UBC Study Links Virus Infections to Honey Bee Queen Supersedure via Pheromone Methyl Oleate

Original article by University of British Columbia explains that in honey bee colonies, viruses can reduce a queen's egg production and her production of methyl oleate, a pheromone that maintains worker loyalty. When pheromone levels fall, workers coordinate to replace the queen, a process known as supersedure. The study, published in PNAS, also shows that synthetic methyl oleate blends reduce the likelihood of rearing new queens in field trials, suggesting a practical management approach for beekeepers, especially during viral outbreaks and peak pollination. The findings highlight the role of varroa mites in spreading the viruses and emphasize the importance of keeping colonies healthy to protect pollination and honey production.

Overview

The University of British Columbia (UBC) team investigates why honey bee colonies frequently overthrow their queen, a behavior known as supersedure, and how this is tied to viral infections and pheromone signaling. Their work, published in the Proceedings of the National Academy of Sciences (PNAS), links infected queens to reduced egg laying and lowered production of methyl oleate, a pheromone that normally keeps workers loyal. With diminished pheromone signaling, workers perceive the queen as weakened and begin rearing a replacement.

Key researchers include Dr. Leonard Foster and Dr. Alison McAfee, with field trials conducted in collaboration with Michael Smith Laboratories at UBC and North Carolina State University. The study emphasizes how colony health, virus infections, and parasite pressure (notably varroa mites) interact to destabilize social structure and productivity in both wild and managed hives.

Mechanism: Virus, Ovaries, and Pheromones

The researchers show that common viral infections shrink queen ovaries, reducing egg production and lowering methyl oleate production. This pheromone loss disrupts the chemical signals that maintain worker loyalty, triggering workers to prepare a successor. Senior author Dr. Leonard Foster notes that queens can lay thousands of eggs daily when healthy, but infection diminishes this capacity and weakens colony cohesion.

Implications for Beekeeping and Pollination

The findings have practical implications. In proof-of-concept field trials, colonies receiving synthetic methyl oleate blends were significantly less likely to rear new queens compared with those without the pheromone, suggesting a potential management tool to stabilize hives during critical production periods. Dr. Alison McAfee emphasizes that keeping varroa levels in check remains crucial since mites spread the viruses linked to queen failure.

Broader Context and Next Steps

Bees pollinate about one-third of global crops, making hive stability essential for food security and agricultural productivity. The study highlights a previously underappreciated problem: viruses inside queens can drive supersedure and raise costs for beekeepers. The researchers call for integrated pest management to limit virus transmission and explore pheromone-based interventions as a means to preserve colony health and pollination services.

Quotes are included to illustrate key points: "Virus infections in queens can destabilize colony social structure," - Dr. Alison McAfee, Research Associate.
"Supplementing colonies with methyl oleate could help stabilize hives during periods of high productivity," - Dr. Leonard Foster, Professor of Biochemistry and Molecular Biology.
"Keeping varroa levels under control is critical for queen health and colony stability," - Dr. Alison McAfee.