Social status shapes the bacterial and fungal gut communities of the honey bee

Abstract

Despite the fungal abundance in honey and bee bread, little is known about the fungal gut community of the honey bee and its effect on host fitness. Using pyrosequencing of the 16S rRNA gene and ITS2 region amplicons, we analysed the bacterial and fungal gut communities of the honey bee as affected by the host social status. Both communities were significantly affected by the host social status. The bacterial gut community was similar to those characterised in previous studies. The fungal gut communities of most worker bees were highly dominated by Saccharomyces but foraging bees and queens were colonised by diverse fungal species and Zygosaccharomyces, respectively. The high fungal density and positive correlation between Saccharomyces species and Lactobacillus species, known yeast antagonists, were only observed in the nurse bee; this suggested that the conflict between Saccharomyces and Lactobacillus was compromised by the metabolism of the host and/or other gut microbes. PICRUSt analysis revealed significant differences in enriched gene clusters of the bacterial gut communities of the nurse and foraging bees, suggesting that different host social status might induce changes in the gut microbiota, and, that consequently, gut microbial community shifts to adapt to the gut environment.

The honey bee gut microbiota: strategies for study and characterization

“…While the presence of the core species is quite consistent, the relative abundances vary slightly but significantly between gut segments, castes, hives, and from larvae to worker (Jeyaprakash et al ., ; Martinson et al ., ; ; Moran et al ., ; Corby‐Harris et al ., ; Powell et al ., ; Kapheim et al ., ; Ludvigsen et al ., ; Jones et al ., ; Yun et al ., ). Fig.…”

“…Crop bacteria are far more likely to be sourced from the honey bees’ surrounding environment than hindgut bacteria (Corby‐Harris et al ., ; Ludvigsen et al ., ), although a systematic exploration of the effects of environment on the hindgut microbiotic abundances is still necessary. Some differences in relative abundances of core species have been observed between the castes, with queens and drones as the predominant outliers (Kapheim et al ., ; Tarpy et al ., ; Yun et al ., ). Larvae and newly emerged bees exhibit barely any bacterial colonization (Martinson et al ., ; Powell et al ., ).…”

“…At the genus level, the newly emerged and nurse bees were dominated by Saccharomyces , accounting for 99 and 97% of the fungal community, respectively. Finally, the authors reported that ITS regions were sufficient for high‐resolution identification of eukaryotic components at the species level (Yun et al ., ). Owing to the limited information available and discrepancy between methods, comparisons of the information retrieved by ITS and 18S rRNA amplification should be performed to evaluate the robustness of available eukaryotic microbiome studies.…”

“…The UNITE (Kõljalg et al ., ) database has been used for the evaluation of ITS reads resulting from Ap. mellifera guts (Yun et al ., ). For 16S and 18S rRNA, SILVA offers datasets of aligned small and large subunit rRNA sequences (Quast et al ., ).…”

“…These ITS regions vary roughly between ~450–750 bp in length and consist of three subregions: the variable spacers ITS1 and ITS2 and the intercalary (between regions) 5.8S rRNA gene (Blaalid et al ., ). Yun et al () analysed fungal gut communities of honey bees of different social castes through an ITS approach, finding that queens have more diverse fungal species than nurse and foraging bees. A complete report of abundance per phylum was reported for worker bees, consisting of 93.28% Ascomycota , 5.89% Basidiomycota , 0.24% Glomeromycota , 0.20% Chytridiomycota and 0.05% Zygomycota .…”