Parallel elevational replacement of hosts and parasites in a highly susceptible songbird genus

Wiley et al., 2025 (in prep) Parallel elevational replacement of hosts and parasites in a highly susceptible songbird genus.In this study, we use pectoral tissues and whole blood samples of three closely related, elevational replacement species of vireo to characterize infection dynamics of avian haemosporidians across their summer breeding sites in the American Southwest. We asked: we (1) compared parasite prevalence and infection intensity among host species, including the first parasite survey for regionally vulnerable Gray Vireos; (2) characterized haemosporidian haplotypes and host specificity; and (3) tested the extent to which community composition was linked to elevational zones and/or their associated host species and habitats.Data are archived on FigShare: https://doi.org/10.6084/m9.figshare.28585943DATASET All birds were sampled during summer months (May–August) spanning the years 1995–2019 across 27 unique sites in New Mexico and a single site in Utah, under appropriate federal, state, and local permits. Majority of samples were accompanied by vouchered specimens that were archived at the Museum of Southwestern Biology (MSB), University of New Mexico (UNM), except in the case of gray vireos that were released after sample collection. Samples used in this study represent 248 wild birds of three closely related vireo species (Bell’s vireo: n = 20, gray vireo: n = 170, and plumbeous vireo: n = 58). We screened samples via nested PCR amplification of the cytochrome b region for Haemoproteus and Plasmodium parasites and positive infections were quantified via microscopy following the protocol described in Valkiūnas (2005). Parasitemia represents the % of parasites counted across 10,000 red blood cells screened.We identified and compared haplotypes to published records stored in the public databases GenBank (National Center for Biotechnology Information, US National Library of Medicine) and MalAvi (Bensch et al., 2009). Haplotypes that differed by one or more base pairs (~0.2% sequence divergence) from published sequences on GenBank or MalAvi were considered novel and named following MalAvi conventions. All sequences are uploaded to GenBank under [Accession nos. PV295634-PV29583].Additionally, we documented aspects of sampling locality (i.e. latitude, longitude, elevation), and environmental factors known to impact pathogen prevalence and distribution (i.e. WORLDCLIM 19 bioclimatic variables to do with temperature and precipitation).Analysis code is available on GitHub: https://github.com/dlfwiley/Vireo-Malaria-Project. Majority of data, except in the case of gray vireos released after sample collection, are linked to vouchered host and parasite specimens, housed at the Museum of Southwestern Biology (MSB) at the University of New Mexico, USA. Specimen records are accessible in the Artcos database (https://arctos.database.museum/).