Researchers at the University of British Columbia have discovered that viral infections in honey bee queens reduce their pheromone production, triggering workers to replace them through a process called supersedure. This finding explains many queen failures faced by beekeepers and suggests synthetic pheromones as a solution to stabilize hives. The study highlights the role of viruses, often spread by varroa mites, in disrupting colony health.
In honey bee colonies, supersedure occurs when worker bees detect that their queen is failing to produce enough eggs, leading them to raise a replacement. This adaptive mechanism helps wild colonies but causes disruptions in managed hives, including reduced pollination and honey output.
A study published in the Proceedings of the National Academy of Sciences reveals that common viruses shrink the queen's ovaries, impairing egg laying and decreasing production of methyl oleate, a key pheromone signaling her health. "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 the University of British Columbia's Faculty of Medicine and Michael Smith Laboratories. In experiments, infected queens laid fewer eggs and produced less methyl oleate, prompting workers to initiate replacement.
Bees pollinate about one-third of global crops, making queen health vital for food security. Beekeepers have long reported rising queen failures, with surveys citing "poor queens" as the top cause of overwintering losses. The research links these issues to viral infections, often transmitted by varroa mites, which underscores the need for parasite control.
Field trials offer hope: colonies supplemented with synthetic methyl oleate blends were less likely to start rearing new queens. "That could be a big deal for beekeepers," Dr. Foster noted. "Supersedure can be disruptive and costly, but supplementing colonies with methyl oleate could help stabilize hives during periods when continuous productivity is most important."
First author Dr. Alison McAfee, a research associate at UBC's Michael Smith Laboratories and North Carolina State University, emphasized the overlooked impact of queen infections. "Our research really emphasizes how virus infections in queens can be a major problem for beekeepers," she said. "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." She added that controlling varroa levels is crucial, as no direct treatments exist for bee viruses.