In a message dated 20/01/2010 23:51:43 GMT Standard Time, [log in to unmask] 
 writes:

"How do  we know they are non-resistant?  Non - resistant to what? Are  
they  
all to be presumed identical in their inherited resistance   mechanisms?"

Chris
Chris,
 
I think what manwithbees has just said covers much about your first  
questions.
 
I said in the post that I was using varroa 'as the main problem, and a  
marker'.  So resistance to varroa is what I meant.  With such  resistance of 
course you also gain resistance to all the disease organisms  vectored by the 
mites.  But the point was general. The key  to health is being adapted to 
the local environment - whatever that  takes.  We could take a broader 
approach and talk about capability to  thrive unaided in the local disease 
environment (in this case the  US).  
 
No, the Aussie bees cannot be presumed identical in their inherited  
resistance mechanisms.  But I think that if the Aussie bees have not been  very 
carefully bred to be fitted to the environment into which they are  imported, 
then the combination of basic biology and our knowledge of the  very tough 
US environment tells us they will be very likely  to fail in that 
environment.  To the best of our knowledge  the only bees currently surviving unaided 
in the US are those that have  naturally adapted to the current environment, 
or been carefully bred to cope,  and/or chosen from stocks known to be able 
to do well there.  Period.   To think that bees taken from a varroa-free 
environment might do well  in the US is simply extraordinary.  At the very 
least we should demand  evidence that they do thrive, and do not undermine the 
defences of local  bees.  
 
Since mating is uncontrollable, importing and maintaining bees that are  
very likely to be relatively defenceless against the local predators, can  be 
predicted (by the basic biological understanding of inherited traits, and/or 
 the slightest acquaintance with the principles of stockraising)  to 
undermine the efforts of local bees - whether wild or apiary - to build  and 
maintain health defences.  What we know of the recessive nature of  the genes 
involved tells us that this effect is very powerful, easily disrupting  the 
delicate natural acquisition of defence mechanisms.  
 
Mike
 
 

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