Delimitation and identification of crescent butterflies (Nymphalidae: Phyciodes) in Alberta using molecular and morphological techniques

• Author / Creator

  Wingert, Brittany Denee

• Species delimitation can be challenging, especially in taxonomic groups that exhibit little morphological divergence. Many techniques and concepts have been developed for detecting species boundaries, and molecular methods are becoming increasingly common. Next generation sequencing techniques make it feasible to obtain hundreds to thousands of genome-wide markers, even for non-model organisms. This can provide powerful insights into species boundaries and the integrity of those boundaries in the presence of gene flow. However, classical taxonomic information, such as morphology, is often excluded from molecular studies, creating a disconnect between delimitation and identification. Integrative and iterative approaches to taxonomy that include morphological data maintain a link between delimitation and identification while providing a more complete understanding of the organisms being studied.
  The Phyciodes tharos species group of nymphalid butterflies is currently thought to comprise four species. However, interspecific overlap and intraspecific variability of the wing patterns have resulted in a complicated taxonomic history with uncertainty regarding the level of divergence between species. Discordance of mitochondrial COI with traditional taxonomic identifications has added to this uncertainty but has been attributed to incomplete lineage sorting and contemporary introgression. In this thesis, I used an iterative approach to examine the species limits of this group using genome-wide single nucleotide polymorphisms (SNPs) and the barcoding region of the mitochondrial COI gene. I then quantitatively examined the utility of eighteen morphological characters for identification based on the genomic species lineages. I focused on Alberta, the only region where all four species occur, and no other species of the genus are present.
  Genomic SNPs resolved all four species boundaries with strong support for P. tharos (Drury, 1773), P. cocyta (Cramer, 1777), and P. pulchella (Boisduval, 1852). Phyciodes batesii (Reakirt, 1865) did not form a monophyletic clade but did form a distinct cluster in all genomic analyses. Evidence of occasional hybridization and low levels of introgression indicate that these lineages maintain their genomic integrity when in contact. The COI haplotypes were discordant with genomic SNPs but provided evidence of unidirectional mitochondrial gene flow likely due to brood timing and opportunistic mating between species. Morphological characters exhibited extensive intraspecific variation and broad interspecific overlap. None of the character states were strictly diagnostic, but the proportions of character states exhibited for each species are provided as an identification resource.

• Subjects / Keywords

  • Phyciodes
  • Molecular Systematics
  • Entomology
  • Species delimitation
  • Lepidoptera
  • ddRAD

• Graduation date

  Fall 2022

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-21n7-rs41

• License

  This thesis is made available by the University of Alberta Library with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.