Exposure to radioactive material released into the environment has caused mutations in butterflies found in Japan, a study suggests. Scientists found an increase in leg, antennae and wing shape mutations among butterflies collected following the 2011 Fukushima accident. By comparing mutations found on the butterflies collected from the different sites, the team found that areas with greater amounts of radiation in the environment were home to butterflies with much smaller wings and irregularly developed eyes. Six months later, they again collected adults from the 10 sites and found that butterflies from the Fukushima area showed a mutation rate more than double that of those found sooner after the accident. The team concluded that this higher rate of mutation came from eating contaminated food, but also from mutations of the parents' genetic material that was passed on to the next generation, even though these mutations were not evident in the previous generations' adult butterflies. The findings from their new research show that the radionuclides released from the accident had led to novel, severely abnormal development, and that the mutations to the butterflies' genetic material [were] still affecting the insects, even after the residual radiation in the environment had decayed away. This study is important and overwhelming in its implications for both the human and biological communities living in Fukushima," explained University of South Carolina biologist Tim Mousseau, who studies the impacts of radiation on animals and plants.