Wild/Feral Survivor-Thrivers: Naturally Selected Resistant Bees.

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This is for discussion of bees that have acquired the ability to cope with varroa without any help. The core assumption is that in the UK and Ireland this has occurred through natural selection for the fittest strain, and any subsequent selection has built on that. The idea is to learn from each-other, what works, and why, in the realm of no-treatment beekeeping. Testimonies, questions, explanations and links to relevant scientific studies are all welcome.

I'd like the thread to be a place where the mechanisms that wild populations employ to locate and maintain resistance can be explored, in the belief that that topic holds the key to understanding why no-treatment beekeeping works in some circumstances and not in others.

 

[JamezF]

In fact, with an ~90% attrition rate of feral colonies annually it’s very unlikely to be the same colony in successive years."

Where does that number come from? Is that escaped 'feral bees' or an adapted population?

As far as I can see that comes from the numbers in the paper. The relevant part would appear to be this:

The majority of nest sites (n = 112) occupied in late summer were unoccupied the following spring, before swarming started. 90% of colonies survived the summer (from July until late September), but only 16% of colonies survived the following winter.


The spring survival rate was calculated as 74% based upon genetic testing of colonies in early spring and mid-summer


Knowing the summer, winter and spring survival rates enables the annual survival rate to be calculated.


This was a sobering 10.6%.

The annual survival rate is the product of the individual seasonal rates, so 0.9 x 0.16 x 0.74, which is actually 10.8%, but I assume there's a bit of rounding involved somewhere that means he has a 10.6% figure. If 10% is the survival rate then 90% would be the attrition rate. Perhaps he should have said 89% (to two sf) given that he's calculated the figure as 10.6%.

And he makes no judgement about whether they're escaped feral bees or an adapted population, perhaps because it's not possible to know based on the evidence collected (or that it might be possible to collect). It's just about colonies of bees that happen to be living in vacated woodpecker nests.

So based on the observations he's quoting, after one year there's a one in ten chance that a colony at a nest site survived from the previous year. After two years it's one in one hundred. After three years given the number of colonies in the survey you'd expect that there will be no original colonies left.

James

 

[user 20297]

Ah! Irony in print and me are not natural bedfellows!

You're in good company on this forum.

 

[JamezF]

Considering how thorough some of the failed efforts have been in trying to eradicate some other insect species from the planet, it looks like the honey bee, for all its millions of years' unaided survival must have some sort of massive "Achilles heel" that prevents its unaided survival against its latest threat, which is not found in other insect species.

Perhaps storing food and attempting to maintain a viable population of individuals through the winter? In a sense that is putting all of one's eggs in a single basket. Introduce some factor that drags the number of individuals down below that needed to survive and the group dies. I don't think it's a common survival strategy in insects, but I am not an entomologist.

Kind of related, David Evans' post from a couple of weeks back (linked in the referenced post) about how varroa were used to eradicate honey bees from Santa Cruz Island is worth a read. I found it shocking.

James

 

[JamezF]

Because the thrust, and the tone are so very different. 'Apiarist' seems determinedly skeptical of the notion of viable feral populations: while the (peer-reviewed) paper he cites selectively from is entirely confident of them.

The abstract of the linked paper says:

We conclude that managed forests in Germany do not harbour self-sustaining feral honeybee populations, but they are recolonized every year by swarms escaping from apiaries.

And in section 3.2:

Accordingly, the net reproductive rate of the feral honeybee population is R0 = 0.318, indicating that it is currently not self-sustaining.

I don't understand that to mean that the authors are confident of the existence of viable feral populations based on the data they collected. They do appear to accept that there are viable feral populations elsewhere in the world (eg. the Arnot Forest), and draw on that data to suggest criteria that need to be met for a random colony to be likely to self-sustaining.

Perhaps it's not completely clear given the wording, but I suspect that what David is saying is that if we accept those criteria there are many feral colonies that do not meet them and therefore won't be self-sustaining. I don't think he actually gives a view on whether there are feral/wild colonies that are self-sustaining. What I think he's saying is that given some random site where people think there have been bees living there "forever", the odds are very much in favour of them not being the same continuous colony.

