Meeting Abstract
Climate change models predict an increase in the co-occurrence of heat waves and water limitation (e.g., drought). Both of these stressors can independently impact an animal’s resource (energy or water) balance, which is tightly linked to survival and reproduction. Yet, the interactive (e.g., additive or synergistic) costs of heat wave and water limitation to animals is poorly understood. Animals experiencing heat wave and/or water limitation may employ two general strategies to limit costs to resource balance. Stressed animals may use a resource conservation strategy via shifts in physiology (e.g., reducing metabolic rate to conserve energy or altering integument to reduce water loss) or behavior (e.g., reducing behavioral activity to limit energy use and water loss). Second, stressed animals may alter their resource investment strategies whereby resources are divested from one trait to maintain investment into another trait. We used a factorial design on fasted wing-dimorphic crickets (Gryllus lineaticeps) to examine the independent and interactive costs of a field-parameterized heat wave and water limitation. We determined survival, energy balance and loss (body mass and metabolic rate, respectively), water balance and loss (total water content and evaporative water loss rate, respectively), behavioral activity, and investment into reproduction (gonad mass), locomotion (flight muscle), and immune function (total phenoloxidase activity). Together, our results will clarify the costs of multiple stressors to several levels of biological organization (from life history to behavior and physiology), and reveal complexities underlying general strategies employed during resource-related stress.
