The Hitchhiker's Guide to the Host: Fleas and the History of Pikas in North America

<p>Parasite phylogenetics can offer windows into the cryptic evolutionary history of hosts, often highlighting events that are not recorded by the phylogenetics of the host. Pikas (small lagomorphs) host a diverse parasite community comprising endoparasites (e.g., coccidians, nematodes, and cestodes) and ectoparasites (e.g., fleas and mites). Phylogenetic analysis of pika endoparasites has revealed pikas evolved in Asia and colonized North America in two waves, and that contact between these two pika lineages allowed parasites to be transferred from one lineage to another and to survive the extinction of their original host. To uncover these cryptic histories, understanding the biogeography of parasites is essential. Comparisons of the distribution of the pika endoparasites with those of pika ectoparasites in North America revealed widespread and relictual lineages of both. Phylogenies of North American pika fleas mirrored the patterns seen in pika cestodes, with relictual populations of fleas belonging to lineages that arrived in North America before the arrival of extant pikas. The discovery of <em>Margopsylla tolli</em> from collared pikas in the Northwest Territories of Canada provides additional context to the history of pikas in North America. <em>Margopsylla tolli </em>parasitizes both <em>Ochotona collaris </em>in Alaska and northern Canada and <em>Ochotona hyperborea</em> in eastern Siberia and Manchuria. The presence of this species on both sides of the Bering Strait is suggestive of late Pleistocene contact between <em>O. collaris</em> and <em>O. hyperborea</em>, supporting previous findings from pika pinworms.</p>

Name thesis:degree_name

Master of Science

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Biology

Year dc:date.available

2026

Author dc:creator

• Pletcher, Josh

Contributors dc:contributor

• Kurt Galbreath

• pika
• Ochotona
• Geusibia
• Margopsylla tolli
• flea
• Siphonaptera
• Ctenophyllus
• phylogenetics
• Cestoda
• Schizorchis
• Biodiversity
• Entomology
• Evolution
• Genomics
• Molecular Genetics
• Paleobiology
• Zoology

Repository record dc:identifier

https://commons.nmu.edu/theses/925

OAI identifier oai:identifier

oai:commons.nmu.edu:theses-1973