James.

 

[Beesnaturally]

Funnily, this is one of my favourite topics.

This strategy is absolutely essential to every living living outside the tropics.

Seasonality: it's detection and management drives all behaviours, animal and if we can so describe it, plants.

The name of the game is entirely energy management: it's collection, storage, defence, and careful use.

Bees are a first class example.

(I'd written more but lost it)

 

[Beesnaturally]

What I think he's saying is that given some random site where people think there have been bees living there "forever", the odds are very much in favour of them not being the same continuous colony.

James.

And I think that is a dramatically unsustainable and amateurish claim.

If you like I'll explain why in the morning.

 

[JamezF]

And I think that is a dramatically unsustainable and amateurish claim.

If you like I'll explain why in the morning.

Given that it's only what I understand him to be saying I'd not bother: I might be completely misinterpreting what he intended and if so it would be a waste of effort.

On the other hand if you interpret his conclusions as not being consistent with the evidence he presents from the paper then I'd suggest you comment on the article (which you are free to do), clearly and precisely explaining where you feel his conclusions are not logically justified by the data he has taken from the paper referenced. I've read many of his posts and have the impression that he is very willing to address coherently-explained queries regarding his reasoning.

James

 

[pargyle]

Play nicely people ... Dani and I have both asked you nicely to keep it polite and about the bees.... it's getting pretty close to the point where we will have to put an end to it ... No more warnings or polite requests. Either keep it civil or face the consequences...everyone on both sides. DISCUSSION is fine anything else is not ....

 

[Beesnaturally]

Given that it's only what I understand him to be saying I'd not bother: I might be completely misinterpreting what he intended and if so it would be a waste of effort.

James

Let's take that as an opportunity to introduce a study of every critic's favourite forest, by T. Seeley.

Not the early one, when resistance was just starting to come through (as deployed by 'Apiarist'), but a follow-up study twelve years later, when the forest bees had had a chance to find their feet.. I post here extracts to ram home a few points central to this thread:

A survivor population of wild colonies of European honeybees in the northeastern United States: investigating its genetic structure
Thomas D. Seeley, David R. Tarpy, Sean R. Griffin, Angela Carcione & Deborah A. Delaney

Abstract
There is a widespread belief that wild colonies of European honeybees have been eradicated in Europe and North America, killed by viruses spread by the introduced ectoparasitic mite, Varroa destructor. In reality, however, several populations of wild colonies of honeybees in Europe and North America are persisting despite exposure to Varroa. To help understand how this is happening, we tested whether the bees in one of these populations of wild colonies—those living in and around the Arnot Forest (NY, USA)—are genetically distinct from the bees in the nearest managed colonies. We found that the Arnot Forest honeybees are genetically distinct from the honeybees in the two apiaries within 6 km of the forest. Evidently, the population of Arnot Forest honeybees is not supported by a heavy influx of swarms from the nearest managed colonies, which implies that it is self-sustaining. These results suggest that if a closed population of honeybee colonies is allowed to live naturally, it will develop a balanced relationship with its agents of disease. Indeed, it is likely to become well adapted to its local environment as a whole. We suggest four ways to modify beekeeping practices to help honeybees live in greater health.

Discussion
[...]
The results of the present study show that a population of wild honeybee colonies with European heritage living in North America is self-sustaining despite living on its own. This finding is relevant to the problem of declining numbers of managed honeybee colonies in Europe and North America.

The contrast between the stability of this population of wild colonies and the declines in the populations of managed colonies suggests that current apicultural practices are contributing to the losses of managed colonies, perhaps by helping perpetuate the spread of lethal viruses vectored by virulent Varroa mites. What apicultural practices might be causing harm? We suggest that the following four are important:

(1) giving colonies mite-control treatments, so there is little or no selection for mite-resistant bees;

(2) crowding colonies together in apiaries, so that horizontal transmission of diseases is favored;

(3) managing colonies to be unnaturally large, so that they have high honey production and low swarming rates; and

(4) moving colonies from place to place, so that there is both strong gene flow that prevents natural selection from altering local allele frequencies in a closed population, and rapid spread of pathogens.

