Host and habitat specialization of avian malaria in Africa

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 vs. 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...