Bees associate warmth with floral colour

Abstract

Floral colour signals are used by pollinators as predictors of nutritional rewards, such as nectar^1,2,3. But as insect pollinators often need to invest energy to maintain their body temperature⁴ above the ambient temperature, floral heat might also be perceived as a reward. Here we show that bumblebees (Bombus terrestris) prefer to visit warmer flowers and that they can learn to use colour to predict floral temperature before landing. In what could be a widespread floral adaptation, plants may modulate their temperature to encourage pollinators to visit.