Why honey bee colonies are revolting and overthrowing their queens

Inside the honey bee’s kingdom, loyalty is fragile. The queen, nurtured and revered, rules her colony through scent and fertility. Yet, when illness creeps in, that same loyalty turns into rebellion. Her subjects, guided by instinct and chemistry, prepare her successor.

This act, called supersedure, ensures the colony’s survival but also reflects the complex biology that binds the hive together.

When bees replace queens

Supersedure happens when workers sense their queen’s decline. Her egg-laying slows, and her chemical signals weaken.

The colony unites to rear a new queen, a process that in wild hives helps adaptation but in managed colonies can cause disruption.

Researchers at the University of British Columbia (UBC) uncovered how this behavior unfolds with such precision and what triggers it at the molecular level.

Their study revealed that viruses like deformed wing virus B and black queen cell virus cause ovarian shrinkage in queens. This limits egg production and reduces a pheromone called methyl oleate, which normally signals strength.

When that pheromone falls, workers “smell” weakness and begin preparations for a replacement.

How viruses change queen bees

Honey bee queens communicate with their colonies through a blend of pheromones. Among these, methyl oleate plays a crucial role in maintaining harmony. It suppresses the urge of workers to create new queens.

UBC’s team found that infected queens produce much less of this compound. The drop in methyl oleate doesn’t just signal illness – it shifts the entire colony’s behavior.

“A healthy queen can lay as many as 850 to 3,200 eggs per day, which is more than her whole body weight. But in our experiments, virus-infected queens laid fewer eggs and produced less methyl oleate,” noted study co-author Dr. Leonard Foster.

“That pheromone reduction seems to be the signal to workers that a queen is no longer fit to continue.”

Viruses drain queen bees

Virus infection does more than reduce pheromones. It drains the queen’s energy reserves by attacking her lipid system.

The researchers discovered severe triacylglycerol deficiencies – key energy molecules – within infected queens.

These losses weaken reproductive tissues and disrupt pheromone production. The result is a cascading breakdown in communication and energy balance across the hive.

Interestingly, when researchers restricted egg-laying artificially, queens also showed lower methyl oleate levels. This finding suggests that pheromone output is closely tied to reproductive activity, not infection alone.

The ovaries themselves might release methyl oleate in proportion to their activity, linking physical fertility with the colony’s perception of leadership.

How sickness changes energy

Queens devote nearly all their biological energy to egg production. Any infection forces a shift in how that energy is spent.

The UBC team found that when immune responses activate, lipid transport systems – especially those involving a protein called apolipophorin-III – are affected.

This protein normally carries fats vital for egg formation, but it can also function in immune defense. When it diverts toward immunity, reproduction suffers.

In virus-infected queens, apolipophorin-III levels dropped alongside ovary mass. The body appeared to prioritize survival over reproduction.

Yet in queens whose laying was only restricted, immune proteins remained unchanged, confirming that infection, not inactivity, drives immune stress.

Helping hives stay stable

Bees pollinate about one-third of global crops, making their stability vital to food systems. Supersedure, while natural, causes temporary gaps in egg-laying and pollination. For commercial beekeepers, such events can mean financial loss.

In field trials, colonies supplemented with synthetic pheromone blends containing methyl oleate were more stable. They produced fewer replacement queens compared to colonies that lacked the compound.

“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.”

What happens inside colonies

The study also explored how virus infection reshapes the queen’s lipid composition. Infected queens showed broad declines in many lipid types, including triacylglycerols, which store energy, and other phospholipids.

These losses weaken pheromone production and signal instability to the workers. Only a few compounds, such as certain prostaglandins, increased – possibly indicating oxidative stress from infection.

High virus levels, the researchers found, make colonies more likely to rear supersedure cells. Queens with smaller ovaries and lower methyl oleate levels face a higher chance of being replaced.

The findings outline a self-regulating system in which chemical signals ensure that the colony replaces failing leaders before collapse.

Saving bee colonies from viruses

Dr. Alison McAfee, the study’s first author, explained the broader implications of the team’s findings.

“Our research really emphasizes how virus infections in queens can be a major problem for beekeepers,” said Dr. McAfee.

“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 study also exposed the influence of varroa mites – parasitic pests that spread these viruses.

“Keeping the queen healthy is one more reason why it is so critical to think ahead and keep varroa levels under control,” added Dr. McAfee.

“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.”

A fragile monarchy

What begins as an invisible viral invasion ends in a social transformation. A queen’s scent fades, her energy drains, and her workers – guided by chemical cues – prepare for succession. The process might seem ruthless, yet it preserves the hive’s survival.

By uncovering the molecular and chemical pathways of this change, scientists now see how deeply health, reproduction, and social behavior intertwine.

Within every honey bee colony, the fall of a queen is not just an ending – it is renewal through biology’s most intricate form of democracy.

The study is published in the journal Proceedings of the National Academy of Sciences.

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