Resistance and Tolerance

Discussions of honeybee genetics, epigenetics, hygiene related genetics, breeding, etc.
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Nordak
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Resistance and Tolerance

Postby Nordak » Sun Sep 04, 2016 11:16 pm

I know there is a significant difference between the two terms, but in a varroa-bee relationship, would it be possible to have bees show resistance but not tolerance in regard to virus loads, and still thrive? My guess is that many folks breeding resistance are actually breeding for both if they are having success, but I have seen these two terms used separately in terms of ideally breeding for one or the other, which doesn't make much sense to me. I see a complete resistance program as a means of practicing avoidance in a way.

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Re: Resistance and Tolerance

Postby Michael Bush » Tue Sep 06, 2016 11:20 am

In my experience this is exactly what the Russians are. They tolerate very high levels of Varroa and then they die. If they were Italians, they would have died much sooner... but I think trying to breed for either is just a waste of effort not to mention a bad idea.

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Nordak
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Re: Resistance and Tolerance

Postby Nordak » Tue Sep 06, 2016 3:36 pm

This explains a lot:

"What we have bred for

No Propolis
Solid brood patterns
Queens that never shut down
Color
Large bees
Less drones
Less swarming
More honey"

I read somewhere, it might have even been second hand knowledge on the matter, but it made sense to me. Some of the oldest beeks that began propagating lines wanted average bees in pretty much all aspects, as they found them easier to manage, something you mention from the link. From my own experience, it seems they might have been onto something. Sometimes it seems the "standouts" when it comes to productive behavior are the first ones to fail from a tolerance perspective.

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Re: Resistance and Tolerance

Postby lharder » Wed Sep 07, 2016 2:50 pm

Its a good question. In simplified terms, bees want to do 2 things, Survive and reproduce. To reproduce maximally, large strong hives are the ticket. Bees that can exploit large cavity spaces and put out swarm after swarm and the sooner they can do it the better to take advantage of empty cavity spaces in the spring. Perhaps this is the force that drives productivity.

I don't see a reason why bees shouldn't be able to deal with varroa with a low level of effort through behaviour. If they can recognize they have an intruder and deal with it at low threshold levels, the problem is more or less solved.

Viral resistance is another matter. I guess dealing with varroa would change the epidemiology (how many bees does a mite take a blood meal from anyway?) a bit. Though in theory behaviour modification could have influence, though I have no idea what that could look like.

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Nordak
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Re: Resistance and Tolerance

Postby Nordak » Wed Sep 07, 2016 6:09 pm

I was hoping you'd weigh in. What is the nature of a typical viral infection in a colony? Is there a "typical?" Is it necessitated by the scenario you described as a parasitic transmission, or once established, transmitted through contact via host? If the way I understand it is correct, and it is by way of both, how does the colony offset the damage of the virus once established given the nature of exponential growth associated with replication?

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Re: Resistance and Tolerance

Postby lharder » Fri Sep 09, 2016 1:49 pm

Seems to me science is just starting to identify viruses, never mind understand their dynamics. Even at the identification level, it seems we have a simplified world view. How many subtypes are there? etc.

I don't think we even have a solid understanding of population level disease dynamics with feral populations. Ie, not confounded by artificial movement of bees and pathogens. With many insects, there are boom and bust cycles where populations build before being ravaged by some virus. Others have episodic bouts of destruction. I'm kinda guessing that would be common. So what would the baseline look like in bees in a natural setting?

Disease dynamics within a hive bring us to a whole new level of ignorance in my opinion. When the research group took samples of bees for pathogens, they would take a cup. I'm sure subsets of that cup were analyzed for different things with end results a simple positive negative. If you wanted a clearer disease dynamic, then time series data with sampling at the individual bee may be useful. At some point even at the tissue level to perhaps get a better idea of modes of transmission. All complicated by whether a hive is resistant or not to a particular pathogen. Something you wouldn't know before you started sampling.

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Re: Resistance and Tolerance

Postby Nordak » Fri Sep 09, 2016 6:41 pm

Well thought out response. Thanks lharder. I will stop trying to wrap my head around this and just enjoy the fact it works, for whatever reason. My brain is wired to try and understand the "why" behind everything, but in this instance I believe I've reached my limitations.

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Re: Resistance and Tolerance

Postby lharder » Sat Sep 10, 2016 1:30 pm

TF may be a black box approach, but half the fun is figuring out how parts of the box works. Lots of interesting science can come of it.

So ask away, find something amenable to experimentation, document, and show it to others. For instance with mites, there are lots of misconceptions of what happens to mite populations in untreated populations. Simple mathematical equations are used to show massive mite build up. Having some time series data in a TF apiary with essentially unproven genetics in my case, so far, has shown mite fluctuations with numbers going up in some cases, and going down in others. The bees are doing something, The mathematical equation doesn't hold even with marginal genetics.

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Re: Resistance and Tolerance

Postby Nordak » Sat Sep 10, 2016 1:53 pm

From an observation I made yesterday, from one of my feral hives, there was a decent patch of capped drone comb on both sides of comb. Yesterday, I witnessed them uncapping all of it, purple eyed stage, while the worker brood had some, but very little activity in relation to VSH, amazing pattern for Fall. We are in a flow, so they either removed it for space or mite activity. Given the worker brood showed few signs, it points to mites. Perhaps this is a Fall strategy developed by the bees? If so, perhaps foundationless is aiding the cause.

