Journal
BIOLOGICAL INVASIONS
Volume 23, Issue 12, Pages 3847-3857Publisher
SPRINGER
DOI: 10.1007/s10530-021-02611-7
Keywords
Invasive alien species; Strongyloides robustus; Sciurus vulgaris; Macroparasites; Parasite mediated competition; Tree squirrels
Categories
Funding
- Universita degli Studi dell'Insubria within the CRUI-CARE Agreement
Ask authors/readers for more resources
This study demonstrates that the spillover of alien helminth S. robustus contributes to the detrimental effects of resource competition and stress induced by grey squirrels, further reducing the fitness of the native species in the presence of the invasive competitor.
It is widely assumed that spillover of alien parasites to native host species severely impacts naive populations, ultimately conferring a competitive advantage to invading hosts that introduced them. Despite such host-switching events occurring in biological invasions, studies demonstrating the impact of alien macroparasites on native animal hosts are surprisingly few. In Europe, native red squirrels (Sciurus vulgaris) are replaced by introduced North American grey squirrels (S. carolinensis) mainly through resource competition, and, only in the United Kingdom and Ireland, by competition mediated by a viral disease. In Italy such disease is absent, but spillover of an introduced North American nematode (Strongyloides robustus) from grey to red squirrels is known to occur. Here, we used long-term (9 years) capture-mark-recapture and parasitological data of red squirrels in areas co-inhabited by grey squirrels in Northern Italy to investigate the impact of this alien helminth on naive native squirrels' body mass, local survival, and reproduction of females. We found no negative effect of the alien parasite on body mass or reproductive success, but intensity of infection by S. robustus reduced survival of both male and female squirrels. Significantly, survival of squirrels co-infected by their native nematode, Trypanoxyuris sciuri, was less affected by S. robustus, suggesting a protective effect of the native helminth against the new infection. Hence, we demonstrate that alien S. robustus spillover adds to the detrimental effects of resource competition and stress induced by grey squirrels, further reducing the fitness of the native species in the presence of the invasive competitor.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available