It seems there's still considerable doubt that DWV replicates in mites.   

>Although it is well established that there is a strong correlation between the DWV load in mites and the corresponding honeybee pupa they feed on, there still is a lack of compelling evidence regarding whether DWV replication occurs in mites. 

>The confusion lies in the fact that when Varroa start to feed on the developing pupa, they normally have very low DWV loads relative to those leaving with the fully developed honeybee 12 days later. This increase in DWV load could be a result of viral replication within the mite or instead simply arise from the mite obtaining increasingly higher doses of DWV from the pupa, which the mites feed upon regularly. 


The study goes on to outline the error-prone detection methods currently available which can and have lead to false assumptions about DWV infectivity in mites.  One intuitive observation is that varroa apparently remain healthy while feeding on larvae that are proven to replicate the virus.  One would think that if mites were capable of DWV infection, there would be a reduction in their fitness do the energetic cost of viral replication. 


Bill Hesbach
Cheshire CT

 

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