Diversity of host-parasite meta-communities
We investigated the patterns of host-parasite interaction of African cichlid fishes and their gill parasites belonging toCichlidogyrus , a proposed model system for macroevolutionary research (Pariselle et al. 2003; Vanhove et al. 2016). The size of this species network (9901 infections, 473 interactions) is comparable to widely used host-parasite datasets in terms of species richness, e.g. the Global Mammal Parasite Database (GMPD) (Nunn & Altizer 2005), the Sevillata interaction network (Dallas & Presley 2014), and other fish-parasite (Lima Jr et al. 2012; Bellayet al. 2015) and plant-arthropod systems (López-Carreteroet al. 2014; de Araújo et al. 2020; Oliveira et al.2020; de Araújo & Maia 2021). Additionally, the dataset here offers the opportunity to investigate the effects of evolutionary mechanisms, especially adaptive radiation events, on species interactions. This system is also the first to encompass closely related parasite species infecting hosts that are a model system for speciation research (Seehausen 2006). Therefore, the cichlid-Cichlidogyrus dataset could be a valuable asset for studies on network ecology and ecological parasitology.
Some of the host-parasite meta-communities inferred from this network (Fig. 2b, c) could be of particular interest for future studies due to their sample size and species richness. Cichlid-Cichlidogyrusinteractions are diverse regarding their meta-community structures (Appendix S1.2). For instance, only one recorded monogenean species infects deepwater cichlids from the tribe Bathybatini (Kmentová et al. 2016) (not in Fig. 2c as less than 10 species) whereas 27 host species in the LV community share multiple parasite species (Fig. 2b, Appendix S1.2). Some communities show a reversed specialisation asymmetry (Appendix S1.2) with the host communities being more diverse than their parasites unlike most host-parasite (Vázquez et al.2005) or mutualistic (Thébault & Fontaine 2008) networks possibly due to the young age of the host radiation (see Appendix S1.2). Furthermore, anthropogenic introductions have expanded the realised host repertoire of some meta-communities (Appendix S1.2) albeit with little changes to their network structure (Fig. 3). The diversity of meta-communities could lay the ground for future comparative studies, e.g. on the communities from the East African lakes mirroring the research conducted on cichlids from the same region (e.g. Duponchelle et al. 2008).