Rising global temperatures are expected to reshape predator-prey interactions, which are central to the structure, dynamics and functioning of natural ecosystems. While predator feeding rates are known to depend on temperature and vary across species, how this relationship varies within species across the different climatic regions conditions they inhabit is still poorly understood. Yet identifying this relationship is essential to predict how natural populations and communities will be affected by climate change across different geographic and climatic regions. Here we address this knowledge gap by experimentally measuring the thermal responses of predators collected from nine populations representing three latitudes spanning most of the continental US (a gradient of 11 degrees). Specifically, we set up 145 independent replicated predator-prey systems across an experimental temperature gradient ranging from 5-35 degrees C to quantify the thermal response curves for each of the nine predator populations. We found stark differences in thermal responses across latitudes ranging from clear humped-shaped curves to a mostly linear increase. Most notably, these intraspecific differences in the overall shapes of thermal responses reveal opposing latitudinal patterns depending on the range of temperature considered. These results reveal that local climate can shape how interactions respond to warming and highlight the need to consider past local climatic conditions when predicting responses of natural systems to climate change at the local, regional, and global scale.
