General Impact
Please read Invasive ants impacts for a summary of the general impacts of invasive ants, such as their affect on mutualistic relations, the competitive pressure they impose on native ants and the effect they may have on vulnerable ecosystems.
There is conflicting evidence as to whether S. invicta inhibits the dispersal of ant-dispersed plants. In some cases, it may interrupt and reduce dispersal by competing with native ant dispersers, eating seeds whole or in-effectively dispersing seeds (ie: by leaving them exposed on the soil surface rather than protecting them by seed-burial). S. invicta may increase or decrease the survival of plant, depending on the species and other biotic variables. They may benefit a plant by killing, or at least deterring, insects that damage the plant (such as plant-feeding insects). Alternatively, or in addition, they may reduce numbers of insects that benefit the plant, such as plant mutualists that protect the plant or disperse plant seeds or carnivorous insects (that prey on plant-feeding insects). In fact, S. invicta is a notable example of an invasive ant which has negative effects on such insects, because it prefers a protein-rich diet (Ness and Bronstein 2004).
S. invicta reduces biodiversity among invertebrates and reptiles, and may also kill or injure frogs, lizards or small mammals. In particular the red imported fire ant has the potential to devastate native ant populations (McGlynn 1999). It is competitively dominant to most other invasive ant species; it has displaced the Argentine ant (Linepithema humile), but not Monomorium minimum, in areas in the USA where the species have been introduced (Holway et al. 2002). In the USA, it has been found to negatively impact at least fourteen bird species, thirteen reptile species, one fish species and two small mammal species (through predation, competition and/or stinging) (Holway et al. 2002). The current economic impact of S. invicta on humans, agriculture, and wildlife in the United States is estimated to amount to at least half a billion, if not several billion, dollars per year (Thompson et al. 1995, Thompson and Jones 1996, in Morrison et al 2004).
S. invicta may impact social and economic activities at all levels. They can sting people and may cause an allergic reaction. Public areas such as parks and recreational areas may become unsafe for children. They may infest electrical equipment (such as computers, swimming pool pumps, cars or washing machines) becoming a nuisance, or even a danger, to people. Agricultural impacts may include damage to crops, interference with equipment and the stinging of workers in the field. The costs associated with S. invicta in the United States, for example, have been estimated at $1 billion per year (Pimentel et al. 2000, Tsutsui and Suarez 2003). The Australian Bureau of Agriculture Resources Economics has estimated the losses procured in rural industries to amount to more than AU $6.7 billion over 30 years. According to a professor at the Texas Agricultural Extension (USA) the agricultural economic losses caused by the ant are an estimated US $90 million annually. In Texas at least US $580 million was spent in 2000 to control this pest. Gutrich et al. (2007) undertook a study to estimate the potential economic costs to Hawaii, in case of the introduction and establishment of the red imported fire ant. The authors of the study conclude that the estimated impact on various economic sectors in Hawaii would be around US $ 211 million/year.
Click here for Information about the relation between colony structure and level of threat
Location Specific Impacts:Abaco Is. (Bahamas) 
Competition: Competes with native ant populations. Cayman Brac (Cayman Islands)
Ecosystem change: Fire ants, Solenopsis invicta carry seeds (including native and introduced weeds) into nests, with various potential effects on plant communities (Burton, 2003 in Varnham, 2006).
Ecosystem change: Fire ants, Solenopsis invicta carry seeds (including native and introduced weeds) into nests, with various potential effects on plant communities (Burton, 2003 in Varnham, 2006).
Human nuisance: Fire ants, Solenopsis invicta bite humans aggressively, and so are considered a serious pest (Burton, 2003 in Varnham, 2006).
Predation: The fire ant, Solenopsis invicta is a predator of a wide range of soil invertebrates (including earthworms), kills and consumes sick or disabled vertebrates.
Reduction in native biodiversity: Anecodotal evidence suggests that fire ants, Solenopsis invicta are severe predators on eggs of Anolis lizards, and geckoes, whose populations recover when control measures are implemented.
Threat to endangered species: Fire ants, Solenopsis invicta may invade nests of endangered Cycluran iguanas, like the 'Critically Endangered (CR)' endemic Cayman island ground iguana (see Cyclura lewisi in IUCN Red List of Threatened Species). Grand Cayman (Cayman Islands)
Ecosystem change: Fire ants, Solenopsis invicta carry seeds (including native and introduced weeds) into nests, with various potential effects on plant communities (Burton, 2003 in Varnham, 2006).
Human nuisance: Fire ants, Solenopsis invicta bite humans aggressively, and so are considered a serious pest (Burton, 2003 in Varnham, 2006).
