Here, our project has the ambition to understand the mechanisms of adaptation, in particular the plasticity of animal organisms (insects) to an increase in temperature, and this in the context of climate change. We have chosen to work with bumblebees, as model organisms, as they are essential pollinators in natural and managed ecosystems, their genome is known, and they have the physiologically unique feature to adapt to ambient temperatures. The question raises whether bumblebees, as cold-adapted bees, will be able to cope with current and future global warming. Two abundant species, Bombus pascuorum and B. lapidarius, will be sampled over their full geographic range and associated climatic conditions. These species are chosen as they are wide but differently distributed in Europe encompassing several climate zones, belong to two different clades within the genus Bombus, and should thus have specific adaptations to the climatic conditions they encounter. Our focus is to determine whether the bumblebees’ability to cope with high(er) ambient temperatures is due to an improved: thermal tolerance, or an improved thermoregulation ability. Therefore, bumblebees’morphologic adaptation will be measured, the specific genes underlying this adaptation capacity identified, and their physiological adaptation tested during different stages of colony development.