Identification of the Argentine ant Linepithema humile (Hymenoptera: Formicidae) using an artificially synthesized trail pheromone and its effects on native Japanese ants.
Invasion by the Argentine ant Linepithema humile (Mayr) (Hymenoptera: Formicidae) causes the collapse of global ecosystems. Attempts to exterminate this invasive ant have mostly been unsuccessful after colonization. However, some attempts are successful when they are applied in the initial stage of invasion, or the invaded area is limited. This indicates that early identification of invasion is crucial for successful extermination. The current methods of identification require special training and skills, suggesting that a new easy and fast method of identification is urgently required. Here, we report a method of identification using a species-specific trail pheromone. The Argentine ant uses (Z)-9-hexadecenal as a trail pheromone. (Z)-9-Hexadecenal is commercially available, because it is used to control the reproduction of a moth (Chilo suppressalis). We applied (Z)-9-hexadecenal 10 cm away from the trails of Argentine ants and 12 native Japanese ant species. The Argentine ant trails were largely disturbed, while the effect on the native Japanese ants was almost undetectable. These results suggest that this "trail disruption identification method" is an easy and fast method of identifying Argentine ants in Japan and that the effects of this method on native Japanese ants, if any exist, are small.