The Influence of Abiotic Factors and Temporal Variation on Local Invasion Patterns of the Argentine Ant (Linepithema humile)

The Argentine ant is a common pest of mediterranean-type ecosystems worldwide, causing widespread extirpation of many native ant species. This study examines spatial and temporal patterns of invasion at a local scale, investigates the effects of this invader on native ant communities and assesses causal mechanisms for these spatial, temporal and numerical patterns, particularly in relation to local climate. Argentine ant workers were more active in the drier months of summer and fall, and abundance was correlated with cumulative precipitation the previous winter. Argentine ant worker abundance greatly increased in conjunction with EI Niño events. No similar relationship existed for native ants. This invasive ant affected native ant abundances differently by species: some species were able to tolerate its presence temporarily. Overall, this study provides a framework of factors to consider when devising control strategies for the invasive Argentine ant.