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| synonyms = ''Solenopsis saevissima wagneri'' Santschi, 1916 | range_map = Solenopsis invicta distribution.svg | range_map_caption = The original, natural range of ''S. invicta'' }} The red imported fire ant (''Solenopsis invicta''), or simply RIFA, is one of over 280 species in the widespread genus ''Solenopsis''. Although the red imported fire ant is native to South America, it has become a pest in the southern United States,〔 Australia,〔 the Caribbean,〔 Taiwan,〔 Hong Kong,〔 the southern Chinese provinces of Guangdong, Guangxi and Fujian, and Macau.〔 RIFAs are known to give a painful, persistently irritating sting that often leaves a pustule on the skin.〔(【引用サイトリンク】url=http://entomology.ifas.ufl.edu/creatures/urban/ants/red_imported_fire_ant.htm )〕 ==Overview== The red imported fire ant, a eusocial species, are far more aggressive than most ant species. Animals, including humans, often encounter them by inadvertently stepping on one of their mounds, which causes the ants to swarm up the legs, attacking ''en masse''. The ants respond to pheromones released by the first ant that attacks, thereafter stinging in concert. RIFAs successfully compete against other ants, and have been expanding their range. Recently, colonies of Rasberry crazy ant (also known as Old World crazy ants) have been introduced in the same ranges as RIFAs. These ants are ecologically dominant over fire ants, which has been limiting their range slightly. They are considered to be a pest, not only because of the physical pain they can inflict, but also because their mound-building activity can damage plant roots, lead to loss of crops, and interfere with mechanical cultivation. It is not uncommon for several fire ant mounds to appear suddenly in a suburban yard or a farmer's field, seemingly overnight. The sting of the RIFA has venom composed of a necrotizing alkaloid, which causes both pain and the formation of white pustules that appear one day after the sting. Fire ants are excellent natural predators and can be used as biological controls for pests such as sugarcane borers, rice stink bugs, striped earwigs, aphids, boll weevils, soybean loopers, cotton leafworms, hornflies, 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 food. They are proficient enough at overwhelming intruders to virtually clear an area of invertebrates, lizards, and ground-dwelling birds. Red imported fire ants are extremely resilient, and have adapted to contend with both flooding and drought conditions. If the ants sense increased water levels in their nests, they come together and form a ball or raft that floats, with the workers on the outside and the queen inside.〔Flatow, Ira (April 29, 2011). (Bug News Roundup: Ant Rafts, Robot Caterpillars ) ((video )) ''Science Friday''. NPR. Retrieved 9 May 2011.〕 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, although they do not hibernate during the winter, colonies can survive temperatures as low as 16 °F (−9 °C). RIFAs were the first species shown to possess a green-beard gene, by which natural selection can favor altruistic behavior. Workers containing this gene are able to distinguish between queens containing this genes and those that do not by apparently using odor cues. The workers kill queens that do not contain the gene. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Red imported fire ant」の詳細全文を読む スポンサード リンク
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