Eco-immunology and bioinvasion: revisiting the evolution of increased competitive ability hypotheses.
Immunity is at the core of major theories related to invasion biology. Among them, the evolution of increased competitive ability (EICA) and EICA-refined hypotheses have been used as a reference work. They postulate that the release from pathogens often experienced during invasion should favour a reallocation of resources from (costly) immune defences to beneficial life-history traits associated with invasive potential. We review studies documenting immune changes during animal invasions. We describe the designs and approaches that have been applied and discuss some reasons that prevent drawing generalized conclusions regarding EICA hypotheses. We detail why a better assessment of invasion history and immune costs, including immunopathologies and parasite communities, could improve our understanding of the relationships between immunity and invasion success. Finally, we propose new perspectives to revisit the EICA hypotheses. We first emphasize the neutral and adaptive mechanisms involved in immune changes, as well as timing of the later. Such investigation will help decipher whether immune changes are a consequence of pre-adaptation, or the result of postintroduction adaptations to invasion front conditions. We next bring attention to new avenues of research that remain unexplored, namely age-dependent immunity and gut microbiota, potential key factors underlying adaptation to invasion front environment and modulating invasion success.
Centre de Biologie Pour la Gestion des Populations (UMR INRA/IRD/CIRAD/Montpellier SupAgro) IRD Montferrier-sur-Lez France.
Stéphane
S
Cornet
Centre de Biologie Pour la Gestion des Populations (UMR INRA/IRD/CIRAD/Montpellier SupAgro) IRD Montferrier-sur-Lez France.
Carine
C
Brouat
Centre de Biologie Pour la Gestion des Populations (UMR INRA/IRD/CIRAD/Montpellier SupAgro) IRD Montferrier-sur-Lez France; Centre de Biologie Pour la Gestion des Populations (UMR INRA/IRD/CIRAD/Montpellier SupAgro) IRD Campus de Bel-Air, Dakar Sénégal; Département de Biologie Animale, Faculté des Sciences et Techniques Université Chiekh Anta Diop Fann, Dakar Sénégal.
Christophe
C
Diagne
Centre de Biologie Pour la Gestion des Populations (UMR INRA/IRD/CIRAD/Montpellier SupAgro) INRA Montferrier-sur-Lez France.
Nathalie
N
Charbonnel
competitive ability; costly immune defences; expansion range; host–parasite coevolution; inflammation; invasive species