Trail pheromone ecology of the pavement ant, Tetramorium immigrans, and the European fire ant, Myrmica rubra

Foragers of many ant species deposit trail pheromones that guide nestmates to food resources. We identified 2-Methoxy-6-methylbenzoate ('MMMB') as the single-component trail pheromone of the pavement ant, Tetramorium immigrans (Hymenoptera: Formicidae). MMMB was sensed by worker antennae, induced trail following in laboratory bioassays, and effectively recruited nestmates to food baits in field settings. We deduced that only groups, and not individuals, of the European fire ant, Myrmica rubra (Hymenoptera: Formicidae) respond to pheromone trails. Furthermore, we determined that a 3-component pheromone blend comprising 3-ethyl-2,5-dimethylpyrazine ('EDP', the previously known trail pheromone component), (Z,E)-α-farnesene, and (Z,E)-α-homofarnesene, was superior to EDP in prompting (i) sustained trail-following behavior in laboratory bioassays and (ii) relatively faster recruitments of foraging ants to apple baits in a field experiment. All data combined provide impetus to develop synthetic trail pheromones coupled with lethal food baits as a tactic for integrated control of pest ants.