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. rs1201

    There's always leakage of radioiactivity from sealed sources. I had a sealed source of radiation in my lab and underneath it, I had stored some clean, sterile, plastic tubes. After a couple of months, I went into that cabinet to get some of the tubes and I was stunned to see that the tubes had turned from being clear polypropylene to yellow polypropylene. I called our radiation officer at the nearby cancer medical center and he confirmed that there was obviously leakage but within the "acceptable" limits. That did not put me at ease. I moved my stuff out of that lab but continued to wonder how much radiation had I already been exposed to. The badges we wear only measure the exposure to the area where the badge is located and really nowhere else. RAdiation is extremely dangerous and cannot be really totally contained. We just have to accept that unfortunate fact.

    August 14, 2012 at 1:06 pm | Report abuse |
  2. FedUp2

    Lucky, the ocean's dead zones of floating plastic will keep the problem to a minimum.

    August 14, 2012 at 1:06 pm | Report abuse |
  3. Mike Hunt

    Pictures or it didnt happen.

    August 14, 2012 at 1:06 pm | Report abuse |
    • sbp

      Pictures or it didn't happen? Like the Revolutionary War?

      August 14, 2012 at 2:59 pm | Report abuse |
  4. Piranha

    Butterfly collectors are salivating in anticipation for this mutant species of butterfly, hope its not radioactive though.

    August 14, 2012 at 1:11 pm | Report abuse |
  5. Sarah

    If you click the link in the top of the story it shows the pictures....

    August 14, 2012 at 1:14 pm | Report abuse |
  6. banasy©

    Well, not really surprising or unexpected, given what happened last year in Japan; I'd have been musch more surprised if there *weren't* mutations...

    August 14, 2012 at 1:14 pm | Report abuse |
  7. joels2000

    I have seen similar like effects with frogs having extra legs. They too, blamed the local factory for producing mutant frogs. It wasn't until another scientist realized that a specific parasite was attacking the tadpole's tail and causing the cells to burst and creating more sets of legs.

    August 14, 2012 at 1:16 pm | Report abuse |
    • Vicki

      Factories can cause mutations in frogs when they pollute. A simplified explanation is that water pollution causes an algal bloom which is an ideal condition for the snail parasite that attacks frogs. So yes, they are related.

      August 14, 2012 at 1:29 pm | Report abuse |
  8. hog

    come on cnn, have a complete story

    August 14, 2012 at 1:17 pm | Report abuse |
  9. DJS NJ

    LOL! Exactly... Next Godzilla shall emerge from the sea and destroy Tokyo

    August 14, 2012 at 1:19 pm | Report abuse |
    • SeilnoigileR

      No, it would be Mothra....

      August 14, 2012 at 4:16 pm | Report abuse |
  10. Mark

    That's nothing, there's a town called Springfield that has 3 eyed fish!

    August 14, 2012 at 1:20 pm | Report abuse |
    • Bill

      That's what i'm talking about... If the fish have three eyes it prob got that way because of leaked rad. The ladies near ANY Nuke Power Plant Prob see a higher rate of abortions due to mutations – Or prob Don't see due to no one asking for the hospitals history. Ignorance is BLISS!

      August 14, 2012 at 1:33 pm | Report abuse |
  11. Bill

    Pedo Bear is a known internet meme featuring a cartoon bear. I would ignore this guy as it's pretty apparent he didn't read the article. I also doubt he knows the significance of the journal Nature.

    August 14, 2012 at 1:25 pm | Report abuse |
  12. Bill

    You better watch your eggs ladies... Your offspring could look worse than a mutated butterfly... Living near a Nuke Power Plant.

    August 14, 2012 at 1:25 pm | Report abuse |
  13. ksocreative

    pics or gtfo

    August 14, 2012 at 1:26 pm | Report abuse |
  14. Enthalpy

    Can't stand when they print some conclusion from one or two measurements (which CNN does a lot) BUT this seems like a true many sampled result. It's very very likely caused by the accident / release. Anyone who thinks no bad legacy from that disater is ignorant – of course those in america who think it will give them cancer are also off track

    August 14, 2012 at 1:29 pm | Report abuse |
  15. saywhat

    The world did not learn from Hiroshima and Nagasaki. The man made devastation of the most horrific kind derived from nuclear source. Why should we learn from an accident?
    Mutant butterflies, so?
    Defects are now appearing in children born in Falujah, Iraq from use of nuclear tipped artillery shells and white phosphorous used when we raided that city during Iraq war. Who cares??

    August 14, 2012 at 1:30 pm | Report abuse |
    • Tesla

      Ummm... what nuclear-tipped artillery shells?

      Do you mean DU? Depleted uranium has a minimal alpha emission pattern, and that's it. Also, DU isn't often used in artillery; it's used in tank sabots because it's so incredibly dense and hard. It's also not used on civilian targets, it's used in anti-armor applications.

      Also, white phosphorus is not radioactive, nor is it mutagenic or carcinogenic. It's toxic, and it's incendiary. It doesn't mutate you, it kills you, plain and simple.

      Be more concerned with the dose you're getting from the flying, burning coal, or eating bananas. It's much more significant that the dose from nuclear power.

      August 14, 2012 at 1:43 pm | Report abuse |
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