Electronic Thesis and Dissertation Repository

Degree

Doctor of Philosophy

Program

Biology

Supervisor

Dr Nusha Keyghobadi

Abstract

Landscape genetics is a rapidly growing field that investigates how landscape and environmental features interact with microevolutionary processes to give rise to spatial genetic variation in populations. The ability to predict landscape effects on genetic patterns has been limited by the lack of studies conducted on more than one species, over multiple spatial scales and in replicated landscapes. A system that allows for such studies are the insect inhabitants of the purple pitcher plant (Sarracenia purpurea): the pitcher plant flesh fly (Fletcherimyia fletcheri), the midge (Metriocnemus knabi) and the mosquito (Wyeomyia smithii). In this thesis, I worked towards developing this as a potential model system in landscape genetics. I successfully developed microsatellite markers for the flesh fly and the midge. In the pitcher plant mosquito microsatellite isolation was very problematic, due to presence of microsatellite families associated with transposable elements and further aggravated by null alleles. I found that the pitcher plant flesh fly exhibits a mixture of metapopulation and patchy population attributes. I found that the pitcher plant midge exhibits a complex pattern of genetic differentiation across spatial scales, significantly associated with landscape variables related to habitat size, abundance and spatial arrangement. Also, in this small insect, both active flight and wind-assisted dispersal mediate gene flow among bogs within a landscape. Overall, this research has laid a foundation for further studies in this system and provided insights that are of interest to the broader community of landscape genetics researchers.

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