Authors

Discussion

Parasites are common participants in biological invasions. Nonetheless, a lack of studies concerned with parasite dynamics during the range expansion of their hosts hampers our understanding of host-parasite co-introductions. In the present study, the globally invasive amphibian Xenopus laevis (Anura: Pipidae) and its two most highly associated parasites across its range, namely the cestode Cephalochlamys namaquensis and the monogenean Protopolystoma xenopodis, were used to investigate the drivers of parasitism during range expansion in both the native and invasive range. The metazoan parasite infracommunities of 186 adult X. laevis from 31 water bodies in the native South Africa and 114 X. laevis from 11 water bodies in the invasive range of western France formed the basis of the generalised linear mixed models that explored the relationship between parasitism and individual host and environmental predictors. In the native range, host body size influenced the abundance of the cestode and overall parasite infracommunity crowding, but not the abundance of the monogenean. However, the predominant portion of the variance in the native metazoan parasite dynamics was related to spatial variation among the collection localities. More anthropogenically disturbed water bodies in the native range had more aggregated and variable parasite infection levels. Moreover, different parasites species exhibited opposing responses to habitat disturbance. In the invasive range, cestode abundance decreased towards the range edge. Overall infracommunity crowding and monogenean abundance did not vary with distance from the introduction point. Thus, anthropogenic disturbance and host translocation can have both positive and negative effects on parasitism. A well-described model host-parasite system, as is presented by X. laevis and its two most highly associated parasites, will enable us to explore the processes driving complex, multi-species invasion packages in an ever-changing world.