The Argentine ant, Linepithema humile: natural history, ecology and impact of a successful invader

The Argentine ant, Linepithema humile, is one of the world’s worst invasive species, with established populations in at least 40 countries on six continents. In this review, we synthesise the vast literature on this species in four areas, concentrating on its introduction to natural systems. The first section reviews its distribution, habitat preferences, and the factors promoting its invasion success. Second, we review current knowledge of its ecological impacts on invertebrates, vertebrates and ecosystem functions. The third section deals with behaviour and genetics, particularly traits promoting invasiveness. Finally, we address applied issues, emphasising the quantification of the economic costs and eradication strategies associated with L. humile invasion. Despite tremendous research efforts, especially over the past 40 years, numerous knowledge gaps remain in the understanding of the distribution, ecology, impacts, management, and economic costs of this species. We conclude by highlighting the most critical gaps and propose a research agenda to tackle the future challenges in the study of L. humile biology.