Revealed: Insects change the way they communicate when drowned out by man-made noises


Birds and frogs do it, even whales have been known to do it. Now scientists have for the first time shown that insects also change the way they sing to one another when drowned out by man-made noises.

Click HERE to listen to a grasshopper battling traffic noise

Grasshoppers living next to a main road respond to the increased background volume of passing traffic by adjusting their summer courtship songs, scientists have discovered.

In order to make themselves heard above the low-rumble noise pollution of moving vehicles, male bow-winged grasshoppers of central Europe alter the pitch of their songs’ lower notes so that they rise to a mini-crescendo, the scientists found.

“Bow-winged grasshoppers produce songs that include low and high frequency components,” said Ulrike Lampe of the University of Bielefeld in Germany, who led the study published in the journal Functional Ecology.

“We found that grasshoppers from noisy habitats boost the volume of the lower-frequency part of their song, which makes sense since road noise can mask signals in this part of the frequency spectrum,” Dr Lampe said.

The effects of man-made noise on the sounds made by animals has been fairly well documented in vertebrates – creatures with a backbone – but has hardly been studied in the invertebrates such as insects, she said.

“We know that birds shift the frequencies of their songs or use songs with higher mean frequencies under noisy conditions. Some frog species alter their calling rate in response to high background noise levels,” Dr Lampe said.

Whales are also believed to alter their acoustic communications in response of the high-volume noises made by military submarines, ships and underwater explosions.

The bow-winged grasshopper, which is a common species in Central Europe, grows about 1.5cm long and varies in colour from green and brown to red and purple. They “sing” by rubbing a toothed file on their hind legs against the “bow” of a protruding vein in their front wings, rather like a cello.

In order to attract females during the months of July and September, adult males sing two second-long “phrases” to each song which increase in volume toward the end. Slow ticking sounds begin each phrase, which increase in speed and amplitude culminating in a buzzing sound towards the end.

Dr Lampe and her colleagues thought that the low-frequency region of the song might be masked by traffic noise which is why they decided to study the species.

“Bow-winged grasshoppers are a good model organism to study sexual selection because females can respond to male courtship songs with their own low-frequency acoustic signal, if they are attracted to a male song,” Dr Lampe said.

“Since males produce broadband signals with a maximum in the ultrasound region (above 30 kHz) and a smaller, but significant peak in the region between 6 and 10 kHz, we thought about the possibility that this lower part of the frequency spectrum might be degraded or masked by anthropogenic noise, such as traffic noise,” she explained.

The scientist collected 188 male bow-winged grasshoppers, half  from next to a busy road  and half from open grassland without any noise pollution, and compared the frequency range of their songs. They recorded nearly 1,000 different songs.

The traffic noise imposed on the urban grasshoppers could be having a serious effect on their ability to find suitable mates, Dr Lampe said.

“Increased noise levels could affect grasshopper courtship in several ways. It could prevent females from hearing male courtship songs properly, prevent females from recognising males of their own species, or impair females' ability to estimate how attractive a male is from his song,” she said.

“We don't know this, yet. We want to find out more about female preferences for spectral parameters of the songs and whether traffic noise affects these preferences in some way,” she added.

More than 90 years of car history are coming to an end with the abolition of the paper car-tax disc
newsThis and other facts you never knew about the paper circle - completely obsolete tomorrow
Piers Morgan tells Scots they might not have to suffer living on the same island as him if they vote ‘No’ to Scottish Independence
peopleBroadcaster has a new role bringing 'the big stories that matter' to US
Arts and Entertainment
Kylie performs during her Kiss Me Once tour
musicReview: 26 years on from her first single, the pop princess tries just a bit too hard at London's O2
Life and Style
Moves to regulate e-cigarettes and similar products as medicines come amid increasing evidence of their effectiveness
healthHuge anti-smoking campaign kicks off on Wednesday
Life and Style
fashionEveryone, apparently
The erotic novel Fifty Shades of Grey has already been blamed for a rise in the number of callouts to the fire brigade for people trapped in handcuffs
voicesJustine Elyot: Since Fifty Shades there's no need to be secretive about it — everyone's at it
ebooksAn unforgettable anthology of contemporary reportage
Arts and Entertainment
A new Banksy entitled 'Art Buff' has appeared in Folkestone, Kent
Arts and Entertainment
Shia LaBeouf is one of Brad Pitt's favourite actors in the world ever, apparently
filmsAn 'eccentric' choice, certainly
Life and Style
An Internet security expert has warned that voice recognition technology needs to be more secure
techExperts warn hackers could control our homes or spend our money simply by speaking
peopleBenjamin Netanyahu trolled by group promoting two-state solution
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Head of Marketing - Acquisition & Direct Reponse Marketing

