Honors Theses

Date of Award

Spring 5-9-2020

Document Type

Undergraduate Thesis



First Advisor

Ryan Garrick

Second Advisor

Rebecca Symula

Third Advisor

Sarah Liljegren

Relational Format



Population genetics as a field of study aims to determine the genetic variation among individuals in a population, and differences among populations. Certain population genetic analyses can provide such information and be used to better understand the biological aspects to a species’ expansion beyond its native range. The southern pine beetle (SPB), Dendroctonus frontalis, has become an invasive pest to pine forests in northeastern United States with its recent range expansion. Nine microsatellite loci were first developed and then used in analyses. To determine what the genetic variation is among individuals in SPB populations across its entire range, including ones at the leading edge, Hardy Weinberg Equilibrium (HWE) tests were performed. To assess the differences among populations, Fst and “exact” tests were performed. It was found that of 27 geographical populations, 6 were inconsistent with HWE and majority with significant (P < 0.05) FIS values indicative of inbreeding. The study also found 4 populations with significant pairwise FST values t (P < 0.05, based on exact tests) indicating that these populations are genetically different and isolated from most others. The analyses performed in this study can be expanded with additional SPB samples and in conjunction with other SPB microsatellite loci. These findings can be used to better understand the biological aspects to SPB recent range expansion and further applied to species management strategies.



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