UC Riverside Study Finds Hybrid California Bees Cut Varroa Mites 68% and Slash Treatment Need
Updated
Updated · SciTechDaily · May 22
UC Riverside Study Finds Hybrid California Bees Cut Varroa Mites 68% and Slash Treatment Need
3 articles · Updated · SciTechDaily · May 22
236 colonies tracked from 2019 to 2022 showed Southern California hybrid bees carried about 68% fewer Varroa mites than colonies headed by commercial queens and were more than five times less likely to hit treatment thresholds.
Laboratory tests pointed to an early defense: Varroa mites were less attracted to larvae from the hybrid bees, especially at seven days old, suggesting resistance may be built into development rather than driven only by adult behavior.
The bees are a genetically diverse, noncommercial population descended from at least four lineages and established partly through feral colonies, after beekeepers reported they were surviving with fewer chemical treatments.
The finding matters as U.S. beekeepers reported losing up to 62% of managed colonies in 2025; researchers say the bees are not mite-free but could help breeding programs reduce reliance on chemicals.
This California bee repels a deadly mite, but can its genetics be harnessed in time to save our food supply?
Will the solution to save honeybees create an even bigger problem for wild pollinators?
If bees have evolved a defense against mites, what new super-parasite will this evolutionary pressure create next?
Naturally Resistant Hybrid Honeybees Identified in Southern California: A Game-Changer in the Fight Against Varroa Mites
Overview
A recent UC Riverside study discovered a unique hybrid honeybee population in Southern California that shows remarkable natural resistance to Varroa mites, a major threat to bee colonies. These hybrid bees can maintain lower mite levels in their colonies, which is a key focus for researchers aiming to understand the traits behind this resilience. While the bees are not completely free of mites, this breakthrough is an important step in protecting pollinators. Researchers emphasize that current mite control practices should continue as they work to identify the specific characteristics that help these bees resist Varroa infestations.