Facing the heat: behavioral and molecular underpinnings of climate hardiness in bumblebees

Climate change heralds an era of increased heat waves, with an estimated 20-30 additional high heat days per year. While climate change is upon us, we still have little understanding of the organismal impacts of high heat and how to combat them. Insects, due to their short generation times and their sensitive ecological requirements, offer a powerful model for studying rapid physiological and behavioral responses to high temperatures. Solitary insects primarily respond to temperature extremes in three ways: by moving in space or time to remain in a constant environment; by exploiting phenotypic plasticity; or by exploiting evolutionary adaptation. Social insects, however, possess an additional tool in mitigating thermal stress: cooperative group behavior. Here, we discuss how bumblebees (Bombus) in particular exemplify the ways in which social living systems can buffer against environmental challenges. In this review, we highlight how the behavioral repertoire of social insects provides a uniquely suitable lens for studying the impact of climate change on dynamic societies. We focus on the urgent gap in understanding bumblebee response to high heat and propose additional studies/analytical frameworks to facilitate the identification of conserved behavioral and neural mechanisms to heat stress.