing diverse genes when breeding. I have read that people worry that the gene pool for bees has narrowed too much, since all the bees breed by breeders from breeder queens are limited to a couple hundred sources and varroa etc. has hammered so many bee populations.

Then, I read in Bee Culture a couple months back that people who are using Russian bees stress the importance of have pure bred Russians not Russian crossed with any old drone. The breeders in the Russian Bee Breeders Assoc. stress that they are striving to only produce pure Russian bees. That also assumes that genetic purity is the goal.

Why is it important in the case of Russian bees that they be pure bred? What happens when they are not? Why does hybrid vigor not work in that context? Are the people running the Russian breeding program already doing all the right crosses between bees to get the diversity they want/need?

Not trying to start an argument, just wondering.

Ndvan

[Beaches' Bee-Haven Apiary]

I'm no expert... so I'll let MB tackle most of those!;)

I think the main reason Russian purity is stressed is so that the naturally resistant genetics are not diluted. I think the best breed would be one prduced in the area these bees are taken from, thus providing natural genetic variety, but with similar resistant traits. When they're brought into a foriegn opperation the genetics should be kept diverse among the Russian stain. In other words... If you take 5 Russian colionies, stick them in a mating area with no other bees and produce queens, you will get pure Russian stock. But if you keep using those colonies and thier offspring without importing more native Russian stock, you will run down and harm the genetic pool of your bees... they start diluting their own genes. Genetic variety is important in any animal, with the Russian stain of bees it is still vital. These bees have naturally, over time, developed a resistance to vorroa destructor but in the wild these bees are still genetcly diverse, yet they share very similar characteristics. In order to capture this resistance scientist must maintain genetic "purity" withing the Russian strain, however, they also must mainain a threshold of genetic variety to maintain strong, healthy, productive bees.

-Nathanael:cool:

[Michael Bush]

>On the one hand, I understand the idea that hybrid vigor results from mixing diverse genes when breeding. I have read that people worry that the gene pool for bees has narrowed too much, since all the bees breed by breeders from breeder queens are limited to a couple hundred sources and varroa etc. has hammered so many bee populations.

Diversity is good for a species' gene pool.

>Then, I read in Bee Culture a couple months back that people who are using Russian bees stress the importance of have pure bred Russians not Russian crossed with any old drone. The breeders in the Russian Bee Breeders Assoc. stress that they are striving to only produce pure Russian bees. That also assumes that genetic purity is the goal.

Predictability is the goal of any breeding program and that is always the opposite of diversity. If you breed any animal for specific characteristics, what you are really doing is breeding out the diversity that would give you different characteristics.

>Why is it important in the case of Russian bees that they be pure bred? What happens when they are not?

Then the characteristics you bred for get mixed with genes that don't have those characteristics. If it's a recessive trait you lose those the first generation where a dominant gene blocks that characteristic. In the second you might even lose a dominant characteristic when it gets lost altogether in that particular line.

>Why does hybrid vigor not work in that context?

Hybrid vigor is an entirely different issue. It only happens when lines that have been separate come together. It works best if those lines are carefully chosen to enhance the characteristics you want and not the ones you don't want. For instance an F1 hybrid in bees is often very agressive. It takes a careful cross to get one that isn't.

> Are the people running the Russian breeding program already doing all the right crosses between bees to get the diversity they want/need?

No breeding program (except maybe Dann Pruvis') is built around diversity. They are built around selective (read "less diverse") breeding. All selective breeding does is remove the characteristics you don't want so that you consistently get what you want.

For instance, if I can get a heterozygous (all sets of color genes are for black) black horse and breed it to a heterozygous black horse I will get a heterozygous black offspring. There is no possibility of diversity in the realm of color if I do this. If I breed cows to have large udders and give much milk, I am not breeding something in, I am breeding something out. I'm breeding out the possibility that I will get a cow with a small udder that gives a small amount of milk. When you do selective breeding you breed out the genes for the characteristics you DON'T want so that you consistently get the characteristics that you do want. After all that work, you don't want to allow those genes you bred out back into the gene pool.

