Croak to croon: the frogs of the city sing more seductive love songs

WASHINGTON (AP) – City frogs and rainforest frogs sing not the same melody, have discovered researchers.

A study published on Monday examined why Panama's tiny tungara frogs adapted their calls in urban areas – an unexpected example of how animals alter communication strategies when cities encroach on forests.

These frogs benefit from the relative absence of predators listening to cities in cities. Longer songs of love, which attract more female frogs.

Tungara frogs do not croak like bullfrogs. For the human ears, their distinctive appeal sounds like a beep sound of serious video game. For female frogs, this sounds like a discussion of pillows.

Every evening at sunset, one-inch male brown frogs slip into puddles to become potential partners. Lady Frog chooses a companion largely inspired by her love song.

The researchers found that urban frogs call faster, more frequently, and add other embellishments – a series of staccato "chucks" at the end of the initial whine – compared to those in the forest.

These sophisticated urban love songs are three times more likely to attract women, as scientists have learned by retranscribing records of city and forest frog calls to a public of female frogs in a laboratory. The researchers report in the journal Nature Ecology & Evolution (1965) that female frogs are native to the city or forest, indicated the same preference for the fast.

The co-author of the study, Michael J. Ryan, a biologist at the University of Texas, who has been studying tungara frogs for over 30 years, said that the highs and lows of notes probably stimulated the inner and outer ear chambers of female frogs in a pleasant or interesting way.

So why do not frogs in the rainforest sing the same way?

Scientists have begun to confirm their hypothesis that frogs would add even more Acute "mandrels" attract not only more partners, but also more problems from frog-eating bats and parasitic midges. With the help of photo traps and sticky paper, researchers have shown that prolonged frog calls greatly increase the risk of attracting predators.

In the rainforest, frogs have to reconcile two goals: to attract a partner and stay safe.

In town, there are no bats eating frogs and many fewer snakes and midges.

"A man in the city can take more risks," said lead author, Wouter Halfwerk, ecologist at Vrije University in Amsterdam.

A city frog must also redouble efforts. find a companion because toads are rarer in town. "Competition for women is increasing," said Halfwerk. "The best adaptation is to be the most attractive, with an elaborate love song."

Corinne Lee Zawacki, a biologist at the University of Pittsburgh who did not participate in the study, said the researchers' methodology confirmed that urbanization was the reason for this call has been modified.

"I like the choice of the study system," she said. "A lot of basic research has already been done on this frog, so we can clearly see how urbanization is altering the interaction between natural and badual selection", or the trade-offs between survival and parry goals. .

But not all amphibians are as lucky as Panama's tungara frogs.

"Amphibian populations are declining worldwide, mainly because of the destruction of their habitat," said Andrew Blaustein, an ecologist at the University of Oregon, who did not participate in the study. "This is a rare case – and very interesting – of an animal adapting rapidly, in terms of evolution, to new circumstances."

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Follow Christina Larson on Twitter @larsonchristina.

___ [19659003] The Associated Press Science & Science Department is supported by the Howard Hughes Medical Institute's Department of Science Education. The AP is solely responsible for all content.