{{Taxobox
| name = Red imported fire ant
| image = Fire ants02.jpg
| regnum = Animalia
| phylum = Arthropoda
| classis = Insecta
| ordo = Hymenoptera
| familia = Formicidae
| tribus = Solenopsidini
| genus = ''Solenopsis''
| species = '''''S. invicta'''''
| binomial = ''Solenopsis invicta''
| binomial_authority = Buren, 1972
}}
The '''red imported fire ants''' (''Solenopsis invicta''), or simply '''RIFA''', is one of over 280 members of the widespread Solenopsis''. Although the red imported fire ant is native to Chinese province of Guangdong. In January 2005, several ant-hills belonging to fire ants were found in northern Hong Kong. Later, after a thorough search for the ant was conducted there, several hundred ant-hills were found in different parts of Hong Kong. There were also reports of ant hills in Macau, the former Portuguese enclave that borders the province of Guangdong.

Colonies were accidentally introduced into the United States in the 1930s through the seaport of Mobile, Alabama.<ref></ref> Cargo ships from Brazil docking at Mobile unloaded goods infested with the ants; they have since spread from Alabama to the coastal plain and piedmont of almost all of the south-eastern states, as well as into California. The ants were accidentally introduced into Australia in 2001, in a similar way.<ref></ref>

==Overview==
RIFA are more aggressive than most native ant species and have a painful sting. A person typically encounters them by inadvertently stepping into one of their mounds, which causes the ants to swarm up the person's legs, attacking ''en masse.'' The ants respond to pheromones that are released by the first ant to attack. The ants then swarm and immediately sting when any movement is sensed.

thumb|left|Texas fire ant

RIFA are efficient competitors to other ants, and have been successful at enlarging their range, notably in the United States, where they have gradually spread north and west despite intense efforts to stop them. Today they are found in most of the south-eastern states, including Georgia, Florida, North Carolina, South Carolina, Maryland, and Virginia. It is not uncommon for several fire ant mounds to appear suddenly in a suburban yard or a farmer's field, seemingly overnight. Even in the San Francisco, California, area, there are large numbers of red imported fire ants.  (At least one community uses the presence of fire ants as a publicity opportunity: Marshall, Texas, hosts an annual [http://www.marshall-chamber.com/pages/fireants.php fire ant festival].)
thumb|right|280px|Current distribution of the RIFA in the [[United States]]
RIFA are still on the move, often travelling from one area to another in turf, root balls of nursery plants, and other agricultural products. They are a pest, not only because of the physical pain they can inflict, but because their mound-building activity can damage plant roots and lead to loss of crops. Their stings are rarely life-threatening to humans and other large animals, causing only 80 documented deaths as of 2006. They often kill smaller animals such as birds. They sometimes kill newborn calves if the calves do not get on their feet quickly enough. The sting of the RIFA has venom composed of a necrotizing alkaloid which causes both pain and the formation of white pustules which appear one day after the sting. 

Red imported fire ants are extremely resilient and have adaptations to contend with both flooding and drought conditions. If the ants sense increased water levels in their nests, they will come together and form a huge ball or raft that is able to float on the water, with the workers on the outside and the queen inside. Once the ball hits a tree or other stationary object, the ants swarm onto it and wait for the water levels to recede. To contend with drought conditions, their nest structure includes a network of underground foraging tunnels that extends down to the water table. Also, despite the fact that they do not hibernate during the winter, colonies can survive cold conditions as low as 16 °F (−9 °C).

At present, RIFA in the United States can be controlled but not eradicated. A number of products are available, which can be used on a mound-by-mound basis to destroy ant colonies when they appear. With all such efforts, it is important to reach and kill the queens, which may be as far as six feet (2&nbsp;m) underground; otherwise, some queens may simply move a short distance away and quickly re-establish the colony.

==Morphology==
''For general ant morphology check here''

Red imported fire ants have both a pedicel and postpediole. In other words they belong to a group of ants that have two humps between the thorax and abdomen. The workers have ten antennal segments terminating in a two segmented club. It is often difficult to distinguish between the red imported fire ant ''Solenopsis invicta'' and the other species in the genus. A number of characters are used, but are not always consistent between the black imported fire ant (''Solenopsis richteri'')or hybrids between the two species. Positive identifications can be made using high performance liquid chromatography (HPLC) to distinguish differences in the cuticular hydrocarbons.

==Spread==
A queen red fire ant, slightly crushed during [[image scanner|scanning|thumb]]
The RIFA's introduction to the US was in the late 1930s. Travelling in the soil used as ballast on cargo ships, they came in through the seaport of Mobile, Alabama. Since then, the RIFA population has increased its territorial range to include most of the East Coast and cm (18&nbsp;in) in diameter and 46&nbsp;cm (18&nbsp;in) in height, although in Alabama some mounds have been reported to be over 60&nbsp;cm high (2&nbsp;ft) and larger, especially in fields where cattle graze, they build on soil close to homes and other buildings, and sometimes forage indoors for food and moisture. They are a nuisance and can threaten sleeping or bedridden individuals, and pets. Occasionally they feed on vegetable plants in home gardens. The worst damage usually occurs during hot, dry weather when they invade flowerbeds while seeking warmth and moisture. If disturbed, fire ants bite and sting the intruder. 

They are somehow attracted to electrical equipment and crawl into air conditioning units and the electrical wiring of stop lights, shorting them out. This is the leading cause of traffic light shorts in Texas, where the ants cause more than US$140 million in damage each year. Several ant species, including fire ants, have been shown to contain ferromagnetic nanoparticles that may contribute information about the geomagnetic field for orientation during foraging or migration.<ref></ref> However, it has not been found that electric or magnetic fields attract the ants.<ref></ref> Rather, when wandering ants cause electrical shorts, they attempt to sting the wire and produce powerful semiochemicals, including defensive and recruitment pheromones.<ref></ref> The chemical signals draw additional ants to the short. The only effective protection is to bar ants from the equipment physically or with insecticides.

