Systematic examination of learning in the invasive ant Linepithema humile reveals fast learning and long-lasting memory

Abstract

The Argentine ant, Linepithema humile, is one of the most damaging and widespread invasive ant species worldwide. A thorough understanding of their learning ability could be critical to improving control efforts. We conducted a systematic investigation of olfactory learning and route learning in Argentine ants. The ants showed rapid route learning after only one visit, and rapid odour learning and a long-lasting long-term memory after only one exposure to food cues. Food flavour information was transferred efficiently between ants in the nest, driving preference: naïve ants housed with ants fed on flavoured food showed a strong preference for that odour after 24 h. Overall, L. humile were found to be outstanding learners. This, coupled with efficient intranidal information transfer and strong pheromonal recruitment, may help explain their ability to discover and then dominate resources. However, these strengths could potentially be used against them, by exploiting learning and information transfer to improve control efforts.