Project Results

Compared to their stationary counterparts, migratory bee colonies returned from CA almond pollination with fewer bees and higher virus loads (black queen cell virus) but lower varroa loads (which we attribute to the lower bee population). Our results indicate that migratory conditions have variable effects on honey bee health, including some important negative impacts.

About This Project

Crop pollination by migratory beekeeping operations presents a highly concentrated convergence of bees where diseases may be transmitted and spread as hives are transported throughout the US. To test if migratory operations contribute to the spread of disease, we propose an experiment where we subject hives to almond pollination in California and compare their disease loads to stationary hives in N. Carolina. Upon the return of the migratory hives, we will measure subsequent disease spread.

Ask the Scientists

What is the context of this research?

Each year, migratory beekeepers transport millions of hives across the country to pollinate our food crops. Perhaps most notably, every February, ~60% of US honey bee colonies are brought to California's almond orchards. Although important for the production of our food, this high density of hives during crop pollination could lead to increased disease transmission.

Previous surveys, including our own preliminary data, found that migratory hives can have high disease loads and that infected hives may transmit diseases to other bees, including wild species. We propose an experiment to test the following: Do migratory hives acquire more pathogens than their stationary counterparts? and Upon return to winter yarding areas, do migratory hives transmit diseases to stationary hives?

What is the significance of this project?

In the US, bees contribute about $14.6 billion in pollination services every year to important crops including blueberries, cranberries, apples and citrus. Pathogens pose a significant threat to both native and managed pollinators. Understanding and reducing disease transmission among bees is a both a conservation and economic priority.

Results could directly influence management strategies proposed in state Managed Pollinator Protection Plans as part of the 2015 National Strategy to Promote the Health of Honey Bees and Other Pollinators. Apiary inspection programs help lessen the risk of disease to pollinators but are often underfunded. Our results could provide the evidence needed to increase funding to these important programs to ensure adequate inspections.

What are the goals of the project?

In February 2017, we will simulate migratory conditions by trucking North Carolina hives to California for almond pollination, then returning them, where they will reside with a control group of stationary hives. We will test both groups for pathogens and colony strength (brood, weight, pollen stores) before and after the migration. To test for disease spread from the migratory hives to their stationary counterparts, we will test both groups one month later. We will compare disease loads of the exposed stationary hives to an isolated control group of hives.

Results of this study will be published in both scientific and beekeeping journals. We will present findings for beekeeping organizations and at the 2018 American Beekeeping Federation Conference.