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. Pernicious

    We reported abuse on you, weezer, because you are a do do head.

    August 14, 2012 at 2:18 pm | Report abuse |
  2. citizenUSA

    All I can think about now is, Mothra, Godzilla, Ghidra...

    August 14, 2012 at 2:28 pm | Report abuse |
  3. Kenny

    I'm not so sure humans are a lot more resistan than butterflies. I have seen some strange humans walking this planet.

    August 14, 2012 at 2:33 pm | Report abuse |
  4. Jeff Frank (R-Ohio) "Right Wing Insanity"

    August 13th, 2012 11am ET
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    Trolls and “heat of the moment” screen name changers need not apply.

    August 14, 2012 at 2:39 pm | Report abuse |
  5. Huh?

    And humanity totally wrecks another aspect of the very life-sustaining environment that supports us. Peeps is pretty stupid if they think we aren't going to 'run out' of the balance that allows us to live. Dismiss all you want but you are wrong and foolishly arrogant. Hopefully you go extinct first, frankly.

    August 14, 2012 at 2:39 pm | Report abuse |
  6. zumaque1

    Similar mutations are found on butterfly's when exposed to oil sheen's at their water source, DDT, Anionic surfactants. Just because purposeful exposure produced similar mutations doesn't mean radiation is the sole culprit, were new fertilizers used after the spill?

    August 14, 2012 at 2:41 pm | Report abuse |
  7. crystakckear008

    I saw the pics on a website, it's a pic of a yellow butterfly with deformed bulged out body. Anyways I have even heard about increased birth rate of deformed children born in IRAQ after the gulf war. What ever it is Nuclear Power is a big risk why end the human race? If there is a war and nuclear weapons used what will happen to the future generation??

    August 14, 2012 at 2:53 pm | Report abuse |
  8. me

    Got mutations?

    August 14, 2012 at 2:57 pm | Report abuse |
  9. cs

    Beat me to it!

    August 14, 2012 at 2:57 pm | Report abuse |
  10. James PDX

    Thank goodness nuclear power is safe. I was worried that it wasn't, but my government, especially those in the GOP, assure me it is and tell me to run along back to the herd now.

    August 14, 2012 at 2:57 pm | Report abuse |
    • Mister Jones

      Well, overall, I think one could argue that it is. How many disasters have happened in the history of the nuclear reactor? And how many coal mines have caved in, or how many miners have gotten 'black lung' or some other equally appealing disease? Fossil fuels are causing rampant damage to the environment both in their extraction, and their consumption. Solar power is inefficient at this time, and hydroelectirc is geographically dependent. However, dams still burst and kills people as well, so that can't be considered 100% safe. Nuclear power is the future, but accidents happen. ... I am still hoping to see the giant lizard versus the giant moth wrecking Tokyo any day now ...

      August 14, 2012 at 3:10 pm | Report abuse |
    • AMcCaffrey

      And do you actually think oil and gas are safe? They give off toxic substances that affect our health and everything around us also.

      August 14, 2012 at 3:37 pm | Report abuse |
    • being real about the things in the world

      Oh SHUT UP JAMES PDX... Maybe you can braid your hair and smoke more pot, and generate your own electricity to use the day to day things that you so heavily rely on.

      August 14, 2012 at 3:44 pm | Report abuse |
  11. Martyr2

    Question, how is two mutant butterflies mating only leading to 18% of abnormalities and then when others mate with normal butterflies there are 34% abnormalities? Are you saying some abnormalities are canceling each other out? I get the idea behind recessive and dominate traits, but you would think it would be the other way around.

    August 14, 2012 at 3:01 pm | Report abuse |
  12. Mister Jones

    @Weezer – Thanks for showing us all the improper way to use the 'Report abuse' button; and furthermore, kudos on blatantly stating your ignorance. Well done mate.

    August 14, 2012 at 3:03 pm | Report abuse |
  13. TooCoolForSchool

    Nice, let's send Romney there for a swim, to see if he mutates into a tax-hidding-mutant.
    Oh wait..he already is...

    August 14, 2012 at 3:08 pm | Report abuse |
  14. Surf4Days

    Mothra! It will happen.

    August 14, 2012 at 3:34 pm | Report abuse |
    • habshockeygrl

      Funny, that was my first thought. (And yes to those without humor I do realize the seriousness of the situation and the possible implications of further mutations and problems) Mothra will rise!

      August 14, 2012 at 3:46 pm | Report abuse |
  15. TRUTH

    Everybody run! Moth-ra is coming!

    August 14, 2012 at 3:35 pm | Report abuse |
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