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Fly that fills fire ants with fear

Fly that fills fire ants with fear

作者:米鱼普  时间:2019-03-01 07:15:00  人气:

By KURT KLEINER A fly that lays its eggs in ants’ brains could be exactly what a group of Texan researchers needs to combat the devastating invasion of Brazilian fire ants that is plaguing the southern states of the US. The fire ants, Solenopsis invicta, were accidentally imported to the US 40 years ago. By the mid-1970s they had spread throughout the southern states. Aggressive and equipped with a fiery sting, they are annoying – and their sting can be fatal to anyone with an allergy to the poison. Worse still, from an ecological standpoint, they are eliminating other insect species. ‘This is one of the hidden tragedies of biodiversity,’ says Larry Gilbert, the entomologist at the University of Texas in Austin who is leading efforts to control the ant. After an invasion, the number of species of ant in a region drops from more than fifty to just three. Other insects are also driven off. Efforts to poison the ants – at a cost of around $200 million – have failed. The team in Texas now thinks the answer lies in small parasitic flies of the Phoridae family, which they want to import from Brazil. The Brazilian fire ant is not especially fearsome as ants go, says Gilbert. But when it was transplanted to the US, it left behind the parasites that helped keep it in check in its native habitat. Although the parasitic fly kills only about 3 per cent of a colony per year, its presence is so disruptive that it gives other ants a chance to compete. Fire ants will run for cover when the flies appear, making it harder for them to scavenge, fight other ants for food, or fend off intruders, says Gilbert. The ants are so afraid of the fly that they have been observed allowing enemy ants to walk off with their brood rather than come out and fight while the parasitic flies are hovering around. ‘The effect of the fly on their behaviour is the key,’ says Gilbert. Researchers still have to make sure the parasite will not prey on native species,