title: Interspecific parasite exchange in a mixed colony of birds.
abstract: Studies of avian host-parasite interactions rarely include consequences of relationships among hosts for either the host or parasite species. In this study, we examine the ectoparasitic burden of adult and nestling European bee-eaters (Merops apiaster) and rock sparrows (Petronia petronia) in a mixed colony. We found that (1) each bird species had its own species of lice; (2) hematophagous mites parasitized both adults and nestlings of both bird species; (3) Carnus hemapterus, a common parasite of nestling bee-eaters, also infested rock sparrow nestlings, a species not previously described as a host for this dipteran; and (4) whereas C. hemapterus did not show high host specificity within the colony, the emergence of adult flies was synchronized with the start of hatching in bee-eater nests. We suggest that coexistence of these 2 bird species results in parasite exchange, bee-eaters obtaining mites from sparrows and sparrows becoming infested by C. hemapterus. Differences in the detrimental effects of parasite transfer for each host species may result in a process of apparent competition mediated by shared parasites. Interspecific parasite exchange is an important aspect of host-parasite relationships in mixed colonies, which requires further attention.
authors.affiliation: Departamento de Ecologia Evolutiva, Museo Nacional de Ciencias Naturales, (CSIC), José Gutiérrez Abascal 2, E-28006 Madrid, Spain. pvalera@eeza.csic.es
authors.forename: Francisco
authors.initials: F
authors.lastname: Valera
authors.forename: Alejandro
authors.initials: A
authors.lastname: Casas-Crivillé
authors.forename: Herbert
authors.initials: H
authors.lastname: Hoi
mesh_terms: D000818:Animals; D001715:Bird Diseases / Q000453:epidemiology / Q000469:parasitology / Q000635:transmission*; D001717:Birds; D004175:Diptera; D004478:Ectoparasitic Infestations / Q000453:epidemiology / Q000635:transmission / Q000662:veterinary*; D006790:Host-Parasite Interactions; D010373:Lice Infestations / Q000453:epidemiology / Q000635:transmission / Q000662:veterinary; D008924:Mite Infestations / Q000453:epidemiology / Q000635:transmission / Q000662:veterinary; D008003:Phthiraptera; D015995:Prevalence; D020308:Songbirds / Q000469:parasitology*; D013030:Spain / Q000453:epidemiology