Date of Award

January 2015

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biology

First Advisor

Jefferson A. Vaughan

Abstract

Passerine birds that primarily use grassland habitats are rarely the focus of a parasite study. With many rapidly declining bird populations that breed at even faster decreasing grassland habitat, it is important to know the potential risks to the birds posed by blood parasites. During the breeding seasons of 2009-2011, 150 samples from 148 individual birds (fourteen species) were collected from five grassland sites in northwest Minnesota, USA and surveyed for blood parasites using microscopy and molecular methods. Eighty-five (56.67%) of the 150 samples were infected with at least one of three haemosporidian genera: Haemoproteus, Plasmodium and Leucocytozoon. Seventy (46.67%) of the 150 samples were infected with either Haemoproteus or Plasmodium (fourteen infections were Haemoproteus, forty were Plasmodium and sixteen were undetermined due to dual infections or lack of sequences) and 41 samples (27.33%) were infected with Leucocytozoon, for a total of 111 infections. Plasmodium infections in two juvenile bobolinks provide evidence of active transmission within the study area. Haemoproteus/Plasmodium prevalence was significantly higher in May and June than in later collection months (July-Sept.) and dual infections were significantly higher in June compared with other sampling months. Of the three bird species that were sampled most, clay-colored sparrows (Spizella pallida) had significantly more Haemoproteus infections than savannah sparrows (Passerculus sandwichensis) and bobolinks (Dolichonyx oryzivorus). Only bobolinks were classified based on sex and/or age and adult males had significantly more Leucocytozoon and dual infections than adult females or juveniles. Parasite prevalence did not differ significantly between study sites or years. Phylogenetic reconstructions based on Maximum Likelihood and Bayesian analyses produced three major clades, corresponding to the three haemosporidian genera. Bird host species were well mixed within the trees, indicating infective vectors fed on bird species opportunistically rather than selectively and also shows that the Haemosporidia are generalists, being able to infect a wide range of the sampled bird species.

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