Are Honeybees Really Harming Native Bees? What the Science Actually Shows

Honeybees are often blamed for harming native pollinators by spreading viruses into the environment. It’s a claim that circulates widely—but like many simplified narratives, it leaves out key biological context.

In one of our Four-Slide Lecture Series session, we examined how viral transmission actually works among pollinators and what current research identifies as the strongest drivers of disease spread.

Viruses can be transmitted between Bee Species

Viral Transmission Is Not One-Way

One of the most important points covered in this lecture is that viral transmission among bees is bidirectional. Viruses move between honeybees, bumblebees, and solitary bees—not exclusively from honeybees outward.

The lecture emphasized that the original host species of many common bee viruses is still unknown. Deformed Wing Virus, for example, may not have originated in honeybees at all. Much of the available research focuses on honeybees simply because they are easier to study, which creates bias in how transmission pathways are interpreted.

Related Bees Share More Viruses

The likelihood of viral transmission increases with genetic relatedness. Honeybees and bumblebees, which are closely related, share many of the same viruses. Distantly related solitary bees share far fewer.

Research discussed in the lecture showed that honeybees can vector only a limited subset of viruses to certain solitary bees. In some studies, no viruses are detected at all in sampled solitary bees, despite high detection rates in honeybees and bumblebees collected from the same landscape.

Detection Does Not Equal Damage

Another major limitation highlighted in the lecture is that most studies track viral presence, not biological impact.

Very few studies investigate whether a virus can replicate within a new host species or whether it produces measurable physiological effects. Detecting viral material does not automatically mean the virus is pathogenic in that bee.

What Actually Drives Viral Spillover

Across the studies discussed, one factor consistently stands out above the rest: viral density within honeybees.

As viral titers increase within honeybee populations—specifically for Black Queen Cell Virus and Deformed Wing Virus A and B—the likelihood of those viruses being detected in wild bees increases as well. This relationship was shown to be much stronger than factors such as bee density, flower sharing, or niche overlap.

In short, higher viral density increases the probability of shedding, while lower viral density reduces the likelihood of transmission.

What This Means for Beekeepers

The lecture concluded by emphasizing that reducing viral density within honeybee colonies is central to minimizing spillover risk.

Research-supported management strategies discussed include:

• Spacing colonies to reduce drift and virus amplification

• Ensuring access to diverse forage

• Providing high-protein supplemental feeding to colonies that are dwindling or not growing as expected, which has been experimentally shown to reduce viral titers

  
  

Lower viral density in honeybees corresponds to a reduced likelihood of viruses appearing in other pollinators.

Why We Teach This in Four Slides

The Four-Slide Lecture Series exists to take complex, often misrepresented research and distill it into clear biological principles and management-relevant findings.

No sensationalism. No oversimplification. Just evidence, context, and decisions beekeepers can apply.

Want access to this lecture and the full Four-Slide Lecture Library?

Members of The Beekeepers Academy receive access to the complete series, along with ongoing research-based education.

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