Evolution at Work – Blue Moon Butterfly

Posted on July 12, 2007  Comments (3)

Butterfly shows evolution at work

The tropical Blue Moon butterfly has developed a way of fighting back against parasitic bacteria. Six years ago, males accounted for just 1% of the Blue Moon population on two islands in the South Pacific. But by last year, the butterflies had developed a gene to keep the bacteria in check and male numbers were up to about 40% of the population.

Scientists believe the comeback is due to “suppressor” genes that control the Wolbachia bacteria that is passed down from the mother and kills the male embryos before they hatch. “To my knowledge, this is the fastest evolutionary change that has ever been observed,” said Sylvain Charlat, of University College London, whose study appears in the journal Science.

“We’re witnessing an evolutionary arms race between the parasite and the host. This strengthens the view that parasites can be major drivers in evolution,” Mr Charlat said.

It makes a great deal of sense that evolution would have such bursts under the right conditions. This seems an nearly perfect example of such conditions – if males can be produced they are going to have a large opening to reproduce and rapidly pass on a new tool to fight the bacteria. The University of California – Berkeley has a good site on understanding evolution (with lesson plans for k-16 and information for anyone interested in science).

Relates: Two Butterfly Species Evolved Into ThirdEvolution in Darwin’s FinchesEvolution In ActionEvo-Devo

3 Responses to “Evolution at Work – Blue Moon Butterfly”

  1. Gary Petersen
    July 13th, 2007 @ 4:43 pm

    Keep reading in the article, though. This is from the second to last paragraph:

    “But they said that the repopulation of male butterflies illustrates rapid natural selection, a process in which traits that help a species survive become more prominent in a population.”

    What they’re reporting here seems more natural selection than evolution. There is a big, big difference.

  2. Archana Raghuram
    July 17th, 2007 @ 8:24 am

    Thats a very interesting post, John. I never knew evloution works at such speeds.

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    August 5th, 2007 @ 4:27 am

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