Parasitic butterflies trick hosts using ant music

February 6th, 2009 - 1:40 pm ICT by ANI  

London, Feb 06 (ANI): Infant blue butterflies dupe ants into protecting themselves by mimicking the tune of their queen, a new study has found.
Researchers at the University of Oxford have found that the larvae and pupae of Maculinea rebeli - a parasitic butterfly native to western Europe, though threatened with extinction - imitate red ants so faithfully that worker ants worship them as if they were queens, caring for the developing caterpillar even at the expense of their own lives.
“They appeared to be treating the caterpillars as if they were the holiest of holiest, the pinnacle of power, the queen ant,” New Scientist quoted Jeremy Thomas, an entomologist at the University of Oxford, who led the new study, as saying.
As young caterpillars, M. rebeli spend their days gorging on leafy greens. When they”re nearly ready to begin their transformation into a butterfly, the caterpillars descend to the forest floor and secrete ant-like chemicals.
Duped worker ants carry the caterpillar to its colony, where it is accepted as another ant, based on its smell alone. However, Thomas found that the interlopers seem to get particularly special treatment.
When he disturbed a laboratory colony, workers sacrificed their own kin to save the butterfly larvae - much as they would if a queen ant were threatened.
“There must be some form of communication by the butterflies that make the ants think they”re royal, and at the same time we were pretty damn sure they weren”t by chemicals,” he said.
The researchers thought whether a mysterious ticking sound emitted by blue butterfly larvae and pupae could explain this privileged treatment.
The ants produce a song of their own, with subtle differences between queen and worker.
The researchers captured the tunes made by queen and worker ants, as well as by the butterfly larvae and pupae using miniature microphones hooked up to an MP3 recorder.
Auditory analysis showed similarities in key acoustic features of the ant and butterfly sounds, such as resonant frequency.
The researchers then used Lilliputian speakers to audition the various songs to workers. When they listened to their own songs, the workers perked up.
“Instead of running away or acting with aggression, the speakers attracted the worker ants to them and they tapped them with their antennae with great interest,” said Thomas.
The recording of a queen’’s song inspired even more interest. Workers surrounded the speaker and refused to budge.
The researchers identified nearly the same behaviour when they played the butterfly songs to the ants - suggesting that auditory mimicry is the key to the butterflies” ascendancy.
David Nash, an entomologist at the University of Copenhagen, said: “This use of sound potentially solves the mystery of how they mimic the queen even though they don”t smell like the queen.”
The study is published in the Journal Science. (ANI)

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