By following these apicultural practices, beekeepers are probably hampering natural selection for increased disease resistance by the bees and for decreased virulence by the mites and viruses, and they are probably creating colonies that are bonanza hosts for Varroa mites and the viruses they vector. Beekeepers are probably also hampering the genetic adaptation of bees to the climate and seasons of the local environment, and in this way are probably further hindering colony vitality (Hatjima et al. 2014). More work is needed to test these ideas, but it now seems likely that if a closed population of honeybee colonies is left alone and allowed to live naturally, then it will evolve a balanced relationship with its agents of disease, and its environment as a whole.

https://link.springer.com/article/10.1007/s13592-015-0355-0
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BTW: the question of how to tell if wild/feral colonies, 'church bees', are escapees, swarmers, part of a well-adapted local population, or anything in-between is a good one, and we can return to it. (note how I break that down: its not a binary question, and anyone treating it as though it is is up the creek before they start)

 

[madasafish]

All very well to suggest not keeping hives in densely populated areas (of bees).. but in the UK that is not real world stuff. Unless you live in parts of Wales or Scotland which have fewer human populations and therefore fewer hobby beekeepers.

 

[user 20297]

In its description, this Blog started with a "core assumption" that there is a wild population of honey bees in the UK that is adapted to cope with varroa without any help. As has just been quoted by @Beesnaturally, a distinguished scientist who specialises in bees has said. "The results of the (his) present study show that a population of wild honeybee colonies with European heritage living in North America is self-sustaining despite living on its own."
Our two countries and our beekeeping may be different, but bees are bees. Why is is impossible that the same observation cannot be true of the UK?

 

[Beesnaturally]

All very well to suggest not keeping hives in densely populated areas (of bees).. but in the UK that is not real world stuff. Unless you live in parts of Wales or Scotland which have fewer human populations and therefore fewer hobby beekeepers.

Before making that sort of definitive statement you need to supply a definition for 'densely', giving distance and number of hives, and details of the treatment regimes of those hives.

The accuracy would also be modulated by the presence of wild bees. If, within say a radius of 5 miles there are 200 wild colonies, 200 treated hives and 50 untreated hives, that will be a very different environment from one of the same size containing 500 treated colonies, 20 wild colonies and 20 untreated hives.

And then you'll need to factor in local concentrations. I have found towns and villages with strong populations of long-lived wild colonies. I have to assume a smallish number of treated hives, because otherwise these populations could not have developed.

The idea that insufficient freedom from (the wrong sort of) hives exists for wild bees to emerge right across Britain is neither credible nor in any way substantiated.

What we can do it explore the conditions under which wild populations can emerge. The paper above supplies us with a very good lead in that.

There is also the interesting question of whether divergent mating times plays a part in keeping wild and managed populations separate even while sharing the same geographical space.

 

[madasafish]

All I can say is that in 2015 I lost 6 out of 7 hives to AFB. (Destroyed with BI). The outbreak was traced (DNA) to a beekeeper locally whose home bees caught AFB -allegedly from imported honey containers. He infected his hives at our local National Trust property, and abandoned them to die . My bees robbed out the dead hives 0.5Miles away.

I assume there were minimal local feral hives as the outbreak then stopped with the destruction of his and then my hives.

 

[Beesnaturally]

All I can say is that in 2015 I lost 6 out of 7 hives to AFB. (Destroyed with BI). The outbreak was traced (DNA) to a beekeeper locally whose home bees caught AFB -allegedly from imported honey containers. He infected his hives at our local National Trust property, and abandoned them to die . My bees robbed out the dead hives 0.5Miles away.

I assume there were minimal local feral hives as the outbreak then stopped with the destruction of his and then my hives.

I would think that to be a reasonable working assumption

 

[user 20297]

All I can say is that in 2015 I lost 6 out of 7 hives to AFB. (Destroyed with BI). The outbreak was traced (DNA) to a beekeeper locally whose home bees caught AFB -allegedly from imported honey containers. He infected his hives at our local National Trust property, and abandoned them to die . My bees robbed out the dead hives 0.5Miles away.

