Date of Award


Degree Type


Degree Name

Master of Science




Dr. Marc-André Lachance

Second Advisor

Dr. Brent Sinclair

Third Advisor

Dr. Greg Thom


This project explores the ecology of the yeast Metschnikowia borealis, its relationship to the nitidulid beetle Conotelus obscurus and to nematodes found in the beetle. It was hypothesized that the yeasts parasitize the nematodes, and are therefore beneficial to the beetles. Adult beetle survival in the presence or absence of nematodes and M. borealis was assessed, as was larval yeast tolerance. Although the nematodes did decrease female beetles’ longevity, adult beetles with yeast did not survive longer than those without. Larvae require yeast but not specifically M. borealis. The adaptive value of the yeasts’ barbed spores therefore remains unclear. Previous work examining the population structure ofM borealis was expanded upon by collecting yeast strains from two additional populations and sequencing strains at three loci. One locus (L0512) had differentiated in two populations indicating that population structuring can be detected even at a small scale.



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