While the male túngara is being romantic and serenading females, frog-eating bats are using the ripples created from its singing to target the frog.
And while these frogs can stop their love songs, consisting of "whines" and "chucks," the bats can still use the ripples created in the water to hunt them. Researchers at the University of Texas at Austin found that bats were more likely to target a frog that was both singing and creating ripples than when the frog was only singing but not creating ripples.
The presence of leaves, which prevent the propagation of the ripples, around the frog seemed to confuse the bats, who could not use their echolocation to home in on the frogs.
"When a frog detects the shadow of a bat overhead, his first defense is to stop calling immediately. Unfortunately for the frog, the water ripples created by his call do not also stop immediately," said lead author Wouter Halfwerk.
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The ripples are created when the male frogs inflate and elate their vocal sacs. Females use the inflated vocal sac as a visual cue along with the call.
The findings, published in the journal Science, also suggest that these ripples seemed to increase the competition among the male frogs.
A call accompanied by ripples was more likely to get a response from competing males than if the call was broadcast without ripples. If the call came from outside a male's zone of defense, then reactionary calls from other frogs would be twice as fast, whereas if the call was from within the zone of defense rival frogs tended to call less or stop altogether.
[University of Texas at Austin] [Science]
