Do pollinators use flowering vegetation under solar panels?

The need to provide both food and energy to a growing human population contributes to declining insect abundance and diversity. There is an opportunity to address these issues by combining renewable energy production with conservation and agricultural practices. An example of this is the development of eco- and agrivoltaics practices that couple solar energy production with various forms of vegetation. We are exploring if pollinators, including honey bees (Apis mellifera, Hymenoptera: Apidae), respond to flowering vegetation cultivated under and between photovoltaic panels within a 10-acre facility developed from a partnership between Alliant Energy and Iowa State University. Our overall hypothesis is that the benefits and cost of management and impact on solar energy production will vary by vegetation type. This facility includes four different configurations of photovoltaic (PV) panels with varying heights and tracking capacity (fixed or single axis tracking). Within the industry standard configuration (1.7m, single-axis), we are using a randomized complete block design with eight vegetation treatments: broccoli, peppers, squash, strawberries, raspberries, a pollinator mix (with two forms of management), and a grass and clover mix. Treatments were planted beginning in the fall of 2023, and measurements of ground cover, floral production, and subsequent response by pollinators initiated during the 2024 growing season. We established a 4-colony apiary to determine the response of A. mellifera to these treatments by measuring change in pollen forage, and honey production. The abundance and diversity of wild pollinators will be assessed using timed visual observation within each treatment.