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Parasitic Butterflies

January 24, 2008

Butterflies use chemical signals to fool ants into raising their young.


Parasitic butterflies. I’m Bob Hirshon and this is Science Update.

Alcon blue butterflies are both pretty and extremely sneaky. They actually fool ant colonies into raising their larvae while the ants’ own young starve. Scientists have known about this parasitic trickery for years, but now researchers at the University of Copenhagen have pinpointed just how the butterflies get away with it. Chemical signaling is important to ants, and according to evolutionary biologist David Nash, the trick is to produce larvae that smell just like ants.

DAVID NASH (University of Copenhagen):
The better they mimic their hosts, the faster or the bit more easily they’ll get into the ant colony and be able to parasitize it.

But he notes that in places where parasitism by butterflies is high, ants have evolved to smell slightly different from other ants of the same species, suggesting that the butterflies and ants are locked in an evolutionary arms race. I’m Bob Hirshon, for AAAS, the science society.