Mike,
JB is fine.
You have elaborated needlessly for the most part. I have a well-founded understanding of fundamental evolutionary principal and animal husbandry.
Hi JB,
I will continue to contend: no you don’t. I often had people say to me that they understand natural selection. But ‘understand’ is a broad word. It often means they’ve heard of it, and have a rough idea of what its about – but little more. I think your comprehension is quite good. But you’ve a little further to go.
Specifically, you are not factoring in the ‘arm’s race’ aspect, nor appreciating to extent of the effect of allowing non-resistant genes to go through wholesale to the next generation.
Let’s try a thought experiment to bring the main issues into focus. We can imagine two apiaries of identical bees, both middle resistant, and both with middle-fecund varroa. For the sake of this thought experiment we’ll ignore any changes in the mite population. We’ll also assume any external input is identical, and similarly both sets of bees are middling in terms of resistance.
Apiary A) will be managed by close selection of the most resistant bees. Their genes will replace the weakest by queen rearing and re-queening.
Apiary B) will be managed by a systematic treatment regime. There will be no attempt to breed through selection.
This represents my way and yours respectively.
In my apiary any non-resistant strains will be swiftly terminated, leaving each new generation to be made from resistant parents. Genetics/the law of inherited traits will ensure the new generations are similarly resistant, and so within a few generations all non-resistant strains will be extinguished except those that have come in from outside. This will throw up non-resistant offspring, but less often that will be happening in your as my own drones will tend to reinforce resistance. My apiary will be made resistant, and kept resistant by systematic selection.
In your apiary both resistant and non-result equally contribute to each new generation. Each new generation, made of the same mix, will result in similar levels of resistance to the previous. This is exactly what the passage we’re interested in means: acaricide use inhibits the rise of resistance. Non-resistance doesn’t result in death – you stop that by treating. It doesn’t – even though it doesn’t work 100% - result in any progress, since many that would have failed go through.
The cost of hygienic behaviours
I can see your point: if the treatments don’t work 100% then you might think there will remain a small pressure toward growing resistance. But actually it doesn’t work like that: for this reason. The hygienic behaviours carry a small penalty – they carry a cost. Bees fussing about over-cleaning the place are not bees fetching pollen and nectar. For that reason the evolved mechanisms are, in nature, dropped as soon as possible. As mites become less of a problem those hives with a lower proportion of resistant patrilines gain an advantage over those with what is now too many. And this dropping of resistance is rapid. What this means is that the slightest easing in pressure to become resistant results in fast abandonment of resistance. And that is exactly the scenario in lightly, or incompletely treated apiaries.
So while my bees, and any feral bees far enough away from treaters to enjoy the benefits of natural selection will rapidly gain resistance due to the ruthless extinction of vulnerable strains, yours will make no progress whatsoever.
Now, separately, we can look at three possible further objections. I’ve mentioned drone input, and we can do that first. Then we’ll look at the possibility of inbreeding and loss of genetic diversity.
Both our apiaries, as you’ve pointed out, will be affected by external drones. In my case any benefits will be enjoyed, and disbenefits rapidly negated by my system. If the inputs contribute to health they’ll be incorporated; if they don’t, they won’t. Neat huh?
In your case the opposite will occur – any benefits will be lost as you press unfit strains forward in your mix, while any unfit drone input will just decrease any nascent resistance still further.
As to the fact of open breeding: yes, we cannot control mating, and so we cannot work with the sort of (probabilistic) precision that closed husbandry enjoys. But we can get ¾ of the way there, by adopting different strategies.
First, we can have total control over the queen side genetics. That’s 50% of the input, and is sufficient alone to start swinging things our way.
Second, we can increase our share of the male side input by two means: 1) by keeping large drone producing hives in and around our apiaries (standard bee farmers practice) and b) by the fact that our modus operandi encourages feral bees to establish and thrive around them – so we get the benefit of their (naturally selected) drones. Note; your management severely represses the local feral population, and so you get none of that resistant input.
Inbreeding.
The fact of open mating, the contact local ferals will have with bees from the wider area, and the possibility of deliberate input of selected resistant strains now and then add up to no danger of inbreeding.
