Journal Article

Ultrasonic communication in frogs

Lin, Wen-Yu, Xu, Zhi-Min, Feng, Albert S., Narins, Peter M., Xu, Chun-He, Qiu, Qiang, Yu, Zu-Lin, Shen, Jun-Xian

2006

Overview

Raising The Tone Some bats, dolphins and rodents are notable among vertebrates in being able to produce and detect ultrasonic frequencies. Now for the first time an amphibian can be added to that select list. The spectacular bird-like sounds made by a type of Chinese torrent frog were known to edge into the ultrasonic range: now these frogs are shown to use ultrasonics as a form of communication. The males do at least, during competition for territory. Frogs are a long way, evolutionarily speaking, from the other known users of ultrasonics so this ability seems to have evolved independently several times. It is possible, too, that many other species are chatting away in the ultrasonic waveband, but that nobody has looked for them. Among vertebrates, only microchiropteran bats, cetaceans and some rodents are known to produce and detect ultrasounds (frequencies greater than 20 kHz) for the purpose of communication and/or echolocation, suggesting that this capacity might be restricted to mammals 1 , 2 . Amphibians, reptiles and most birds generally have limited hearing capacity, with the ability to detect and produce sounds below ∼12 kHz. Here we report evidence of ultrasonic communication in an amphibian, the concave-eared torrent frog ( Amolops tormotus ) from Huangshan Hot Springs, China. Males of A. tormotus produce diverse bird-like melodic calls with pronounced frequency modulations that often contain spectral energy in the ultrasonic range 3 , 4 . To determine whether A. tormotus communicates using ultrasound to avoid masking by the wideband background noise of local fast-flowing streams, or whether the ultrasound is simply a by-product of the sound-production mechanism, we conducted acoustic playback experiments in the frogs' natural habitat. We found that the audible as well as the ultrasonic components of an A. tormotus call can evoke male vocal responses. Electrophysiological recordings from the auditory midbrain confirmed the ultrasonic hearing capacity of these frogs and that of a sympatric species facing similar environmental constraints. This extraordinary upward extension into the ultrasonic range of both the harmonic content of the advertisement calls and the frog's hearing sensitivity is likely to have co-evolved in response to the intense, predominantly low-frequency ambient noise from local streams. Because amphibians are a distinct evolutionary lineage from microchiropterans and cetaceans (which have evolved ultrasonic hearing to minimize congestion in the frequency bands used for sound communication 5 and to increase hunting efficacy in darkness 2 ), ultrasonic perception in these animals represents a new example of independent evolution.

• Publisher: Nature Publishing Group UK,Nature Publishing,Nature Publishing Group
• Subject: Acoustic Stimulation / Amolops tormotus / Amphibia and reptilia / Amphibia. Reptilia / Amphibians / Animal Communication / Animal ethology / Animals / Anura / Biological and medical sciences / Biological Evolution / Birds / Brain - physiology / Cetacea / China / Ear - physiology / Ears & hearing / Evoked Potentials, Auditory - physiology / Evolution / Frogs / Fundamental and applied biological sciences. Psychology / Hearing - physiology / Hot springs / Humanities and Social Sciences / letter / Male / Mammals / Marine / multidisciplinary / Psychology. Psychoanalysis. Psychiatry / Ranidae - physiology / Reptiles / Rodents / Science / Science (multidisciplinary) / Ultrasonics / Vertebrata / Vertebrates / Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution