title: An invasive species reverses the roles in a host-parasite relationship between bitterling fish and unionid mussels.
abstract: The impact of multiple invading species can be magnified owing to mutual facilitation--termed 'invasional meltdown'--but invasive species can also be adversely affected by their interactions with other invaders. Using a unique reciprocal host-parasite relationship between a bitterling fish (Rhodeus amarus) and unionid mussels, we show that an invasive mussel reverses the roles in the relationship. Bitterling lay their eggs into mussel gills, and mussel larvae parasitize fish. Bitterling recently colonized Europe and parasitize all sympatric European mussels, but are unable to use a recently invasive mussel, Anodonta woodiana. The parasitic larvae of A. woodiana successfully develop on R. amarus, whereas larvae of European mussels are rejected by bitterling. This demonstrates that invading species may temporarily benefit from a coevolutionary lag by exploiting evolutionarily naive hosts, but the resulting relaxed selection may facilitate its exploitation by subsequent invading species, leading to unexpected consequences for established interspecific relationships.
authors.affiliation: Academy of Sciences of Czech Republic, Institute of Vertebrate Biology, Květná 8, 60365 Brno, Czech Republic. reichard@ivb.cz
authors.forename: Martin
authors.initials: M
authors.lastname: Reichard
authors.forename: Milan
authors.initials: M
authors.lastname: Vrtílek
authors.forename: Karel
authors.initials: K
authors.lastname: Douda
authors.forename: Carl
authors.initials: C
authors.lastname: Smith
mesh_terms: D000818:Animals; D049877:Anodonta / Q000254:growth & development* / Q000469:parasitology; D005075:Biological Evolution; D003530:Cyprinidae / Q000254:growth & development / Q000469:parasitology*; D005260:Female; D049810:Genetic Speciation; D005880:Gills / Q000469:parasitology; D006790:Host-Parasite Interactions; D058865:Introduced Species; D008297:Male; D010058:Oviposition; D013045:Species Specificity; D018709:Statistics, Nonparametric; D061350:Sympatry