In other words, diversity is bad for a breeding program.

Now the evolutionists will try to argue this, and you can expect me to not respond, but no real breeder nor any geneticist will. This is and always has been the goal of selective breeding.

[BjornBee]

I think there may be some confusion of what diversity is.

There is diversity within the lines, such as MB pointed out in regards to such items as color, etc. A breeder is selecting for a consistent criteria to benefit from, in choosing such items as gentleness, color or anything else. You don't want a vast variance (diversity) of output that is from wide spectrum. You want all good honey producers, you want all hives to be gentle, you want all hives to handle mites, etc.

Then there is diversity from a breeding aspect. This is why the Russian program has each breeder responsible for 2 lines of Russians. Each breeder is selecting for the same traits, but with separate lines. And its these lines that then can be selected from, for breeder lines, drone lines, etc. You can not maintain a line of bees without having a long term plan of using hybrid vigor and crossing of the different lines. That's why the Russian breeder association is setup the way it is, and when you order breeders from such places as Glenn's, that getting the different "colored" lines is important from one year to the next.

So there is diversity within the traits that individual lines carry, those are what one selects for to maximize the traits that are desirable. Then there is diversity between the individual lines that produce hybrid vigor, ward off inbreeding, and can be used for other goals.

I think the term "diversity" is used loosely, but it has different applications that should be defined.

It should be noted that its not one or the other. (Purity or hybrid vigor) You can achieve both by a program such as the Russian association. And you can have hybrid vigor without a closed system of using exclusively pure similar lines (all russian), such as what Brother Adam did when he produced the buckfast by taking many lines(italian, carni, etc.) and selecting for the best traits within the lines.

And it should also be noted that the whole use of the term "purity" or "pure", is certain to be incorrect.

[NeilV]

Thanks, I think you straightened me out. Just to be sure I follow, this is, taken together, my understanding of what everybody had to say:

1. The goal of a breeding program is to eliminate diversity as to specific genes/traits to eliminate undesirable genes/traits.

2. Eliminating diversity in general is bad.

3. Breeders of anything face an inherent conflict between 1 and 2.

4. A really good breeding program tries to manage that conflict by having multiple lines of breeding stock where breeding is done to select for traits (eliminate diversity) but maintain other diversity to the extent possible. In other words, everybody ends up with blonde hair, but nobody marries his cousin.

5. The Russian program has tried to do just that, which is why they cringe at the idea that somebody would open mate their bees and ruin all the work they did to attaining the goal in paragraph 1.

Does that about sum it up?

Also, Michael, I don't want to start an argument over the meaning of life, but what did you mean by the "evolutionists will argue" comment. (Just so you'll know, my personal view is that God is the creator -- after all, why does anything exist at all -- but am interested in the idea of just how he did it. I also have a best friend who both has a biology degree and is a hard-core Creationist, and we have had many talks about that subject).

Also, Bjorn, what did you mean by the use of the term "pure" is certain to be incorrect?

[Kieck]

For instance, if I can get a heterozygous (all sets of color genes are for black) black horse and breed it to a heterozygous black horse I will get a heterozygous black offspring. -Michael Bush

I believe you mean "homozygous" in all instances where "heterozygous" was used above.

So there is diversity within the traits that individual lines carry, those are what one selects for to maximize the traits that are desirable. Then there is diversity between the individual lines that produce hybrid vigor, ward off inbreeding, and can be used for other goals. -BjornBee

I believe the goal is to maintain enough diversity to avoid inbreeding depression, yet reduce diversity enough to increase predictability within the breeding program (like Michael Bush suggests).

"Hybrid vigor" refers to a cross between two different breeds or races, not to a cross between two different lines within a breed. Think of cattle breeding. The "hybrid vigor" seen in black baldies, for example, comes from crossing a black angus and a hereford. The offspring from two separate lines within the black angus breed will not have the "hybrid vigor." The reason, in a simplified explanation, is that even separate lines within a breed are still remarkably similar to one another.

