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. eddie53

    Mutation is a part of evolution, some mutates for the better and some mutates for the worst. And all species follow the law of nature" Survival of the fittest". There will come a time when the new mutants will be stronger than the present generation and they will become dominant and will multiply. Time will come when we, the present generation, will no longer be on top of the food chain and become a source of food for this mutants. We will then be like cows, bread to be eaten later.

    August 14, 2012 at 11:42 am | Report abuse |
    • Gee Gog


      August 14, 2012 at 11:44 am | Report abuse |
    • Jason

      Luckily that's going to take a while considering how eukaryotes have a lot of backups systems to reduce the likelihood of a mutation occurring, which is a double edged sword since it prevents the entire species from getting a gene that kills its individuals before it gets to mate but it also makes it really hard for a species to get some extra resistance to radiation.

      August 14, 2012 at 11:50 am | Report abuse |
    • RuckRow in summation butterflies are going to eat us? or mutant cattle?

      August 14, 2012 at 11:57 am | Report abuse |
    • eddie53

      GEE GOG, thank you for checking my spelling " I meant BRED and not BREAD", happy now?
      what I am expecting is some intellectual who would counter my point of view and say Eddie53 you are wrong because of the following reasons… but if checking my spelling is the farthest your brain could manage then there is nothing I could do. Like I said some would mutate for the worst.

      August 14, 2012 at 12:11 pm | Report abuse |
  2. Gee Gog

    Oh no! Teenage Mutant Nuclear Butterflies!

    August 14, 2012 at 11:43 am | Report abuse |
  3. Radiating Joy

    Now some lunkhead is going to post and claim that it is not radiation but the effects of genetically modified crops on the butterflies - more non-science.

    August 14, 2012 at 11:51 am | Report abuse |
  4. Jack 63

    Here comes Mothra

    August 14, 2012 at 11:54 am | Report abuse |
  5. Leonid Brezhnev

    Mothra lives!!!!!

    August 14, 2012 at 11:59 am | Report abuse |

    I'm glad I read the part about humans being different that butterflies, I was worried we would grow funny shaped wings tool

    August 14, 2012 at 11:59 am | Report abuse |
  7. Jack

    Terrifying; not only from a butterfly standpoint, but the affect something like this could have on me! I live in PA and I can practically see the reactors at Three Mile Island from my back yard. I wonder what my insurance will cover if i'm displaced. I bet those 'good hands' won't be so quick to assist.

    August 14, 2012 at 11:59 am | Report abuse |
  8. Greenspam

    Don't they call this The butterfly effect

    August 14, 2012 at 12:01 pm | Report abuse |
  9. Russ

    Are any huge man-eaters yet? That's what always happened in the 50's movies when insects were nuked..

    August 14, 2012 at 12:03 pm | Report abuse |
  10. Pika


    August 14, 2012 at 12:04 pm | Report abuse |
  11. somethingwrongwiththatdudesbrain

    mothra? bah someone beat me to it!

    August 14, 2012 at 12:05 pm | Report abuse |
  12. Dimensional Rider God

    " well as what we can learn for future nuclear disasters"

    foolish humans.. there is no need for any more nuclear disasters

    shut down all your artificial matter generation plants immediately because you're not doing it right!

    August 14, 2012 at 12:07 pm | Report abuse |
    • Tesla

      artificial matter generation plants? what?

      Do... do the plants make artificial matter? or do they use artificial matter to generate power? What's your definition of artificial in this case? Fissile uranium occurs naturally... the Oklo mine reactor is one hundred percent accidental and natural, so the byproducts of fission are natural... where does the artifical matter come in?

      August 14, 2012 at 2:08 pm | Report abuse |
  13. Tyokol

    That "Mutant butterfly" is nothing but a malicious fabrication from idiot anti-nuclear zealots. It's made of a regular butterfly plus some glue and the wing of another butterfly and fools fall for it all over the world, specially in Germany and the US.

    August 14, 2012 at 12:08 pm | Report abuse |
  14. Pedro Ramirez

    I'm looking forward to when they start having two headed babies.

    August 14, 2012 at 12:09 pm | Report abuse |
  15. New Gawker

    Where's blinky the fish?

    August 14, 2012 at 12:14 pm | Report abuse |
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