University of Notre Dame
RyanSF082015D.pdf (5.63 MB)

An Evaluation of Spatio-Temporal Changes in the Population Genomics of a Butterfly Hybrid Zone Over a Thirty Year Period of Climatic Change

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posted on 2015-08-27, 00:00 authored by Sean F. Ryan
As a result of human activities, changes in global climatic patterns are predicted to dramatically alter contemporary geographic patterns of biological and genetic diversity. However, due to the complexity of biological communities, accurate predictions of species responses will depend on our understanding of the factors influencing these responses. Evolution (adaptation) and species interactions are both factors that have the capacity to mitigate and exacerbate organism’s responses to climate change. Unfortunately our understanding of these factors is still poorly understood. Here, I take advantage of a historically sampled and ecologically well studied butterfly hybrid zone to explore how historical changes in climate have influenced the genetic composition of this hybrid zone across space and through time. Specifically, by combining molecular (genetics and genomics) and simulation modeling approaches I explore how spatio-temporal changes in climate have influenced the geographic and genomic landscape of divergence between these hybridizing species. First, I characterized the extent of divergence across the hybridizing genomes of P. glaucus and P. canadensis and explored how this divergence varied geographically and with climatic and ecological factors. I found evidence of climate maintaining genome-wide patterns of divergence, particularly on the Z chromosome where divergence was greatest. Next, I determined that the hybrid zone, based on a genome-wide set of genetic and a morphological trait, has shifted northward, coinciding with a lengthening growing season from 1980-2012. Using simulation modelling I discovered that spatio-temporal changes in climate during this period of warming has led to differential phenological responses that were dependent on genetic background. Further, I found that climate-mediated changes in voltinism may be leading to different reproductive phenological pathways that can have a dramatic influence on geneflow across the hybrid zone. Last as part of a working group I researched the capacity of citizen science to inform natural resource management and policy. In short, we found that citizen science has already affected natural resource management and policy in positive and measureable ways and that there is enormous potential for public participation to continue to improve the efficacy of scientific research.


Date Modified


Defense Date


Research Director(s)

Jessica Hellmann


  • Doctor of Philosophy

Degree Level

  • Doctoral Dissertation


  • English

Program Name

  • Biological Sciences

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