HONEY BEE NUTRITION ACROSS LANDSCAPES - A MULTIDIMENSIONAL ANALYSIS OF POLLEN, BEE BREAD AND FATTY ACIDS REGULATION

Our overarching hypothesis states that honey bees can simultaneously regulate an intake of multiple nutrients through a two-tiered process. First, foragers show preferences for pollen based on its availability and nutritional content, and store it for fermentation into bee bread. Second, nurses regulate their nutrient intake by selectively feeding on bee breads of different nutritional compositions. We predict that the nutritional content of pollen changes seasonally, but that both foragers and nurse bees can assess these changes and respond appropriately (Figure 1). However, we also predict that a decrease in pollen diversity in agricultural and urban settings limits honey bees' nutritional regulation process and negatively impacts colony health.Our long-term goalis to develop a standardized and multidimensional nutritional approach for characterizing and quantifying the key suite of nutrients that influence honey bee foraging behavior and colony-level performance. Our results will enable us to develop solutions tailored to agricultural, rural, and urban settings that mitigate the serious economic and agricultural problems associated with poor honey bee health.Objective 1.Perform a multidimensional nutrient analysis of pollen to characterize the nutritional space for honey bees in selected agricultural, urban, and rural settings at different times of the year, and determine how the consumption of different pollen types affects colony health.Hypothesis 1:Pollen diversity is lowest in agricultural sites, intermediate in urban sites, and highest in rural sites. Given this trend, the nutritional space available for honey bee foragers will be narrow in agricultural sites, intermediate in urban sites, and broad in rural sites. Also, colony health will be highest in rural settings and lowest in agricultural settings.Objective 2.Perform a multidimensional nutrient analysis of bee bread to understand the role of pre-digestive pollen processing in the hive. This will bridge the gap between nutritional inputs (i.e.,bee-collected pollen) and the diet available to the nurses (i.e.,bee bread).Hypothesis 2:The nutritional content of bee bread differs from pollen in a predictable fashion, contributing to its easier digestibility and longer preservation, but reducing its content in essential fatty acids.Objective 3.Determine the extent to which nurse bee feeding behavior and metabolism is influenced by diet fatty acid composition and measure its impact on colony-level performance, particularly to understand how fatty acids are metabolized by nurse bees to produce brood food.Hypothesis 3:Essential fatty acids (i.e.,fatty acids that cannot be synthesizedde novoand must be acquired from the diet) such as linoleic acid (omega-6) and alpha-linolenic acid (omega-3) are critical for developing honey bees. Thus, their intake should be tightly regulated, especially in nurse bees that require these lipids for their own development and for the production of brood food. We predict that the amounts and ratios of omega-6 and omega-3, and their metabolites, will be under strict regulation in the brood food, and that departures from functionally optimal quantities will have significant repercussions on colony health and development.