>Perhaps I miss read the article in Bee World?


I don't know what you mean by misreading the article but the article does claim that there's a reported "tolerance" to varroa in the Irish region of North County Dublin. The author offers some possible explanations using examples associated with management practices while mixing in a suggestion of biological resistance that developed over time and became evident starting in 2010.  From what I can tell the study was looking for possible answers as to why this happened but did not conclude anything in particular. 

> The study considered: the seasonal mite population levels; possible bee-damage to mites; changes to idiosoma dorsal-dimples; prevalence of clinical signs of DWV and the virus status using RT-PCR and changes to brood nest temperature.

> It is remarkable that this tolerance is being demonstrated while mite-drops are still high, however, according to Moritz (1981) the small daily resource-drain by a mite on a bee probably has little impact on a healthy bee. There are similarities to mite fall values found in tolerant feral colonies reported from the Arnot Forest, United States where mite infestation growth was in the same order as in those colonies
with mite-susceptible bees (Seeley, 2007). High infestation rates have been reported in an island population in northeastern Brazil that has survived with varroa for over thirty years (De Mattos, De Jong, & Soares, 2016).

>McMullan, John. (2018). Adaptation in Honey Bee ( Apis mellifera ) Colonies Exhibiting Tolerance to Varroa destructor in Ireland. Bee World. 95. 39-43. 


Bill Hesbach
Cheshire CT.


 

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