Gut microbiota structure differs between honeybees in winter and summer

Abstract

Adult honeybees harbor a specialized gut microbiota of relatively low complexity. While seasonal differences in community composition have been reported, previous studies have focused on compositional changes rather than differences in absolute bacterial loads. Moreover, little is known about the gut microbiota of winter bees, which live much longer than bees during the foraging season, and which are critical for colony survival. We quantified seven core members of the bee gut microbiota in a single colony over 2 years and characterized the community composition in 14 colonies during summer and winter. Our data show that total bacterial loads substantially differ between foragers, nurses, and winter bees. Long-lived winter bees had the highest bacterial loads and the lowest community α-diversity, with a characteristic shift toward high levels of Bartonella and Commensalibacter, and a reduction of opportunistic colonizers. Using gnotobiotic bee experiments, we show that diet is a major contributor to the observed differences in bacterial loads. Overall, our study reveals that the gut microbiota of winter bees is remarkably different from foragers and nurses. Considering the importance of winter bees for colony survival, future work should focus on the role of the gut microbiota in winter bee health and disease.

Applying the core microbiome to understand host–microbe systems

“…and Lactobacillus and Bartonella predictably increase over winter in the gut microbiomes of Honey bees (Kešnerová et al, 2020). The extent to which such dynamics are externally and internally driven are unclear, although laboratory studies show that seasonal shifts in at least some taxa are host controlled in response to changes in temperature/light stimuli (Carey, Walters, & Knight, 2013;Ferguson et al, 2018;Segers, Kaltenpoth, & Foitzik, 2019).…”

The direct and indirect effects of environmental toxicants on the health of bumble bees and their microbiomes

“…The distinct gut microbiomes present in social bees are largely consistent worldwide (24–28) and positively affect bee health via toxicant metabolism (29), immune system stimulation (30) and protection against pathogens (25,31,32). While the bacterial members of the microbiome remain generally consistent, stressors have been found to alter the microbial community, as found during times of inconsistent forage availability (33,34), antibiotic exposure (35), infection (36), and pesticide exposure (37). During times of host stress, the symbiotic community of bacteria within the gut can collapse, removing its positive effect on bee health and effectively causing dysbiosis of the gut microbiome.…”

Hymenoptera associated eukaryotic virome lacks host specificity

“…These pressures encompass ecological factors such as habitat loss (7), pollution (8), pesticide use (9,10) and adverse agricultural practices (11), but biological factors including bacterial, parasitic, and viral infections (12)(13)(14)(15), also play a pivotal role. Recently, more attention is being given to the microbiota and their influence on bee health, development and homeostasis (16)(17)(18), and it has been shown that the microbiota can be exploited to protect bees from other pathogens (19). The influence these factors have can be cumulative or even synergistic.…”