Date of Award


Degree Type


Degree Name

Master of Science




Dr. Marc-André Lachance

Second Advisor

Dr. Mark Bernards

Third Advisor

Dr. Jeremy McNeil


Each species of Nitidulid beetle in the genus Conotelus is associated with a specific yeast species in the genus Metschnikowia. However, the reason for this selectivity is still unknown. Insects produce antimicrobial peptides (AMPs) that inhibit the growth of microorganisms. I hypothesized that Conotelus obscurus would produce specific AMPs that select in favor of its associated Metschnikowia species and that peptides produced by a particular Conotelus species can be induced by other yeast species. I investigated the antifungal activity of Conotelus obscurus larval extracts and compared their effect on three yeast species, Metschnikowia borealis, which is normally found in association with the beetle, and Metschnikowia reukaufii and Debaryomyces maramus, which are not commonly present. Although the hypothesis was rejected, differential inhibition was observed. I also demonstrated that adult beetles carry the yeasts in their digestive tract and release them during excretion.



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