Color and scent are well-known pollinator cues. Some plants also produce heat, but its role remains unclear. Here, we report that plant-generated thermal infrared radiation serves as a pollination signal and describe the underlying mechanisms of heat production and infrared detection. Mitochondrial adaptations heat plant reproductive structures in a circadian pattern, radiating infrared that is sufficient to attract beetle pollinators. Beetle antennae contain infrared-activated neurons with thermosensitive ion channels that are structurally tuned to match host plant thermogenesis. Comparative analyses revealed that infrared is among the earliest pollination signals, and indicate a deep-time transition from infrared-based to color-dominated signaling in flowering plants. Our findings uncover an ancient sensory modality shaping the early evolution of pollination, one of the world’s most vital processes linking plants and animals.
Valencia‐Montoya et al. (2025) studied this question.