Mutant Butterflies Near Fukushima Linked to Nuclear Radiation

By Veronique Greenwood | August 15, 2012 10:55 am

A mutated butterfly

Japanese authorities may have cleared out the human population around the ruined Fukushima Daiichi nuclear power plant, but the native wildlife is still there. A month after the accident, scientists who study the pale grass blue butterfly collected 144 near the plant, and found that they had begun to show mutations like dented eyes and deformed wings.

Six months later, they caught another batch—and, worryingly, found they had twice as many mutations. This suggested that the butterflies’ germ line—the cells that turn into egg and sperm—had suffered damage, so mutations could be expected to continue to accumulate down through the generations. Exposing butterflies in the lab to radiation at the levels around the Fukushima plant triggered similar malformations, further strengthening the link between the radiation and the mutations.

The levels of radiation absorbed by the butterflies are not enough to harm humans, and this species is notoriously sensitive to environmental contaminants (in fact, that’s why scientists were studying it to begin with). But this study is a reminder that the disaster’s effects will reverberate for a long time in the natural environment and animal inhabitants of Fukushima.

Image courtesy of Hiyama et al. / Scientific Reports

  • Hapless Human

    all hail MOTHRA

  • James Aach

    This is an interesting study – as the report itself notes, the life cycle of the butterfly is about one month. This means geneitic effects in the population would become apparent faster. Since times of rapid cell reproduction associated with growth is a particularly bad period to receive excess radiation exposure (hence children are more vulnerable than adults) the short butterfly lifespan might also make it more vulnerable than longer-lived species.

    FYI: For a look at daily life in a US nuclear plant and what a bad day might be like, my novel “Rad Decision” covers that ground from an insider’s perspective. The book is free online (no advertisements or sponsors) – just Google the title or see my website. As a bonus, the plant design and bad day resemble Fukushima. Readers seem to like it, judging from their comments.

  • Randy Tayler

    And all this says nothing about the butterflies whose mutations make them less susceptible to being caught and studied by scientists. Who even KNOWS how many invisible Monarchs we have cruising around out there.

  • labman57

    Meanwhile, Team Romney touts nuclear power as a preferable alternative energy source over wind or solar.

    If ignorance is bliss, then Mitt must be in a state of rapture.

  • Michael Brady

    I know this is very serious and all but I can’t get the image of Mothra out of my head.

  • Gizelle Janine

    @Hapless Human: Yes. All hail Mothra and his destructive glory!

  • jross307

    labman, nuclear power is much more effective than solar and wind by far… If the companies making the nuclear facilities would use updated equipment instead of 30 year old reactors maybe crap like Fukushima wouldn’t happen. Obama & Romney both suck. Ron Paul was our last hope but you guys blew it. Hope you don’t have kids, because we’re doomed.

  • George Goldtrap Jr.

    The editors of Discover magazine should check the author of this story and find out what kind of mutation caused use of the ‘word’ … worryingly!

  • Critter

    Worryingly is a word, look it up.

  • Rod Adams

    The full paper mentioned in this brief article is available on the web at

    It is worth reading for anyone who is interested in the way that people who have an agenda can lie with statistics. For example, a single butterfly with deformed wings is described as a 20% rate of mutation because there were only 5 butterflies in that particular sample.

    The researchers made no attempt to isolate radiation from other potential causes of mutations or deformities. Please remember those videos that we all saw of the way that the tsunami overturned everything in its path and then remember that industrial societies are rife with petroleum, pesticides, paints, solvents, and other materials that are potentially mutagenic if indiscriminately released from their containers and spread around the landscape by the forces of a huge wave of salt water.

    The publisher of this paper, though hiding under the URL of “”, is Scientific Reports.

    They have a rapid turnaround publishing model that calls a paper “peer reviewed” after being reviewed by ONE reviewer. The advantageous part of their model is that Scientific Reports publishes the entire work in an accessible location so we can all see the good, the bad and the ugly and determine the validity – or lack of validity in the published work. It is incumbent upon skeptical readers to do their homework and not just trust the headlines sent out by the publicists who are seeking to make a big splash.

    Nuclear energy’s competitors in the global energy market have a strong monetary motive for spreading as much fear, uncertainty and doubt as they can. That effort is the only thing that keeps nuclear energy from forcing them to accept a smaller market share and lower prices for their more dangerous and less capable products – coal, oil, natural gas, wind, solar, and hydro.

  • jay

    The Mutants are coming!!! RUUUUN!!!


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