Predation: The fire ant, Solenopsis invicta is a predator of a wide range of soil invertebrates (including earthworms), kills and consumes sick or disabled vertebrates.
Reduction in native biodiversity: Anecodotal evidence suggests that fire ants, Solenopsis invicta are severe predators on eggs of Anolis lizards, and geckoes, whose populations recover when control measures are implemented.
Threat to endangered species: Fire ants, Solenopsis invicta may invade nests of endangered Cycluran iguanas, like the 'Critically Endangered (CR)' endemic Cayman island ground iguana (see Cyclura lewisi in IUCN Red List of Threatened Species). Little Cayman (Cayman Islands)
Human nuisance: Fire ants, Solenopsis invicta bite humans aggressively, and so are considered a serious pest (Burton, 2003 in Varnham, 2006).
Predation: The fire ant, Solenopsis invicta is a predator of a wide range of soil invertebrates (including earthworms), kills and consumes sick or disabled vertebrates.
Reduction in native biodiversity: Anecodotal evidence suggests that fire ants, Solenopsis invicta are severe predators on eggs of Anolis lizards, and geckoes, whose populations recover when control measures are implemented.
Threat to endangered species: Fire ants, Solenopsis invicta may invade nests of endangered Cycluran iguanas, like the 'Critically Endangered (CR)' endemic Cayman island ground iguana (see Cyclura lewisi in IUCN Red List of Threatened Species). China
Agricultural: Red fire ants (RIFA) have caused following damage in China: crops and vegetables have fewer new sprouts; rice paddies and orchards have been abandoned. RIFA can attack various parts of plants such as: seeds, fruit, sprouts, young branches and roots, etc (DOA 2006. Translated from Chinese by Jia Ren 2006).
Competition: RIFA is a strong competitive ant species that can severely affect domestic ant species (DOA 2006. Translated from Chinese by Jia Ren 2006).
Economic/Livelihoods: According to an estimate, if no effective prevention and control activities are taken, fire ants could cause a total loss of 128.04 billion Yuan (equals about 15.5 billion US dollars) in the next 35 years in China (DOA 2006. Translated from Chinese by Jia Ren 2006).
Ecosystem change
Human nuisance: The national survey revealed that there have been around 15,000 humans were bitten by RIFA and more than 200 people needed specific medical treatments (DOA 2006. Translated from Chinese by Jia Ren 2006).
Physical disturbance: In severely affected areas, wires, electric facilities and irrigation dams have been damaged by RIFA (DOA 2006. Translated from Chinese by Jia Ren 2006).
Reduction in native biodiversity Alabama (United States (USA))
Agricultural: Damages seeds and crops. Mounds interfere with equipment. Deters hand labour.
Competition: Competes with native ant populations.
Economic/Livelihoods: Economic loss through crop damage and control operations.
Human nuisance: Sting is toxic with 1% allergic reaction in humans.
Predation: Predates native fauna (frogs, lizards, birds, small mammals). Arkansas (United States (USA))
Agricultural: Damages seeds and crops. Mounds interfere with equipment. Deters hand labour.
Competition: Competes with native ant populations.
Economic/Livelihoods: Economic loss through crop damage and control operations.
Human nuisance: Sting is toxic with 1% allergic reaction in humans.
Predation: Predates native fauna (frogs, lizards, birds, small mammals). California (United States (USA))
Agricultural: Damages seeds and crops. Mounds interfere with equipment. Deters hand labour.
Competition: Competes with native ant populations.
Economic/Livelihoods: Economic loss through crop damage and control operations.
Human nuisance: Sting is toxic with 1% allergic reaction in humans.
Predation: Predates native fauna (frogs, lizards, birds, small mammals). South Carolina (United States (USA))
Agricultural: Damages seeds and crops. Mounds interfere with equipment. Deters hand labour.
Competition: Competes with native ant populations.
Economic/Livelihoods: Economic loss through crop damage and control operations.
Human nuisance: Sting is toxic with 1% allergic reaction in humans.
Predation: Predates native fauna (frogs, lizards, birds, small mammals). Tennessee (United States (USA))
Agricultural: Damages seeds and crops. Mounds interfere with equipment. Deters hand labour.
Competition: Competes with native ant populations.
Economic/Livelihoods: Economic loss through crop damage and control operations.
Human nuisance: Sting is toxic with 1% allergic reaction in humans.
Predation: Predates native fauna (frogs, lizards, birds, small mammals). Texas (United States (USA))
Agricultural: Damages seeds and crops. Mounds interfere with equipment. Deters hand labour.
Economic/Livelihoods: Economic loss through crop damage and control operations.
Human nuisance: Sting is toxic with 1% allergic reaction in humans.
Predation: Predates native fauna (frogs, lizards, birds, small mammals).
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