Using genomics to uncover the evolutionary histories of ectoparasites on birds

Parasitism is one of the most common life strategies on Earth. While decreasing the fitness of their hosts, parasites are a major component of ecosystems and can regulate host populations. However, much about parasite biology remains unknown. Parasite livelihood is dependent on one or more host species, and this interaction creates complex dynamics between host and parasite. Host parasite systems are ideal for studying coevolutionary mechanisms because of parasite dependence on their hosts and the constant battles to evolve to meet the adaptations of the hosts and vice versa. Ectoparasites of the insect order Phthiraptera, more commonly known as lice, exist on a wide variety of hosts. Genomics allows us to study several aspects of parasite evolution and diversification. I leveraged whole genome sequencing feather lice to study patterns of parasite diversification in relation to host diversification at multiple evolutionary scales. Incorporating datasets of diverse scales allow us to explore the patterns of speciation that are present across these parasites. At a higher taxonomic scale, among genera, I focused on lice from tinamous, a group of paleognath birds, which host some of the greatest diversity of lice. I used genome sequence data from individual lice to estimate phylogenetic trees using both concatenated (RAxML/IQTree) and coalescent (ASTRAL) methods of phylogenetic estimation. The estimated phylogeny provided evidence that tinamou lice are more closely related to each other than previously expected. Our results also indicated diversification of these parasites occurred within tinamous, and not by repeated host switching from other bird lineages. I found one louse genus, Rallicola, in the same broader clade as tinamou lice. Unlike the genera of lice found on tinamous, Rallicola is found on 6 different bird orders and 14 families. We analyzed the phylogenetic, biogeographic, and cophylogenetic relationships of the genus Rallicola and found that the ancestral host of this genus had a New World and most likely South American origin. We also found that host switching events were very common in this group of lice, and then we decided to study cospeciation pattens at a deeper level and focused on Rallicola on woodcreepers, ovenbirds, and leaftossers (one bird family). Cophylogenetic analysis of Rallicola on these specific hosts revealed several cospeciation events, but also equally as many host switching events. In general, avian lice show evidence of occasional cospeciation with their hosts, but there also appears to be considerable host switching, both between and within major groups of birds. Studying diversification patterns at shorter scales allowed us to gain insight on what we may have been missing with broader sampling and scales. Genomics, and specifically phylogenomics and cophylogenetic analyses, allow us to begin to tease apart these complex relationships.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Ecol, Evol, Conservation Biol

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2023

Author dc:creator

• Virrueta Herrera, Stephany

Contributors dc:contributor

• Johnson, Kevin
• Hauber, Mark
• Dietrich, Christopher
• Harmon-Threatt , Alexandra
• Heath, Katy

• Phylogenomics
• Lice
• Coevolution

Statement dc:rights

• Copyright 2023 Stephany Virrueta Herrera

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/120531

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F120531