Values of the NIP descriptors (abridged). For each group comparison, the descriptors of the structure and complexity of NIPs reported are those shown to best discriminate the different groups of taxa considered. Bars represent the average value and standard deviation of a given descriptor for each group of taxa, based on metabolic networks extracted from KEGG. The hypothesis that the descriptor value is the same over all groups was evaluated for each metabolic dataset either by a Kruskal-Wallis test (comparisons of three groups) or Mann-Whitney U test (comparisons of two groups). Resulting p-values were corrected for multiple testing using Bonferroni correction. Values for all 52 descriptors are available in Additional file 1. A.I., N.I., T.I.: Average, Normalized and Total Information, respectively.