California scientists found hybrid honeybees which will naturally repel one of many deadliest parasites threatening pollinators.
Southern California is house to an uncommon kind of honeybee which will assist researchers higher perceive easy methods to shield struggling pollinators. Throughout the US, industrial honeybee colonies are collapsing below strain from lethal parasites, however this regionally tailored hybrid bee inhabitants seems much better at surviving the menace.
Beekeepers within the U.S. reported shedding as much as 62% of their managed honeybee colonies in 2025, a development that might have main penalties for agriculture and meals manufacturing. A number of components are contributing to the losses, together with pesticides, local weather stress, shrinking habitats, and parasites. Among the many most harmful is the Varroa mite.
How Varroa Mites Hurt Honeybees
Varroa mites assault honeybees by feeding on their fats physique tissue, which performs a crucial function in immune protection, vitality storage, and general well being. Should you have been evaluating it to human biology, the organ features considerably like a mixture of the liver, pancreas, and immune system. Bees weakened by the mites typically lose physique weight, grow to be extra weak to illness, and die sooner.
The mites additionally unfold dangerous viruses, together with Deformed Wing Virus and Acute Bee Paralysis Virus. They go these infections instantly right into a bee’s bloodstream. To manage infestations, beekeepers typically depend upon chemical remedies, although these strategies can grow to be much less efficient over time.
A brand new UC Riverside examine revealed in Scientific Reports found that a naturally adapted population of Californian honeybees can consistently keep mite levels lower without eliminating them completely.
“We kept hearing anecdotally that these Californian honeybees were surviving with way fewer treatments. I wanted to test them rigorously and understand the driving force behind what the beekeepers were seeing,” said Genesis Chong-Echavez, a UCR graduate student and lead author of the study.
Study Tracks 236 Honeybee Colonies
Working with researchers from UCR’s Center for Integrative Bee Research (CIBER), Chong-Echavez monitored 236 honeybee colonies between 2019 and 2022.
The hybrid Californian bees were not fully resistant to the mites. However, colonies led by locally raised hybrid queens averaged about 68% fewer mites than colonies headed by commercial honeybee queens. They were also more than five times less likely to reach infestation levels that required chemical treatment.
The bees involved in the research are not part of a commercial strain. Instead, they belong to a genetically diverse population that has become established in Southern California, often from feral colonies living in trees. Previous studies found that these bees trace their ancestry to at least four honeybee lineages, including African, Eastern European, Middle Eastern, and Western European bees.
Honeybee Larvae Show Early Defense Against Parasites
Researchers also carried out laboratory experiments on developing honeybee larvae to better understand why the bees appeared more resistant. Varroa mites reproduce by entering brood cells, so the scientists tested whether the parasites were equally attracted to larvae from commercial colonies and Californian hybrid colonies.
They were not.
The mites were less attracted to larvae from the Californian hybrid bees, especially when the larvae were seven days old, which is normally the stage when mites are most likely to invade. The results suggest the bees’ defenses may begin very early in development, before adult worker bee behavior becomes a factor.
“What surprised me most was the differences showed up even at the larval stage,” Chong-Echavez said. “This suggests the resistance mechanism may go deeper than some kind of behavior and may be genetically built into the bees themselves.”
Hope for Future Honeybee Health
The findings may have implications far beyond Southern California. Honeybees pollinate crops worth billions of dollars, yet they continue to face mounting environmental pressures worldwide. The research suggests that naturally occurring biological traits could play an important role in improving honeybee survival.
Boris Baer, a UCR entomology professor and co-author of the study, said the project also demonstrates the importance of listening to beekeepers who observe these colonies firsthand.
“This question did not start in the lab. It started in conversations with beekeepers,” Baer said. “They were not just observers; they helped shape the questions behind this research.”
The researchers emphasized that the Californian hybrid bees are not completely free of mites, and they are not recommending that beekeepers abandon current treatment practices. Instead, the team hopes to identify the traits that help these bees maintain lower mite levels and determine whether those traits could be used in future breeding programs or reduce reliance on chemical controls.
The next phase of the research will focus on the genetic, behavioral, and chemical factors that may make the larvae less appealing to mites.
“At a time when pollinators are facing global decline, this work offers a hopeful message: solutions may already be emerging in the field, and we just need to understand them,” Chong-Echavez said.
Reference: “Varroa mite resistance in a hybrid honey bee (Apis mellifera) population in Southern California” by Genesis Chong-Echavez, and Boris Baer, 27 March 2026, Scientific Reports.
DOI: 10.1038/s41598-026-45759-9
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