We are working on issues such as location.  However, one has to consider
exposure to infested bees.  Bees drift within yards, so if one colony has
them, the others are likely to be exposed via drifting and robbing.
 
We have noticed a colony specific effect, some have them, some don't,
which is not surprising.  Would like to figure out more concerning
themechanisms which may be genetically controlled (i.e., resistance).
 
However, I do suspect that stress plays an important role in resistance.
So one could find location differences due to diffferent stressors or a
different degree of stress at one location versus another.
 
Jerry
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