It is useful to distinguish immediate from subsequent causes, and ask about
multiple causes, causal hierarchies, and causal trains.
The actual cause of death may be overwhelming viral infection, but mites
acting as vectors and damaging the bee fabric are clearly joint causal
factors.
Again the resistance or tolerance offered by different races, strains and
individual bloodlines clearly makes a difference. So this too is a causal
factor, in that cause of failure may ultimately be identified as lack of
resistance.
Inasmuch as treatments disturb the acquisition of resistance, they too are
causal factors.
None of this is to say there is no connection between varroa and CCD; just
that indentifying that as a sole or even main cause is problematic.
Mike Bispham
***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software. For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html
Access BEE-L directly at:
http://community.lsoft.com/scripts/wa-LSOFTDONATIONS.exe?A0=BEE-L