The gut bacterial microbiome of adult Apis mellifera has extensively been investigated, with a particular emphasis on the taxonomy 3, 5, 6, evolution 2, genomics, and physiology of its bacterial members 1, 4, 7, 8, 9, as well as on its modification under different environmental conditions, diet, and abiotic and biotic stressors 10, 11, 12, 13, 14, 15. Recent studies on the role of bacterial symbionts of the honeybee gut have shed light on their importance for host metabolism, biomass gain, pathogen resistance, and behavioral health 1, 2, 3, 4. We observed that changes in the distribution and abundance of microbial components in the gut are consistently compartment-specific for all the three microbial components, indicating that the ecological and physiological interactions among the host and microbiome vary with changing physico-chemical and metabolic conditions of the gut. The diversity and distribution of such three microbial components were investigated in the context of the physico-chemical conditions of different gut compartments. In the present study, we hypothesized that the microbial components of forager honeybees (i.e., core bacteria, minor environmental phylotypes, and fungal members) are compartmentalized along the gut portions. By contrast, the diversity and distribution of the minor environmental phylotypes and fungal members in the gut remain overlooked.
Several mutual interactions and functional services to the host, including the support provided for growth, hormonal signaling, and behavior, are attributed to the core and lineage-specific taxa. The core gut microbiome of adult honeybee comprises a set of recurring bacterial phylotypes, accompanied by lineage-specific, variable, and less abundant environmental bacterial phylotypes.