Fig. 1: Gut bacterial communities differ between foraging and winter season in a single colony monitored over 2 years.

a Monthly changes in the absolute abundance assessed by qPCR, as determined by the number of genome equivalents per sample, of seven phylotypes monitored monthly, depicted as mean values (±SE) of the analyzed bees. The number of bees per month is indicated at the bottom of the plot. Asterisk indicates missing data for July 2015 due to DNA extraction failure. Double asterisk indicates that the queen of the colony was replaced in the corresponding month. b Relative community composition of the gut microbiota of bees sampled in each month as based on the seven monitored phylotypes. c Absolute bacterial abundance of each phylotype per gut in foragers (F) and winter bees (W), as determined by the number of genome equivalents. The sum of the abundances of the seven monitored phylotypes is also plotted. Mean values are shown as black horizontal lines. Only bees with detectable levels were plotted (the number of bees is given at the bottom of the plot; for prevalence see Supplementary Fig. S1). d Copy number of the 16S rRNA gene in gut samples of a subset of the analyzed months (Apr 2015, Aug 2015, Oct 2015, Jan 2016, Apr 2016, Jul 2016, Oct 2016, Jan 2017, and Apr 2017). e Effective number of species calculated from cell numbers of different bacterial phylotypes in foragers (F) and winter bees (W). f Projection of the abundances of monitored phylotypes into the first and second principal components in all analyzed bees, together with correlation vectors representing variables driving the separation on both axes. Permutation T-Test was used for pairwise comparisons. ns, nonsignificant; ***P < 0.001.