It sounds like the plot of a medieval historical drama: A once-powerful monarch, weakened by illness, is overthrown by her previously loyal subjects. But in honey bee colonies, such high-stakes coups aren't just fantasy — they're a common occurrence that comes with both risk and reward for bee colonies and the food systems that depend on them.
Known as supersedure, the process occurs when the tens of thousands of worker bees in a colony sense their queen is no longer laying enough eggs and coordinate to replace her with a new, healthier queen. While this survival strategy helps wild colonies adapt, it can spell trouble for managed hives, leading to gaps in egg-laying, weaker colony populations and ultimately less pollinating and honey production.
Now, researchers at the University of British Columbia have made an important discovery that illuminates why these violent revolts occur and how they're coordinated with such remarkable synchronicity.
Published recently in PNAS , the research team found that common viral infections shrink a queen's ovaries, reducing both her egg-laying capacity and her production of methyl oleate, a pheromone that normally keeps workers loyal. When methyl oleate levels drop, workers will "smell" the queen's weakness and begin preparing her successor.
"A healthy queen can lay as many as 850 to 3,200 eggs per day, which is more than her whole body weight," said senior author Dr. Leonard Foster , a professor of biochemistry and molecular biology at UBC's Faculty of Medicine and Michael Smith Laboratories. "But in our experiments, virus-infected queens laid fewer eggs and produced less methyl oleate. That pheromone reduction seems to be the signal to workers that a queen is no longer fit to continue."
Bees pollinate about one-third of the world's crops, making them essential to healthy food systems, food security and the health of people and communities worldwide.
Beekeepers have been reporting problems with queen failure and premature supersedure for many years, with recent surveys identifying "poor queens" as the most frequently reported cause of overwintering losses.
The research highlights how viral infections are a driving factor behind these challenges, disrupting the delicate balance of chemical signals that maintain order in a hive.
Importantly, the findings also point to a practical way for beekeepers to intervene and manage supersedure. In proof-of-concept field trials, colonies given synthetic pheromone blends that included methyl oleate were much less likely to rear new queens compared to colonies that received blends without it.
"That could be a big deal for beekeepers," said Dr. Foster. "Supersedure can be disruptive and costly, but supplementing colonies with methyl oleate could help stabilize hives during periods when continuous productivity is most important."
The findings open the door to new management strategies for commercial beekeepers dealing with viral outbreaks, especially during periods of peak pollination or honey production to prevent untimely queen loss.
"Our research really emphasizes how virus infections in queens can be a major problem for beekeepers," said first author Dr. Alison McAfee , a research associate at UBC's Michael Smith Laboratories and North Carolina State University. "Previous studies showed that failing queens were heavily infected with viruses, and now we know that those infections can lead to supersedure, which is risky for the colony and expensive for beekeepers to manage."
The research also highlights the role of varroa mites — parasitic pests that can spread the viruses linked to queen failure — underscoring the importance of keeping colonies healthy and parasite-free.
Queen infections are so far an underappreciated problem, said Dr. McAfee, who hopes that this research will change that.
"Keeping the queen healthy is one more reason why it is so critical to think ahead and keep varroa levels under control," Dr. McAfee added. "There is currently no treatment for viruses in honey bee colonies, but now that we better understand their impact, we can change the way we manage varroa to give the queen a better chance."
Interview language(s): English
