Electronic Thesis and Dissertation Repository

Degree

Master of Science

Program

Biology

Supervisor

Dr. Nusha Keyghobadi

Abstract

A major question in landscape genetics is how habitat structure influences spatial patterns of genetic differentiation. In this study, I evaluate the relative importance and effects of aspects of habitat composition (habitat amount) and configuration (patch size and isolation) on the spatial genetic structure of the pitcher plant midge, Metriocnemus knabi, whose larvae are found exclusively within the water-filled leaves of pitcher plants (Sarracenia purpurea) in a system that is naturally patchy at multiple spatial scales (i.e., leaf, plant, cluster, bog). I estimated genetic differentiation (FST) among leaves, plants, and clusters using 11 microsatellite loci, and measured the amount of habitat, patch size, and patch isolation at each spatial scale. Multi-model inference analyses indicate that the amount of habitat in the surrounding landscape (i.e., bog) and broad-scale patch isolation are the strongest predictors of genetic differentiation at local spatial scales (i.e., plant, cluster), and habitat amount and isolation have an interactive effect on FST estimates at the broader bog scale. These results reinforce the value of considering how ecological and evolutionary processes (i.e., behaviour, dispersal, gene flow, drift) occurring across multiple spatial scales may influence patterns of genetic differentiation.

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