In other words, diversity is bad for a breeding program.

Now the evolutionists will try to argue this, and you can expect me to not respond, but no real breeder nor any geneticist will. This is and always has been the goal of selective breeding. -Michael Bush

If your comment about arguing the point refers to your statement that, "Diversity is bad for a breeding program," I won't argue it. (And I am an "evolutionist.") Even in nature, selective pressures restrict genetic diversity. This about the pressure put on honey bees by Varroa mites: only the bees with one or two specific traits, perhaps, are likely to survive on their own once Varroa became a problem. All of the other traits in all susceptible bees would be lost. That reduces (not increases) genetic diversity.

[BjornBee]

edited due to some unexplained reason.

[BEES4U]

If you want to improve the gene pool.
1. Buy semen straws
2. Buy a purebred sire
3. Breed up to the standards of perfection without inbreeding
The Cocker Spanial was a good dog in the 50's. To much backyard breeding ruined the pedigree. (The term is close breeding) Check out the genetic negatives of in-breeding in animals and see what happens.
Set your genetic goals 10-20 years into the future.
Breed record. Breed record
Can you afford to buy purebred Bull?
No, buy his semen straws by selecting the bull index that fits your operation.
The genetics work is out there. It is tested and proven.
A large beekeeper located in the Mid-west did a trial for his own research and proved that his new strain of queens was superior to his old stock.
The new strain pulled through winter quite well. The control block had very high winter dead outs.
What was the new strain of bee?
They were Russians!
Imported by the USA.
Selected by the USA.
Tested in the USA.
Proven in the USA.
Accepted in the USA.
The Russian traits are carried into the 3-4 generation from a instumentaly inseminated queen's daughters.
FYI
I have over wintered my Russian breeder queens in 1/2 length top bars with full depth side bars. Last year was the worst drought in 130 years. The bees covered 8 frames going into winter with no pollen patties or substitutes being fed in the fall. No syrup. I basically stressed the bees on purpose just to see how they would perform. They now cover 4-6 frames 2/06/08.
The other reason that I over wintered them in small nucs was because I did not want the queen to get burned out in a larger hive,
My othe breeder queens performed as well.

Best regards,
Ernie
Lucas Apiaries
(I start grafting in late February)

[BjornBee]

ndvan,

As to your question of my comment regarding "pure"....
There is no past genetic isolation or sampling to show what "pure" is. Malcolm Sanford, has the right idea about going about doing this in the future, but till this point, there is no profile of what an Italian is, or should be. And this is true with the other lines. (If you notice in the Russian breeders site, no mention of "pure" is used.

On another thread, there is a post about what happened when U.S. Italians bees were compared to Italian bees from Italy. The genetic combinations in the U.S. group was much higher than they of the standard italian bees. Showing a vast hybridization of the stock in the states. But italians have been moved and cross breeding is almost certain to of happened just not here, but all over the world. It probably can be assumed the same with carni, etc. To even suggest that Russians, as we know them, are pure, is not proven. We have no profile or genetic standard, and have no idea if they have already changed since coming to the states.

I am interested in your #5 comment about open mating? Who is cringing about what? Are you talking about what people do after getting Russian breeders? (Breeders outside the Russian association?) As I understand it, the Russian association is open mating themselves. Are they suggesting their idea of drone saturation and breeding efforts is on a level worth cringing when the next breeder does it? There are many competent breeders doing exactly what they are doing, except that they are not members of the association.

Who decided the russians have everything that is needed for the average beekeeper when it comes to honey production, or anything else? Certainly they have good qualities. And its something I want in my breeding system. But its not the only thing. For those who only want usda russian stock, thats fine. The market will dictate what the beekeeping community desires. For me, I want the hybrid vigor and qualities that I can find and breed from with several lines coming together. And I'll occasionally add in a good russian now and then. I can not breed myself the number of lines I need to continue having good queens long-term. But I'm also not interested in joining the russian breeders association for personal reasons. Everything has its place. And I am amazed the number of "bandwagon" types that go all or nothing when the next hot item rolls down the street.

