Fukushima caused 'mutant butterflies'_美文_趣味英语-查字典英语网

Fukushima caused 'mutant butterflies'

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Genetic mutations have been found in three generations of butterflies from near Japan's crippled Fukushima nuclear plant, scientists said on Tuesday, raising fears radiation could affect other species.

Around 12 percent of pale grass blue butterflies that were exposed to nuclear fallout as larvae immediately after the tsunami-sparked disaster had abnormalities, including smaller wings and damaged eyes, researchers said.

The insects were mated in a laboratory well outside the fallout zone and 18 percent of their offspring displayed similar problems, said Joji Otaki, associate professor at Ryukyu University in Okinawa, southwestern Japan.

That figure rose to 34 percent in the third generation of butterflies, he said, even though one parent from each coupling was from an unaffected population.

The researchers also collected another 240 butterflies in Fukushima in September last year, six months after the disaster. Abnormalities were recorded in 52 percent of their offspring, which was "a dominantly high ratio", Otaki said.

Otaki said the high ratio could result from both external and internal exposure to radiation from the atmosphere and in contaminated foodstuffs.

The results of the study were published in Scientific Reports, an online research journal from the publishers of Nature.

Otaki later carried out a comparison test in Okinawa exposing unaffected butterflies to low levels of radiation, with the results showing similar rates of abnormality, he said.