The survival of animals under global warming strongly depends on their
individual thermal niches, which result from the balance between energy
loss and gain. Active movement is an important component of this
energetic balance, as it affects not only energy gain via food intake
but also energy loss via activity metabolism. Here, we develop a novel
trait-based approach for how thermal niches arise from
temperature-dependent movement. Therefore, we used image-based tracking
to quantify the unimodal responses of the movement speed of carabid
beetles to temperature. We used these empirical data to parameterize a
mathematical model based on metabolic and predator-prey theory for net
energy gain to derive a general mechanistic concept of thermal niches.
This trait-based approach allows a relatively rapid and cost-effective
assessment of climate change vulnerability for a wide range of animal
taxa on broad geographic scales.