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Understanding the ecological and evolutionary processes that drive host–pathogen interactions is critical for combating epidemics and conserving species. TheVarroa destructormite and deformed wing virus (DWV) are two synergistic threats to Western honeybee (Apis mellifera) populations across the globe. Distinct honeybee populations have been found to self-sustain despiteVarroainfestations, including colonies within the Arnot Forest outside Ithaca, NY, USA. We hypothesized that in these bee populations, DWV has been selected to produce an avirulent infection phenotype, allowing for the persistence of both host and disease-causing agents. To investigate this, we assessed the titre of viruses in bees from the Arnot Forest and managed apiaries, and assessed genomic variation and virulence differences between DWV isolates. Across groups, we found viral abundance was similar, but DWV genotypes were distinct. We also found that infections with isolates from the Arnot Forest resulted in higher survival and lower rates of symptomatic deformed wings, compared to analogous isolates from managed colonies, providing preliminary evidence to support the hypothesis of adaptive decreased viral virulence. Overall, this multi-level investigation of virus genotype and phenotype indicates that host ecological context can be a significant driver of viral evolution and host–pathogen interactions in honeybees.
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This content will become publicly available on February 1, 2026
Avoiding the tragedies of parasite tolerance in Darwinian beekeeping
Bee declines have been partly attributed to the impacts of invasive or emerging parasite outbreaks. For western honeybees,Apis mellifera, major losses are associated with the virus-vectoring mite,Varroa destructor. In response, beekeepers have focused breeding efforts aimed at conferring resistance to this key parasite. One method of many is survival-based beekeeping where colonies that survive despite significantVarroainfestations produce subsequent colonies. We argue that this ‘hands-off’ approach will not always lead toVarroaresistance evolving but rather tolerance. Tolerance minimizes host fitness costs of parasitism without reducing parasite abundance, whereas resistance either prevents parasitism outright or keeps parasitism intensity low. With clear epidemiological distinctions, and as honeybee disease dynamics impact other wild bees owing to shared pathogens, we discuss why tolerance outcomes in honeybee breeding have important implications for wider pollinator health. Crucially, we argue that unintentional selection for tolerance will not only lead to more spillover from honeybees but may also select for pathogens that are more virulent in wild bees leading to ‘tragedies of tolerance’. These tragedies can be avoided through successful breeding regimes that specifically select for lowVarroa. We emphasize how insights from evolutionary ecology can be applied in ecologically responsible honeybee management.
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- Award ID(s):
- 2011109
- PAR ID:
- 10636680
- Publisher / Repository:
- Royal Society
- Date Published:
- Journal Name:
- Proceedings of the Royal Society B: Biological Sciences
- Volume:
- 292
- Issue:
- 2040
- ISSN:
- 1471-2954
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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