Temporal stability of insular avian malarial parasite communities.

Avian malaria is caused by a diverse community of genetically differentiated parasites of the genera Plasmodium and Haemoproteus. Rapid seasonal and annual antigenic allele turnover resulting from selection by host immune systems, as observed in some parasite populations infecting humans, may extend analogously to dynamic species compositions within communities of avian malarial parasites. To address this issue, we examined the stability of avian malarial parasite lineages across multiple time-scales within two insular host communities. Parasite communities in Puerto Rico and St Lucia included 20 and 14 genetically distinct parasite lineages, respectively. Lineage composition of the parasite community in Puerto Rico did not vary seasonally or over a 1 year interval. However, over intervals approaching a decade, the avian communities of both islands experienced an apparent loss or gain of one malarial parasite lineage, indicating the potential for relatively frequent lineage turnover. Patterns of temporal variation of parasite lineages in this study suggest periodic colonization and extinction events driven by a combination of host-specific immune responses, competition between lineages and drift. However, the occasional and ecologically dynamic lineage turnover exhibited by insular avian parasite communities is not as rapid as antigenic allele turnover within populations of human malaria.

Patterns of Knemidokoptes jamaicensis (Acari: Knemidokoptidae) infestations among eight new avian hosts in the Dominican Republic.

The ectoparasitic mite Knemidokoptes jamaicensis Turk burrows into the cornified epithelium of the legs and feet of Passeriform birds and has been reported from 12 species of North American birds. Here we establish new host and distribution records for K. jamaicensis from eight species of birds from three habitats in the Dominican Republic. These species include Hispaniolan pewee (Contopus hispaniolensis Bryant), northern mockingbird (Mimus polyglottos L.), Cape May warbler (Dendoica tigrina Gmelin), prairie warbler (Dendroica discolor Vieillot), palm warbler (Dendroica palmarum Gmelin), green-tailed warbler (Microligea palustris Cory), black-crowned palm tanager (Phaenicophilus palmarum L.), and Greater Antillean bullfinch (Loxigilla violacea L.). Rates of infestation were as great as 18.2% but varied between species and habitats. Mites were far more common in the dry desert thorn scrub than they were in higher elevation and more moist habitats, despite the fact that many of the affected species had distributions that spanned multiple habitat types. Results suggest that the abundance of scaley-leg mites is controlled by the abundance of suitable host species and by specific ecological conditions that promote transmission.