Microscopic Signals, Macroscopic Ecology: The Chemical Ecology Logic of Multispecies Interactions

Chemical cues on a microscopic scale enable complex interactions among insects, plants, and microbes, from organismal to ecosystem scales. These signals ranging from plant volatile organic compounds to insect pheromones and microbial metabolites act as information cues that influence behavior, defense, and symbiosis. By linking individual physiology to community processes, these cues shape food web dynamics, community structure, and ecosystem function. Here, we review advances in deciphering the chemical ecology of multispecies interactions with emphasis on genomic and molecular insights. We emphasize signal biosynthesis, perception, and network transmission, and present case studies such as pine wilt nematode transmission and plant volatiles induced by herbivores for recruitment of natural enemies. We also move on to agricultural and conservation applications such as biocontrol strategies (e.g., pheromone traps, push–pull cropping) and microbial amendments that modulate plant defense. A systems perspective highlights the manner by which natural chemical information networks can render pest management and ecosystem conservation sustainable. Our integration underscores that chemical communication at all scales is needed to forecast and manage ecological outcomes.