(Possible loss of genetic diversity is covered below)
Your points are well taken and spot on. They work well in the lab, or petri dish or in completely controlled populations. Our bees are none of the above. Your bees and my bees will mate with feral and transient populations that we have no husbandry control over whatsoever.
First, I’m grateful for your appreciation, and I’d like to return it.
To real-world application. First, many people have been keeping bees treatment free for many years by using these techniques. The empirical evidence is there. The explanations for why it works are also there.
I’ve already addressed external input above, will add: the systematic nature of the selective propagation program is easily capable of dealing with input from neighbouring (treating) apiaries and transients – as long as they are not overwhelming. So its sensible to be at some distance from larger operations, and to make your own operation as large as possible so as to dominate the drone space. As to ferals – well as indicated above – their input is highly desirable.
In the real world, the evidence fits my way of thinking perfectly.
We agree on much but disagree on a few important points. Really only disagree on only one important and basic point. That revolves around your words of “prevent “, “never” and “stop”. Once again you read “hinder” as prevent and I read it as impede. Once again you ignore the time part. I’ll also quote from the article (I usually don’t for copyright issues) From the article:
“The coevolutionary process required for establishing a coexisting relationship between this parasite and its new host is lacking, both in time and in selective pressures because the selective disadvantage of being virulent is removed by apicultural practices aiming to control this damaging new mite pest.”
I agree, the paper does speak of a time factor. I will maintain that under strong treatment regimes, with no compensating feral or non-treater or deliberate resistant breeding to ameliorate, development of resistance cannot occur. I’ve covered that under ‘the cost of hygienic behaviours’.
It appears that you disagree with the time element as much as I disagree with the “selective pressure is removed” aspect. Selective pressure is impeded, not removed and there is a difference, removal dictates 100% success of treatments which is not the case.
Well, lets imagine you are right about this. Can you state the factors, the parameters under which resistance will rise, and give us a time frame? I’m not asking for guesses – I can give you a time frame for doing things my way – and prove that it works. Can you make a substantial claim that your slow development of resistance will outpace any compensating evolution in the mites? What is your evidence?
At least can we agree: my way clearly works; your way might do, but we know, and we can’t know when either?
Also history has shown husbandry is capable of making the wrong selections and breeding out a characteristic that was later determined to be important and desirable.
(Possible loss of genetic material or valuable traits)
I’m sure this is true (though I’d appreciate some examples with references). However, as far as I’m aware there is no comparable danger in what I’m advocating. In fact its exactly the point made by Marla Spivak: to have lots of beekeepers all maintaining their local populations by breeding on a local basis is the best possible protection for genetic diversity.
I’m no expert here, but my understanding is that there is little to no cost in diversity in allowing nature to play out in this sort of situation – which the bees have faced countless times before – nor in the kind of husbandry that mimics natural selection. The ‘winners’ carry through pretty much all the diversity in the prior population. Very very small populations may be at risk of ‘bottlenecks’ But we’re talking here about a handful of individuals – not the millions at large in the US or the UK.
A single isolated apiary that is overbred might suffer such a problem. But a bit of new (preferably resistant) blood will sort it out.
Evolution will march right on with or without human muddling. And it will likely march to a tune of it’s choosing not ours.
If you consider domesticated animal have marched very much to our tunes – and then think how much influence we have over bees wherever the great majority are in apiary hands – you’ll see that we can and are influencing them strongly. And … that is what the paper tells us is happening. Its not the first scientific study to make the point:
Survival of mite infested (Varroa destructor) honey bee
(Apis mellifera) colonies in a Nordic climate (2006)
Ingemar Fries, Anton Imdorf, Peter Rosenkranz
"Our results allow us to conclude that the problems facing the apicultural industry with mite infestations is probably linked to the apicultural system, where beekeepers remove the selective pressure induced from the parasitism by removing mites through control efforts."
http://www.apidologie.org/index.php...129&url=/articles/apido/pdf/2006/05/m6039.pdf
This is the part most beekeepers – and, it seems regulators and the advisors don’t understand: giving medical aid to an openly mating species has a horrific effect. The species simply adapts to the new situation, and doesn’t bother raising any defences against what it perceives to be non-problem. The pathogens, meanwhile, continue adapting – resulting in their growing resistance to the treatments.
