Fukushima Disaster Caused Mutant Butterflies, Study

Japanese researchers have found mutations in butterflies in the Fukushima region, signaling early changes to the local ecosystem after the March 2011 disaster.

AsianScientist (Aug. 20, 2012) – Radioactive fallout from the nuclear disaster in Fukushima Prefecture has created abnormalities among butterflies in the area, according to researchers at the University of the Ryukyus in Okinawa, Japan.

A new article in Scientific Reports has linked artificial radionuclides from the Fukushima nuclear power plant to physiological and genetic damage to the pale grass blue butterfly (Zizeeria maha), a common species in Japan.

The researchers collected 144 specimens of the pale grass blue butterfly in May 2011, two months after the disaster. Only 12 percent of the butterflies showed relatively mild mutations and abnormalities such as antennae disfigurement, small wings, and a change in color patterns.

Second generation offspring of the radionuclide-exposed female butterflies showed more severe abnormalities, with the rate of mutation rising to 18 percent and some dying before adulthood.

When second generation butterflies with abnormal traits mated with healthy ones, the rate of abnormalities rose to 34 percent in the third generation, the researchers found.

Adult butterflies collected in September 2011 showed more severe abnormalities than those collected in May. Of the 238 butterflies collected in September, 28 percent were mutated and 52 percent of their offspring were affected.

The researchers explained that second generation offspring and those collected in September were more severely affected than those collected in May because they suffered heavy exposure at a far earlier stage while they were still fertilized eggs or just reproduction cells.

The impact of artificial radiation exposure on the butterflies was also investigated using larvae collected in Okinawa, one of the prefectures least affected by fallout from the nuclear disaster.

After the larvae were exposed to radiation and fed with leaves contaminated with radioactive materials, similar rates of abnormalities and premature deaths were observed.

But the authors urged caution when extrapolating the results from butterflies to humans, as humans are far more resistant to mutation caused by radiation.

“Sensitivity (to irradiation) varies between species, so research should be conducted on other animals,” said senior author Joji Otaki, an associate professor at the University of the Ryukyus in Okinawa. “Humans are totally different from butterflies and they should be far more resistant to the health effects of radiation,” he noted.

The article can be found at: Hiyama A et al. (2012) The biological impacts of the Fukushima nuclear accident on the pale grass blue butterfly.


Copyright: Asian Scientist Magazine; Photo: Joji Otaki/Nature Publishing Group.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

Aparna received a PhD in Translational Medicine (Immunology) on a scholarship from the University of Milano-Bicocca, Italy. She is now a research scientist at the Agency for Science, Technology and Research (A*STAR), Singapore.

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