Hi Everyone,
Just a comment on the issue of resistance to Varroa.  As Aaron points out nicely John Harbo has shown that the SMR trait is fairly widely distributed in Apis m populations and can be selected for.  Peter asks why and the answer is we don't know at present but maybe the work of Anderson regarding Varroa populations has some implications here.  He found that only very few Varroa mite populations were able to switch from Apis cerana to A m and even those that made the jump were not fully able to exploit A.m.  When a parasite jumps to a new host, it is not always a good fit in either direction ( host or parasite)  and whatever the mechanism underlying the SMR trait is it  involves a critical function needed by varroa for reproduction.  So it could just be a case of the parasite not being fully compatible with the new host.

FWIW

blane


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Blane White
MN Dept of Agriculture
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