Diversity, abundance, and host relationships in the avian malaria community of New Mexico pine forests

Avian malaria parasites (genera Haemoproteus, Plasmodium, and Leucocytozoon) affect bird demography, distribution limits, and community structure, yet most bird communities and populations remain unsurveyed. We conducted a community-level survey of these vector-transmitted parasites in New Mexico, USA, to describe the diversity, abundance, and host associations. We focused on the breeding-bird community in the transition zone between piñon-juniper woodland and ponderosa pine forests (elevational range: 2150–2460 meters). We screened 186 birds representing 49 species using both standard PCR and microscopy techniques to detect infections of all three avian malaria genera. The combined infection rate was 36.6%, with the highest infection rate for Haemoproteus (20.9%), followed by Leucocytozoon (13.4%), then Plasmodium (8.0%). We sequenced mtDNA for 77 infections representing 43 haplotypes (25 Haemoproteus, 12 Leucocytozoon, 6 Plasmodium). When compared to all previously known lineages in the MalAvi and GenBank databases, 65% (28) of the haplotypes that we recovered were novel. We found evidence for host specificity at the avian clade and species level, but this specificity was variable among parasite genera. Haemoproteus and Leucocytozoon were each restricted to three avian host-clades or groups (out of six), while Plasmodium occurred in all groups except non-passerines. We found striking variation in infection rate among host species, with nearly universal infection among vireos and no infection among nuthatches. Using rarefaction and extrapolation, we estimated the total avian malaria diversity to be 70 haplotypes (95% CI: 43–98); thus, we may have already sampled ~60% of the diversity of avian malaria in New Mexico pine forests. It is possible that future studies will find higher diversity in microhabitats or host species that are under-sampled or unsampled in the present study. Fortunately, this study is fully extendable via voucher specimens, frozen tissues, blood smears, parasite images, and documentation provided in open-access databases (MalAvi, Genbank, and ARCTOS).