Electronic Thesis and Dissertation Repository

Degree

Master of Science

Program

Biology

Supervisor

Sinclair, Brent J.

2nd Supervisor

Gariepy, Tara D.

Joint Supervisor

Abstract

The invasive crop pest Halyomorpha halys has been established in Ontario since 2012 and poses a significant threat to Canadian agriculture. I investigated the tolerance of H. halys to three stressors - low temperatures, desiccation, and energy depletion - in addition to investigating the role of lab-induced diapause in enhancing stress tolerance. Overwintering H. halys depress their supercooling point to -15.4 °C and LT50 to -17.5 °C after acute (1 h) exposure, however they do not encounter these temperatures while overwintering indoors. Moreover, overwintering H. halys maintain their water balance through a reduction of water loss rates, while conserving energy stores (lipids and carbohydrates). This is consistent with lab-reared-diapausing H. halys who exhibit reduced water loss rates and temperature-independent metabolic suppression relative to non-diapausing adults, suggesting that diapause enhances desiccation resistance and energy conservation. Thus, H. halys are likely to persist in Ontario barring any significant changes in overwintering conditions.

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