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Temporal isolation and genetic divergence in the Choristoneura fumiferana species complex
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- Author / Creator
- Nelson, Tyler D
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Temporal isolation contributes to ecological speciation in a diversity of insect taxa. Such prezygotic isolation can reduce or stop hybridization between closely related taxa or populations, leading to speciation. Within the spruce budworm (Choristoneura fumiferana) species complex, hybridization between species occurs freely in laboratory settings but hybrids are rarely found in the wild. Temporal isolation has been suggested as a mechanism that reduces their hybridization, but this has not been assessed for members of the complex that interact in west-central Alberta and adjacent British Columbia. I sought to determine whether temporal isolation reduces hybridization between C. fumiferana and C. occidentalis biennis, using ddRADseq to genotype 261 individual Choristoneura collected over two years. I found that C. fumiferana and C. o. biennis have significantly different flight peaks, partially due to post-diapause degree-day requirements. However, adults of these taxa contact each other with sufficient frequency to allow hybridization at an estimated rate of 2.9%. I did not find significant genetic differentiation between the even- and odd-year cohorts of C. o. biennis. Additionally, collections of C. o. biennis extended at least to Elk Island National Park in central Alberta, which is more than 100 km further east than previously recognized. In conclusion, temporal isolation likely contributes to the maintenance of genomic integrity between species of spruce budworm, but the role of other mechanisms should also be investigated.
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- Subjects / Keywords
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- Tortricidae
- Hybrid zone
- Introgression
- Ecological speciation
- Admixture
- Spruce budworm
- Single nucleotide polymorphisms
- Choristoneura
- Genomics
- Temporal isolation
- Pheromones
- Choristoneura fumiferana
- Choristoneura occidentalis occidentalis
- SNPs
- Choristoneura occidentalis biennis
- Phenology
- Lepidoptera
- Genomic architecture
- Hybridization
- Speciation
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- Graduation date
- Fall 2019
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- Type of Item
- Thesis
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- Degree
- Master of Science
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- License
- Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.