Flowers with bad breath.

Plants and insects have coexisted for millions of years (1). The evolution of flowers—the reproductive organs of angiosperms—has played a foundational role in shaping interactions between plants and insects (2). In addition to visual and structural adaptations, flowers evolved the ability to produce complex mixtures of volatile compounds that allow the plant to communicate with insects, often conveying specific messages (3). The emission of these floral scents can either seduce insects to visit the plant's reproductive organs, thereby increasing the chances of successful pollination, or repel unwanted visitors. During evolution, plants have modulated the molecular composition of these scents to address specific insect audiences. On page 656 of this issue, Okuyama et al. (4) report one example of a molecular mechanism by which plants can add a chemical message to their scent language. [ABSTRACT FROM AUTHOR]