Gut microbiota structure differs between honey bees in winter and summer

Lucie Kešnerová; Olivier Emery; Michaël Troilo; Joanito Liberti; Berra Erkosar; Philipp Engel

The core members Gilliamella, Snodgrassella, Lactobacillus Firm-5 and Bifidobacterium 294 were present in all analyzed bees, and the core member Lactobacillus Firm-4 was 295 detectable in 98.4% of all bees (Supplementary Fig. S1A) . Notably, the two designated non-296 core members Bartonella and Frischella were also present at relatively high prevalence 297 with only 5.3% and 26.9% of the samples giving signals below the detection limit, The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/703512 doi: bioRxiv preprint from the summed abundances of all seven phylotypes (Supplementary Fig. S3, Fig. 1A) . 309 Specifically, we found a 10-to 100-fold increase in the levels of the core members 310 Lactobacillus Firm-4, Lactobacillus Firm-5, and Bifidobacterium, as well as the non-core 311 member Bartonella when comparing across all winter bees relative to foragers (Fig. 1C , 312 Permutation T-Test P=1e-4). We also observed a small increase of Snodgrassella levels in 313 winter bees (Fig. 1C , Permutation T-Test P=6e-4), but no difference in the levels of 314 Gilliamella (Fig. 1C , Permutation T-Test P=0.7). Frischella was the only member of the 315 community that displayed the opposite trend, i.e. lower abundance in winter bees (Fig. 1C , 316 Permutation T-Test P=1e-4). The overall bacterial load was about 10x larger in winter bees 317 than in foragers based on both the summed abundances of all seven phylotypes (Fig. 1C , 318 Permutation T-Test P=1e-4) as well as the number of total 16S rRNA gene copies, which 319 was determined with universal 16S rRNA gene qPCR primers for a subset of the samples 320 (Fig. 1D , Permutation T-Test, P=1e-4).