Nutrient composition and microbial interaction for honey bee health

Nutritional stress is one of the major factors playing critical roles in the deterioration of bee health and the decline of the population. We carried out a series of investigations to figure out the nutritional quality of the honey bee feed. The study on the foraging behaviour of honey bees demonstrated that the floral preference depended on the nutritional reward, as exhibited by the protein content of pollen in our study. However, honey bees do not often consume the pollen fresh; they collect and bring pollen into the hive. Bee pollen stored in the hive is mixed with glandular secretions, and nectar, provisioned by microbes and becomes bee bread. To investigate the compositional changes during the processing, we supplied the pollen patty, prepared from bee pollen, to the experimental honey bee colonies and examined the nutrient content of bee pollen, pollen patty, and bee bread. Briefly, the reduction of protein, fat, and increment of the carbohydrate content in the pollen patty was found, presumably because of the addition of sugar in the making of patty. On the other hand, bee bread was found to have increased amino acids, including some essential amino acids and proline content with storage period, in contrast to fatty acids, than that of pollen patty. Provisioning by the gut symbionts like Proteobacteria and Firmicutes presumably have roles in the process. This paper presents a detailed account of the compositional changes of nutritional components and provisioning prospection by pollen-borne as well as bee bread bacteria.