Seasonal patterns of beneficial phytochemical availability in honey and stored pollen from honey bee colonies in large apiaries

Authors: BERNKLAU, ELISA - Colorado State University; Seshadri, Arathi

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/10/2023
Publication Date: 5/29/2023
Citation: Bernklau, E., Seshadri, A.H. 2023. Seasonal patterns of beneficial phytochemical availability in honey and stored pollen from honey bee colonies in large apiaries. Journal of Economic Entomology. 116(4):1069-1077. https://doi.org/10.1093/jee/toad096.
DOI: https://doi.org/10.1093/jee/toad096

Interpretive Summary: Honey bees face challenges relating to imbalanced nutrition resulting from habitat loss. Bees depend on plants for their nutritional needs. The pollen and nectar in flowers, in addition to protein, lipids and carbohydrates, provide bees with beneficial phytochemicals such as flavanols,sterols and alkaloids. This study analyzed the amounts of caffeine, gallic acid, kaempferol and p-coumaric acid, four beneficial phytochemicals, in pollen and honey collected from colonies in commercial apiaries. Being the first of its kind, this study provides important baseline information for future efforts in developing appropriate doses of phytochemicals as nutritional supplements. The study also demonstrates the low amounts of the above listed beneficial phytochemicals in almond flowers, reiterating the importance of access to diverse forage habitats when bees are providing pollination services in monocrop orchards.

Technical Abstract: Honey bees are the most efficient pollinators in agroecosystems, responsible for the successful production of fruits, nuts, and vegetable crops but they continue to face debilitating challenges. The foundational factor leading to these challenges lies in the imbalanced and poor nutrition that result in weakening the colony, increasing susceptibility to pests and pathogens and reducing the ability of bees to adapt to other abiotic stresses. Extensively used for commercial pollination, honey bee colonies regularly face exposure to limited diversity pollen diet as they are placed in flowering monocrops. Lack of access to diverse plant species compromises the availability of plant secondary compounds (phytochemicals) which in small amounts provide significant benefits to honey bee health. Here, we determine the beneficial phytochemical content of honey and pollen in colonies at commercial apiaries through the active bee season. We collected pollen and honey from beekeeper colonies in commercial apiaries and evaluated the amounts of four beneficial phytochemicals (caffeine, kaempferol, gallic acid and p-coumaric acid) that are known to improve honey bee health. Our analyses indicated that other than p-coumaric acid, beneficial phytochemicals are not uniformly available through the season. Caffeine is completely absent, and gallic acid and kaempferol are not regularly available. Our results suggest the need to explore the potential to deliver phytochemicals as nutritional supplements to ensure bees remain healthy and productive. It is vital for the pollination industry to consider supplemental diet as commercial apiaries strive to meet the increasing demand for crop pollination services.