With the help of a robotic frog, biologists at The University of Texas at Austin and Salisbury University have discovered that two wrong mating calls can make a right for female túngara frogs.
he “rather bizarre” result may be evidence not of a defect in the frog brain, but of how well frogs have evolved to extract meaning from noise, much the way humans have. The research, which was published last month in Science, may also provide insight into how complex traits evolve by hooking together much simpler traits.
When choosing a potential mate, female túngara frogs listen to the sounds of the male calls, which are based on a pattern of “whines” and “chucks.” If visible, the sight of the male frogs inflating their vocal sacs adds to the appeal of the calls. It makes a whine more attractive, though still less attractive than a whine-chuck, and it makes a whine-chuck more attractive still.
In an innovative experiment, biologists Michael Ryan and Ryan Taylor played around with those visual and auditory signals. They took a recording of a basic whine, then added a robotic frog that inflated its vocal sac late. They ran a parallel experiment with a chuck that arrived late relative to the whine.
On their own neither the late vocal sac expansion or the sluggish chuck added to the sex appeal of the whine. In both cases it was as if the frog had just whined.
When the late cues were strung together, however, something extraordinary happened. The vocal sac “perceptually rescued” the chuck and bound it together with the first part of the whine-chuck call. The resulting signal was as attractive to the female túngara frogs as a well-timed “whine-chuck.”
Túngara frogs ar challenged by AN sense modality world like what confronts humans in buzzing environments (what’s known as the “cocktail party problem” by psychological feature scientists). At breeding choruses there’s lots of noise and cross speak, with sounds and pictures of many males reaching the feminine at completely different times. The females have to be compelled to extract substantive info from all of that. Ryan same it’s plausible the neural mechanisms that alter them to properly analyse these stimuli in nature ar being hijacked by this artificial situation.
“We have to be compelled to be ready to hook things along perceptually in sudden ways that to extract substantive stimuli from lots of noise,” same Ryan. “So what we predict is occurring here is that the vocal sac, the visual cue, is functioning quite just like the dissonance, giving sensory activity continuity between these 2 sounds, binding the temporally displaced whine and chuck along.”
Ryan same that though the frogs’ aggressive hunt for that means leaves them receptive being tricked by clever researchers, it may conjointly alter additional flexibility in complicated things. He believes it should have a far longer-term organic process advantage moreover.