Buzz-Worthy Discovery: New Test Spots Super-Resistant Honey Bees as Colony Losses Mount

A promising new tool for beekeepers could help combat alarming honey bee losses, which reached their highest levels on record last year. The UBeeO test, which mimics pheromones emitted by sick bees, accurately identifies colonies with natural resistance to multiple devastating diseases, according to research published April 2 in Frontiers in Bee Science.

The timing couldn’t be more critical. Beekeepers in the United States lost more than 55 percent of managed colonies last year—the highest loss rate since official tracking began in 2011.

“Beekeepers are losing bees at a rate that they say is unsustainable,” says Samantha Alger, director of the Vermont Bee Lab at the University of Vermont and lead author of the study. “In the ’80s, beekeepers lost colonies 10-12 percent of the time … but now it’s like 30-50 percent. Imagine that happening to someone who’s a cattle farmer or a pig farmer every year.”

While beekeepers have managed to maintain populations by creating new colonies, this stopgap solution comes at significant cost in time and resources. It also increases the risk of pathogen spillover to wild bee populations, potentially threatening native pollinators.

The international research team, which included scientists from Vermont, North Carolina, Mississippi, and Australia, found that the UBeeO test identifies colonies resistant to several key threats: Varroa mites, multiple viruses, Vairimorpha (previously known as Nosema), and chalkbrood fungus.

How Bees Protect Themselves

Healthy honey bee colonies naturally exhibit “hygienic behavior” – the ability to detect, uncap, and remove unhealthy developing bees from the hive before diseases can spread. This social immune mechanism has long interested researchers seeking to breed hardier bees.

Traditional testing methods for hygienic behavior involved killing bee pupae with liquid nitrogen and measuring how quickly workers removed the dead brood. The UBeeO test takes a different approach by using synthetic versions of the chemical signals naturally emitted by sick or infected developing bees.

“Rather than using liquid nitrogen to kill the developing pupae or larvae, you are using a blend of synthetic pheromones that mimics the same chemicals that are emitted by dying or diseased brood,” Alger explains. “So rather than testing the bees’ ability to identify dead brood, you are testing the bees’ ability to identify diseased brood, which means that this test is a little bit more selective and realistic to what bees experience.”

Kaira Wagoner, research scientist at University of North Carolina Greensboro and study co-author, developed UBeeO during her doctoral studies after identifying chemical compounds associated with unhealthy brood odors. The test became publicly available earlier this year through Optera, a company she co-founded.

“It’s a really young technology,” Wagoner says. “We’ve now tested it in over 10 different countries, and there are breeding programs in at least 5 now so there’s a lot more data to come.”

Setting Thresholds for Disease Resistance

The research revealed that different diseases require different levels of hygienic sensitivity. For some pathogens, colonies needed to achieve only modest UBeeO scores to demonstrate resistance.

“What we found, at least with this Australian dataset, is they only needed to achieve a 13 percent response on the UBeeO test to be really pretty resistant to chalkbrood. In contrast, colonies need to achieve a response of 55 or 60% on the UBeeO test to be resistant to mites,” Wagoner explains. “The honey bee responsiveness largely depends on how virulent or how harmful the specific disease is to the brood. Chalkbrood kills the brood, so the bees don’t have to be as sensitive to detect it.”

Perhaps the most unexpected finding was that colonies scoring high on the UBeeO test also showed resistance to Vairimorpha, a microsporidian parasite that primarily affects adult bees rather than developing brood.

“In the case of Vairimorpha, what they’re doing is kind of the mystery,” Alger says. “There might be other behaviors that hygienic colonies are performing aside of what we know.”

For beekeepers, the implications are significant. By identifying and breeding from colonies that score well on the UBeeO test, they can potentially reduce reliance on chemical treatments while improving colony survival rates.

“It’s definitely more desirable for a beekeeper to have bees that are better adapted at taking care of their diseases themselves rather than using chemical treatments and interventions to try to reduce these pathogen loads, which of course may have negative impacts on the bees,” Alger notes.

As climate change and agricultural intensification continue to stress pollinator populations, tools like UBeeO offer a pathway toward more resilient honey bee stocks. For an industry facing unprecedented challenges, that possibility offers a rare glimmer of hope amid troubling loss statistics.

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