Ernie, I'd be interested in what your friends "block" consisted of. I have had usda russians now for a number of years. And the talk of their overwintering ability has been heard now for several years. I'm convinced that if I took my stock and overwintered them against some other line such as my italians of 5 years ago, I'd see vast differences also.

[Kieck]

To even suggest that Russians, as we know them, are pure, is not proven. We have no profile or genetic standard, and have no idea if they have already changed since coming to the states. -BjornBee

This, I think, is an important point. To the best of my knowledge, no one has yet published any paper revealing which subspecies (singular or plural) include(s) "Russian bees." The bees imported by the USDA from the Primorsky region were previously imported to the Primorsky region from western Russia on the Trans-Siberian Railroad.

Are the Apis mellifera mellifera? A. m. caucasica? A. m. carnica?

And what makes the Russian bees better able to tolerate Varroa? Is it some hygienic trait, like VSH? Is it possible that the Russian bees are similar to whatever ancestral race like Minnesota hyienics are similar to Italian bees?

[MichaelW]

Then, I read in Bee Culture a couple months back that people who are using Russian bees stress the importance of have pure bred Russians not Russian crossed with any old drone.

'any old drone' is probably key to the comment. A grad student here at UTK looked at so called 'Russian bee' beekeepers and found their bees to be less effective at controlling mites than Italians run in the same operation. She concluded it was due to mating to bees that where not selected for varroa control. So in summary, you could loose the varroa tolerance very quickly depending on what you breed to. I wouldn't think the comment would be suggesting that if you breed a Russian to an SMR or Minnesota Hygenic, or any other varroa tolerant line that you are going to loose varroa tolerance.

real breeder nor any geneticist
We'll at least you don't necessarily have to be a 'real' geneticist, unlike those 'real' breeders out there. :rolleyes:

[CSbees]

Hybrids with just some of the Russian traits are very valuable. I have some that have some Russian influence as far as survivorship goes, however, they do not display the degree of agression that pure Russians are know for.

[Aspera]

'any old drone' is probably key to the comment. A grad student here at UTK looked at so called 'Russian bee' beekeepers and found their bees to be less effective at controlling mites than Italians run in the same operation. She concluded it was due to mating to bees that where not selected for varroa control.

Is this work published anywhere? I would really like to read more about this study.

[JC]

The discussion about Russian bees and their breeding got me to wondering.

On the one hand, I understand the idea that hybrid vigor results from mixing diverse genes when breeding. I have read that people worry that the gene pool for bees has narrowed too much, since all the bees breed by breeders from breeder queens are limited to a couple hundred sources and varroa etc. has hammered so many bee populations.

Then, I read in Bee Culture a couple months back that people who are using Russian bees stress the importance of have pure bred Russians not Russian crossed with any old drone. The breeders in the Russian Bee Breeders Assoc. stress that they are striving to only produce pure Russian bees. That also assumes that genetic purity is the goal.

Why is it important in the case of Russian bees that they be pure bred? What happens when they are not? Why does hybrid vigor not work in that context? Are the people running the Russian breeding program already doing all the right crosses between bees to get the diversity they want/need?

Not trying to start an argument, just wondering.

Ndvan

I do not want Russian hybrid queens! By a hybrid I mean a Russian queen bred with Italian drones, etc. A Russian hybrid would not be as good at resisting mites. Since I do not use any treatments for mites, I want 100% Russian bees.

There is gene diversity within the Russian bees, however. The USDA Bee Breeding Lab in Baton Rouge maintains different lines of Russian bees. The production queens that I get have a different genetic diversity each year.

[Michael Bush]

>Does that about sum it up?

Yes.

>Also, Michael, I don't want to start an argument over the meaning of life, but what did you mean by the "evolutionists will argue" comment.

Some on this board will argue that evolution has something to do with breeding. I don't wish to spend my time on this discussion as evolution is irrelevant to breeding.

>I believe you mean "homozygous" in all instances where "heterozygous" was used above.

