Hygienic bees beating varroa - a myth?

[mjt68]

If you stick enough selection pressure on anything with a big population you'll breed resistance, by everyone treating at different times your allowing susceptible mite populations to stay high and water down any emerging resistance.

Edit: no observed resistance doesn't mean its not or can't happen

Absolutely agree. Lots of very well educated people thought bacteria couldn't evolve resistance to antibiotics but the evolutionary biologists were right in the end! An important feature of the current anti-Varroa advice is an integrated approach using different means of control. If we, collectively as beekeepers, decided to throw everything we had at the problem we could make a dent but I doubt we'd eradicate it. Look at rabbits and myxomatosis - population crash followed by widespread resistance or acquired immunity.

The upside is that evolutionary biology also shows us that just as mites can evolve resistance to treatment, both viruses and bees will coevolve to minimise the lethality (more mites/viruses spread from living rather than dead colonies) and that we can help things along by selective breeding.

Mites are vectors for a truly mind boggling amount of viruses and insects are generally infected with lots of viruses (sequence an insect's RNA and look at how many viruses there are) and the biological picture is very complicated indeed. I think we should try everything we have and need to be vigilant and never complacent!

 

[jenkinsbrynmair]

If you stick enough selection pressure on anything with a big population you'll breed resistance

We've been shooting foxes around here for over a century - still no sign of them being resistant to an ounce and a quarter of No 4 shot

 

[mjt68]

We've been shooting foxes around here for over a century - still no sign of them being resistant to an ounce and a quarter of No 4 shot

But I bet they're a bit more scared of gunshots now? Or more scared of people? Urban foxes where there are fewer shotguns around are tamer!

 

[jenkinsbrynmair]

But I bet they're a bit more scared of gunshots now? !

And your point? or are you saying that varroa will vacate the hive at the first whiff of OA then sneak back in the day after?

 

[Hivemaker.]

Smallpox was once one of the biggest killers of all time, that didn't do too well in building up resistance to the treatments, seems to have almost gone the same way as the passenger pigeons.

 

[mjt68]

And your point? or are you saying that varroa will vacate the hive at the first whiff of OA then sneak back in the day after?

Just that advantageous traits will arise and persist.

 

[mjt68]

Smallpox was once one of the biggest killers of all time, that didn't do too well in building up resistance to the treatments, seems to have almost gone the same way as the passenger pigeons.

If (big if) we could vaccinate bees against DWV a similar thing would hopefully happen. But I don't think you could vaccinate against a mite which is what's needed to stop Varroa infestation.

Vaccinating any insect is pretty unknown territory. Insect immune systems are very different to ours, with less of a role for adaptive immunity (where the immune system 'remembers' a pathogen, which is key for vaccination to work). Immune systems are very expensive to run and insects generally don't live long enough for the cost to be worth it. Any given insect could be carrying several sub-lethal infections.

 

[charlievictorbravo]

.....

The way type B protects is by 'super infection exclusion'. In other words, the bees have so much type B that any small amounts of type A are eradicated by recombination between A and B.

Fascinating early research and definitely a reason for optimism.

Have you read anywhere whether the type B DWV also protects against the type C DWV virus?

The research carried out on the Swindon bees shows that SIE and type B protects bees from type A but the work on the Devon bees that followed made no mention of SIE or type B, only, I think, that type C killed bees in winter.

Ron Hoskins of Swindon Bees is trying to put together a research project involving an academic virologist. He hopes to get bee samples from beekeepers who have not treated their bees recently. If you'd like to be involved, fill in the attached form and send off to Ron at the address o the form.

CVB

 

[foghornleghorn]

We've been shooting foxes around here for over a century - still no sign of them being resistant to an ounce and a quarter of No 4 shot

Meant the sort of population you only get with microorganisms, plants and insects. Might be wrong but would assume the UK fox population is fairly small if you compared it to something like varroa

 

[mjt68]

Meant the sort of population you only get with microorganisms, plants and insects. Might be wrong but would assume the UK fox population is fairly small if you compared it to something like varroa

There's a bigger problem with the analogy to foxes or pigeons. Shooting is finding individual target organisms and ensuring kills using very lethal means. What we do with Varroa is apply a treatment in the vicinity of the mites and hope that it kills lots of mites without killing lots of bees. For DWV we're hoping that infection with a mild strain precludes infection with another.

Applying the shooting analogy (foxes, passenger pigeons, whatever) to bees would be to comb each bee and pupa, killing each individual mite by hand.

