Shifts in immune responses of an invasive alien species: A test of the evolution of increased competitive ability hypothesis using American Eastern gray squirrels in Italy.

Autor: Romeo C; Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, Via Bianchi 9, 25124 Brescia, Italy. Electronic address: claudiarosa.romeo@izsler.it., Filipe J; Università degli Studi di Milano, Department of Veterinary Medicine and Animal Science, Via dell'Università 6, 26900 Lodi, Italy., Wauters LA; Università degli Studi dell'Insubria, Department of Theoretical and Applied Sciences, Environment Analysis and Management Unit - Guido Tosi Research Group, Via Dunant 3, 21100 Varese, Italy; University of Antwerp, Department of Biology - Evolutionary Ecology Group, Universiteitsplein 1, 2610 Wilrijk, Belgium., Comazzi S; Università degli Studi di Milano, Department of Veterinary Medicine and Animal Science, Via dell'Università 6, 26900 Lodi, Italy; Università degli Studi di Milano, WildlifeHealth Lab, Via dell'Università 6, 26900 Lodi, Italy., Riva F; Università degli Studi di Milano, Department of Veterinary Medicine and Animal Science, Via dell'Università 6, 26900 Lodi, Italy., Ferrari N; Università degli Studi di Milano, Department of Veterinary Medicine and Animal Science, Via dell'Università 6, 26900 Lodi, Italy; Università degli Studi di Milano, WildlifeHealth Lab, Via dell'Università 6, 26900 Lodi, Italy.
Jazyk: angličtina
Zdroj: The Science of the total environment [Sci Total Environ] 2023 Nov 20; Vol. 900, pp. 165747. Date of Electronic Publication: 2023 Jul 24.
DOI: 10.1016/j.scitotenv.2023.165747
Abstrakt: Based on the Evolution of Increased Competitive Ability (EICA) hypothesis, a reduced investment in immunity, consequent to parasite loss, could partly explain the success of invasive alien species. We investigated variation in parasite load and immune responses of alien Eastern gray squirrels (Sciurus carolinensis) along the invasion wave of an expanding population. We first verified by fecal analyses that 1) parasite abundance decreased moving from the core towards the invasion front. Next, we used multiple measures of immunity to investigate whether, in response to the lower parasite pressure, individuals at the invasion front 2) dampened their costly inflammatory response, and 3) increased their investment in less expensive acquired immunity. We first explored variation in hematological variables related either to the inflammatory or the acquired response. On a subset of individuals, we carried out ex vivo cell cultures to analyse the basal expression of MHC class II genes and the expression of TNF-α genes in response to an immune challenge. Platelet counts and TNF-α expression suggested higher inflammation in individuals living at the invasion core, whereas parameters associated with an acquired response (lymphocyte counts and MHC II expression by spleen cells), conversely, were higher in squirrels at the front. Overall, our results suggest a shift between different immune strategies along the invasion wave, supporting a reduced investment in costly inflammatory responses and an increased investment in acquired immunity in individuals at the expanding edge of the range, which are subjected to high selective pressures for dispersal and reproduction.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2023 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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