Network metrics and community structure
We identified 41 meta-communities in the cichlid-Cichlidogyrusnetwork through the Louvain algorithm. A majority of these meta-communities included only a few species and were completely unconnected to the other communities (Fig. 2a). Six of these meta-communities included 10 or more species (Fig. 2b, c; Appendix S4): the ‘Coptodon zillii ’ (CZ ), ‘Oreochromis niloticus ’ (ON ), ‘Hemichromis ’ (He ), ‘Ophthalmotilapia ’ (Op ), and ‘Tilapia sparrmanii ’ (TS ), and Lake Victoria (LV ) clusters. These names were chosen to reflect the host taxa accounting for a majority of reported infections except for the LV community (Appendix S1.2). The network structure differed between the meta-communities but anthropogenic introductions had only a limited effect (Fig. 3; Appendix S1.2). Parasite community memberships showed no significant phylogenetic signal (ΔAICc = -0.28, p > 0.05). However, some parasites infecting coptodonine and oreochromine cichlids are closely related as previously indicated by Cruz-Laufer et al. (2021b).