Hive Tracking Project

Project Description

The bees are in trouble. We want to find out why. Counting both summer and winter losses, beekeepers are losing about 50% of their colonies each year. 2014 was a particularly devastating for Midwest beekeepers. We humans are losing our field force for pollinating the fruits and vegetables we all depend on for a healthy diet.  We need to stop the downhill slide. To do that, we need to untangle the different factors that may be affecting the bees.

PRI is working with the Pollinator Stewardship Council and several commercial beekeepers to evaluate the effects of pesticides, pathogens, and combinations of the two on honey bee survival.

What Is the Project?

Pesticide Research Institute (PRI) and Pollinator Stewardship Council are working together to better understand how different stressors (pesticides, pathogens) affect bees’ ability to thrive. Scientists from PRI and commercial beekeepers from PSC worked together to track 60 beehives over the course of a year and making measurements of:

  • Pesticide residues in pollen, wax and honey (180 different pesticides)
  • Pollen identification (to see what the bees are foraging on)
  • Pathogen levels (in collaboration with Montana State University scientists)
  • Varroa mite loads
  • Hive strength, queen performance, disease, bee mortality, and any abnormal bee behavior

Why This Project is Important

This research will provide documentation of the types of pesticides and pathogens commonly encountered by commercial beekeepers in agricultural areas over the course of a year, with a focus on agricultural locations with almonds and corn—two crops that most U.S. bees are exposed to. The work will also provide insights into the effects of combined pesticide exposure and pathogen levels on hive health over time.  We anticipate that we can use the data in a number of ways.BeesHelping

  • At the regulatory level (US EPA), the research will provide data on which to base decision-making for pesticides to enhance pollinator protection.
  • For beekeepers, the study will provide a quantitative estimate of hazards posed by particular crop-pesticide combinations and will enable them, where possible, to keep their bees away from such crops.
  • Growers and Regional IPM centers will be able to use the information to make pollinator-friendly choices when selecting pest control products for crops.
  • Knowing which factors are most closely associated with decreased colony fitness will enable everyone to focus pollinator protection efforts on the factors that are most important for improving bee health.


Many causes for the unusually high managed honey bee colony losses have been proposed, including pesticides, the Varroa mite, pathogens such as Nosema and various viruses, and loss of forage due to increased corn production to make biofuels. It is likely that an interactive combination of these stressors is responsible for the observed colony declines. More study is needed to determine the primary factor or mix of factors causing colony losses, with a focus on combined effects.

Understanding the relative contribution of the different factors to the problem of unsustainable colony losses is paramount to solving it, yet few studies are focused on this outcome. The PSC-PRI Hive Tracking Project will provide unique and valuable insights into the agricultural landscape in the U.S. and its effects on pollinators by evaluating multiple colony stressors and their interactions in commercial managed honey bee colonies.

bees crawling outPrevious work in this area has laid the groundwork for doing this study, showing the necessity of tracking the multiple parameters that may affect colony health. Van Englesdorp et al. conducted a comparison of multiple stressors (pesticides, pathogens, and parasites) on collapsed colonies vs healthy colonies at a single point in time, finding no single factor that explained the differences. Runckel, Flenniken, et al. tracked pathogen loads for a migratory bee operation, assessing their changes over time and correlations to colony health, but did not measure pesticide residues. Flenniken and Andino have also studied the honey bee antiviral immune response, an essential piece of the puzzle for understanding potential interactions between exposure to immune-suppressing pesticides and a colony’s ability to combat pathogens.

To date, there has been no prospective study that tracks temporal changes in pesticide residues, pathogen loads, and parasites in a migratory beekeeping operation, yet there is great potential to obtain data that will help untangle the role of multiple stressors on the bees. Ultimately, this work will provide data to inform evidence-based decisions regarding pesticide regulation, in order to better protect pollinators. The U.S. regulatory system is in dire need of such data, and a major part of the outreach efforts for dissemination of project results will focus on US EPA, USDA, the CA Department of Pesticide Regulation, and other Departments of Agriculture in states around the U.S. This study will provide data to document the scope and magnitude of agrochemical levels within managed honey bee colonies in agricultural areas—an essential first step to understanding the issue and providing a scientific basis for any needed regulatory change.
hives on grass