In the wake of last year's massive earthquake and subsequent tsunami in Japan, the Fukushima nuclear power plant on the country's northeast coast barely avoided a complete meltdown. Tens of thousands of residents were displaced and officials assured the world that the release of harmful radiation posed little threat. Now a new paper published in Scientific Reports has found that this is likely far from the truth, as at least one species of butterfly from the surrounding area has suffered major damage stemming from radiation exposure.

According to the report, mutations caused by Fukushima radiation had affected 12% of adult pale grass blue butterflies in the surrounding area two months after the March 2011 disaster. When they mated, these butterflies produced an offspring with an 18% mutation rate. In the next generation, mutations were found in 34% of the insects born. When scientists returns to Fukushima in September 2011, the adult butterflies they collected displayed a 28% mutation rate and their offspring had a whopping 58% mutation rate.

Butterflies affected by the radiation have suffered genetic damage resulting in malformed wings, legs, antennae, and eyes. In addition, their trademark spotted markings have completely disappeared as the mutation rate has increased, according to Tecca.