Frogs form ‘boy bands’ and sing together to woo females into their pools, study finds 


A frog species forms ‘boy bands’ that sing in unison to woo females into their pools, a new study shows.

Researchers have recorded wood frogs (Rana sylvatica) at ponds in New Hampshire to learn more about individual contributions to a frog chorus. 

Findings indicate that females are generally attracted to songs in lower frequencies – likely because they indicate bigger bodies and good physical health.

Males, meanwhile, time their songs to other chorus members and may even be choosy about singing with certain other males to enhance their breeding success. 

In this way, they’re akin to boy bands choosing the right bandmates to enhance their appeal to the ladies.   

Researchers have recorded wood frogs (Rana sylvatica) using advanced recording technology to see how individual songs in amphibian choruses may influence mating

THE REMARKABLE WOOD FROG

Wood frogs, which have a broad range over North America, breed in temporary pools rather than permanent water bodies like ponds or lakes. 

The species is known for its remarkable adaptation to withstanding sub-zero conditions. 

During the winter, wood frogs stop breathing and their hearts stop beating. 

Their bodies produce a special antifreeze substance that prevents ice from freezing within their cells, which would be deadly. Ice does form, however, in the spaces between the cells. 

When the weather warms, the frogs thaw and begin feeding and mating again. 

Source: NWF 

A frog chorus is made up of individual calls of various frogs, creating a cacophony of bizarre quacking or gobbling sounds. 

‘A chorus of wood frogs can sound a lot like the chaotic gobbling from a group of rowdy turkeys,’ said study author Ryan Calsbeek at Dartmouth College in Hanover, New Hampshire.

‘No one has figured out a way to extract the voice of one individual from a chorus to understand how membership in a group influences that individual’s chance at getting a mate.’ 

Wood frogs, which have a broad range over North America, breed in temporary pools rather than permanent water bodies like ponds or lakes. 

The species is known for its remarkable adaptation to withstanding sub-zero conditions during the winter. 

After emerging from their winter hideouts in early spring, wood frogs move to the thawing pools to breed.

Hundreds of male frogs group together in ‘armies’ in the pools and sing in large choruses with the hope of attracting females. 

Once a female enters a pond, males compete to determine mating pairs. 

It’s thought that females seeking a mate associate certain male body types with low or high-pitched songs – for example, a larger frog with a lower-pitched song. 

To learn more about the individual contributions to a chorus, researchers stationed an acoustic camera – a device used to locate sound sources – at ponds near Hanover and Norwich in Vermont. 

Researchers used an acoustic camera positioned in front of the pond (pictured) to separate individual frog songs from their choruses

Researchers used an acoustic camera positioned in front of the pond (pictured) to separate individual frog songs from their choruses

Acoustic cameras consist of a group of microphones from which signals are simultaneously collected and processed to form a representation of the location of the sound

Acoustic cameras consist of a group of microphones from which signals are simultaneously collected and processed to form a representation of the location of the sound 

SIX OF THE WORLD’S SMALLEST FROGS ARE DISCOVERED IN MEXICO 

Six new species of frog – some smaller than the diameter of a 1p coin – have been identified by scientists. 

The amphibians were spotted living across a variety of habitats in Mexico and have only just been described because they bear a striking resemblance to other close relatives.

Experts who helped to identify the six new Craugastor species say they should be classed as endangered. 

Read more

It consists of a hula hoop-like antenna on a pole that holds directional microphones that can pinpoint the source of individual songs.  

Prior to now, no one had figured out a way to extract the voice of one individual from a chorus, according to the team.

‘The camera allowed us to analyze individual calls as well as group dynamics,’ said study author Laurel Symes at Cornell University in Ithaca, New York. 

‘This is the audio equivalent of picking out the trees from the forest.’

The experts then overlayed heat maps of the sounds onto videos of breeding ponds and matched them against the locations of eggs as an indicator of breeding success. 

Results showed that female frogs aren’t so interested in individual male songs, but they do seem to be attracted to group choruses featuring low-pitch collective ‘voices’.

Because male body size determines audio frequency, more variable choruses should tell females that there is more variety in the size of males in that group. 

Interestingly, males may choose whether to sing with frogs of similar or different body types depending on how that might influence their ability to find a mate, the results suggest. 

The species (Rana sylvatica) is known for its remarkable adaptation to withstanding sub-zero conditions

The species (Rana sylvatica) is known for its remarkable adaptation to withstanding sub-zero conditions

‘It seems that the chorus calls are used to attract the female wood frogs to a breeding site,’ said Calsbeek. 

‘The individual songs play a role in positioning the male frogs within that site, but it then becomes a physical showdown to decide who mates.’ 

Factors such as environmental conditions and predation require further study to fully determine the connection between singing on mating decisions, the team say.

Their new research has been published in the journal Ecology Letters. 

TREE FROG HAS LUNGS WHICH ‘ACT LIKE NOISE CANCELLING HEADPHONES’ TO ENSURE IT ONLY HEARS THE ROMANTIC CALLS OF POTENTIAL SUITORS 

A species of frog just needs to inflate its lungs to ensure it hears the calls of potential mates over background noise, just like noise cancelling headphones, a study reveals.

US researchers used precise laser measurements of the eardrums of the American green tree frog (Hyla cinerea) in response to sound. 

When the lungs were inflated, it had no impact on how the green tree frog’s eardrum responded to mating calls of its own species. 

However, inflated lungs reduced the sensitivity of the eardrum to sound frequencies commonly used by other species.  

Inflated lungs makes it harder for the tree frog to hear the calls of other species that it’s not interested in, while leaving the ability to hear the calls of their own species intact – letting them be more easily located. 

‘Essentially, what female frogs are doing is putting on noise-cancelling headphones,’ said senior author Mark Bee, a professor at the University of Minnesota’s College of Biological Sciences.

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