title: Relative fitness of a generalist parasite on two alternative hosts: a cross-infestation experiment to test host specialization of the hen flea Ceratophyllus gallinae (Schrank).
abstract: Host range is a key element of a parasite's ecology and evolution and can vary greatly depending on spatial scale. Generalist parasites frequently show local population structure in relation to alternative sympatric hosts (i.e. host races) and may thus be specialists at local scales. Here, we investigated local population specialization of a common avian nest-based parasite, the hen flea Ceratophyllus gallinae (Schrank), exploiting two abundant host species that share the same breeding sites, the great tit Parus major (Linnaeus) and the collared flycatcher Ficedula albicollis (Temminck). We performed a cross-infestation experiment of fleas between the two host species in two distinct study areas during a single breeding season and recorded the reproductive success of both hosts and parasites. In the following year, hosts were monitored again to assess the long-term impact of cross-infestation. Our results partly support the local specialization hypothesis: in great tit nests, tit fleas caused higher damage to their hosts than flycatcher fleas, and in collared flycatcher nests, flycatcher fleas had a faster larval development rates than tit fleas. However, these results were significant in only one of the two studied areas, suggesting that the location and history of the host population can modulate the specialization process. Caution is therefore called for when interpreting single location studies. More generally, our results emphasize the need to explicitly account for host diversity in order to understand the population ecology and evolutionary trajectory of generalist parasites.
authors.affiliation: CNRS, Université de Lyon, Université Lyon 1, Department of Biometry and Evolutionary Biology, Villeurbanne, France.|Evolutionary Ecology Lab, Institute of Ecology and Evolution, University of Bern, Bern, Switzerland.|MIVEGEC UMR 5290 CNRS-IRD-UM, Center IRD, Montpellier, France.
authors.forename: A
authors.initials: A
authors.lastname: Appelgren
authors.affiliation: MIVEGEC UMR 5290 CNRS-IRD-UM, Center IRD, Montpellier, France.
authors.forename: K D
authors.initials: KD
authors.lastname: McCoy
authors.affiliation: Evolutionary Ecology Lab, Institute of Ecology and Evolution, University of Bern, Bern, Switzerland.
authors.forename: H
authors.initials: H
authors.lastname: Richner
authors.affiliation: CNRS, Université de Lyon, Université Lyon 1, Department of Biometry and Evolutionary Biology, Villeurbanne, France.|Department of Ecology and Genetics/Animal Ecology, Evolutionary Biology Centre, University of Uppsala, Uppsala, Sweden.
authors.forename: B
authors.initials: B
authors.lastname: Doligez
mesh_terms: D000818:Animals; D002645:Chickens / Q000469:parasitology; D005260:Female; D058267:Flea Infestations; D056084:Genetic Fitness; D006790:Host-Parasite Interactions; D010271:Parasites; D005423:Siphonaptera
keywords: Ficedula albicollis; Parus major; ecological speciation; ectoparasite adaptation; host race; host range; individual fitness; multi-host systems; reproductive success; spatial scale