Butterfly Evolves in Blink of Eye
Parasite forces hyper-speed adaptation in male blue moon butterflies
By Colleen Barry,  Newser Staff
Posted Jul 13, 2007 8:20 AM CDT
Common Eggfly, commonly known as "Blue Moon Butterfly" Hypolimnas bolina. Taken in the Melbourne Zoo, Nov 2006   (www.flagstaffphotos.com)
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(Newser) – One of the fastest evolutionary changes ever observed has been witnessed by scientists studying butterflies in the South Pacific, the BBC reports. Blue Moon butterflies managed to fight off a deadly parasitic bacteria by developing suppressor genes to fight the bacteria in just six years. Hard-hit males rebounded from 1% of the population to 40% in that time.

"We usually think of natural selection as acting over hundreds of thousands of years, but in this study [it] happened in the blink of the eye," said a scientist. Investigators are uncertain if the gene developed as a mutation or was introduced by migratory butterflies. The findings reveal how such biological "arms races" can drive evolution.