says researchers are reporting an increase in leg, antennae and wing shape mutations among butterflies collected two months after the 2011 Fukushima accident.
A team of Japanese researchers collected 144 adult pale grass blue (Zizeeria maha) butterflies from various locations around Japan, including the Fukushima area. They posted their findings in Scientific Reports
saying that when they compared mutations found on the butterflies from the different sites, the insects found in areas with the highest levels of radiation had much smaller wings and irregularly developed eyes.
Lead researcher Joji Otaki tells BBC News
says the results were surprising, "It has been believed that insects are very resistant to radiation."
The link between the mutations and the radioactive material was obvious during lab experiments. Japan Times
says the researchers initially collected 121 of the butterflies in and around Fukushima in May of last year, two months after the nuclear crisis began. 12% were found with unusually small wings. But when the butterflies mated the rate for the second generation rose to 18% and some didn't survive to adulthood. Then when the second generation butterflies with abnormal traits mated with healthy butterflies, the rate of abnormalities rose to 34% in the third generation.
The team collected another 238 butterflies last September and determined that the abnormality rate was around 28 percent. However, it nearly doubled to 52 percent among a second generation born to the original butterflies caught.
The researchers say the butterflies collected in May were exposed to radiation as larvae. The impact was apparently more severe on the second generation, as well as on the butterflies collected in September, because they had exposure at an earlier stage of developments, when they were just fertilized eggs.
says the researchers believe that radiation exposure damaged the butterflies genetics and that damage could be passed on to future generations.
But what does it mean for other species, including humans? Team researcher Joji Otaki is quoted in the Japan Times
saying, "Sensitivity (to irradiation) varies between species, so research should be conducted on other animals." "Humans are totally different from butterflies and they should be far more resistant (to the effects of radiation)."
US based biologist Tim Mousseau, who wasn't involved in the study, tells the BBC
, "This study is important and overwhelming in its implications for both the human and biological communities living in Fukushima." "These observations of mutations and morphological abnormalities can only be explained as having resulted from exposure to radioactive contaminants."