Recently published paper shows that a protein found in adult Varroa saliva kills Apis cerana worker bees.   The same "Varroa toxic protein" does not affect A. cerana drones.   The VTP potentiates DWV virus expression in Apis mellifera.   

 The  authors of the paper hypothesize the Varroa Toxic Protein from the varroa saliva represents a "mutually assured destruction" strategy which preserves the health of the A. cerana colony, at the expense of sacrificing Varroa found in those cells.  

Thus the celebrated "resistance" of A. cerana to Varroa is a side effect of the Varroa deliberately killing the worker larvae, and the resident Varroa (which made the poor decision to invade those hosts).

They propose a RNAI strategy to duplicate the toxic brood system in A. mellifera.  -- hyper efficient hygiene.

Cite: https://www.nature.com/articles/s41598-018-21736-9
A Saliva Protein of Varroa Mites Contributes to the Toxicity toward Apis cerana and the DWV Elevation in A. mellifera
    Yi Zhang & Richou Han
    Scientific Reportsvolume 8, Article number: 3387 (2018) 

             ***********************************************
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