Peter Dight wrote:
>Does this not suggest CCD is caused by a disease or parasite spread from
>colony to colony by drift, rather than through an external environmental
>event such as a pesticide poisoning?

It is very difficult to pin down cause and effect in such cases as these.
Almost everyone thinks the honey bee population is "immune compromised" on
the whole. Just what caused that is in dispute, but even so, given a
weakened immunity the bees could be much more susceptible to just about any
pathogen. But then, the final knockout is not the "cause" but the agent of
final demise. 

That's why we are calling it a "syndrome" -- which may have its root: 
1) weakness due to sublethal pesticide doses; 
2) weakened immune response caused by varroa parasitism; 
3) narrowing of the gene pool = inbreeding = lack of viability; 
4) your pet theory here.

pb

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