Journal Article

Parasite spillback: A neglected concept in invasion ecology?

Poulin, R., Paterson, R. A., Tompkins, D. M., Kelly, D. W., Townsend, C. R.

2009

Overview

While there is good evidence linking animal introductions to impacts on native communities via disease emergence, our understanding of how such impacts occur is incomplete. Invasion ecologists have focused on the disease risks to native communities through \"spillover\" of infectious agents introduced with nonindigenous hosts, while overlooking a potentially more common mechanism of impact, that of \"parasite spillback.\" We hypothesize that parasite spillback could occur when a nonindigenous species is a competent host for a native parasite, with the presence of the additional host increasing disease impacts in native species. Despite its lack of formalization in all recent reviews of the role of parasites in species introductions, aspects of the invasion process actually favor parasite spillback over spillover. We specifically review the animal-parasite literature and show that native species (arthropods, parasitoids, protozoa, and helminths) account for 67% of the parasite fauna of nonindigenous animals from a range of taxonomic groups. We show that nonindigenous species can be highly competent hosts for such parasites and provide evidence that infection by native parasites does spillback from nonindigenous species to native host species, with effects at both the host individual and population scale. We conclude by calling for greater recognition of parasite spillback as a potential threat to native species, discuss possible reasons for its neglect by invasion ecologists, and identify future research directions.

• Publisher: Ecological Society of America
• Subject: Adaptation, Physiological / Animal and plant ecology / Animal, plant and microbial ecology / Animals / Arthropoda / Biological and medical sciences / Concepts & Synthesis: Emphasizing New Ideas to Stimulate Research in Ecology / Conservation biology / Ecological competition / Ecological invasion / Ecologists / Ecology / Ecosystem / enemy release / Fundamental and applied biological sciences. Psychology / General aspects / Health risks / Host-Parasite Interactions / Host-Parasite Interactions - physiology / host-parasite relationships / Impact analysis / Indigenous species / Infections / infectious disease / Introduced species / invasion ecology / Invasive species / literature reviews / Marine ecology / nonindigenous species / Nonnative species / parasite / Parasite hosts / parasite-spillback hypothesis / Parasites / Parasitism / physiology / Population Dynamics / Species Specificity / spillover of infectious agents / Taxonomy / Viruses / Wildlife ecology