MELLEIN, A TRAIL PHEROMONE COMPONENT OF THE ANT LASIUS-FULIGINOSUS

3,4-Dihydro-8-hydroxy-3-methylisocoumarin (mellein) and 2,3-dihydro-3, 5-dihydroxy-6-methyl-4H-pyran- are among the volatile constituents ide ntified from the hindgut of the formicine ant Lasius (Dendrolasius) fu liginosus Mellein induces trail-following behavior in worker ants of t his species and evokes electrophysiological responses from their anten nae. The trail-following activity released by (R)-(-)-mellein is signi ficantly higher than that elicited by its (S)-(+) antipode, or the rac emic mixture. The above-mentioned pyranone is found also in the honeyd ew of aphids, the customary diet of this ant species. The pyranone als o evokes some trail-following behavior, but its activity is far less p ronounced than that of mellein. Apparently, extra pheromone components are present in the hindgut, since the activity of these two constitue nts, either individually or as a mixture, does not completely account for the total activity released by a hindgut extract containing simila r amounts of these two compounds.