Leveraging propolis across the landscape to improve beekeeping

Commodities

Practices

Honey bees experience numerous stressors in their environment, including pesticide exposure, pathogens/pests, and suboptimal nutrition. Especially in the United States, limited non-crop vegetation can lead to landscape-level deficits in food availability for honey bees, and numerous studies have documented the ramifications of nutritional deficits on honey bee responses to pathogens and pesticides.

Beyond food resources, however, honey bees collect resin from some plants, which they then process into propolis. This sticky material is used as a sealant and 'glue' in bee colonies but also provides many other benefits to honey bees. An amalgam of potentially hundreds of plant chemicals, propolis is highly antimicrobial and can modulate honey bee immune systems and detoxification pathways, helping bees cope with pathogens and pesticides. Although resin collection and propolis deposition demonstrably benefits bee health, its full potential remains untapped. Like honey and bee bread, propolis is typically created from a mixture of plant sources, resulting in substantial heterogeneity in propolis chemistry.

However, virtually nothing is known about how the individual chemicals vary with resin source or how each constituent contributes to propolis benefits. Here, we propose to

1. characterize the phytochemical variation of propolis in the North Central region,
2. measure how landscapes shape the quantity and chemical composition of propolis, and
3. experimentally determine the contributions of different propolis constituents to stress resistance phenotypes.

Together, achieving these aims can help

a) predict how landscape resources contribute to valuable propolis resources in the North Central region and beyond, and b) identify natural chemicals that could be used as bee-safe in-hive treatments to enhance resistance to disease and agrochemical exposure.

Both of these goals are directly relevant for pollinator management in the North Central region, as they will help beekeepers identify apiary locations with valuable resin resources, inform
landuse practices aimed at improving beekeeping, and potentially lead to safe and inexpensive natural chemical treatments to increase honey bee resilience. In this project, we also plan to integrate cooperator beekeepers into our research and work with them to communicate our findings to a stakeholder audience.

Objective 1: Using researcher-managed colonies, we will develop a 'propolis atlas' that characterizes propolis chemical diversity across the North Central region.

Objective 2: Using researcher-managed and cooperator beekeeper-managed colonies, we will test the hypothesis that propolis chemistry varies across a land-use gradient.

Objective 3: Using experimental laboratory assays, we will test the hypothesis that individual propolis-derived chemicals can improve stress resilience in honey bees.

Together, this will expand knowledge of propolis chemistry and provide insights into its potential importance for honey bee health. Further, we can inform best management practices and potentially identify propolis-derived chemicals for use as in-hive treatments.