semiochemical

Semochemical is a chemical substance that conveys information between living organisms, influencing behavior, physiology, or development. Semochemicals mediate a wide range of interactions, from mating and foraging to alarm signaling and host selection. The study of these signals falls within chemical ecology, an interdisciplinary field that considers the chemistry, production, reception, and ecological context of signaling.

Semochemicals are broadly categorized by sender and recipient. Pheromones are signals released by individuals of a species that trigger responses in other members of the same species, such as mating cues or trail following. Allelochemicals are signals between different species and include kairomones, allomones, and synomones. Kairomones benefit the receiver but not the emitter (for example, prey odors that attract predators or parasitoids). Allomones benefit the emitter (for instance, plant volatiles that repel herbivores or attract their natural enemies). Synomones benefit both sender and receiver, typically in mutualistic or protective interactions, such as plant volatiles that attract pollinators while deterring herbivores.

Most semiochemicals are volatile and detectable at a distance via olfactory receptors, but many cues require physical contact. They occur in insects, plants, mammals, and other organisms, and may be produced by the emitter or released passively by the environment.

Applications include pest management and agriculture: pheromone-based monitoring traps, mating disruption, lure-and-kill strategies, and push-pull systems. More broadly, semiochemicals are used in wildlife management, crop protection, and medical research, reflecting their central role in mediator signaling in ecosystems.