A mature colony may contain 100,000 to 500,000 workers and a few thousand winged or reproductive forms. The winged reproductives mate in flight and shortly afterward the male dies. The fertilized female, after shedding her wings, constructs a cell in the ground in which the initial cluster of eggs is laid. Imported fire ants build mounds. These mounds grow to 1 m or more in diameter and 20 to 25 cm or more in height.
Taller mounds occur in heavier soils.
Red imported fire ant mounds are larger than those built by other fire ant species.