I assume there were minimal local feral hives as the outbreak then stopped with the destruction of his and then my hives.

All I can say is that bees in the wild might be no better equipped to fight AFB than kept bees. That the infection did not reoccur does not necessarily prove that no wild bees existed near you; it may just mean that they were decimated by the AFB.

 

[Apiarist]

In its description, this Blog started with a "core assumption" that there is a wild population of honey bees in the UK that is adapted to cope with varroa without any help. As has just been quoted by @Beesnaturally, a distinguished scientist who specialises in bees has said. "The results of the (his) present study show that a population of wild honeybee colonies with European heritage living in North America is self-sustaining despite living on its own."
Our two countries and our beekeeping may be different, but bees are bees. Why is is impossible that the same observation cannot be true of the UK?

It can be true here in the UK (and Ireland)... and IF it was true here then it would have a paper published about it... the fact that we do not suggests very strongly that they may not exist.

I did make an attempt to start a Tolerance List of characteristics in Posting #41, heavily based on the paper Beenaturally linked to in Posting #229 (the irony was not lost on me).

But these characteristics are not the bees becoming adapted to varroa; swarming occurs with or without varroa (though it might be affected somewhat) BUT the fact that feral colonies will swarm, which in turn reduces the varroa count, which can in turn lengthen their life span (Tolerance) and that apiary colonies will usually be prevented from swarming would be an explanation why feral colonies should outlive apiary colonies - certainly doesn't mean they're becoming adapted!

However the only paper that I am aware which has attempted to identify tolerant non-apiary colonies could not do so, and only showed that the bees here had an even higher death rate than untreated hives in apiaries!

 

[Apiarist]

All I can say is that bees in the wild might be no better equipped to fight AFB than kept bees. That the infection did not reoccur does not necessarily prove that no wild bees existed near you; it may just mean that they were decimated by the AFB.

I remember reading research into AFB resistance, basically if the bees were Resistant (different from Tolerant) to varroa mites they also became resistant to AFB: in other words they needed a high VSH.

 

[user 20297]

It can be true here in the UK (and Ireland)... and IF it was true here then it would have a paper published about it... the fact that we do not suggests very strongly that they may not exist.

I did make an attempt to start a Tolerance List of characteristics in Posting #41, heavily based on the paper Beenaturally linked to in Posting #229 (the irony was not lost on me).

But these characteristics are not the bees becoming adapted to varroa; swarming occurs with or without varroa (though it might be affected somewhat) BUT the fact that feral colonies will swarm, which in turn reduces the varroa count, which can in turn lengthen their life span (Tolerance) and that apiary colonies will usually be prevented from swarming would be an explanation why feral colonies should outlive apiary colonies - certainly doesn't mean they're becoming adapted!

However the only paper that I am aware which has attempted to identify tolerant non-apiary colonies could not do so, and only showed that the bees here had an even higher death rate than untreated hives in apiaries!

In the statement I quoted, Seeley does not say that the bees in his study were either "tolerant" or "resistant". Proof of the latter term always strikes me as having a very high benchmark.
There will not be a binary point at which bees become able to overcome mites. As with all things in Nature, it's a continuum of change.
Things can happen that have not been proven by the publishing of scientific papers, and even when they are published they are often disputed.

 

[user 20297]

I remember reading research into AFB resistance, basically if the bees were Resistant (different from Tolerant) to varroa mites they also became resistant to AFB: in other words they needed a high VSH.

That would be a useful, additional benefit, but it's a claim that possibly muddys the waters of discussion even further!

 

[Wilco]

All I can say is that bees in the wild might be no better equipped to fight AFB than kept bees. That the infection did not reoccur does not necessarily prove that no wild bees existed near you; it may just mean that they were decimated by the AFB.

That's rather the point. If the feral bees then die out from AFB, they would in turn be robbed out, resulting in further spread. The lack of further spread suggests that there are no feral colonies in that location.