Food Web Assembly Rules for Generalized Lotka-Volterra Equations
a, Barplots indicate distributions of node richness for each approximate trophic level in the seven empirical foodwebs and a generic foodweb derived by averaging the empirical node richnesses in each trophic level. b, Interaction matrix corresponding to the generic food web, containing 110 free-living and 47 parasite species (Details: Methods and Sec. S10 in S1 Text). c, Addition of parasites that form random links to any existing free-living species. d, Addition of parasites that are confined to consumer at a specific trophic level. e, Similar to (c) but with the restriction of parasites consuming only free-living species at levels 3 and 4. f, Similar to (e) but with additional parasite-parasite interactions (hyperparasitism), approximately 5 percent of parasite links are from parasite to parasite. Note the color coding along the edges of the matrices in (c)—(f), chosen as in Fig 5a, 5d and 5e. g, The lack of niches, i.e. rank deficiency, as a function of the number of links per parasite for each of the four cases described in (c)—(f).