 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 especially prevalent during periods of heavy precipitation and flooding. Fire ant colonies have been found inside automobiles, trucks and recreation vehicles resulting in traffic accidents caused by fire ants stinging the drivers. Imported fire ants are attracted by electrical currents and have caused considerable damage to heat pumps, air conditioners, telephone junction boxes, transformers, traffic lights, and gasoline pumps.
Because of their reputation people fear fire ants. In some areas playgrounds, parks, and picnic areas are rarely used because of the presence of fire ants. In campsites of state and national parks in fire ant infested areas, it is often difficult to put up or take down a tent without being stung by angry ants.
Stings. Fire ants are best known for their behavior of stinging, frequently in mass. If a nest is disturbed hundreds if not thousands of ants will quickly emerge and attack the intruder. This occurs so quickly and in mass that is not uncommon to have hundreds on the victim before the first sting is felt. To make matters even worse a single fire ant can sting repeatedly and will continue to do so even after their venom sac has been depleted. Once reaching the victim the ant will typically attach with its mandibles to the skin and then insert its stinger. Subsequently it will rotate it abdomen and repeatedly sting using the attached head as a pivot. The result is a circle of several stings from the same ant.
Initially, the sting(s) result in a localized intense burning sensation (hence the name "fire" ant). Within a day or two a white pustule forms at the sting site (Figure 8). Pustule formation occurs only with the red and black imported fire ant and not the southern fire ant or fire ant. There is a possibility of secondary infection and scarring if the wounds are not kept clean or if they are continually picked at or scratched (Figure 9). As with any other hymenopterous stings, there are a few individuals who are hypersensitive to the venom and can react quite strongly and be severely affected. Symptoms in these cases can include chest pains, nausea, dizziness, shock or, in rare cases, lapsing into coma. In cases of an allergic reaction, even a single sting can lead to a potentially serious condition called anaphylactic shock. There are recorded cases of human death resulting from fire ant stings but these are rare.
Pustular formation for sting of red imported fire ant. Image courtesy of USDA Archives.
Figure 9. Secondary infection of sting from red imported fire ant. Image courtesy of USDA Archives.
Individuals with disabilities, reduced feeling in their feet and legs or reduced mobility, are at greater risk from serious stinging incidents and the incidence of resulting medical problems may be even greater. Large numbers of ants can sting and even overcome victims before they can safely escape. There was a recent case where fire ants entered a room of an elderly gentleman in a retirement hospital and basically stung him to death. In his case he was unable to escape their attack.
Individ