Nutrients for Honey Bees, distinct from that of other animals, is intricate and not as well-understood. Operating within a superorganism, honey bee colonies exhibit a structured caste system and reproductive division of labor. Nutrition in honey bees is multifaceted, involving colony, adult, and larval levels. As honey bee workers age, they shift from high-essential-amino-acid diets to mainly carbohydrates.
The nutritional well-being of honey bees is closely tied to the environment, particularly the floral composition of the landscape. Dynamic changes in floral resources pose challenges in terms of pollen diversity, quantity, and quality based on geographic location. Nationwide efforts aim to enhance nutrition for various bees by planting forage, but this approach often prioritizes visually attractive species rather than considering nutritional composition or specific bee needs.
Despite protein supplements available to beekeepers, essential nutrient gaps persist. Substantial knowledge gaps in honey bee nutrition hinder the development of an optimal and balanced diet for these crucial pollinators.
Macronutrients:
Carbohydrates: Nectar and honeydew, rich in sugars, serve as the primary carbohydrate sources for honey bees. Foragers collect and store these liquids in their honey stomachs, converting them into honey within the colony. This honey, stored in cells, plays a crucial role in sustaining the colony, especially during brood rearing and overwintering. Adult bees have lower glycogen stores compared to larvae, emphasizing the importance of carbohydrate-rich diets. A worker bee requires approximately 11 mg of dry sugar per day, and a colony with 50,000 bees needs about 700 lb (318 kg) of sugar per year.
Proteins: Pollen stands as the primary protein source for honey bee colonies, with a content ranging from 2.5% to 61%. Ten essential amino acids are critical for reproduction, growth, and development, necessitating their acquisition through diets. Good pollen sources, such as sweet clovers, mustards, and rapeseed, contribute to the colony’s protein intake. Worker bees process collected pollen into “bee bread,” crucial for the nutrition of developing larvae. Protein shortages may lead to decreased colony size and increased vulnerability to stressors.
Lipids: Pollen lipids, comprising 1% to 20% by weight, include essential fatty acids crucial for physiologic functions. Fatty acids like linoleic and g-linoleic acids, along with phospholipids, play vital roles in honey bee health. Specific lipid preferences influence foraging choices, highlighting the importance of lipid-rich host plants. Sterols, a vital micronutrient in pollen, contribute to overall honey bee well-being.
Micronutrients:
Phytosterols: Sterols, a lipid form, play vital physiologic roles in honey bees, serving as precursors for molting hormones and cellular membranes. The most crucial phytosterol for honey bees is 24-methylenecholesterol. Studies demonstrate its positive impacts on bee survival and brood production. Nurse bees assimilate this sterol progressively, transferring it through brood food to growing larvae. Access to diverse floral sources is essential for obtaining required phytosterols.
Phytochemicals: Nectar’s phytochemical composition, including phenolic acids and flavonols, varies across floral taxa. Notable compounds like p-coumaric acid and quercetin provide significant health benefits, enhancing longevity, reducing Nosema infection, and countering pesticide stress. Phytochemical consumption by honey bees activates genes with antimicrobial properties, contributing to overall colony well-being. Diverse floral resources ensure access to varied phytochemical compositions essential for honey bee health.
