[Perspective] Bee happy

In his book, The Expression of the Emotions in Man and Animals, Charles Darwin noted that “Even insects express anger, terror, jealousy, and love by their stridulation.” Almost 150 years later, spurred by an interest in the evolutionary roots of emotional (affective) processes and their underlying mechanisms, there has been a sudden upsurge of research into the question of whether insects and other invertebrates may indeed have emotion-like states (1–4). Recent work has focused on negative