Do parasite communities differ between invasive and native fish hosts? A case of monogeneans infecting the gills of Nile tilapia

Abstract

A release from parasites is assumed to be a major factor to the success of invasive species. However, strong evidence for a lower parasite load in invasive species is sparse on a larger geographical scale. To test this hypothesis, we analysed the monogenean gill parasite communities of invasive and native Nile tilapia across the African continent. We find significantly lower parasite loads in invasive populations, but no difference in parasite richness between invasive and native populations. Additionally, significant differences in parasite load and richness within the native range were found. We analysed the parasite community composition with a permanova and found strong variation in parasite communities both among native and invasive Nile tilapia. About 16% of this variation could be explained by two significant explanatory variables: introduction status of the host (4%) and ichthyofaunal province (12%), meaning both introduction status and geographical location influence parasite community composition. Furthermore, significant indicator parasite species were found for introduction status, river basin and ichthyofaunal province. Overall, we illustrate the potential value of ectoparasites to inform about the native environment and introduction history of fish. Possibly, this type of forensic parasitology, easily performed on museum specimens, could be useful to help resolve enigmatic invasions.