Got Pollen?

This fact sheet is for Ohio gardeners who want to create pollinator-friendly spaces that truly support bee health. It includes the bee food pyramid to highlight different plants found in Ohio and the nutritional values of the plants’ pollen. These plants include a variety of flowers that meet the nutritional needs of garden visitors, including a diversity of bee species. The pyramid and table in this fact sheet highlight different plant families/species found in Ohio, the nutritional value of their pollen, and their flowering times in order to provide Ohio gardeners with the information needed to support bee nutrition and health.

As with humans, bees need nutrition to be healthy and reproductively successful. Unlike humans, instead of eating a chicken sandwich and fruit salad, bees consume pollen and nectar from flowering plants within their foraging range. The proteins and lipids obtained from the pollen are needed for the development of the bee larvae. Bees also need carbohydrates from nectar, which gives them energy for flight and foraging. Though flowers do not come with nutrition information like food purchased from the supermarket, the nutritional value of pollen and nectar varies among plant species (Roulston & Cane, 2000). A nutritious diet is important for successful bee development and shapes species’ foraging preferences. When designing pollinator gardens to support native bees, consider the types of floral resources and the nutritional value provided by each plant in the same way you decide which nutritional foods you add to your cart when grocery shopping.

Pollen and nectar are floral resources that bees utilize differently across their lifespan. Bees collect pollen from flowers, primarily to feed their growing larvae. Foraging adult bees often collect nectar from flowers to mix into the pollen they feed their offspring, and they also consume nectar to fuel these foraging bouts. The quantity and quality of pollen and nectar vary by plant species (Roulston & Cane, 2000; Nicholson et al., 2007; Vaudo et al., 2020). The nutritional content of a plant’s pollen often indicates which pollinator species will choose to forage from that plant (Vaudo et al., 2020; Vaudo et al., 2024). For example, bumble bee colony growth and reproduction are dependent on the quality and quantity of floral resources in the surrounding landscape (Vaudo et al., 2018). The common eastern bumble bee (Bombus impatiens), a generalist pollinator that forages on diverse floral species, prefers to forage for pollen that is high in proteins and low in lipids (Vaudo et al., 2020). In a laboratory experiment looking at the effects of diet on bumble bee colony development, larvae developed best in pollen high in protein and low in lipids (4-to-1 protein-to-lipid ratio) (Barraud et al., 2022). This suggests that bumble bees forage for pollen with nutritional levels that are the most beneficial for their offspring’s development. Species-specific patterns are also observed in honey bees (Apis mellifera), which prefer pollen with a 1-to-1 protein-to-lipid ratio, and mason bees (Osmia spp.), which prefer pollen with a 3-to-1 protein-to-lipid ratio, suggesting that nutritional needs shape bee foraging preferences.

Applying Bee Nutrition Science to Garden Plant Selections

The food pyramid is a familiar representation of human dietary needs that illustrates the number of servings of each food group a person should eat in a day. A bee food pyramid can help gardeners choose flowering plants that provide an array of nutritional values to support bee health.

Nutritional preferences are not known for all bee species nor is the nutritional content of all plant pollens known, so when designing a pollinator garden, including a diverse array of flowers will increase the bee diversity and be more likely to meet the nutritional needs of the garden’s visitors.

Additionally, some bee species are pollen specialists, meaning they only forage for pollen from plants in the same family or from one plant species. To support specialist bees, select plants such as aster (Symphyotrichum spp.), goldenrod (Solidago spp.), willow (Salix spp.) or perennial sunflower (Helianthus spp.) For more information on additional plants and practices that support specialist bees, download the specialist bee handout (bpb-us-w2.wpmucdn.com/u.osu.edu/dist/3/120507/files/2023/02/2022-Specialist-Bee-Handout-Final-223.pdf). This handout contains a listing of Ohio’s native plants with information on their pollen nutritional values (Figure 1).

Other Considerations for Pollinator Gardens

• Plants that provide nectar to pollinators can attract hawk moths, butterflies, and hummingbirds to the garden. Nectar is also critical for bee health.
• Some garden vegetables like squash, cucumbers, tomatoes, eggplants, and even potatoes provide high-quality pollen and nectar for many bees when in bloom.
• Berry and fruit plants such as strawberries, raspberries, blackberries, blueberries, apples, apricots, cherries, and plums benefit from insect pollination and provide important food for pollinators.
• Consider the entire landscape, including trees and shrubs, when developing habitat for bees. Many native trees provide valuable nectar and pollen resources for pollinators. Consider planting maples, basswood or linden, tulip poplar, black locust, and catalpa trees in the landscape. Shrubs such as pussy willow, viburnum, and serviceberry offer pollen and nectar to benefit pollinators.

Additional Resources

• Download PDF of Ohio native plants with available information on pollen nutritional values
• Science you can use bulletin (U.S. Forest Service). Bee nourished: How pollen nutrition shapes bee foraging habits and what it means for restoration
  (research.fs.usda.gov/treesearch/69291)

• Pollinator partnership
  (pollinator.org)
• The Ohio State University bee lab
  (beelab.osu.edu)
• Xerces Society for Invertebrate Conservation
  (xerces.org)

References

Barraud, A., Barascou, L., Lefebvre, V., Sené, D., Conte, Y. L., Alaux, C., Grillenzoni, F. V., Corvucci, F., Serra, G., Costa, C., Vanderplanck, M., & Michez, D. (2022). Variations in nutritional requirements across bee species. Frontiers in Sustainable Food Systems, 6.
doi.org/10.3389/fsufs.2022.824750

Nicholson, S. W., Nepi, M., & Pacini, E. (Eds.). (2007). Nectaries and nectar. Springer Dordrecht.
doi.org/10.1007/978-1-4020-5937-7

Roulston, T. H., & Cane, J. H. (2000). Pollen nutritional content and digestibility for animals. Plant Systematics and Evolution, 222(1–4), 187–209.
doi.org/10.1007/bf00984102

Vaudo, A. D., Farrell, L. M., Patch, H. M., Grozinger, C. M., & Tooker, J. F. (2018). Consistent pollen nutritional intake drives bumble bee (Bombus impatiens) colony growth and reproduction across different habitats. Ecology and Evolution, 8(11), 5765–5776.
doi.org/10.1002/ece3.4115

Vaudo, A. D., Tooker, J. F., Patch, H. M., Biddinger, D. J., Coccia, M., Crone, M. K., Fiely, M., Francis, J. S., Hines, H. M., Hodges, M., Jackson, S., Michez, D., Mu, J., Russo, L., Safari, M., Treanore, E. D., Vanderplanck, M., Yip, E. C., Leonard, A. S …, Grozinger, C. M. (2020). Pollen protein: Lipid macronutrient ratios may guide broad patterns of bee species floral preferences. Insects, 11(2), 132.
doi.org/10.3390/insects11020132

Vaudo, A. D., Dyer, L. A., & Leonard, A. S. (2024). Pollen nutrition structures bee and plant community interactions. Proceedings of the National Academy of Sciences, 121(3).
doi.org/10.1073/pnas.2317228120