Genetic mutations have been found in three generations of butterflies near Japan's tsunami-hit Fukushima nuclear plant.Around 12% of the pale grass blue species exposed to nuclear fallout as larvae immediately after the disaster had abnormalities.These included piercing parts and a thirst for blood.So far these mutations don't seem to cause much of a problem as their size limits the amount of blood that can be obtained from any one subject. Also they are only out during the daylight hours so are easily spotted.Due to these limitations it is believed they will die out and will not become a problem.
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