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Fukushima's Mutant Butterflies Aren't Pretty

It's been nearly 18 months since the Tohuku earthquake and tsunami decimated northern Japan, and the locals are still dealing with the fallout. Literally.

It’s been nearly 18 months since the Tohuku earthquake and tsunami decimated northern Japan, and the locals are quite literally still dealing with the fallout. And by locals, I don’t just mean people.

Lingering radiation around the Fukushima Daiichi nuclear power plant is producing unnerving effects on wildlife near the plant. A new study published in Nature‘s Scientific Reports charts the increasingly dramatic mutations of the pale grass blue butterfly in the area. Starting in May 2011, the researchers began collecting samples of the butterflies and found some mild abnormalities. Some of them had strange spots on their wings and dents in their eyes. However, they found that these mutations got dramatically worse from generation to generation, and some of those in the most recent sample population are hardly recognizable. Their wings are mangled, their legs and antennae deformed, their abdomens misshapen. It’s not a good look.


Scientists are sure that radiation is to blame for the butterflies’ mutation. To confirm the cause, they took normal pale grass blue butterflies from areas not affected by the disaster and exposed them to radiation in a laboratory setting. This produced the same sorts of abnormalities that they found in the Fukushima butterflies. There are also precedents for this sort of thing. “Our results are consistent with the previous field studies that showed that butterfly populations are highly sensitive to artificial radionuclide contamination in Chernobyl and Fukushima,” the study says. “Together, the present study indicates that the pale grass blue butterfly is probably one of the best indicator species for radionuclide contamination in Japan.”

The big question, of course, is what this means for the human beings living near the plant. While there have been no radiation-related deaths at Fukushima, over 100 people have been exposed to levels likely to cause cancer later in life. Mutations, however, are unlikely. “Sensitivity (to irradiation) varies between species, so research should be conducted on other animals,” one of the researchers told the Japan Times. “Humans are totally different from butterflies and they should be far more resistant.” Either way, mangled mutant butterflies aren’t a good sign.

If only all the Fukushima mutants could be as cute as the earless bunny born by the plant last year. However, unlike the poor pale grass blue butterflies, the bunny’s affliction was probably just a birth defect. And an adorable defect at that.

Image via Open Cage