Flowers shape the spread of viruses among wild bees, new study finds

A new study shows that viruses in wild bees are closely linked to the flowers they visit and the availability of floral resources across the landscape. Researchers found that certain floral communities increase the likelihood of virus presence, and that flowers can serve as hubs for virus transmission between wild bees and honey bees. The findings suggest that pollinator conservation efforts must consider disease dynamics alongside habitat restoration.

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A new study led PhD. student Idan Kahnonitch under the guidance of Prof. Yael Mandelik of Hebrew University and Dr. Asaf Sadeh of the Volcani Institute in collaboration with Prof. Nor Chejanovsky of the Volcani Institute, Prof. Michelle Flenniken and Dr. Katie Daughenbaugh of Montana State University, reveals that the spread of viruses among wild bees is closely linked to the composition and availability of flowering plants, from the immediate local habitat to the wider landscape.

Published in Ecological Applications, the study shows that viruses commonly associated with honey bees are also present in wild solitary bees, and that their distribution is strongly influenced by floral communities. By surveying wild bee populations across multiple sites in a Mediterranean agroecosystem, the researchers found that both the diversity of flowers at a site and the availability of floral resources in the surrounding landscape play a key role in shaping where and when bee viruses occur.

The team focused on mining bees (Andrena species), an important group of wild pollinators, and screened them for several widespread bee viruses. The results indicate that flowers act as shared meeting points for different pollinator species, creating opportunities for virus transmission. Certain floral communities were associated with higher likelihoods of viral presence, while landscape-level floral resource availability, extending up to one kilometer from a site, emerged as a particularly strong predictor.

“Our findings show that flowers are not just food sources for pollinators,” the researchers said. “They also shape disease dynamics within pollinator communities. This means that decisions about habitat management and restoration, often focusing actions on the plant communities can have unintended consequences for pollinator health if disease transmission is not taken into account.”

Importantly, the study also found evidence that viruses can be shared between managed honey bees and wild bees, reinforcing concerns about how intensive agriculture and beekeeping may influence the health of native pollinator populations. While virus levels in wild bees were generally low, their presence was consistently linked to ecological conditions, especially floral composition and resource availability.

The researchers emphasize that pollinator conservation strategies should move beyond simply increasing flower abundance or diversity. Instead, they argue for a landscape-level approach that considers which plant species are present, how pollinators share floral resources, and how these interactions may affect disease spread.