Bee fear responses are mediated by dopamine and influence cognition.

Abstract

Predatory threats, even when they do not involve direct consumption (non-consumptive effects, NCEs), can profoundly influence the physiology and behaviour of prey. For example, honeybees that encounter hornet predators show responses similar to fear. However, the physiological mechanisms that are connected with this fear-like response and their effects on bee cognition and olfaction remain largely unknown. We show that bees decreased time spent near the hornet, demonstrated fearful behaviour and moved with greater velocity to escape. After a prolonged 24-h exposure, bees adopted defensive clustering, displayed greater predator avoidance, and experienced a decline in brain dopamine levels. Prolonged predator exposure also diminished bee olfactory sensitivity to odours and their mechanical sensitivity to air currents, contributing to impaired olfactory learning. However, boosting brain dopamine reversed one fear-like behaviour (average bee velocity in the presence of a hornet) and rescued olfactory sensitivity and learning. We therefore provide evidence linking dopamine to sensory and cognitive declines associated with fear in an insect.