This article is from the source 'bbc' and was first published or seen on . It last changed over 40 days ago and won't be checked again for changes.

You can find the current article at its original source at http://www.bbc.co.uk/news/science-environment-35064827

The article has changed 2 times. There is an RSS feed of changes available.

Version 0 Version 1
Cricket's chirp may have 'predatory roots' Cricket's chirp may have 'predatory roots'
(about 11 hours later)
Scientists have discovered that the chirps of some crickets could be a cunning way to "startle" potential mates into revealing their location.Scientists have discovered that the chirps of some crickets could be a cunning way to "startle" potential mates into revealing their location.
The Dartmouth College team discovered the insects' communication system and studied females' reactions to the males' songs.The Dartmouth College team discovered the insects' communication system and studied females' reactions to the males' songs.
They say the call is likely to have evolved from males impersonating hunting bats and startling females.They say the call is likely to have evolved from males impersonating hunting bats and startling females.
The females shuddering response appears to allow males to locate a mate. Females' shuddering response appears to allow males to locate a mate.
Close examination of females' nervous systems suggested that this shudder evolved from a startle reflex, the researchers say.Close examination of females' nervous systems suggested that this shudder evolved from a startle reflex, the researchers say.
The findings are published in the journal Current Biology.The findings are published in the journal Current Biology.
Lead researcher Prof Hannah ter Hofstede investigated this unusual insect duet after a colleague presented some recordings of the insects' particularly high frequency chirps.Lead researcher Prof Hannah ter Hofstede investigated this unusual insect duet after a colleague presented some recordings of the insects' particularly high frequency chirps.
"It struck me as very strange that these crickets would use such high frequencies for mating purposes," the scientists said."It struck me as very strange that these crickets would use such high frequencies for mating purposes," the scientists said.
Other cricket species avoid sounds at these frequencies, which are similar to the sounds that bats make when navigating and hunting.Other cricket species avoid sounds at these frequencies, which are similar to the sounds that bats make when navigating and hunting.
Escape behaviourEscape behaviour
Prof ter Hofstede used playback experiments - playing males' songs through speakers - to test females' reaction to the high, bat-like chirps.Prof ter Hofstede used playback experiments - playing males' songs through speakers - to test females' reaction to the high, bat-like chirps.
"I expected the females to walk to the speaker, because this is the usual behaviour for female crickets, but they did not do this - [they instead] made a small jerking motion after each male call," she explained."I expected the females to walk to the speaker, because this is the usual behaviour for female crickets, but they did not do this - [they instead] made a small jerking motion after each male call," she explained.
"From many observations of males and females together, I noticed that it was always the male walking to the female when she produced these vibrational signals.""From many observations of males and females together, I noticed that it was always the male walking to the female when she produced these vibrational signals."
Further study revealed that the male calls also triggered activity in a nerve cell known to be responsible for triggering escape behaviour in crickets.Further study revealed that the male calls also triggered activity in a nerve cell known to be responsible for triggering escape behaviour in crickets.
This, along with careful tracking of the cricket evolutionary tree, led Prof ter Hofstede and her colleagues to conclude that what is now a mating song and dance routine originated from a reflex startled "jump".This, along with careful tracking of the cricket evolutionary tree, led Prof ter Hofstede and her colleagues to conclude that what is now a mating song and dance routine originated from a reflex startled "jump".
This, the scientists say, is an example of "how communication systems can change over evolutionary time.This, the scientists say, is an example of "how communication systems can change over evolutionary time.
"And that even something as unlikely as a reflex response to a predator can be the origin for a new communication signal.""And that even something as unlikely as a reflex response to a predator can be the origin for a new communication signal."