You are correct. Sorry, at 6:00 am I had a brain fart.

>"Hybrid vigor" refers to a cross between two different breeds or races, not to a cross between two different lines within a breed.

Not necessarily. You can get the same vigor from two lines of the same race. That's what the Starline was and what many hybrids are.

[Bizzybee]

"I have some that have some Russian influence as far as survivorship goes, however, they do not display the degree of aggression that pure Russians are know for."

Pure Russians aren't known for aggression. I think that has come from sellers claiming purity when in fact they were crossed causing the aggression.

I'm not sure where this is going?? There is only one source of Russian bees to my knowledge. And that's from the USDA. They are not going to get any more "pure" than that. And only if II is used from that point of release. Unless you follow the program that they are using to maintain the lines, then you can only start inbreeding. Increasing diversity isn't an option, decreasing it is if you are looking to mask a trait.

Aside from II purity has no course other than diminishing return. Is that a bad thing? Not in my opinion, but it does not support any theory of purity.

Grading for purity and grading for traits have nothing in common in my estimation. If pure is what you want for whatever reason then so be it. If specific traits or a wide range of traits are your preference then choose accordingly. But simply crossing bees randomly is going to yield random results at best. As Micheal mentioned with repeatability, that isn't easily obtained and unless II isn't incorporated somewhere along the line it isn't sustainable. And then you wind up full circle in the maintenance of a line in the same way that purity of the Russian bees is maintained.

But then what happens when the next threat comes along and the line isn't capable of coping with the threat? You make changes or introduce traits from another line. But, which is possible when purity isn't an issue.

[MichaelW]

Aspera, try this url for Laura L. Bryant's Thesis
Examining Varroa-resistant honey bee queens from commercial breeders colony productivity, hygienic behavior, suppression of mite reproduction, and the relationship of juvenile hormone III to mite abundance / .

http://etd.utk.edu/2004/BryantLaura.pdf

I'm not sure if its published in a journal.

I don't wish to spend my time on this discussion as evolution is irrelevant to breeding.
But your the only one spending time on this discussion. :confused:

[BjornBee]

Oh great MichaelW, I just posted a thread on the subject.. ;)

[Kieck]

The production queens that I get have a different genetic diversity each year. -JC

Each queen that you get is likely to be somewhat different than any other queen genetically. Otherwise, they would have to be "identical twins." But "diversity" is a measure of the differences within or among populations. As long as all your bees are coming from one source and are of one race/breed/isolate/type/whatever, the "diversity" will be very limited.

If the diversity is great, like Michael Bush pointed out, you will be able to make no accurate predictions about the subject. You couldn't predict whether or not those bees will "resist" Varroa whether they would produce large or small wintering clusters, their temperment, etcetera.

Honestly, I think we're getting a bit too caught up in the "my bees need to be diverse" bandwagon here. So long as you're not seeing the results of inbreeding depression (lethal effects that lead to spotty brood, etc.), who cares how diverse your bees are? Are you expecting to expose your bees to a wide range of habitats and climates, pests and parasites and predators, etcetera? If you are, diversity can increase the odds that at least one of your colonies will survive all the odd things you throw at them. If not, less diversity might be just what you desire in your bees.

Not necessarily. You can get the same vigor from two lines of the same race. That's what the Starline was and what many hybrids are. -Michael Bush

"Hybrid vigor" is necessarily what I described. Yes, you can get organisms that are just as vigorous from two lines (or even one line) within a race, but they fail to be "hybrids." Conversely, hybridization does not necessarily confer increased vigor. Some (many? most?) hybrids actually have decreased vigor. This "out-breeding depression" is great enough in some instances that the offspring fail to survive.

But to be "hybrid vigor," you must start with a "hybrid."

If Starline was derived from within Apis mellifera liguistica, it was not a hybrid. (That doesn't mean it wasn't vigorous.) And, in thinking about it, I don't know that I've heard "Starline" referred to as a "hybrid," but only as a "strain." Sort of like "New World Carniolans" are a "strain" of A. m. carnica, largely.

