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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Invasive Species and Pollinator Health » Research » Publications at this Location » Publication #432593
Research Project: Determining Effects of Nutritional and Agrochemical Stressors on Honey Bee Health, via Longitudinal Studies on Colony Performance and Direct Tests

Location: Invasive Species and Pollinator Health

Title: RNAi targeting ABCB1-like efflux transporters improves miticide efficacy in resistant Varroa mites

Author
item Ricigliano, Vincent
item Fine, Julia
item Mueller, Rebecca
item Drouville, Laura
item Litsey, Eliza
item LUCADELLO, MICHELLE - University Of California, Davis
item Rinkevich Jr, Frank
item Rector, Brian
item NICKLISCH, SASCHA - University Of California, Davis

Submitted to: Parasites & Vectors
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/11/2026
Publication Date: 6/3/2026
Citation: Ricigliano, V.A., Fine, J.D., Mueller, R.C., Drouville, L., Litsey, E.M., Lucadello, M., Rinkevich, Jr., F.D., Rector, B.G., Nicklisch, S. 2026. RNAi targeting ABCB1-like efflux transporters improves miticide efficacy in resistant Varroa mites. Parasites & Vectors. 19. Article 280. https://doi.org/10.1186/s13071-026-07461-7.
DOI: https://doi.org/10.1186/s13071-026-07461-7

Interpretive Summary: The parasitic mite Varroa destructor is the most serious biological threat to managed honey bee colonies, and beekeepers rely heavily on amitraz—one of the few effective and bee-safe miticides available—to control it. However, growing resistance in mite populations threatens the long-term usefulness of this critical treatment. This study presents a new, precision biotechnology strategy to help preserve amitraz efficacy by using RNA interference (RNAi) to temporarily suppress a mite gene (ABCB1) involved in pumping toxins out of cells. By reducing this detoxification mechanism, mites became significantly more susceptible to amitraz in laboratory tests. Importantly, the RNA treatment showed no harmful effects on honey bees, even under conservative safety scenarios. Practically, this approach could restore or enhance amitraz performance against resistant mites, reduce the selection pressure that drives resistance evolution, and extend the functional lifespan of an essential Varroa control tool—all without introducing broad-spectrum chemical synergists that might harm bees. This targeted RNA-based synergist strategy offers a promising, bee-safe resistance management solution to support colony health and protect pollination-dependent agriculture.

Technical Abstract: Background The ectoparasitic mite Varroa destructor is the primary biotic threat to managed honey bees, but its control relies on a limited number of chemical miticides. Amitraz remains widely used because of its efficacy and relatively low bee toxicity. However, resistance is increasingly reported, threatening its long-term utility. While mutations in the octopaminergic signaling pathway are strongly associated with amitraz resistance, additional mechanisms influencing toxicant uptake and efflux are likely to contribute. ATP-binding cassette (ABC) transporters, including ABCB1/P-glycoproteins, are well-established mediators of xenobiotic efflux and pesticide tolerance across arthropods.