Red-tailed bumblebees can act as hosts for a dangerous bee virus.
Photo Credit: Uni Halle / Patrycja Pluta
Scientific Frontline: Extended "At a Glance" Summary: Viral Transmission Dynamics in Multispecies Bee Communities
The Core Concept: Wild red-tailed bumblebees (Bombus lapidarius) act as the primary reservoir hosts for the acute bee paralysis virus (ABPV), carrying the pathogen with minimal harm while posing a fatal transmission risk to vulnerable honeybee populations.
Key Distinction/Mechanism: Historically, scientific consensus held that managed honeybees were the primary source of viral infections, spilling pathogens over into wild bee populations. This research fundamentally shifts that paradigm by demonstrating that wild bumblebees can serve as the key epidemiological reservoir for certain viruses, transmitting the pathogen back to honeybees via contaminated pollen and nectar at shared floral feeding sites.
Major Frameworks/Components:
- Epidemiological Modeling: Utilization of the basic reproduction number (\(R_0\)) to quantify and estimate the specific viral spread potential from one insect to others of the same species.
- Multispecies Network Analysis: Observational tracking of shared floral visitation patterns among diverse bee species to map potential interspecies transmission nodes.
- Comprehensive Pathogen Screening: Molecular virus screening of 1,725 insects to determine host-specific viral prevalence and vector capabilities.
- Differentiated Host Profiling: Identification of distinct primary hosts for specific pathogens (e.g., honeybees as main carriers for deformed wing virus and black queen cell virus; red-tailed bumblebees for acute bee paralysis virus).
Branch of Science: Entomology, Viral Ecology, Epidemiology, Conservation Biology.
Future Application: These findings will directly inform agricultural policies and landscape management strategies, specifically driving the implementation of high-diversity flower strips. Expanding the spatial and botanical diversity of foraging areas is projected to lower interspecies contact rates and dilute viral transmission networks within pollinator ecosystems.
Why It Matters: The acute bee paralysis virus causes rapid paralysis, trembling, and death in honeybees, frequently leading to total colony collapse. Accurately identifying the true reservoir hosts and ecological transmission pathways is critical for developing targeted, evidence-based interventions to protect global pollinator health, ensure agricultural food security, and maintain vital ecosystem services.
Wild bumblebees serve as key hosts for acute bee paralysis virus. While the virus appears to cause little harm to bumblebees, infection is usually fatal to honeybees. Until now, it was assumed that honeybees were the key host for the virus. By using data from extensive field trials, a team from Martin Luther University Halle-Wittenberg (MLU) and Georg August University of Göttingen has now identified the red-tailed bumblebee as the key host for acute bee paralysis virus. Their study was published in the journal “Ecology Letters” and could help inform policies that aim at curbing the spread of such diseases in nature.
Honeybees, wild bees, and other insect species are connected by their shared visits to flowers. “A flowering summer meadow is therefore both a source of food and a potential site for the transmission of viral infections. This is because insects searching for food there come into contact with material that may be contaminated with viruses, such as pollen and nectar,” says biologist Professor Robert Paxton from MLU. Until now, research has assumed that honeybees serve as primary hosts for various viruses and can thus infect bumblebees and other wild bees. However, the new study paints a different picture: according to it, wild bees can also be reservoir hosts for viruses and thus theoretically contribute to the infection of honeybees.
This result is based on field data collected by the team at 32 locations in Lower Saxony and Hesse. The researchers first observed whether different bee species visit the same flower species. They also used virus screening of 1,725 insects comprising multiple bee species to analyze how much each bee species contributes to the spread of various viruses. “To identify the bee species that contribute the most to the spread of viruses, we used the basic reproduction number, \(R_0\). This measure estimates how widely a virus can spread from one insect to others of the same species,” explains Patrycja Pluta from MLU, lead author of the study. The team calculated precisely for each combination of virus and bee species how easily a virus can spread and how much each bee species potentially contributes to the spread of viruses.
The researchers identified the most important host insects for three known bee viruses. They found that honeybees are the main carriers of deformed wing virus (DWV) and black queen cell virus (BQCV) at the sites studied. „However, the main host insect for the acute bee paralysis virus is a wild bee: the red-tailed bumblebee Bombus lapidarius,” says Patrycja Pluta. When honeybees become infected with the virus, they are unable to fly after a short time, start to tremble, and die within a few days. This can lead to the rapid collapse of an entire colony.
Another finding: the composition of bee species at a location has less influence on the spread of viruses than previously assumed. In contrast, direct contact with bees that transmit many viruses plays a decisive role. And this occurs when visiting flowers. According to Robert Paxton, these findings are important for understanding how diseases spread in nature and how they can possibly be counteracted. “The more space and the more diverse food bees have; the less likely infections are to occur. To minimize the risk of further spread of disease, more flower strips with many different plant species would be very helpful, for example,” says Paxton.
Funding: The study was funded by the Federal Ministry of Food and Agriculture (BMEL) based on a resolution of the German Bundestag via the Federal Office for Agriculture and Food (BLE) as part of the Federal Organic Farming Program and by the German Research Foundation.
Published in journal: Ecology Letters
Authors: Patrycja Pluta, Annika L. Hass, Kathrin Czechofsky, Catrin Westphal, and Robert J. Paxton
Source/Credit: Martin Luther University Halle-Wittenberg
Reference Number: ent032426_01
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