Coinfection rates of avian blood parasites increase with latitude in parapatric host species

• Type of Material: Article
• Authors: Naima C Starkloff, Emory University; Spencer C Galen, University of Scranton
• Language: English
• Date: 2023-04-01
• Publisher: Cambridge University Press (CUP)
• Publication Version: Final Published Version
• Copyright Statement: © The Author(s), 2023. Published by Cambridge University Press
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1017/S0031182022001792
• Title of Journal or Parent Work: PARASITOLOGY
• Volume: 150
• Issue: 4
• Start Page: 329
• End Page: 336
• Grant/Funding Information: S. C. G. was supported by an NSF Postdoctoral Research Fellowship in Biology (award 1811806).; N. C. S. was supported by the New York State Museum, State University of New York (Albany), and a Frank Chapman grant from the American Museum of Natural History.
• Keywords: Haemosporida; Leucocytozoon; coinfection; latitudinal diversity gradient; Catharus

Abstract

Animals are frequently coinfected with multiple parasites concurrently, and advances in our sampling of these complex intra-host parasite communities have revealed important ecological impacts on their hosts. However, the spatial distributions and environmental determinants of parasite coinfection remain infrequently studied. Here, we investigated the drivers of haemosporidian blood parasite coinfection in the Bicknell's thrush (Catharus bicknelli) and grey-cheeked thrush (Catharus minimus), parapatric sister species that occur across a broad latitudinal range in northern North America. Using 298 samples from across the distributions of these species, we found high overall infection (86%) and coinfection (41%) rates within host populations. Coinfection rates within populations were highly variable across sampling sites, ranging from 7 to 75%. Latitude was a more important predictor of coinfection frequency than host species identity, with coinfections becoming more abundant at higher latitudes. The 2 host species exhibited similar parasite faunas, and an analysis of the co-occurrence patterns among haemosporidians showed that host species identity was largely not a factor in structuring which parasites were found within coinfections. To our knowledge, this is the first study to illustrate a reverse latitudinal gradient in coinfection frequency in a eukaryotic parasite system. Further work is necessary to determine whether vector ecology or some other factor is the primary proximate driver of this pattern.