Changes in native and introduced host–parasite networks

Abstract

Introduced species can alter the dynamics and structure of a native community. Network analysis provides a tool to study host–parasite interactions that can help to predict the possible impact of biological invasions or other disturbances. In this study, we used weighted bipartite networks to assess differences in the interaction patterns between hosts and helminth parasites of native (Sea of Japan) and invasive (Black Sea and Sea of Azov) populations of Planiliza haematocheilus (Teleostei: Mugilidae). We employed three quantitative network descriptors, connectance, weighted nestedness and modularity, to gain insight into the structure of the host–parasite networks in the native and invaded areas. The role of parasite species in the networks was assessed using the betweenness centrality index. We analyzed networks encompassing the whole helminth community and subsets of species classified by their transmission strategy. The analyses were downscaled to host individual-level to consider intraspecific variation in parasite communities. We found significant differences between networks in the native and invaded areas. The latter presented a higher value of nestedness, which may indicate a co-occurrence between parasite species with many connections in the network and species with fewer interactions within the same individual-host. In addition, modularity was higher in the native area’s networks than those of the invaded area, with subgroups of host individuals that interact more frequently with certain parasite species than with others. Only the networks composed of actively transmitted parasites and ectoparasites did not show significant differences in modularity between the Sea of Azov and the Sea of Japan, which could be due to the introduction of a part of the native community into the invaded environment, with a lower diversity and abundance of species. We show that network analysis provides a valuable tool to illuminate the changes that occur in host–parasite interactions when an invasive species and its parasite community are introduced into a new area.

Major drivers of biodiversity loss and their impacts on helminth parasite populations and communities

“…A network analysis showed that the invasive mullet played a peripheral role in host–parasite networks in the invaded range, compared to its native range as well as compared to another native mullet that inhabited both the invaded and native areas (Llopis-Belenguer et al , 2020). Taking these data a step further, significant differences occurred between parasite networks of the so-iuy mullet in connectedness, nestedness and modularity in the invaded and native areas (Llaberia-Robledillo et al , 2022). These network properties differed between actively-transmitted and trophically-transmitted parasites, varying not only between the parasites themselves but between invaded and native ranges (Llaberia-Robledillo et al , 2022).…”

“…Taking these data a step further, significant differences occurred between parasite networks of the so-iuy mullet in connectedness, nestedness and modularity in the invaded and native areas (Llaberia-Robledillo et al , 2022). These network properties differed between actively-transmitted and trophically-transmitted parasites, varying not only between the parasites themselves but between invaded and native ranges (Llaberia-Robledillo et al , 2022). Integrating data together at different organizational and hierarchical scales and comparing ectoparasite and endoparasite subsets between the regions in a macroecological approach, Sarabeev et al (2022) proposed fundamental differences in parasites between those co-introduced and those acquired in an invaded range that include abundance–variance and abundance–occupancy relationships, core-satellite species, patterns of aggregation and prevalence frequency distributions, infrapopulation size, and infracommunity species richness.…”

Host-parasite relationships in invasive species: macroecological framework

“…The proposed framework can be used to assess how invasive hosts integrate new ecosystems. In this regard, we think that network analysis of the host-parasite system opens an avenue of further research, providing a tool to study host-parasite interactions and to predict the possible impact of biological invasions on ecosystems (Llopis-Belenguer, Blasco-Costa, et al, 2020;Llaberia-Robledillo et al, 2021). Despite these encouraging findings, the current study is limited to a single invasive host and encompassing ectoparasitic and endoparasitic subsets of species.…”

“…Moreover, by considering parasite subsets according to transmission mode, we can obtain additional insights into understanding host-parasite relationships of invasive hosts (e.g. Llopis-Belenguer et al 2020a;Llaberia-Robledillo et al 2021). The key objective of both the researchers and stakeholders is a search for effective and safe methods to control invasive species in an ecosystem, while the framework described here can be used as a tool to assess the suppressive effect of parasites on host populations.…”

Helminth Communities of Common Fish Species in the Coastal Zone off Crimea: Species Composition, Diversity, and Structure

“…Pankov [ 69 ] assessed diversity indices of helminths in four species of the family Mugilidae from Bulgarian waters of the Black Sea. A number of papers analyzed parasite communities in the grey mullet Mugil cephalus and the invasive redlip mullet Planiliza haematocheilus [ 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 ].…”