[CSbees]

Bizzybee,

I am just going off of what the Tennessee and Florida state inspector told me. I really don't have any experience with pure Russians myself.

[tecumseh]

kieck writes:
"Hybrid vigor" refers to a cross between two different breeds or races, not to a cross between two different lines within a breed. Think of cattle breeding. The "hybrid vigor" seen in black baldies, for example, comes from crossing a black angus and a hereford. The offspring from two separate lines within the black angus breed will not have the "hybrid vigor." The reason, in a simplified explanation, is that even separate lines within a breed are still remarkably similar to one another.

tecumseh writes:
I would suggest this is not the best example since the two breeds mentioned are both from the british isle and are therefore not that distantly related. a better example (and the one most often used in animal science text) would be any english cattle breed crossed to zebu stock.

I would suspect (based on what other more knowledgeable folks have told me) that the idea of keeping the russian stock 'pure' in regards to mating has much more to do with the aggressive nature of the cross than anything else. for most beekeepers and many queen breeder how you might accomplish this simple thing would seem to me to be quite complex.

[Aspera]

Just a couple of notes on some very interesting aspects to this thread.

Firstly, a BIG shout-out for the thesis link. Its cool research and a monumental amount of effort. I'm grateful that someone did this and also that someone posted it.

With regard to the Russian program, I don't really think that it is necessary, possible or desirable to maintain the Russian lines exactly as they were in Primorsky. The main concept is to preserve the totality of the genetic material imported by the USDA. Closed mating yards help, but the main thing is to maintain LARGE apiaries of Russian only stock in multiple geographic locations to prevent genetic bottle-necks, drift, and genes lost to calamity.

Also I think that the relationship between artificial and natural selection is clear, but not necessarily relevant to this thread. I guess you might label me an "evolutionist". Breeding systems using inbred lines, crossed to one another to produce heterosis work well, but often result in a net loss of genetic material. This means that there is a value to both AI and the work of groups like the Russian bee consortium. Now that AHB and varroa are putting the squeeze on feral bee populations, this work is more valuable than ever. This post is just my random pseudo-science ramblings and I would hasten to point out that the pleural of anecdote is not "data".

[BEES4U]

FYI:
The Russians stock have been proven by experiments to groom off the mites primarily by using the center pair of legs.
Regards,
Ernie
Lucas Apiaries:)

[BEES4U]

http://www.springerlink.com/content/j2k8248u00p8l515/


Ralph Büchler1 , Wilhelm Drescher2 and Ingo Tornier2

(1) Abteilung für Bienenzucht, HLT, Erlenstr. 9, 3575 Kirchhain, Germany
(2) Institut für Landwirtschaftliche Zoologie und Bienenkunde der Universität, Bonn, Germany


Abstract OneApis mellifera and oneApis cerana observation hive were used to test the response to individually introducedVarroa jacobsoni mites. Within 60s, 88.6% of the involved cerana worker bees (n=44) showed auto-grooming behaviour. Within 5 min, allo-grooming behaviour, involving up to four nestmates, was observed in 33.3% of the infested bees. Successful mite removal was observed in 75% of the not-prematurely discontinued observations (n=36); 32% of the mites removed were caught with the mandibles.
For mellifera auto-grooming behaviour was observed in most cases but delayed in comparison to cerana, and allo-grooming behaviour was rarely observed. Within 5 min, 48% of the mites in notprematurely discontinued observations (n=25) were removed, but none of the mites was caught with the mandibles.
ForApis dorsata auto-grooming behaviour in response to the infestation withTropilaelaps clareae andVarroa mites is reported for the first time.Varroa was removed at a higher rate thanTropilaelaps. The higher survival chance ofTropilaelaps seems to be due to differences in mite behaviour and the preference for certain parts of the bee-body

[BEES4U]

http://findarticles.com/p/articles/mi_m3741/is_12_52/ai_n8580080
This data is a little old . But, factual.