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Re: Resistance and Tolerance

Postby SiWolKe » Thu Oct 20, 2016 7:45 am

Very interesting thread.

The only hive I lost so far was a paralyze hive.

The former owner :
- never allowed superseding
- made many splits, so the queen`s colony always had to struggle to be strong again
- wanted to keep the old pure bred queen because she was of a production line ( but likely inbred), so she was old, it´s her I got
- the hive was completely harvested and always overwintered with artificial food

The hive was on small cell and never treated.
The queen failed in spring 2016 and the hive tried to raise a new. Before this one was laying the virus was present in 80% of bees.

I´m not drawing any conclusions myself because I´m a newbie still. My managements came too late, I had no mated queen to introduce.
I just have some thoughts about this.
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Nordak
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Re: Resistance and Tolerance

Postby Nordak » Thu Oct 20, 2016 5:01 pm

What are your thoughts on it? If I'm understanding it correctly, the hive exhibited signs of paralysis virus after the queen failure?

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Re: Resistance and Tolerance

Postby SiWolKe » Thu Oct 20, 2016 5:58 pm

I understand virus varieties are always present in a latent way ( like herpes virus is).
They change constantly with mutation.
Outbreak comes when the immune system is weak.

So to me the most important thing in hive management is to strengthen the immune system. The health of the single bee and actions of all together are the immune system of the hive.

This was a typical situation of a hive loosing its strength. I saw some small effects of the virus in fall but since they were able to renew their population for some time it was just a normal situation. I see the colony as an unit and this was just as if you had some influenza and recovered. ( Compare yourself with the whole hive as one person).
So they started strong into early spring, in fact, they were very strong! Fresh pollen did it!
But the moment the queen failed early april, one part of the immune system, the most important part, they lost.

I was sad, but it was a lesson. Time was too long to renew themselves with a new queen. If you have fever too long you dwindle and maybe your heart stops. Just like that.

So I believe to cull out supersedure cells is not the best action to do if you have no queen bank. :(
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Nordak
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Re: Resistance and Tolerance

Postby Nordak » Thu Oct 20, 2016 6:13 pm

I definitely think nutrition is key, and goes hand in hand with strength of a hive. The two times I've seen paralysis virus in my apiary, it completely devastated one hive, a hive that was thriving up until that point, and barely noticeable in another. They were both swarm captures. The hive it nearly decimated, before I requeened, by all appearances was an Italian breeder, as all the bees were uniform and exhibited Italian behavior, built larger cell on natural comb, heavy brooding. The other was a feral type by all appearances, which is what I am propagating from today. I always attributed the differences in survival between the two based on genetic diversity, which the breeder queen had little to none of.

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Re: Resistance and Tolerance

Postby SiWolKe » Sat Oct 22, 2016 4:55 pm

lharder wrote:Its a good question. In simplified terms, bees want to do 2 things, Survive and reproduce. To reproduce maximally, large strong hives are the ticket. Bees that can exploit large cavity spaces and put out swarm after swarm and the sooner they can do it the better to take advantage of empty cavity spaces in the spring. Perhaps this is the force that drives productivity.

I don't see a reason why bees shouldn't be able to deal with varroa with a low level of effort through behaviour. If they can recognize they have an intruder and deal with it at low threshold levels, the problem is more or less solved.

Viral resistance is another matter. I guess dealing with varroa would change the epidemiology (how many bees does a mite take a blood meal from anyway?) a bit. Though in theory behaviour modification could have influence, though I have no idea what that could look like.


Very good analyzing.
Going practical this means to provide the right kind of housing to ensure the colony`s expansion and developing as much as possible and allow them to expand to the necessary strength to swarm maybe without a gap of deeps between brood nests. ( like TBH or a deep the right size).
When splitting, this could be your key how to do it imitate the swarm as much as possible.
Second: the viral resistance which could be supported by hive managements.
Propolis, leaving burr comb as much as possible to start microfauna, leaving honey and so on.
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Re: Resistance and Tolerance

Postby lharder » Mon Oct 24, 2016 2:51 pm

Not getting in the way seems to be a good start. But I'm not so sure how this is to be done. Not treating and making increase from strong hives is akin to what nature would do anyway. But beyond that? Everything gets a bit fuzzy and admit to wallowing in some ignorance, and am learning how not to be too disruptive. The less the bees have to work, the more things they can get accomplished. That means optimizing housing. But even here there is some debate about what bees actually want say in terms of ventilation. Maybe learning to take cues from bee behaviour instead of having preconceived notions.

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Re: Resistance and Tolerance

Postby SiWolKe » Mon Oct 24, 2016 3:07 pm

If you see something like that in the alpine area you know that bees are much more tough than we believe.
freihängender Wabenbau.jpg
freihängender Wabenbau.jpg (493.21 KiB) Viewed 701 times

The swarm build this nest in summer and we rescued them before winter, they are of a treated LC hive.
Good ventilation!
The cluster is still strong but on the pic you don´t see it very good.
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Re: Resistance and Tolerance

Postby lharder » Tue Oct 25, 2016 1:19 am

We have a few of those around here and aren't they beautiful? They are pretty rare though. A swarm I caught last year was just beginning to make comb, but they seemed pretty happy to have a box to move into. Our houses are reasonably well insulated, so not so many available void spaces that can be taken advantage here compared to the south.


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