A relationship where one species inhibits another via chemical secretion, unaffected itself:
Chemical inhibition with no detectable effect on the producer exemplifies amensalism, a (-,0) interaction. Antibiotic-producing microbes may suppress neighboring species, and plants can release allelochemicals that reduce germination or growth of nearby competitors. If the producer gains through reduced competition, the interaction may functionally become competition or interference rather than strict amensalism, so the neutral component should be interpreted from evidence. Commensalism reverses the signs to (+,0), parasitism couples a consumer benefit with host harm, and mutualism benefits bo
Ref: Ecology: From Individuals to Ecosystems, Begon et al., 5th Ed., Ch. 8-13