Genetic care is an art. Go wrong and the results can quickly be catastrophic. As you yourself point out, bees are not closed mating populations, and the usual rules do not apply. Treating openly mating animals as you can closed populations is very much taking a wrong turn. The predictable – and now deeply demonstrated - result is a kind of ‘addiction’. The more you treat, the more the bees will adapt to your lifting their burden – and so it goes on.
Your stance, if accurate will doom any of your results to fail as soon as exposed to the “treated” populations. By your stance, the superior genetics you are breeding to, will fail. So where does that superiority go and what does it achieve? How does that flow into fundamental evolution?
Not where the sorts of precautions I’ve outlined, if needed, are taken. The point is to raise the number of resistant patrilines to a sufficient level (and variety of required behaviours) not to seek complete dominance. And then to keep them at a suitable level through ongoing selective propagation. That’s what nature does, and we can improve and lose most of the weakest. The trick is: build the selective _process_ into your management. Genetic management is part of the art of beekeeping – just as in closed populations.
Sorry, but you are wrong. Superior genetics will win out, treatments or not.
This is not substantiated, either by reference to theory or by any evidence. Its an article of faith. The well-established theory says: treatments supply an environment in which the pressure for change is removed. No change.
When an inferior genetic line is allowed to reproduce it produces inferior genetics. AGREED?
Two weak lines will most often produce a weak offspring. Agreed.
When an inferior line is allowed to cross breed with superior genetics, the superior genetics have a better chance at survival with or without treatments/intervention.
More or less, yes.
But everything above aside, I am going to ask a series of questions, I will provide my answers and you (or anyone else) can provide your/their answers, and then maybe a more focused conversation can follow. I am sure you will get a feel of where I am headed from the questions.
What is the currently accepted average time from introduction of mites to colony collapse if untreated and nonresistant?
JB: 3 years
MB Depend on level of resistance in bees and voracity of mites. I’m not sure, given that, that an average really indicates mush that is of use to us. What we want to know is: you much resistance do _these_ bees have.
Are treatments 100% effective at removal of varroa?
JB: No
MB I don’t know. Some might be some of the time.
Do 100% of the treated non-resistant hives survive?
JB: No
MB I doubt it. 100% of any hives anywhere anytime is unlikely given a reasonably large sample.
Which has the better chance of survival, a treated resistant colony or a treated nonresistant colony?
JB: Resistant colony.
MB Close to equal (dependent on effectiveness of treatment), but I’ll grant you the point.
Which has the better chance of survival, a non-treated resistant colony or a non-treated nonresistant colony?
JB: Resistant colony.
MB Resistant colony
Which has the better chance of reproduction whether treatments are present or not, Superior or inferior genetics?
JB: Superior genetics.
MB I’m not sure that speaking in terms of ‘superior’ and ‘inferior’ is useful. Resistance is supplied by specific genes that confer specific behaviours. In the natural context possession of those behaviours confers superiority. Only when all colonies have those protective behaviours can other considerations come into play. Same in the non-treated apiary.
However, in the context of a treating apiary, all sorts of other factors come into play that make resistance irrelevant. So the ‘superior’ bee (i.e. good producer) may have no resistance, but be a outstanding layer.
Are there less tracheal mite treatments applied in US apiaries today than 5 years ago?
JB: yes, tracheal mite treatments are almost never applied.
MB No idea – I’ll take your word for it. But how widely were tracheal mite treatments applied? I’m not sure a simple parallel can be made.
Are there less Varroa treatments applied in US apiaries today than 5 years ago?
JB:yes; less people treat and treat less often than 5 years ago.
MB Again, I’ll have to take your word for that. Can you supply proper support for the claim? How much have treatments been fine-tuned – just as effective though applied less often? How much have alternative systems of mite management been substituted? Don’t forget, they have exactly the same effect in breeding terms.
Are feral populations rebounding at all?
JB: Yes, the feral populations are slowly returning.
MB: Yes. And, its noteworthy that, as Joe Waggle predicted, this is happening first in those remote places where apiaries are few and far between. Treatments suppress feral populations by supplying incoming genetic material that undermines self sufficiency.