Researchers in Japan say radioactive fallout from the Fukushima meltdown have created abnormalities among the nation's butterfly species.
The researchers collected hundreds of butterflies in the weeks and months after the disaster at the nuclear plant in northern Japan following the earthquake and tsunami of 11 March 2011.
They found abnormalities in more than 10%, including unusually small wings.
The rate of abnormalities then rose to more than a third with the second generation, with some butterflies dying before reaching adulthood.
The scientists have called for further research into other animal species.