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

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A species of frog forms “boy groups” that sing in unison to attract females to their pools, a new study has found.

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

The results indicate that women are generally attracted to songs with lower frequencies – likely because they indicate a bigger body and good physical health.

The males, on the other hand, synchronize their songs with the other members of the choir and can even be difficult to sing with certain other males to improve their breeding success.

In this way, they are akin to groups of boys who pick the right bandmates to boost their appeal to women.

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

THE REMARKABLE WOOD FROG

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

The species is known for its remarkable adaptation to resistance to negative 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 in their cells, which would be deadly. However, ice forms in the spaces between the cells.

When the weather warms up, the frogs thaw out and start feeding and mating again.

Source: NWF

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

“A chorus of wood frogs can sound a lot like the chaotic chasm of a rowdy flock of turkeys,” said study author Ryan Calsbeek of Dartmouth College in Hanover, New Hampshire.

“No one has found a way to extract an individual’s voice from a choir to understand how group membership influences that individual’s chances of having a mate.”

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

The species is known for its remarkable adaptation to resistance to negative conditions during the winter.

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

Hundreds of male frogs gather in “armies” in the pools and sing in loud choruses in the hope of attracting females.

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

Females looking for a mate are thought to associate certain male body types with low-pitched or high-pitched songs – for example, a larger frog with a lower-pitched song.

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

The researchers used an acoustic camera positioned in front of the pond (pictured) to separate the frogs' individual songs from their choruses

The researchers used an acoustic camera positioned in front of the pond (pictured) to separate the frogs’ individual 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 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 sound

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

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

Amphibians have been spotted living in 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 identify the six new Craugastor species say they should be listed as endangered.

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It consists of a hula hoop-shaped antenna on a pole that contains directional microphones that can locate the source of individual songs.

Previously, no one had found a way to extract an individual’s voice from a choir, according to the team.

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

“It’s the audio equivalent of selecting trees from the forest.”

Experts then overlaid sound heatmaps on videos of breeding ponds and compared them to egg location as an indicator of breeding success.

The results showed that female frogs are not so interested in individual male songs, but they seem to be attracted to group choruses featuring low-pitched collective “voices.”

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

Interestingly, males may choose 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 resistance to negative conditions

The species (Rana sylvatica) is known for its remarkable adaptation to resistance to negative conditions

“It appears that chorus calls are used to attract female wood frogs to a breeding site,” Calsbeek said.

“Individual songs play a role in positioning male frogs at this site, but then it becomes a physical confrontation to decide who mates.”

According to the team, factors such as environmental conditions and predation require further study to fully determine the link between singing and mating decisions.

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

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

A species of frog just needs to inflate its lungs to make sure it hears the calls of potential mates over background noise, much like noise-canceling headphones, a study reveals.

American researchers have 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 the mating calls of its own species.

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

The swollen lungs make it harder for the tree frog to hear the calls of other species they are not interested in, while leaving the ability to hear the calls of their own species intact, making them easier to locate.

“Essentially what female frogs do is put on noise-canceling headphones,” said lead author Mark Bee, a professor in the College of Biological Sciences at the University of Minnesota.

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