Assessing the role of key genes involved in the reproductive success of the honey bee parasite Varroa destructor.

The ectoparasite Varroa destructor is the primary global threat to the western honey bee, Apis mellifera. Growing resistance to acaricide-based treatments has spurred interest in alternative control strategies. In this study, we employed a novel and efficient dsRNA delivery method to explore the potential of RNA interference (RNAi)-based approaches for Varroa control in honey bee colonies. We assessed the effects of silencing six target genes (ptch1, ap-1, larp6, chisal, vg1, and vg6) on mite mortality and reproduction through a semi-field experiment. Gene expression analysis revealed significantly reduced transcript levels in mites treated with dsRNA compared to dsGFP controls, with knockdown efficiencies ranging from 88.6% to 97.2%. Silencing of ptch1, ap-1, and vg1 genes resulted in a significant increase in mite infertility, aligning with their known roles in oocyte maturation and embryogenesis. Additionally, silencing of chisal, previously described as essential for effective Varroa feeding, led to a marked increase in mite mortality. These results highlight promising gene targets for RNAi-based Varroa control strategies. Furthermore, our study provides new insights into the molecular pathways involved in mite reproduction and survival, including Wnt, c-Jun N-terminal kinase, Hedgehog, and apoptosis, paving the way for the development of more effective biotechnological control tools.