Pollen nutrition in honey bees (Apis mellifera): impact on adult health

Pollen is the main protein source for honey bees, and its quality and digestibility are important factors for bee health. We compared the effects of eight different mixed-pollen diets on queenless adult survival and physiology. The mixtures represented the pollen source for bees in a natural environment. They consisted of three to five familial pollen types, and the protein percentage varied from 8.4 to 18.1 %. The mixtures that contained mainly Asteraceae pollen were less consumed and enhanced bee mortality, suggesting that this pollen type offers poor nutritional quality and assimilation for the bees. All pollen diets promoted ovarian activation, but among the pollen-treated groups, the percentage of bees with activated ovaries was not related to the protein content of the diet, which suggests that ovarian activation may also depend on other nutrients. Survival was also positively correlated to the vitellogenin levels in the hemolymph. Our results showed that the amount of protein consumption and the pollen type influenced bee survival and physiology.