A community of biological invaders facilitates the emergence of a melting-pot of exotic parasites in the Panama Canal

Background/Question/Methods

The spread of non-native exotic species can have important impacts on the composition, diversity and structure of native ecological communities but can also affect the ecology and evolution of native and introduced species across functional and taxonomic groups. Of particular concern to public health, biodiversity conservation and economic intests is the role of biological invaions in driving the ecolgoy and evolution of infectious processes. While introduced species generally escape natural enemies from their native range, the demographic expansion of biological invaders can also facilitate the transmission dynamics of infectious agents and provide the pathway for the spread of parasites and pathogens. It is therefore critical to understand how biological invasions will affect the ecology and evolution of host-parasite interactions in novel ranges. We evaluate the extent to which exotic parasites interact with a community of invasive species in the watershed of the Panama Canal and how these host-parasite interactions with biological invaders affect the distribution and transmission dynamics of emerging parasites. Conducting field surveys, laboratory infection experiments and molecular phylogenetics, we evaluate 1) what is the diversity and distribution of exotic parasites that infect an invasive snail, Melanoides tuberculata, in Panama in the last five years 2) how parasites interact with a heterogeneous assemblage of introduced snail hosts 3) the extent to which interactions with invasive snail and fish hosts affect the transmission of exotic parasites.

Results/Conclusions

A unique and highly diverse assemblage of helminth parasites (cl: trematoda) has established in Panama due to multiple introductions of their vector snail hosts (M. tuberculata) from different parts of their native range. We found evidence of host specificity of these parasites to particular varieties of M. tuberculata with which they share a common evolutionary history. We also found that Centrocestus formosanus, the most prevalent of these introduced flukes infecting M. tuberculata, naturally and experimentally prefers the dominant invasive cichlid, Cichla ocellaris, in the Panama Canal, over other native and introduced cichlids. Our results suggest that the spread of exotic parasites is facilitated by multiple interactions with invasive species with which they may or may not share a common evolutionary history. This study underscores the need to understand the increasing complex role of biological invasions in driving infectious processes and the ways in which invasive species will influence the ecology and evolution of host-parasite interactions in a rapidly changing world.