Parasite Ecology of Invasive Species: Conceptual Framework and New Hypotheses

Biological invasions have the potential to influence parasite dynamics by altering ecological interactions. Similarly, parasitism can influence invasion by aiding or limiting expansion. While many parasite-invasion relationships have been evaluated, many have not been described. Here, we present a conceptual framework of potential interactions, and introduce two new concepts. The first, disease facilitation, nested within the parasite spillback hypothesis, is when invasive species facilitate parasite transmission through habitat alteration or physical transfer. The second, suppressive spillover, is when the deleterious effects of parasitic infection limit the expansion of an introduced species (and hence invasion success). Taken together, the proposed framework may aide in our understanding of ecological drivers of invasion and parasite ecology and can be used to improve mitigation strategies.