Robotic frogs help UT researchers understand mating calls

Gefei Liu

UT and Salisbury University biologists have discovered the secrets of tungara frogs mating call with the help of a robotic frog imitating the sounds of the real frogs. 

Biology professor Michael Ryan conducted research that found male tungara frogs can produce “whines” and “chucks” when they attract a female frog.  Males always make a whine and can add chucks to the end of the whine. They never make a chuck without a whine.

“When males add chucks to their whine, it makes the call more attractive and the male is more likely to attract a mate,” Ryan said.

A robotic tungara frog is designed to mimic a live, calling male. With the robot frog, scientists can present a female tungara frog with both the visual component of what looks like a calling male with its inflating vocal sac and a call.  This is called a multimodal signal – the combination of a visual and auditory signal.  

According to Ryan Taylor, a Salisbury University professor, the research was based on the previous finding that female Tungara frogs prefer the “males” they can see to the ones they just hear. They prefer multimodal signals instead of only calls.  

“Interestingly, we also discovered that if we decouple the call and vocal sac inflation, females change their preference and will avoid the robot frog,” Taylor said. “In nature, males cannot decouple the timing of their call and vocal sac inflation; these must happen at the same time.” 

Taylor said the insights they learned from this study have already begun to inform new experiments they are now pursuing. 

“In particular, we are interesting in better understanding how female tungara frogs integrate the auditory and visual components of the mating signal in time,” Taylor said. “This experiment provided us a much deeper understanding of how this sensory integration works, but we still have many more questions.