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The olfactory response of fire ants to plant leaves, mealybugs and the honeydew excreted by mealybugs was tested with a Y-tube olfactometer. The foraging activities of fire ants on three plants were also measured. Our results showed that plant leaves and mealybugs alone had no significant attraction to the fire ant workers, while fire ants could be obviously attracted by honeydew. The selection rate of fire ants on honeydew of Hibiscus rosa-sinensis, cotton (Gossypium spp.) and tomato (Solanum lycopersicum) was 60.22%, 57.45% and 64.29% respectively. When mealybugs were present on plants, fire ant workers foraged more frequently on the plants than controls (P<0.05). As to different plants, fire ants preferred foraging on tomato (66.3 per plant) to Hibiscus rosa-sinensis (50.4 per plant) and cotton (45.1 per plant). However, there was no significant difference in foraging frequency of fire ants on the three kinds of plant, with 24.9, 22.9 and 32.3 ants foraging per five minutes respectively.