title: Host density and ectoparasite avoidance in the common lizard (Lacerta vivipara).
abstract: Increased transmission of parasites and diseases is generally considered as a major cost of social life. In this study we tested the hypothesis regarding ectoparasites as a cost of living in crowded habitats in the common lizard (Lacerta vivipara). We used two approaches to explore this question. First, we tested if ectoparasite load and prevalence are positively correlated with host density in the field. Second, we experimentally tested if lizards avoid parasitized conspecifics. Contrary to expectation, we found that (1) ectoparasite load is negatively correlated with lizard density; (2) prevalence does not significantly increase with density; (3) unparasitized lizards do not avoid parasitized conspecifics but are attracted by them whatever their parasite load. These findings suggest that ectoparasites cannot be considered as a cost of living at high density in the common lizard, in spite of the potential negative impact mites may have on lizard fitness.
authors.affiliation: Laboratoire d'Ecologie, CNRS URA 258, Université Pierre et Marie Curie, Bât. A., 7ème étage, 7 quai St. Bernard, Case 237, F-75252 Paris Cedex 05, France Fax: (33)-1-44273516; e-mail: gsorci@snv.jussieu.fr, , , , , , FR.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Sorci
authors.affiliation: Laboratoire d'Ecologie, CNRS URA 258, Université Pierre et Marie Curie, Bât. A., 7ème étage, 7 quai St. Bernard, Case 237, F-75252 Paris Cedex 05, France Fax: (33)-1-44273516; e-mail: gsorci@snv.jussieu.fr, , , , , , FR.
authors.forename: Michelle
authors.initials: M
authors.lastname: de Fraipont
authors.affiliation: Laboratoire d'Ecologie, CNRS URA 258, Université Pierre et Marie Curie, Bât. A., 7ème étage, 7 quai St. Bernard, Case 237, F-75252 Paris Cedex 05, France Fax: (33)-1-44273516; e-mail: gsorci@snv.jussieu.fr, , , , , , FR.
authors.forename: Jean
authors.initials: J
authors.lastname: Clobert
keywords: Host density; Key words Ectoparasites; Lizards; Parasite transmission