Figure 3: 𝛼-diversity of the bumblebee gut microbiomes for the different
treatments. A) Observed ASVs, B) Pielou’s Evenness, C) Shannon
Diversity, D) Faith’s PD. Asterisks indicate significant differences
compared to the other treatments (P < 0.05). Boxplots show
median, first, and third quartile. Dots represent individual data
points.
𝛽-diversity of the gut microbiome
The community composition of the bumblebee gut microbiome differed
between treatments indicated by significant differences between the
robust Aitchison distances (Overall PERMANOVA pseudo-F4,
73 = 16.844, P = 0.001). Microbial community composition of the
DEP treatment differed from all other treatments (Pairwise-PERMANOVA
with BH adjusted p-values; DEP vs. control: pseudo-F = 32.247, P= 0.002; DEP vs. solvent control: pseudo-F = 30.651, P = 0.002;
DEP vs. brake dust: pseudo-F = 25.699, P = 0.002). We found no
differences between the other treatments (Pairwise-PERMANOVA with BH
adjusted p-values: P > 0.05) (Figure 4 ).