The idea that native species are better appears to hold true in the United States as well. Hybrids that settled long ago in Southern California were found to be more resistant to parasites than managed honey bees (Apis mellifera). Last year, beekeeping colonies disappeared by as much as 62% across the United States, dealing a major blow to agriculture that relies on bees for pollination. The finding suggests that native bees adapted to local ecosystems could be an alternative to sustain agriculture.
Boris Baer, a professor at the University of California, Riverside (UC Riverside) Center for Integrative Bee Research, and his team said on the 9th (local time), "Tracking 236 bee colonies from 2019 to 2022, we found that colonies led by California-bred hybrid queens had 68% fewer Varroa mites than managed honey bee colonies." The findings were published in Scientific Reports, a sister journal of Nature.
◇Need for chemical control is five times lower in natives
Recently, cases of bees vanishing without a trace have continued, flashing a red alert for agriculture. Colony collapse disorder began in the United States in 2006. In Korea, 7.8 billion bees disappeared in the first quarter of 2021, drawing public attention. There are multiple causes for the disappearance of bees. Climate change, habitat loss, pesticides, and parasites are cited. The most fatal among them is the Varroa mite.
Unlike other mites, Varroa feeds on fat instead of hemolymph. For bees, fat functions like the human liver. It maintains immunity, helps them overwinter, and withstand insecticides. That makes Varroa deadly to bees. It even spreads viruses that cause deformed wings and acute paralysis.
The survey found that California hybrids were also infected with Varroa, but far less than imported managed honey bees. Chemical control is applied when three out of every 1,000 worker bees in a colony are infected, and California native bees exceeded this threshold at a rate five times lower than managed honey bees. Native bees mainly nest in trees. Recent research shows these bees are hybrids of African, Eastern European, Middle Eastern, and Western European bees.
Varroa infects bee larvae. The researchers conducted experiments infecting hybrid and managed honey bee larvae with Varroa. The mites chose managed honey bee larvae more often. The gap was largest in larvae 7 days after hatching. This is when Varroa most aggressively targets larvae. Genesis Chong-Echavez, the paper's first author, said this suggests that resistance mechanisms to Varroa are embedded in the genes.
The study revealed that wild bees adapted to local ecosystems could be an alternative to protect agriculture. Bee safety is directly tied to human survival. According to the Food and Agriculture Organization (FAO), 71 of the world's top 100 crops rely on bees for pollination.
The UC Riverside team plans to investigate the genes, behaviors, and chemical signals that make Varroa less likely to choose native bee larvae. If genes that repel the parasite are identified, it could lead to breeding bee strains strong against Varroa.
◇Native bees that could protect agriculture are being outcompeted by managed honey bees
The problem is that humans themselves are eliminating these helpful wild bees. Managed honey bees introduced for pollination to boost agricultural output are sweeping up the pollen that native bees would eat. Last year, researchers at the University of California, San Diego (UCSD) released a paper in Insect Conservation and Diversity, published by the Royal Entomological Society, reporting that on the first day of blooming in Southern California, managed honey bees took about 80% of the pollen.
The researchers measured how much pollen bees collected from three common flowers in Southern California. Large managed honey bees vacuum up pollen at tremendous speed, leaving almost none for the more than 700 native bee species. The UCSD team said, "Honey bees are an indispensable asset to humans, but in ecosystems where they are not native, they can pose a serious threat."
In earlier work, the researchers found that 90% of foraging bees in Southern California were managed honey bees, also known as European or Western honey bees. The team estimated that if the pollen and nectar taken by managed honey bees had been available to native bees, their populations would be about 50 times larger than they are now.
American marine biologist Rachel Carson warned in her 1962 book "Silent Spring" that the overuse of pesticides would wipe out the insects that birds eat, leaving spring silent. Now even the sound of bees in spring is at risk of disappearing. For human survival, it is time to find ways for native bees and managed honey bees to coexist.
References
Scientific Reports (2026), DOI: https://doi.org/10.1038/s41598-026-45759-9
Insect Conservation and Diversity (2025), DOI: https://doi.org/10.1111/icad.12858