Dissertation Research: Integrative species delimitation, cryptic coloration, and climatic niche breadth in songbirds

点击翻译按钮获取中文摘要

All species exhibit some level of phenotypic variation, such that individuals and populations differ in their appearance. The amount of phenotypic diversity and the number of species, however, vary dramatically among different types of organisms and regions of the world. Understanding the evolutionary and ecological processes that cause differences in the number of species among different groups of organisms and geographic regions is a longstanding goal in evolutionary biology. This research first seeks to improve our estimation of the number of species of horned locks, which would help in better understanding how biodiversity evolves and is maintained. This project will then measure geographic variation in camouflage by quantifying how feather coloration on the backs of larks matches the color and composition of the ground among different populations. Species that possess distinct forms of camouflage, or background matching, have provided some of society's most celebrated examples of natural selection; yet we lack an understanding of the evolutionary and ecological dynamics behind such complex, subtle, and continuous patterns of color variation related to camouflage. This research will advance our understanding of how animals adapt to environmental conditions that vary over space and time. The researchers will actively recruit and train undergraduate research assistants from underrepresented demographic groups in science to complete this work. This project will also generate online educational resources and popular science articles to educate the public about natural selection and camouflage in nature. This research proposes an integrative study of phenotypic and genetic differentiation within a recent, widespread, and highly polytypic lineage of larks in the bird genus Eremophila. The project will leverage traditionally data sources, including multiple forms of remote sensing data, digital photography, and ancient DNA from museum toepads via Sequence Capture using PCR-generated Probes (SCPP), to delimit species and undertake comparative analyses of cryptic coloration. Using SCPP, the researchers will generate a panel of 60 loci, including the mitochondrial genome, sex-linked markers, and autosomal introns and exons, for phylogeographic analyses and integrative species delimitation alongside phenotypic variation in song, plumage, and morphology. Upon delimiting species and resolving relationships within the genus, the project will use the revised taxonomy and corresponding species tree to quantify the prevalence of geographic variation in cryptic coloration--or the degree of background matching between dorsal plumage and corresponding substrates--among populations and species. Finally, the project will test whether the amount of variation in cryptic coloration is correlated with abiotic niche breadth among species in Eremophila, which would suggest that evolvability of cryptic coloration plays an important role facilitating range expansions into different habitats.