Resolving biological impacts of multiple heat waves: interaction of hot and recovery days

Heat waves are increasing with global warming and have more dramatic biological effects on organisms in natural and agricultural ecosystems than mean temperature increase. However, predicting the impact of future heat waves on organisms and ecosystems is challenging because we still have a limited understanding of how the different components that characterize heat waves interact. Here we take an experimental approach to examine the individual and combine consequences of two important features that characterize heat waves: duration of successive hot days and recovery days between two hot spells. Specifically we exposed individuals of a global agricultural pest, the aphid Sitobion avenae to different heat wave scenarios by factorially manipulating the number of extreme hot days vs. normal days and altered which period individuals experienced first in their life cycle. We found that effects of heat waves were driven by a delicate balance of damage during hot periods vs. repair during norm...