Abstract: 【Aim】 Discovery-dominance trade-off plays an important role in interspecific competition. This study aims to clarify how the red imported fire ant, Solenopsis invicta, with different invasion intensities affects the discovery-dominance trade-off of species of native ant communities, and to explore the competition mechanism between the red imported fire ant and native ant species. 【Methods】 From October to November 2017, ants in an Phyllanthus emblica plantation in Mouding County, Chuxiong Prefecture, Yunnan Province were collected by using baits and pitfall methods, and then the discovery ability, recruitment ability, dominance ability, the earliest time period of discovering baits and the individual number of each ant species were measured and recorded. 【Results】 The invasion of the red imported fire ants significantly affected the discovery-dominance trade-off of species of the native ant communities. There was no correlation between the relative discovery ability and the relative dominance ability of species of the native ant community in the strong invasion plot (5.6 ant colonies/100 m²), a weak but not significant correlation in the weak invasion plot (0.14 ant colonies/100 m²), and a significantly negative correlation in the control plot (without ant colonies)(strong invasion plot: r=-0.01, P=0.97; weak invasion plot: r=-0.60, P=0.21; control plot: r=-0.81, P=0.04). The red imported fire ants in the strong invasion plot discovered baits significantly faster than those in the weak invasion plot. The ant communities in the strong invasion plot discovered baits within 5 min, but the ant communities in the weak invasion plot needed 10-60 min to discover baits (χ²₍₅₎=33.37, P<0.001). The frequencies of discovering baits and dominance behavior of the red imported fire ants in the strong invasion plot were significantly higher than those in the weak invasion plot (frequency of discovering baits: χ²₍₁₎=17.27, P<0.001; frequency of dominance behavior: χ²₍₁₎=6.25, P=0.03), but there was no significant difference in the recruitment frequency between the two invasion plots (χ²₍₁₎=1.75, P=0.55). 【Conclusion】 The red imported fire ants break the discovery.dominance trade-off of species of native ant communities, and with the increase of its population, the discovery-dominance trade-off is affected and even destroyed. These results provide the scientific evidence for understanding the invasion mechanism of the red imported fire ant.

Key words: Solenopsis invicta; ant community, discovery-dominance trade-off, invasive species, foraging strategy