£90000 - £135000 per annum: Ashdown Group: Head of Marketing (B2C, Acquisition...

1st Line Service Desk Analyst

£27000 - £30000 Per Annum: Clearwater People Solutions Ltd: Our client who are...

Trainee Recruitment Consultant - Birmingham - Huxley Associates

£18000 - £23000 per annum + Commission: SThree: Huxley Associates are currentl...

Trainee Recruitment Consultant - Birmingham - Computer Futures

£18000 - £23000 per annum + Commission: SThree: Computer Futures are currently...

Day In a Page

Isis is an hour from Baghdad, the Iraq army has little chance against it, and air strikes won't help

Isis an hour away from Baghdad -

and with no sign of Iraq army being able to make a successful counter-attack
Turner Prize 2014 is frustratingly timid

Turner Prize 2014 is frustratingly timid

The exhibition nods to rich and potentially brilliant ideas, but steps back
Last chance to see: Half the world’s animals have disappeared over the last 40 years

Last chance to see...

The Earth’s animal wildlife population has halved in 40 years
So here's why teenagers are always grumpy - and it's not what you think

Truth behind teens' grumpiness

Early school hours mess with their biological clocks
Why can no one stop hackers putting celebrities' private photos online?

Hacked photos: the third wave

Why can no one stop hackers putting celebrities' private photos online?
Royal Ballet star dubbed 'Charlize Theron in pointe shoes' takes on Manon

Homegrown ballerina is on the rise

Royal Ballet star Melissa Hamilton is about to tackle the role of Manon
Education, eduction, education? Our growing fascination with what really goes on in school

Education, education, education

TV documentaries filmed in classrooms are now a genre in their own right
It’s reasonable to negotiate with the likes of Isis, so why don’t we do it and save lives?

It’s perfectly reasonable to negotiate with villains like Isis

So why don’t we do it and save some lives?
This man just ran a marathon in under 2 hours 3 minutes. Is a 2-hour race in sight?

Is a sub-2-hour race now within sight?

Dennis Kimetto breaks marathon record
We shall not be moved, say Stratford's single parents fighting eviction

Inside the E15 'occupation'

We shall not be moved, say Stratford single parents
Air strikes alone will fail to stop Isis

Air strikes alone will fail to stop Isis

Talks between all touched by the crisis in Syria and Iraq can achieve as much as the Tornadoes, says Patrick Cockburn
Nadhim Zahawi: From a refugee on welfare to the heart of No 10

Nadhim Zahawi: From a refugee on welfare to the heart of No 10

The Tory MP speaks for the first time about the devastating effect of his father's bankruptcy
Witches: A history of misogyny

Witches: A history of misogyny

The sexist abuse that haunts modern life is nothing new: women have been 'trolled' in art for 500 years
Shona Rhimes interview: Meet the most powerful woman in US television

Meet the most powerful woman in US television

Writer and producer of shows like Grey's Anatomy, Shonda Rhimes now has her own evening of primetime TV – but she’s taking it in her stride
'Before They Pass Away': Endangered communities photographed 'like Kate Moss'

Endangered communities photographed 'like Kate Moss'

Jimmy Nelson travelled the world to photograph 35 threatened tribes in an unashamedly glamorous style