Kairomone

Definition

A semiochemical released by one species that is detected and exploited by a different species, to the benefit of the receiver and detriment or neutral effect on the emitter. Kairomones function as intercepted signals—chemical cues that receivers "eavesdrop" upon to locate prey, hosts, mates, or habitat, even when the emitter gains no advantage and may suffer increased predation or parasitism risk. The term distinguishes such exploited signals from allomones (benefit emitter, cost receiver) and synomones (mutual benefit).

Etymology

Greek kairos, "opportune moment" + -mone (from pheromone pattern), coined to emphasize the receiver's opportunistic exploitation of the signal.

Example

The parasitoid wasp Cotesia marginiventris detects and follows (Z)-3-hexen-1-ol and other green-leaf volatiles emitted by plants in response to feeding damage by caterpillar hosts; these plant kairomones betray the herbivore's location to the wasp, offering no benefit to the plant or caterpillar.

Related Terms

• Semiochemical
• allomone
• synomone
• Pheromone
• infochemical
• allelochemical

Usage Notes

Kairomone is defined strictly by fitness outcomes, not chemical structure: the same compound may function as kairomone, allomone, or synomone depending on ecological context. In pest management, synthetic kairomones are deployed to enhance biological control by attracting natural enemies to target pests. Contrast with synomone (mutualism) and allomone (emitter benefit).