Bacterial community structure from 16S rRNA analysis, and functional predictions using PICRUST. (a) PCoA plots based on weighted UniFrac distances of samples. Red triangle=manure samples under vermicomposting (red triangle); green circle=manure samples under traditional composting without larvae input; blue square=larvae gut samples. The average distances for each category by connecting all points with minimal total length divided by the total numbers of these involved samples are further shown. (b) Relative abundance (%) of taxa at the genus level, clustered using UPGMA on the weighted UniFrac distances. Taxa with <1% of reads were merged together as ‘others’; while ‘unknown’ represents unclassified taxa at the genus level (see Supplementary Table S6). (c) PICRUST predictions using KEGG subsystem level II. Raw manure (C0d+S0d), larvae gut (L1d to L6d) and vermicompost (S6d) are compared using non-parametric Kruskal–Wallis test with Dunn’s multiple comparison. Only functions with >1% abundance are shown. Red on y axis indicates increased (P<0.05) functional abundance in vermicompost compared with raw manure (see Supplementary Table S13).