kairomone
noun
kai·ro·mone ˈkī-rə-ˌmōn 
-rō-
: a chemical substance emitted by one species and especially an insect or plant that has an adaptive benefit (such as a stimulus for oviposition) to another species
Word History
Etymology
Greek kairos critical time, opportunity + English -mone (as in pheromone)
First Known Use
1970, in the meaning defined above