 

[madasafish]

There's a bigger problem with the analogy to foxes or pigeons. Shooting is finding individual target organisms and ensuring kills using very lethal means. What we do with Varroa is apply a treatment in the vicinity of the mites and hope that it kills lots of mites without killing lots of bees. For DWV we're hoping that infection with a mild strain precludes infection with another.

Applying the shooting analogy (foxes, passenger pigeons, whatever) to bees would be to comb each bee and pupa, killing each individual mite by hand.

Which is exactly what Hedgerow Pete did.

 

[Hivemaker.]

Applying the shooting analogy (foxes, passenger pigeons, whatever) to bees would be to comb each bee and pupa, killing each individual mite by hand.

That analogy was put in reply to the quote below....note..anything.

If you stick enough selection pressure on anything with a big population you'll breed resistance

Now, how about the small pox virus, that would of had huge worldwide populations as well, and microscopic.

 

[mjt68]

Now, how about the small pox virus, that would of had huge worldwide populations as well, and microscopic.

Vaccination is an interesting case. By vaccinating people against smallpox, we completely blocked the viruses ability to reproduce by denying it suitable hosts. I'm not sure what the equivalent for bee viruses and Varroa would be, given that vaccination in insects is a very long shot. No beekeeping allowed for ten years to allow infected colonies to die and we can start again with a clean sheet?

 

[jenkinsbrynmair]

There's a bigger problem with the analogy to foxes or pigeons. Shooting is finding individual target organisms and ensuring kills using very lethal means.

Which is what Oxalic acid sublimation achieves - very lethal to mites, doesn't affect the bees.

 

[mjt68]

Which is what Oxalic acid sublimation achieves - very lethal to mites, doesn't affect the bees.

Lethal at the moment, resistance could evolve. All it would take is a bit of resistance so you had to start using enough to damage the bees. OA is a very important tool in the arsenal, but I think it would be bad if we relied too heavily on any one measure of control.

 

[domino]

Lethal at the moment, resistance could evolve. All it would take is a bit of resistance so you had to start using enough to damage the bees. OA is a very important tool in the arsenal, but I think it would be bad if we relied too heavily on any one measure of control.

Doesn't it melt parts of them off?

 

[jenkinsbrynmair]

Doesn't it melt parts of them off?

yes, but evolution is a wonderful thing - apparently now we have mites being born with Kevlar reinforced legs

 

[pargyle]

yes, but evolution is a wonderful thing - apparently now we have mites being born with Kevlar reinforced legs

And stainless steel mouths ....

I really can't see mites evolving to live alongside OA in the short to medium term - perhaps over millennia - but in the meantime I really think it's the best shot we have at the mites - and reducing mite numbers on an organised national basis at an agreed point in time STILL looks attractive to me.

It's been an interesting thread so far ..

 

[mjt68]

So I've done a quick look on google scholar. A few interesting things to note.

Firstly, and very importantly, OA is not 100% effective. Some mites always survive, it is reasonable to assume these may include those more resistant to the effects of OA. OA can be over 98% effective when there is zero brood in the hive, but just a bit of brood brings that number down. Repeated treatments will be more effective, but 100% kill seems unachievable. Remember they don't have to become completely resistant to it, rather to just get a similar level of resistance as the bees as keepers are unlikely to dose their hives to the point where bees start falling down dead.

OT, but this from BBC shows what evolution can do in terms of resisting what seems pretty deadly at face value. "There's a species of mouse in Israel that weighs 20g and can survive a bite from a saw-scaled viper that would have you or me bleeding from every orifice and in intensive care," Wuster continues. "I would put a fair bit of money on there being one tough mother of a rat in Australia that can survive taipan venom."

Secondly, there are some reports of long-term negative impacts in terms of slowed growth to repeated OA spraying. Whether the same thing will happen with vapour is unknown, but I'd suspect so. It is not true to say OA treatment doesn't harm bees, just that it is less acutely toxic to bees compared to mites.

Thirdly, nobody in the scientific literature has ever suggested that resistance mites won't emerge - the question is when, not if.

The good news - the proportion of resistant mites quickly falls when a treatment falls out of favour.

I absolutely agree that OA is a very important weapon, but think we shouldn't view it as a magic bullet and should continue to use other treatments alongside. If 10% of mites survive OA treatment and then you use another treatment as well, you're going to kill a lot of that 10%, OA resistant or not!

 

[jenkinsbrynmair]

It's been an interesting thread so far ..

And why I chucked it in to start with.For a talk at the Convention which was a last minute change due to illness it turned out to be amongst the best of which, in all honesty, was a pretty mediocre lineup.