Parasite spillback: a neglected concept in invasion ecology?

Area of Science:

• Ecology
• Invasion Biology
• Parasitology
• Disease Ecology

Background:

• Introduced animal species can negatively impact native ecosystems through disease.
• Current research often focuses on pathogen "spillover" from introduced to native species.
• The role of "parasite spillback," where introduced species amplify native parasites, is less understood.

Purpose of the Study:

• To investigate the prevalence and impact of parasite spillback as a mechanism of harm from introduced animal species.
• To challenge the focus on spillover and highlight the significance of spillback in invasion ecology.
• To review existing literature and provide evidence for parasite spillback.

Main Methods:

• Literature review of animal-parasite interactions involving nonindigenous species.
• Analysis of parasite fauna associated with introduced animals across various taxonomic groups.
• Evaluation of evidence for nonindigenous species acting as competent hosts for native parasites.
• Assessment of documented instances of parasite spillback to native host species.

Main Results:

• Native parasites (arthropods, parasitoids, protozoa, helminths) constitute 67% of the parasite fauna found in introduced animals.
• Nonindigenous species can be highly competent hosts for native parasites.
• Evidence confirms that parasite spillback from introduced to native species occurs, impacting hosts at individual and population levels.

Conclusions:

• Parasite spillback is a significant and potentially underestimated threat to native species.
• Invasion ecology needs to formally recognize and integrate parasite spillback into risk assessments.
• Further research is needed to understand the mechanisms and consequences of parasite spillback.