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 ).