Statistical analysis
We used the Kruskal–Wallis test to see (1) if there were differences in host breadth, cross-species transmission connections, and graph density across parasite species; (2) if there were differences in eigenvector centrality across host species; and (3) if there were differences in epidemic size of different parasites across host species. For the centrality and epidemic size data, we looked at each parasite species separately. For all comparisons, if the Kruskal–Wallis test suggested a significant main effect, we then used the Conover–Iman test with Bonferroni corrections for pairwise comparisons across parasite or host species.
We used R version 4.2.3 for all of the data processing and statistical analyses. We used the “frame2webs” function in the bipartite package (Dormann et al. 2008) to construct host adjacency matrices and the igraph package (Csardi and Nepusz 2006) to calculate network metrics such as graph density and centrality.