Bees that resist mites are busy groomers
Agricultural Research, Dec, 2004 by Erin Peabody
We're not the only ones to brush off an annoying mosquito or other buggy pest.

Honey bees, when plagued by tiny tracheal mites, will use their legs like a fine-tooth comb to rid themselves of the life-threatening parasites. But, as entomologists with the Agricultural Research Service recently confirmed, some honey bees groom themselves more fastidiously than others.

For the first time, ARS bee researchers Robert Danka and Jose Villa provoked grooming responses in honey bees by placing tracheal mites directly onto individual bees. Tracheal mites invade the breathing tubes, or airways, of adult honey bees--eventually harming or killing the important pollen carriers.

Regards,
Ernie
Lucas Apiaries

[BEES4U]

!
http://www.honeycouncil.ca/users/folder.asp?FolderID=4922

1st you build the Trans Siberian RR
2nd you discover the local established Russian honey bee stocks in the Primorsky Territory, Russia.

Origin of the Russian Bee Stock
Varroa resistant Russian honey bee stocks, which were introduced to North America in1990's, originated in Primorsky Territory, Russia. This region is in the eastern most part of Russia lying between 43o and 48o latitude, with winter temperatures falling as low as -40oC. It is part of the Apis cerana natural range, however, in the late 19th century, A. mellifera was introduced by Ukranian settlers. This was the first area where A. mellifera was exposed to varroa mites. The European honey bees of this area are dark, indicating that they are Carniolan ancestry (Danka et al. 1995). The first problems associated with mites in this area were reported in the 1960's to 70's.

[BEES4U]

History

In 1905 the trans-Siberian railroad was completed, opening eastern Russia to the rest of Europe. The European honeybee was imported into this area which had only been inhabited by the Asian honey bee Apis cerana, the natural host of Varroa mites.

The Asian honeybee and varroa mites have co-evolved into a balanced host/parasite relationship without much harm being done. Varroa only reproduces on drone pupae in these bees, and drones are only available part of the year, so high populations of mites never build up.

When the European bees encountered varroa, things were different. Varroa is able to reproduce on worker pupae which allows extremely high numbers of mites to build up. This high infestation eventually kills the colony. Beekeepers have been keeping mite populations down at great effort and expense, using miticides such as Apistan ( fluvalinate). But today, mite resistance to fluvalinate is clearly taking place, and will likely spread across the country just as rapidly as varroa did originally.

Feral bees or bees managed without miticides have intense natural selection pressure, allowing only the most mite resistant colonies to survive. There are at least four resistance mechanisms that scientists have identified. They include, bees grooming mites off themselves and each other, hygienic behavior of removing infested pupae, acceleration of brood development, and suppression of mite reproduction. The ultimate goal of bee breeders is to produce bees with all these traits in a single stock of bees. It's hoped that the Russian bees will provide resistant genes that will let us take a giant step forward in the breeding effort. An earlier USDA introduction of bees from Yugoslavia did much in enhancing resistance to another serious pest, the tracheal mite.

Every beekeeper can help in the effort by using some of these Russian bees in their hives. Drones are produced from the queen's unfertilized eggs, so all drones from the Russian queens will be 100% Russian. This fact will greatly help in the spreading of the resistant genes, as drones fly for miles in search of queens to mate. If all goes well we may see the emergence of Varroa resistant bees across the country.

The USDA scientists, led by Dr. Thomas Rinderer, have done their part, now it's up to breeders and beekeepers to do their part in distributing these resistant bees. It may be our best option for getting off the chemical treadmill.
Regards,
Ernie

[aszalan]

Aspera, try this url for Laura L. Bryant's Thesis
Examining Varroa-resistant honey bee queens from commercial breeders colony productivity, hygienic behavior, suppression of mite reproduction, and the relationship of juvenile hormone III to mite abundance / .

http://etd.utk.edu/2004/BryantLaura.pdf

I'm not sure if its published in a journal.


nothing on the ISI science citation index for a journal article by Bryant on this. one great thing about the internet is being able to find MS and PhD thesis and dissertations that has never been published.