Host-Driven Functional Divergence in Gut Microbiota of Honeybees Apis cerana and Apis mellifera: Implications for Pollination, Nutrition, and Sustainable Apiculture.

Abstract

Honeybees are indispensable in sustaining natural ecosystems and global crop production by pollinating key food crops. Understanding their gut microbiota is crucial for insights into their health, nutrition, and behavior, with broader ecological and agricultural relevance. This study compares the gut microbiota of Apis cerana and Apis mellifera, focusing on bacterial composition, diversity, and functional roles. Using culture-dependent and metagenomic methods, core bacteria such as Lactobacillus, Fructobacillus, Gilliamella apicola, Bartonella apis, and Snodgrassella alvi were identified, linked to carbohydrate and nitrogen metabolism, immune modulation, and polysaccharide degradation. A. mellifera exhibited greater microbial and functional diversity, reflected in higher Shannon (1.22 vs. 1.08) and Simpson (0.675 vs. 0.655) indices. Strong intraspecies correlations and weaker interspecies correlations (Pearson's r = 0.6486) indicated distinct microbial profiles, supported by PCA (75.3% variation) and Adonis test (P = 0.04, R² = 0.723). Functional analysis via MG-RAST and UniFrac-based PCoA showed species-specific differences in key metabolic pathways. Enzymatic profiling revealed Fructobacillus fructosus with high invertase activity (7.31 ± 0.30) and Apilactobacillus apinorum with strong pectinolytic activity (4.707 ± 0.36), enhancing honeybee nutrition. These findings have significant implications for pollination efficiency, probiotic development, and sustainable apiculture, ultimately supporting conservation strategies and the resilience of honeybee populations.