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The sterile insect technique〔Vreysen , M. J. B. , Robinson , A. S. , and Hendrichs , J. ( 2007 ) . “ Area-wide Control of Insect Pests, From Research to Field Implementation . ” 789 pp. Springer , Dordrecht, The Netherlands〕 is a method of biological control, whereby overwhelming numbers of sterile insects are released. The released insects are normally male as it is the female that causes the damage, usually by laying eggs in the crop, or, in the case of mosquitoes, taking blood from humans. The sterile males compete with the wild males for female insects. If a female mates with a sterile male then it will have no offspring, thus reducing the next generation's population. Repeated release of insects can diminish small populations, though it could be impossible to eradicate it and is not efficient against dense insect populations.〔 The technique has successfully been used to eradicate the Screw-worm fly (''Cochliomyia hominivorax'') in areas of North America. There have also been many successes in controlling species of fruit flies, most particularly the Medfly (''Ceratitis capitata''), and the Mexican fruit fly (''Anastrepha ludens''). Insects are mostly sterilized with radiation, which might weaken the newly sterilized insects if doses are not correctly applied, making them less able to compete with wild males.〔Collins S. R. , Weldon C. W., Banos C., Taylor P. W. 2008. Effects of irradiation dose rate on quality and sterility of Queensland fruit flies, Bactrocera tryoni (Froggatt). Journal of Applied Entomology 132 (5): 398-405.〕〔Kumano Norikuni; Kawamura Futoshi; Haraguchi Dai; Kohama Tsuguo 2008. Irradiation does not affect field dispersal ability in the West Indian sweetpotato weevil, Euscepes postfasciatus. Entomologia Experimentalis et Applicata Volume 130 (1) : 63-72.〕〔Kumano Norikuni; Haraguchi Dai; Kohama Tsuguo 2008. Effect of irradiation on mating performance and mating ability in the West Indian sweetpotato weevil, Euscepes postfasciatus. Entomologia Experimentalis et Applicata, Volume 127, Number 3, pp. 229-236(8).〕 However, other sterilization techniques are under development which would not affect the insects' ability to compete for a mate. The technique was pioneered in the 1950s by American entomologists Dr. Raymond C. Bushland and Dr. Edward F. Knipling. For their achievement, they jointly received the 1992 World Food Prize. ==Development of the sterile insect technique== Raymond Bushland and Edward Knipling first developed the technique to eliminate screwworms preying on warm-blooded animals, especially cattle herds. With larvae that invade open wounds and eat into animal flesh, the flies were capable of killing cattle within 10 days of infection. In the 1950s, screwworms caused annual losses to American meat and dairy supplies that were projected at above $200 million. Screwworm maggots are also known to parasitize human flesh. Since a female screwworm mates only once in her lifetime, this physiological phenomenon has been exploited by biologists in breaking its life cycle. After mating with a sterile male, the screwworm female will not mate again nor lay any fertile eggs. The quest of Bushland and Knipling to find an alternative to chemical pesticides in controlling the devastation wrought by these insects began in the late 1930s when both scientists were working at the United States Department of Agriculture Laboratory in Menard, Texas. At that time, the screwworm was decimating livestock herds across the American South. Red meat and dairy supplies were also affected across Mexico, Central America, and South America. While Bushland initially researched chemical treatment of screwworm-infested wounds in cattle, Knipling developed the theory of autocidal control – breaking the life cycle of the pest itself. Bushland's enthusiasm for Knipling's theory sparked both men to intensify the search for a way to rear large numbers of flies in a "factory" setting, and most importantly, to find an effective way to sterilize flies. Their work in this area was interrupted by World War II, but Drs. Bushland and Knipling resumed their efforts in the early 1950s with their successful tests on the screwworm population of Sanibel Island, Florida. The sterile insect technique worked; near eradication was achieved using X-ray sterilized flies. In 1954, the technique was used to completely eradicate screwworms from the island of Curaçao, off the coast of Venezuela. Screwworms were eliminated in a span of only seven weeks, saving the domestic goat herds that were a source of meat and milk for the island people. During the 1960s and 1970s, SIT was used to control the screwworm population in the United States. The 1980s saw Mexico and Belize eliminate their screwworm problems through the use of SIT, and eradication programs have progressed through all of Central America, with a biological barrier having been established in Panama to prevent reinfestation from the south. In 1991, Knipling and Bushland's technique halted a serious outbreak in northern Africa. Similar programs against the Mediterranean fruit fly in Mexico and California use the same principles. In addition, the technique was used to eradicate the melon fly from Okinawa and has been used in the fight against the tsetse fly in Africa. The technique has been able to suppress insects threatening livestock, fruit, vegetable, and fiber crops. The technique has also been lauded for its many environmentally sound attributes: it leaves no residues, and has no negative effect on non-target species. Proven effective in controlling outbreaks of a wide range of insect pests throughout the world, the technique has been a boon in protecting the agricultural products to feed the world’s human population. Both Bushland and Knipling received worldwide recognition for their leadership and scientific achievements, including the World Food Prize. Their research and the resulting Sterile Insect Technique were hailed by former U.S. Secretary of Agriculture Orville Freeman as "the greatest entomological achievement of (the 20th) century." 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「Sterile insect technique」の詳細全文を読む スポンサード リンク
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