Peter L. Borst wrote:
> Keith wrote:
>   
>> How is lowered defensiveness tied to survival?  
>>     
I was sort of asking tongue in cheek.  It gets lost in the email 
translation.
> Lowered defensiveness in some strains could have arisen by 
>
> 1) Lack of need.  
>
> 2) Reallocation. 
> You have to view these factors as all *interconnected*.

Indeed - though as a more direct mechanism, I suspect that the lack of 
need is the major player. As you say - if it costs an organism to have a 
trait, but there i no survival advantage to said trait, it's expression 
in the population tends to decrease.  Many bacteria do the same thing as 
some resistance factors are quite metabolically expensive.  When the 
antimicrobial is present, having said factor is favored even if it is 
expensive.  Drop the pressure of the antimicrobial and the population 
rapidly ceases to express the trait, as the bugs that spend that energy 
reproducing eventually dominate.

The other big thing to note here is that this is a population thing, not 
an individual organism or colony thing.  Sometimes folks get this 
confused (not that you do, but we have been down that road on this and 
other lists.)


>
> It simply isn't good enough to be very good in only one thing: the hive has
> to be really good in the things that matter for the environment in which
> they are trying to survive.
Yes - life is a balance sheet.  Being a superstar at a single thing 
rarely gets you anywhere (unless you are a human and that trait involves 
throwing a baseball at ludicrous speeds.  Roger Clemens is getting 7K 
per pitch under his new contract.)  Being "good enough" at a great many 
things tends to get you much farther ahead.
> As we have said, perhaps the colony selection process is
> actually selecting less virulent mites. 
If varroa follows common host-parasite interaction dynamics over time, 
and there is no reason to suspect it will not, then we are breeding both 
mite-resistant bees, and less virulent mites.
> When you talk about leaving bees alone and letting nature takes its course,
>   
You realize I didn't say anything of the sort right?
> you might remember that WE are a product of evolution, that evolution is
> still going on and we are a major force in it.
Yep, corn, marijuana, most dog breeds, domestic cattle, chickens, white 
tailed deer, racoons etc.  Our foot prints on other species are legion.  
Some would not exist without us as a pressure that makes their 
particular phenotype advantageous.  Bananas anyone?
>  Of course, with that
> realization comes responsibility for the the many species that are now under
> our care.
I would argue that they all better all be under our care, as opposed to 
being merely there for our use, but then I am a bid of a tree-hugger, 
comes with the job.

Standard caveat about speculation applies.

Keith

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