Butterflies' scent tactics
Friday, 04 Jan 2008 14:20
The Alcon Blue butterfly is able to disguise the scent of its young
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A Danish butterfly is able to fool ants into looking after its young by disguising the smell of the larvae, scientists have discovered.
This 'evolutionary scent war' results in the ants bringing up the butterflies' young to the detriment of their own.
But the battle is being fought on both sides, with the ants learning to adapt to change their scent as well, according to a study published in the journal Science.
Large blue Alcon butterflies use chemical mimicry to disguise the smell of their larvae so that ants will neglect their own brood and feed them.
But this only works when the host ants that live close to the initial food plant of the caterpillars, a rare marsh plant, do not interbreed with ants from neighbouring sites.
Scientists from the University of Copenhagen found that in the sites without the food plant ant colonies are never parasitised, so they do not evolve resistance.
Selection for resistance was only found to work when the ant queens mate locally with males from colonies that have suffered from butterfly parasitism.
The researchers say the findings give important insights into the fundamentals of evolutionary biology.
"Our results also have important implications for the conservation of the Alcon Blue, which is increasingly threatened throughout much of its range."