Overwintering biology of the brown marmorated stink bug, Halyomorpha halys (Hemiptera: Pentatomidae)
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.