autoinducer
/ˌɔːtəʊɪnˈdjuːsə/ /ˌɔːtəʊɪnˈdʒuːsə/Biology
noun
A substance causing autoinduction; especially an extracellular molecule produced by a population of microorganisms which induces a particular process in the population as a whole once a sufficient concentration is reached.
Origin
1960s. From auto- + inducer, after autoinduction.