The tobacco plant synthesizes nicotine to protect itself from herbivores. The female moth broadcasts sex pheromones to attract a mate, while a soldier ant deploys an alarm pheromone to call for help. The carbon dioxide on a mammal's breath beckons hungry ticks and mosquitoes, while a flower's fragrance speaks to the honey bee. Indeed, much of the communication that occurs within and between various species of organisms is done not by sight, sound,...