In an effort to curb populations of the fire ant, shown here, the Agriculture Department plans to release hundreds of thousands of flies whose larvae decapitate the ants and then feed on their brains.

WASHINGTON, Nov. 17 — The South's newest weapon against the dreaded fire ant sounds like something out of a sci-fi thriller: An insect whose larvae eat the heads off their prey.

The Agriculture Department plans to release hundreds of thousands of tiny ant-eating flies in Georgia, across the South and possibly in California, where the fire ants have now spread. USDA says the gnat-like phorid flies, imported from Brazil, pose no harm to anybody or anything other than fire ants.

The flies don't kill enough of the ants to destroy colonies, but they cause enough panic to keep the ants in check, Brenner said. The ants, which have an innate fear of the flies, stop foraging and flee when they spot them, giving native ants a chance to move back into the territory.

Fire ants can make life miserable for homeowners and gardeners and cause billions of dollars in damage every year to air conditioners, electrical equipment and farms, experts say. The ants can blind and even kill livestock and wildlife, and their sting is occasionally fatal to humans.

The flies hover over ant mounds before darting down and injecting a torpedo-like egg into the ants. After the egg hatches, the maggot decapitates the ant by eating the brain and other contents of the head. The maggot later turns into a fly and the cycle is repeated.

Some scientists are skeptical that there are enough native ants in the South to compete with the fire ants, even with the help of the flies. The native ants have either been poisoned by humans or driven away by fire ants.

Scientists also are studying other biological enemies of the fire ant, including a microorganism and a parasitic ant.

"Anything that will take care of these fire ants will be fine with me, as long as it doesn't hurt anything else or the environment," said Kym Bell, a Cottondale, Ala., woman whose 5-year-old daughter missed several days of kindergarten this fall because of repeated ant bites on her school playground. The stings left welts the size of a half dollar on her skin.

The flies were released at four sites near Gainesville, Fla., three years ago and now have spread to 700 square miles. USDA scientists are now studying the area to see how the flies have affected ant populations.

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你可能不相信小小的蚂蚁在美国南部引起了不小的恐慌，但你更想不到的是科学家们研究了数年之后，找到的对付这些扰人的蚂蚁的武器竟然是——苍蝇。所谓一物克一物，或许真是这样吧……

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larva [n] 幼虫 （pl.）larvae
check [n] 控制，制止 in check 控制
innate [adj] 天生的
livestock [n] 家畜，牲畜
mound [n] 土墩，垛
torpedo [n] 鱼雷
maggot [n] 空想，蛆
decapitate [v] 斩首
parasitic [adj] 寄生的
welt [n] 伤痕

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