title: Host and habitat specialization of avian malaria in Africa.
abstract: Studies of both vertebrates and invertebrates have suggested that specialists, as compared to generalists, are likely to suffer more serious declines in response to environmental change. Less is known about the effects of environmental conditions on specialist versus generalist parasites. Here, we study the evolutionary strategies of malaria parasites (Plasmodium spp.) among different bird host communities. We determined the parasite diversity and prevalence of avian malaria in three bird communities in the lowland forests in Cameroon, highland forests in East Africa and fynbos in South Africa. We calculated the host specificity index of parasites to examine the range of hosts parasitized as a function of the habitat and investigated the phylogenetic relationships of parasites. First, using phylogenetic and ancestral reconstruction analyses, we found an evolutionary tendency for generalist malaria parasites to become specialists. The transition rate at which generalists become specialists was nearly four times as great as the rate at which specialists become generalists. We also found more specialist parasites and greater parasite diversity in African lowland rainforests as compared to the more climatically variable habitats of the fynbos and the highland forests. Thus, with environmental changes, we anticipate a change in the distribution of both specialist and generalist parasites with potential impacts on bird communities.
authors.affiliation: Department of Biology, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132, USA. cloiseau@sfsu.edu
authors.forename: Claire
authors.initials: C
authors.lastname: Loiseau
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Harrigan
authors.forename: Alexandre
authors.initials: A
authors.lastname: Robert
authors.forename: Rauri C K
authors.initials: RC
authors.lastname: Bowie
authors.forename: Henri A
authors.initials: HA
authors.lastname: Thomassen
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Smith
authors.forename: Ravinder N M
authors.initials: RN
authors.lastname: Sehgal
mesh_terms: D000818:Animals; D001717:Birds / Q000145:classification / Q000235:genetics*; D002163:Cameroon; D017753:Ecosystem; D049810:Genetic Speciation; D058507:Host Specificity / Q000235:genetics*; D008289:Malaria, Avian / Q000453:epidemiology* / Q000469:parasitology*; D010802:Phylogeny; D010961:Plasmodium / Q000145:classification / Q000235:genetics*; D013019:South Africa; D013045:Species Specificity