Do Dominant Native Ants Outcompete the Invasive Argentine Ant in Mediterranean Citrus Ecosystems? A Laboratory Test.

Simple Summary: Invasive Argentine ants threaten Mediterranean citrus ecosystems. We investigated how native ants, like Tapinoma nigerrimum and Lasius grandis, compete with Argentine ants. Our experiments showed that native ants, with their larger size and unique defences, outperformed Argentine ants in individual confrontations. At the colony level, Tapinoma nigerrimum effectively defended food resources against Argentine ants. These findings suggest that native ants play a crucial role in preventing Argentine ant invasion in citrus orchards. Understanding these interactions helps us better protect our ecosystems and agricultural lands. By studying how native ants resist invasions, we can develop strategies to conserve biodiversity and maintain healthy ecosystems, benefiting both the environment and society in general. The invasive Argentine ant (Linepithema humile) poses a significant threat to ecosystem stability worldwide. In Mediterranean citrus ecosystems, its spread may be limited by interactions with dominant native ant species. We conducted laboratory experiments to investigate the competitive dynamics between Argentine ants and two major native species, Tapinoma nigerrimum and Lasius grandis. At the individual level, both native species exhibited superior competitive performance, attributed to their larger body sizes and potential differences in chemical defences. At the colony level, T. nigerrimum demonstrated efficiency in interference competition, successfully defending food resources from Argentine ants. However, the Argentine ant exhibited higher recruitment capacity, albeit it was density-dependent. Our findings support the hypothesis that dominant native ants can serve as barriers against Argentine ant invasion in citrus ecosystems, highlighting the importance of interspecific competition in shaping community dynamics and invasive species management. This study underscores the potential role of native ant species in mitigating the impacts of invasive ants on ecosystem functioning and biodiversity conservation in agricultural landscapes, offering valuable insights for invasive species management strategies in Mediterranean citrus ecosystems. [ABSTRACT FROM AUTHOR]

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