Animals have developed physiological mechanisms allowing them to respond to ecologically-relevant acute stressors, but whose prolonged activation under chronic stress may lead to exhaustion. In insects, these mechanisms are poorly understood. Since honey bees are insects of uttermost economic and ecological importance that face many stressors, this project aims at characterizing their stress response and identifying its modulating factors. More specifically, we will explore how they respond to a social stress signal, how this response is influenced by season and social context, and whether we can modulate it to limit the impact of chronic stress due to predation by the yellow-legged hornet. Our previous work showed that exposure to a social alarm signal leads to reduced learning, and that this effect is mediated by brain neuropeptides : allatostatins. Yet, not all bees respond in the same way to the signal or to allatostatin injections, meaning that the physiological response is differentially regulated, depending on the season (winter vs. summer) or the individual social role in the colony (e.g. nurses vs. foragers). Our three-partner consortium will use a unique combination of complementary approaches (behavioral assays, functional brain imaging, neuroanatomy, pharmacology, molecular biology, chemistry) in order to address three main objectives: 1) characterize the factors responsible for response variations within the colony; 2) identify the neural and hormonal mechanisms of this plasticity; 3) evaluate how these mechanisms are impacted by chronic predation by hornets, and test strategies to improve bees’ capacity to adapt to this recently emerged major stressor. Hence, this project should bring a breakthrough in our comprehension of bee biology and of its capacity to cope with stress, and should open avenues for possible applications to improve their resilience and welfare.