The FDA estimates that more than US$5 billion is spent annually on medical treatment, damage, and control in RIFA-infested areas. Further, the ants cause approximately US$750 million in damage to agricultural assets, including vet bills and livestock loss as well as crop loss.<ref> </ref>

Fire ants are excellent natural predators and are biological controls for pests such as the sugarcane borer, the rice stink bug, the striped earwig, aphids, the boll weevil, the soybean looper, the cotton leafworm, the hornfly, and many other pests harmful to crops. However, they also kill beneficial pollinators such as ground-nesting bee species. Seeds, fruits, leaves, roots, bark, nectar, sap, fungi, and carrion are all fire-ant prey, and they are not shy from creating their own carrion either. They are proficient enough at overwhelming intruders that they can virtually clear an area of invertebrates, lizards, and ground-dwelling birds.

Since September 2004, Taiwan has been seriously affected by the red fire ant. A few people are reported to have succumbed to venom from the ant stings. A large campaign to kill the ants has been partially effective, but it has not been able to eliminate all of them. 

In China in January 2005, a controversy arose when it became known that Guangdong's provincial government had suppressed all information about the spread of fire ants in the province since the middle of 2004. Hong Kong newspapers, including ''Appledaily'', ''Mingpao'', ''Hong Kong Economic Times'', ''Singtao'' and ''Takungpao'' (the latter funded by the Chinese government), have also reported that the ants have been found in both Shenzhen and Wuchuan in Guangdong province. 

According to a press briefing of the Agriculture, Fisheries and Conservation Department of Hong Kong, the city authorities have also located several ant-hills of ''Solenopsis invicta'' in an artificial wetland in Hong Kong's north-western section. 

<!-- Für Informationen zum Umgang mit dieser Tabelle siehe bitte Wikipedia:Taxoboxen. -->
{{Taxobox
| Taxon_Name       = Rote Feuerameise
| Taxon_WissName   = Solenopsis invicta
| Taxon_Rang       = Art
| Taxon_Autor      = Buren, 1972
| Taxon2_Name      = Feuerameisen
| Taxon2_WissName  = Solenopsis
| Taxon2_Rang      = Gattung
| Taxon3_WissName  = Solenopsidini
| Taxon3_Rang      = Tribus
| Taxon4_Name      = Knotenameisen
| Taxon4_WissName  = Myrmicinae
| Taxon4_Rang      = Unterfamilie
| Taxon5_Name      = Ameisen
| Taxon5_WissName  = Formicidae
| Taxon5_Rang      = Familie
| Taxon6_Name      = Hautflügler
| Taxon6_WissName  = Hymenoptera
| Taxon6_Rang      = Ordnung
| Bild             = Fire ants.jpg
| Bildbeschreibung = ''Solenopsis invicta''
}}

Die '''Rote Feuerameise''' (''Solenopsis invicta''), eine ursprünglich aus USA verbreitet.

== Lebensweise ==

Die Kommunikation verläuft, wie bei allen Ameisen, vornehmlich über Geruchsstoffe, sogenannte Pheromone. Die Ameisen produzieren eine ganze Palette dieser Stoffe und verständigen sich so innerhalb ihrer Kolonie. Hinzu kommen Geräusche, die durch Stridulation oder Klopfen der Beine entstehen, die allerdings nur in einem Umkreis von wenigen Zentimetern hörbar sind und von Artgenossen aufgenommen werden.

== Ausbreitung und Probleme ==

Ihre rasche Verbreitung nach ihrer Einschleppung in den USA ist auf ihr aggressives Verhalten zurückzuführen, das sie sowohl gegen andere Ameisenarten als auch gegen potentielle Angreifer wie den Menschen an den Tag legt. Dieses Verhalten hat ihr einen recht ungewöhnlichen wissenschaftlichen Artnamen eingebracht: ''Solenopsis invicta'' bedeutet übersetzt „Die unbesiegte Feuerameise“.

Unter der Ausbreitung der Insekten hat allerdings nicht nur der Mensch zu leiden. Die Feuerameisen sind effektive Raubtiere unter den Insekten. Sie ernähren sich von beinahe allen anderen Insekten und wurden somit zu einer der wirksamsten Waffen gegen Schädlinge in der Landwirtschaft. Hier wird sie teilweise eingesetzt, um die Populationen der Kornbohrer (das sind mehrere Arten kleiner Rüsselkäfer), verschiedener Blattläuse und einer Reihe weiterer Schadinsekten zu reduzieren.

Besonders aggressiv gehen die importierten Roten Feuerameisen jedoch gegen andere Ameisenarten vor. So haben sie in den südlichen USA die ehemals hier heimischen Feuerameisen ''Solenopsis xyloni'' und ''Solenopsis geminata'' beinahe ausgerottet. Auch die Populationen der Ernteameisen (''Pogonomyrmex badius'') wurden durch die eingeführte Art drastisch reduziert und auch alle anderen Ameisenarten werden durch die Feuerameise bedroht.

In China begannen die Behörden Anfang 2005 mit der Bekämpfung von Kolonien in Hongkong und Guangdong. <ref>[http://english.peopledaily.com.cn/200502/04/eng20050204_172915.html Urgent action taken against fire ants]</ref>

== Angriff und Wirkung auf den Menschen ==
thumb|Ein von Feuerameisen zerbissenes Bein