Mutant butterflies a result of Fukushima nuclear disaster, researchers say
This image from a study on Fukushima's impact on butterflies shows wings mutated by the radiation.
August 14th, 2012
10:35 AM ET

Mutant butterflies a result of Fukushima nuclear disaster, researchers say

In the first sign that the Fukushima nuclear disaster may be changing life around it, scientists say they've found mutant butterflies.

Some of the butterflies had abnormalities in their legs, antennae, and abdomens, and dents in their eyes, according to the study published in Scientific Reports, an online journal from the team behind Nature. Researchers also found that some affected butterflies had broken or wrinkled wings, changes in wing size, color pattern changes, and spots disappearing or increasing on the butterflies.

The study began two months after an earthquake and tsunami devastated swaths of northeastern Japan in March 2011, triggering a nuclear disaster. The Fukushima Daiichi plant spewed radiation and displaced tens of thousands of residents from the surrounding area in the worst nuclear accident since the 1986 Chernobyl disaster in Ukraine.

In May 2011, researchers collected more than 100 pale grass blue butterflies in and around the Fukushima prefecture and found that 12% of them had abnormalities or mutations. When those butterflies mated, the rate of mutations in the offspring rose to 18%, according to the study, which added that some died before reaching adulthood. When the offspring mated with healthy butterflies that weren't affected by the nuclear crisis, the abnormality rate rose to 34%, indicating that the mutations were being passed on through genes to offspring at high rates even when one of the parent butterflies was healthy.

The scientists wanted to find out how things stood after a longer amount of time and again collected more than 200 butterflies last September. Twenty-eight percent of the butterflies showed abnormalities, but the rate of mutated offspring jumped to 52%, according to researchers. The study indicated that second-generation butterflies, the ones collected in September, likely saw higher numbers of mutations because they were exposed to the radiation either as larvae or earlier than adult butterflies first collected.

To make sure that the nuclear disaster was in fact the cause of the mutations, researchers collected butterflies that had not been affected by radiation and gave them low-dose exposures of radiation and found similar results.

"We conclude that artificial radionuclides from the Fukushima Nuclear Power Plant caused physiological and genetic damage to this species," the study said.

The results of the study bring up concerns about the larger impact of the Fukushima disaster and the impact it will have on the ecosystem in Japan and nearby areas, as well as what we can learn for future nuclear disasters.

"Our results are consistent with the previous field studies that showed that butterfly populations are highly sensitive to artificial radionuclide contamination in Chernobyl and Fukushima," the study said. "Together, the present study indicates that the pale grass blue butterfly is probably one of the best indicator species for radionuclide contamination in Japan."

One of the researchers, Joji Otaki, an associate professor at the University of the Ryukyus in Okinawa, told reporters that while butterflies may be the best indicator, the study should also lead to more research on what else may be affected by the radiation.

"Sensitivity (to irradiation) varies between species, so research should be conducted on other animals," Otaki told the Japan Times.

Otaki said while there is still plenty of research to be done on radiation, there shouldn't be large-scale concern about this kind of mutation in humans.

"Humans are totally different from butterflies and they should be far more resistant" to radiation, he told the newspaper.

Read more:

Inside Fukushima's meltdown zone

What Fukushima did to the ocean

Gallery: Then and now

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Filed under: 2011 tsunami • Animals • Insects • Japan
soundoff (316 Responses)
  1. NUNYA

    "Humans are totally different from butterflies and they should be far more resistant" to radiation, he told the newspaper.

    August 15, 2012 at 12:49 am | Report abuse |
  2. fatblackfrancis

    This is old news. The butterflies are now fighting crime in the Tokyo metropolitan area.

    August 15, 2012 at 2:38 am | Report abuse |
  3. noname

    So the land of Godzilla has mutating life forms. Cool.

    August 15, 2012 at 3:19 am | Report abuse |
  4. UsayWha?

    Exactly my first thought!!

    August 15, 2012 at 6:17 am | Report abuse |
  5. Runes77

    We can only hope and pray that these butterflies use their powers for the betterment of mankind.

    August 15, 2012 at 6:38 am | Report abuse |
  6. Rose Red

    I would be interested in a follow-up article on the effects of radiation in this region and the local corals. This region is so rich in very delicate sea life because of the black current, I wonder if they lost anything? Any real experts out there? I am afraid to ask questions in these blogs because I am looking for folks with true expertise not the wingnuts that typically respond!

    August 15, 2012 at 6:42 am | Report abuse |
    • Ric

      True: I too would be interested.
      What was the amount of wast that was lost and to what level of strength was it . Also what was the time period that it was release, min.s, hours,days, weeks, ? . They do not tell too much.
      And what will be the effects be on the ocean life from there to Alaska and Cal. ?

      August 15, 2012 at 9:58 am | Report abuse |
  7. ed

    Don't you hear those little twins singing......

    August 15, 2012 at 7:50 am | Report abuse |
  8. Deb

    oh boy, does this mean they should be looking for Godzilla?...I'm not making a joke, I'm serious.

    August 15, 2012 at 11:32 am | Report abuse |
  9. queenbutterfly

    Ah earthlings. Absolutely hell-bent on making their planet a nuclear wasteland all in the name of "progress". Fools.

    August 15, 2012 at 1:10 pm | Report abuse |
  10. Mrmagoo

    Mothra has returned!! Where is Godzilla?!

    August 15, 2012 at 2:31 pm | Report abuse |
  11. alex

    I cannot believe I haven't seen......................ITS MOTHARA!!! in butterfly form....where is Godzilla??

    August 15, 2012 at 2:45 pm | Report abuse |

    It looks like Mothra will soon be a reality....

    August 15, 2012 at 4:04 pm | Report abuse |
  13. Yo Mammy

    Godzirra coming foh you!

    August 15, 2012 at 4:04 pm | Report abuse |
  14. AMFD

    I've been trying to tell people for years that TOHO wasn't just making all those Godzilla movies for entertainment. They were warnings. Now look... This is how Mothra is created. Soon We'll have Rodan, Godzilla, The Giant Lobster, and the whole gang to deal with...

    August 15, 2012 at 6:10 pm | Report abuse |
  15. SteveJT

    Just let me know when "Mothra" shows up...

    August 15, 2012 at 6:12 pm | Report abuse |
    • Hybridhor


      August 16, 2012 at 1:32 pm | Report abuse |
    • sassysticks53


      August 17, 2012 at 4:12 pm | Report abuse |
    • Wonjune Lee

      Only thing we're missing is Godzilla to start fighting it.

      August 19, 2012 at 8:12 am | Report abuse |
    • Jennifer Pirante


      August 20, 2012 at 10:52 am | Report abuse |
    • Dervid

      Beat me to it ... LOL!

      August 27, 2012 at 6:31 am | Report abuse |
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