>What I am trying to say is that  a low amount of brood  IE smaller hives like Dr. Seeley follows will always have lower mites  than the huge hives we try to run here in the commercial operations.  
I suspect the difference might rather be explained by hive density/m² and nutrition.


>That said I also suspect there are environmental factors involved.  Way to much variation year to year in mite levels IMO.  We have some seasons they are kicking but,  and the next year not an issue.  My guess is that Larval nutrition in the bees plays a big portion of that.  If you apply what Dr. Ramsey showed,  one can suspect that the Reproduction rate of varro would be linked with the nutritional aspects of the bee larva also.  I have no proof,  just a guess.  

Just last week I read a relevant paper for this.  Pollen did not affect mite rates, but pollen consumption buffered/mitigated negative effects on the bees. 


I also wonder if certain types of nectar/pollen  may play a role in the reproduction of mites.  That might be a huge stretch,  but  it’s a thought I have as I cannot explain at all  some of the mite numbers we see.   Many times we will have  3 out of 4 hives on a pallet with low counts,  and 1 with sky high numbers.  The only thing that I have ever been able to attribute that to, is a hive foraging in some other plants than the rest.

There is evidence of medicinal effect of pollen (sunflower if I remember) but I don´t think for mites. The situation you are describing I believe is quite common in host-pathogen interactions.

"Early studies that explored host–pathogen interactions assumed that infected individuals within a population have equal chances of transmitting the infection to others. Subsequently, in what became known as the 20/80 rule, a small percentage of individuals within any population was observed to control most transmission events." https://www.sciencedirect.com/science/article/pii/S1201971211000245

I believe Randy termed them "mite bombs". In other disease they are called "Super-Spreaders". That´s also why limiting drift by the way hives are spaced/oriented can help reduce mite levels in an apiary at whole. 
As a risk factor to becoming a super spreaders co morbidities are discussed. So maybe there is a correlation to other disease/stress factors?

Patrick

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