Electronic Thesis and Dissertation Repository

Degree

Master of Science

Program

Biology

Supervisor

Brent Sinclair

Abstract

The crop pest Drosophila suzukii, native to Southeast Asia, has been found in Ontario since 2010. This raises concern with respect to it establishing permanent populations, however, little is known about its cold tolerance. I investigated the low-temperature tolerance, including phenotypic plasticity, of D. suzukii. While acclimation increased cold tolerance, there was no evidence of short-term cold-hardening. Chill coma occurs at -1.2 °C, which will limit winter activity. Cold shock decreased the reproductive output of females, but this negative effect may be mitigated by re-mating. Drosophila suzukii is chill-susceptible and 80 % of the flies die after exposure to -7.5 °C (females) and -7 °C (males). Even acclimated flies could not survive at 0 °C for more than seven days, or in overwintering field cages. These results suggest that D. suzukii might not be able to survive winter conditions in the field in Ontario.

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