A study of the pale grass blue butterfly in the regions around the Fukushima Nuclear Power Plant, site of the 2011 radiation disaster, has revealed that the insects are giving birth to mutants at an alarming rate. Indeed, the butterflies collected from younger generations have more abnormalities than butterflies born directly after the power plant began leaking radioactive particles into the environment. That means the genetic damage caused by the radiation leak has been inherited by subsequent generations.


Above, you can see images taken from the study, published this week in Nature, showing the various kinds of abnormalities the scientists spotted. Among them are dented eyes, deformed eyes, deformed wings, and a misshapen right palpus (a sensory organ the butterfly also uses to eat). Butterflies were collected from a wide region around Fukushima, and the highest number of mutations were found nearest to the power plant.

Write the authors of the study in their introduction:

Here we show that the accident caused physiological and genetic damage to the pale grass blue Zizeeria maha, a common lycaenid butterfly in Japan. We collected the first-voltine adults in the Fukushima area in May 2011, some of which showed relatively mild abnormalities. The F1 offspring from the first-voltine females showed more severe abnormalities, which were inherited by the F2 generation. Adult butterflies collected in September 2011 showed more severe abnormalities than those collected in May. Similar abnormalities were experimentally reproduced in individuals from a non-contaminated area by external and internal low-dose exposures. We conclude that artificial radionuclides from the Fukushima Nuclear Power Plant caused physiological and genetic damage to this species.


This is one of the first studies to demonstrate the effect that the Fukushima accident is having on local wildlife. The researchers write their work has "invaluable implications for the possible future effects of radiation on animals." They recommend further study of animals exposed to contamination, as well as "the possible risk of internal exposure from ingestion [of plutonium]."

Read their whole paper via Nature