title: Variation between populations and local adaptation in acanthocephalan-induced parasite manipulation.
abstract: Many trophically transmitted parasites manipulate their intermediate host phenotype, resulting in higher transmission to the final host. However, it is not known if manipulation is a fixed adaptation of the parasite or a dynamic process upon which selection still acts. In particular, local adaptation has never been tested in manipulating parasites. In this study, using experimental infections between six populations of the acanthocephalan parasite Pomphorhynchus laevis and its amphipod host Gammarus pulex, we investigated whether a manipulative parasite may be locally adapted to its host. We compared adaptation patterns for infectivity and manipulative ability. We first found a negative effect of all parasite infections on host survival. Both parasite and host origins influenced infection success. We found a tendency for higher infectivity in sympatric versus allopatric combinations, but detailed analyses revealed significant differences for two populations only. Conversely, no pattern of local adaptation was found for behavioral manipulation, but manipulation ability varied among parasite origins. This suggests that parasites may adapt their investment in behavioral manipulation according to some of their host's characteristics. In addition, all naturally infected host populations were less sensitive to parasite manipulation compared to a naive host population, suggesting that hosts may evolve a general resistance to manipulation.
authors.affiliation: Université de Bourgogne, Laboratoire Biogéosciences, UMR CNRS 5561, Equipe Ecologie Evolutive, 6 Boulevard Gabriel, 21000 Dijon, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Franceschi
authors.forename: Stéphane
authors.initials: S
authors.lastname: Cornet
authors.forename: Loic
authors.initials: L
authors.lastname: Bollache
authors.forename: François-Xavier
authors.initials: FX
authors.lastname: Dechaume-Moncharmont
authors.forename: Alexandre
authors.initials: A
authors.lastname: Bauer
authors.forename: Sébastien
authors.initials: S
authors.lastname: Motreuil
authors.forename: Thierry
authors.initials: T
authors.lastname: Rigaud
mesh_terms: D000049:Acanthocephala / Q000472:pathogenicity / Q000502:physiology* / Q000528:radiation effects; D000220:Adaptation, Biological; D033304:Amphipoda / Q000469:parasitology*; D000818:Animals; D003530:Cyprinidae / Q000469:parasitology; D006790:Host-Parasite Interactions; D016014:Linear Models; D008954:Models, Biological