There are unusual butterflies in Fukushima

Radioactive contamination may be the cause of mutations in butterflies in Fukushima - Japan. They have more legs, whiskers and transforms into wing shapes.

The link between these mutations and radioactivity has been demonstrated experimentally, according to a report published in Scientific Reports.

Two months after the nuclear disaster at Fukushima No. 1 nuclear power plant in March 2011, a Japanese research group collected 144 adult Zizeeria maha butterflies at 10 different locations across the country, including Fukushima area. When disaster strikes, they are just larvae growing in the middle of winter.

Butterfly Zizeeria maha is in Fukushima normally (right) and mutated. (Photo: BBC)

By comparing the differences between butterflies collected in different places, the team found butterflies in areas where radiation was much smaller and their eyes developed abnormally.

'Previously, people still believed that insects have high radiation resistance. Therefore, the results of this study are surprising '- Professor Joji Otaki, of Ryukyus University (Okinawa) - who led the research, told the BBC.

Later, Professor Otaki's group gave the number of butterflies mating with each other in a laboratory far away from Fukushina by 1,750km to suppress the effects of radiation in the environment. The next generation of butterflies gave rise to unprecedented abnormalities on their parents like heterosexual antennae.

By November 2011, they continued to collect butterflies in 10 locations and found butterflies in the Fukushima area were twice as mutated as those of butterflies and the area caught right after the disaster. The reason for the high rate of mutation is because they ingest contaminated food plus genetic mutations.

With more than 10 years of experience in surveying these butterflies, the team says they are very sensitive to environmental changes. They changed the color of the wings when reacting to global warming. Therefore, this severe mutation indicates that radioactivity still affects animals even though they have decayed in the natural environment.