colony during the cold winter months.
Mound of red imported fire ant. Image courtesy of USDA Archives.
In areas with hot, dry summers these mounds may not be maintained or may not be formed at all. In a dark, protected site with sufficient moisture and an adequate supply of food, fire ants will nest in a wide variety of locations (e.g. rotten logs, walls of buildings, under sidewalks and roads, in automobiles, in dried cow manure).
Fire ants are omnivorous, feeding on almost any plant or animal material; although dead and living insects seem to be their preferred food. In rural habitats, they have a major impact on ground nesting animals (birds, reptiles, mammals). Studies have shown that once established in a new area there is typically a minimum of a two-fold reduction in the populations of field mice, snakes, turtles and other vertebrates and a maximum of a total elimination of some species. Fire ants also feed on plants attacking young saplings and seedlings, destroying buds and developing fruits and have been shown to feed on the seeds of over a hundred species of native wildflowers and grasses.
Damage to plants is increased during periods of drought as fire ants
seek alternate water sources. In fields where drip irrigation is used, these
insects build their mounds over the emitters reducing or blocking the flow of
water to crops. In some cases, actual physical destruction of microsprinkler
assemblies has occurred. Finally, the mere presence of fire ants on plants and
within the field will deter hand-harvesting of crops.
As an urban pest, imported fire ants cause many of the same problems experienced in rural areas. In addition they nest within the walls of homes and offices. Colonies are established under sidewalks and roadways frequently resulting in complete collapse of sections of these structures if the nests are eventually abandoned. The presence of fire ants can deter outdoor activities in yards, parks and school grounds. Home invasions can threaten small children and the elderly. House invasions are 