Haemosporidian prevalence and community composition vary little across a chickadee hybrid zone

Abstract Within animal hybrid zones, parasites may determine competitive outcomes between host species and thus affect hybridization dynamics. We addressed this hypothesis by evaluating haemosporidian prevalence community composition in a rapidly moving zone Black-capped Chickadees (Poecile atricapillus) Carolina (P. carolinensis). Using molecular methods, we screened for haemosporidians multiple chickadee populations across the investigated whether parasite varied as function of admixture among these birds. identified 36 lineages from 3 genera (Plasmodium, Haemoproteus, Leucocytozoon) but found no or more likely to infect any particular taxon. Instead, sites seasons: Leucocytozoon was prevalent during chickadees’ breeding season, whereas Haemoproteus peaked nonbreeding periods. infected proportionally fewer birds at leading edge than near its center. However, communities were similar populations, evidence exchanges taxa lacking. These results underscore complexity bird–parasite relationships suggest that are unlikely play major role ongoing movement zone.