Butterfly that mimics ants gives conservation clue

By Alister Doyle, Environment Correspondent

OSLO (Reuters) - A blue butterfly died out in Britain 30 years ago because of disruptions to a life cycle that includes pretending to be an ant, according to a study published on Tuesday that points to smarter ways to protect wildlife.

Research into the large blue butterfly -- now successfully re-introduced to Britain from Sweden -- hints at how governments can use science to achieve U.N. goals of slowing a loss of animal and plant species, scientists said.

For decades, over-zealous human collectors were blamed for dwindling numbers of the large blue until scientists found that wrong-minded conservation had let grass grow taller and made soils unsuitable for the red ants that its caterpillars eat.

"We discovered that the butterfly was much more specialized than anyone had thought," said Jeremy Thomas of Oxford University who led a study with British colleagues published in the journal Science.

"It only took the grass growing 1-2 cms (0.4-0.8 inch) taller for the species of ant it relied upon to be replaced by another," he told Reuters. Longer grass means more shade and can make the soil 2-3 Celsius (3.6-5.4 Fahrenheit) cooler.

"To human beings the change looks like absolutely nothing. But when you are on the scale of insects it makes a huge difference to the micro-habitats where they live," he said.

The butterfly, which vanished from Britain in 1979, lays its eggs on thyme flowers and the caterpillars fall to the ground after hatching. They secrete chemicals and even make noises that make the red ants believe they are wayward grubs.

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