Widespread anthropogenic translocation of the African Clawed Frog across its native range is revealed by its co-introduced monogenean parasite in a co-phylogeographic approach

Abstract

bioRxiv preprint 1. The management of biological invasions relies upon the development of methods to trace their origin and expansion. Co-introduced parasites, especially monogenean flatworms, are ideal tags for the movement of their invasive hosts due to their short generations, direct life cycles and host specificity. However, they are yet to be applied to trace the intraspecific movement of species in their native ranges. 2. As proof of this concept, we conducted a co-phylogeographic analysis based upon two mitochondrial markers of a globally distributed frog Xenopus laevis and its monogenean flatworm parasite Protopolystoma xenopodis in both its native range in southern Africa and its invasive range in Europe. 3. Translocation of lineages was largely masked in the frog's phylogeography. However, incongruent links between host and parasite phylogeography indicated host switches from one host lineage to the other after these were brought into contact due to human-mediated translocation in the native range. Thus, past translocation of host lineages is revealed by the invasion success of its co-introduced parasite lineage. 4. This study demonstrates the concept that parasite data can serve as an independent line of evidence in invasion biology, also on the intraspecific level, shedding light on previously undetected invasion dynamics. Based upon the distribution of these invasive parasite lineages, we infer that the widespread translocation of hosts is mainly facilitated by the frog's use as live bait by the local angling communities and not via official export routes. 5. Synthesis and applications. Data from co-introduced, host-specific parasites can add value to investigations in invasion biology and conservation. A better understanding of the translocation history and resulting genetic mixing of animals in their native ranges prior to introduction into new environments can inform management strategies in the invasive range. Knowledge of the intraspecific movement of different lineages of animals in their native ranges also has conservation implications, since contact between divergent lineages of hosts and parasites can facilitate host switches and altered parasite dynamics in both native and invasive populations. Therefore, we recommend the inclusion of parasite data as a more holistic approach to the invasion ecology of animals on the intraspecific level.