title: Evolutionary ecology of microsporidia associated with the invasive ladybird Harmonia axyridis.
abstract: Invasive species are characterized by the rapid growth and spread of their populations after establishing a foothold in new habitats, and there are now many examples of such species negatively affecting biodiversity and the economy. It is unclear why some species can become successful invaders, whereas most (even if closely related) remain noninvasive. We previously proposed a hypothesis that parasites associated with invading species can promote their invasive success if they are harmless toward the invaders but harmful to their competitors and/or predators in the newly colonized habitat. Here we discuss whether microsporidia that have recently been discovered in the invasive ladybird Harmonia axyridis contribute to its invasive success. We show that all H. axyridis beetles sourced from diverse collection sites all over the world carry abundant microsporidia. This suggests that both native and invasive H. axyridis populations are associated with these tolerated parasites, which were likely to have existed in native populations before expansion rather than being acquired in newly colonized areas. We describe the pathogenesis of the microsporidia during different developmental stages of H. axyridis and we address the possibility that the predation of its infected eggs and larvae by competing native ladybird species may lead to their infection and ultimately to their decline. Finally, we discuss our initial hypothesis: microsporidia that are tolerated by an invasive vector insect can be active against susceptible native competitors and/or predator species.
authors.affiliation: Institute of Phytopathology and Applied Zoology, Justus-Liebig-University of Giessen, Heinrich-Buff-Ring 26-32, Giessen, D-35392, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Vilcinskas
authors.affiliation: Fraunhofer Institute for Molecular Biology and Applied Ecology, Winchester Strasse 2, Giessen, D-35394, Germany.
authors.forename: Henrike
authors.initials: H
authors.lastname: Schmidtberg
authors.affiliation: UMR 1062 CBGP, Inra, 34988, Montpellier, France.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Estoup
authors.affiliation: UMR 1062 CBGP, Inra, 34988, Montpellier, France.
authors.forename: Ashraf
authors.initials: A
authors.lastname: Tayeh
authors.affiliation: UMR 1062 CBGP, Inra, 34988, Montpellier, France.
authors.forename: Benoit
authors.initials: B
authors.lastname: Facon
authors.affiliation: Max Planck Institute for Chemical Ecology, Hans-Knöll-Strasse 8, D-07745, Jena, Germany.
authors.forename: Heiko
authors.initials: H
authors.lastname: Vogel
mesh_terms: D000818:Animals; D005075:Biological Evolution; D001517:Coleoptera / Q000382:microbiology*; D058865:Introduced Species; D007814:Larva / Q000382:microbiology; D016814:Microsporidia / Q000302:isolation & purification*; D010063:Ovum / Q000382:microbiology; D011235:Predatory Behavior
keywords: Coccinellidae; Harmonia axyridis; evolutionary ecology; innate immunity; intraguild predation; invasion biology; microsporidia