> Gottland, where bees were co-existing happily with their mite loads, with no ill effects at all.
People tend to point to Gotland, but there things about that situation that do not apply to bee colonies in other situations.
Fries & al (2006) wrote:
> Our data suggest that a host-parasite co-adaptation has occurred ensuring survival of both the host and the parasite. ... It remains unknown if this development occurs because of increased mite tolerance in the host, reduced virulence in the parasite (with the virus infections vectored), or both ... The only possible conclusion that explains the experimental outcome is an adaptive process on behalf of the bees, the mites, or both.
More recently:
> despite the individual level mite resistance of inhibiting mite reproduction, colony level varroa infestation rates in the Gotland honeybee population can still be high, suggesting other factors could contribute to the population’s natural long-term survival. The results of this study demonstrate that tolerance rather than resistance, plays an important role in defence against varroa-vectored virus infections, at both levels of colony organization for this population. However, these studies did not exclude confounding influences on virus infections by the virus-vectoring varroa mite, which likely could have impacted their results.
Fries, I., Imdorf, A. & Rosenkranz, P. (2006). Survival of mite infested (Varroa destructor) honey bee (Apis mellifera) colonies in a Nordic
climate. Apidologie 37, 564–570
Thaduri, S., Stephan, J. G., de Miranda, J. R., & Locke, B. (2019). Disentangling host-parasite-pathogen interactions in a varroa-resistant honeybee population reveals virus tolerance as an independent, naturally adapted survival mechanism. Scientific reports, 9(1), 6221.
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