The Reflections series takes a look back on historical articles from The Journal of the Acoustical Society of America that have had a significant impact on the science and practice of acoustics.
Albert S.-H. Feng was an outstanding family man and brilliant scientist, with a creative mind, a gift for dealing with people of all types, and a warm, personable demeanor. He was blessed with many ...talents, making him a sought-after colleague and collaborator. His love for people and travel took him to many destinations around the world where he studied the neuroethology of frog and bat communication both in the field and in the lab. He has made many fundamental contributions to our understanding of the vertebrate auditory system. These include characterizing the “delay-tuned” neurons in the bat midbrain underlying target detection, and in discovering several terrestrial amphibians in which the upper limit of hearing extends well into the ultrasonic range, forever changing our long-held perception of frogs as “low-frequency animals”.
Temperature affects nearly all biological processes, including acoustic signal production and reception. Here, we report on advertisement calls of the Puerto Rican coqui frog (Eleutherodactylus ...coqui) that were recorded along an altitudinal gradient and compared these with similar recordings along the same altitudinal gradient obtained 23 years earlier. We found that over this period, at any given elevation, calls exhibited both significant increases in pitch and shortening of their duration. All of the observed differences are consistent with a shift to higher elevations for the population, a well-known strategy for adapting to a rise in ambient temperature. Using independent temperature data over the same time period, we confirm a significant increase in temperature, the magnitude of which closely predicts the observed changes in the frogs’ calls. Physiological responses to long-term temperature rises include reduction in individual body size and concomitantly, population biomass. These can have potentially dire consequences, as coqui frogs form an integral component of the food web in the Puerto Rican rainforest.
Acoustic communication plays a vital role in frog reproduction. In most anuran species, long-distance sound communication is one-way from males to females; during the reproductive season, males ...produce species-specific advertisement calls to attract gravid females, and females are generally silent but perform phonotactic movements that lead to amplexus. One exception is the concave-eared torrent frog (
Odorrana tormota
). In this species, females produce courtship calls that elicit antiphonal vocalizations by males, followed by precise phonotactic movements. The large odorous frog
O. graminea
(previously
Odorrana livida
) in southern China is subject to the same environmental constraints as
O. tormota
, with which it is sympatric; it is unclear whether their sound communication is one-way or bidirectional. Here, we provide the first data on female
O. graminea
vocalizations and their functions. Using playbacks of female calls, we conducted acoustic behavioral experiments in the laboratory in response to which males emitted single- or multi-note antiphonal calls with a varying fundamental frequency. Moreover, they were attracted to female call playbacks, exhibiting precise phonotaxis. The female courtship call–male response interaction thus forms a duet between partners of a receptive pair. These results demonstrate that this unique communication system likely reflects an adaptation to an environment in which short-distance communication is at a premium given the high levels of ambient noise.
Frogs and toads are capable of producing calls at potentially damaging levels that exceed 110 dB SPL at 50 cm. Most frog species have internally coupled ears (ICE) in which the tympanic membranes ...(TyMs) communicate directly via the large, permanently open Eustachian tubes, resulting in an inherently directional asymmetrical pressure-difference receiver. One active mechanism for auditory sensitivity reduction involves the pressure increase during vocalization that distends the TyM, reducing its low-frequency airborne sound sensitivity. Moreover, if sounds generated by the vocal folds arrive at both surfaces of the TyM with nearly equal amplitudes and phases, the net motion of the eardrum would be greatly attenuated. Both of these processes appear to reduce the motion of the frog’s TyM during vocalizations. The implications of ICE in amphibians with respect to sound localizations are discussed, and the particularly interesting case of frogs that use ultrasound for communication yet exhibit exquisitely small localization jump errors is brought to light.
While most anuran species are highly vocal, few of them seem to be endowed with a complex call repertoire.
Odorrana tormota
, combines a remarkable vocalization complexity with auditory sensitivity ...over an extended spectral range spanning from audible to ultrasonic frequencies. This species is also exceptional for its ability to modify its middle ear tuning by closing the Eustachian tubes (ET). Using scanning laser Doppler vibrometry, the tympanal vibrations were measured to investigate if the tuning shift caused by the ET closure contributes to intraspecific acoustic communication. To gain insight into the inner ear frequency selectivity and sensitivity of this species, distortion product otoacoustic emissions were recorded at multiple frequency-level combinations. Our measurements of inner ear responses indicated that in
O. tormota
each sex is more sensitive to the frequencies of the other sex's vocalizations, female ears are more sensitive to 2–7 kHz, while male ears are more sensitive to 3–15 kHz. We also found that in both sexes the ET closure impacts the sensitivity of the middle and inner ear at frequencies used for communication with conspecifics. This study broadens our understanding of peripheral auditory mechanisms contributing to intraspecific acoustic communication in anurans.
During the 99 years of its history, the
Journal of Comparative Physiology A
has published many of the most influential papers in comparative physiology and related disciplines. To celebrate this ...achievement of the journal’s authors, annual Editors’ Choice Awards and Readers’ Choice Awards are presented. The winners of the 2023 Editors’ Choice Awards are ‘Contact chemoreception in multi‑modal sensing of prey by
Octopus
’ by Buresch et al. (J Comp Physiol A 208:435–442, 2022) in the Original Paper category; and ‘Magnetic maps in animal navigation’ by Lohmann et al. (J Comp Physiol A 208:41–67, 2022) in the Review/Review-History Article category. The winners of the 2023 Readers’ Choice Awards are ‘Coping with the cold and fighting the heat: thermal homeostasis of a superorganism, the honeybee colony’ by Stabentheiner et al. (J Comp Physiol A 207:337–351; 2021) in the Original Paper category; and ‘Einstein, von Frisch and the honeybee: a historical letter comes to light’ by Dyer et al. (J Comp Physiol A 207:449–456, 2021) in the Review/Review-History category.
The effects of airplane flyby noise and playbacks of low-frequency motorcycle sounds on calling activity were examined in a mixed-species anuran calling assemblage in central Thailand. In response to ...these stimuli, three of the most acoustically active pond-edge species (
Microhyla butleri,
Rana nigrovittata and
Kaloula pulchra) significantly decreased their calling rate. Yet under the identical stimulus regime,
Rana taipehensis consistently increased its calling rate. Moreover, during the occasional natural lulls in the chorus in which males collectively stop calling, resulting in a conspicuous reduction in chorus intensity, calls of
R. taipehensis would appear to emerge from the background noise. These results suggest that man-made acoustic interference may affect anuran chorus behavior either directly by modulating call rates of the chorus participants or indirectly, by suppressing calling behavior of one set of species which in turn stimulates calling in other species. The results of our playback experiment coupled with the natural calling behavior of these species support the latter hypothesis.
Despite the predominance of low-frequency hearing in anuran amphibians, a few frog species have evolved high-frequency communication within certain environmental contexts.
Huia cavitympanum
is the ...most remarkable anuran with regard to upper frequency limits; it is the first frog species known to emit exclusively ultrasonic signals. Characteristics of the Distortion Product Otoacoustic Emissions from the amphibian papilla and the basilar papilla were analysed to gain insight into the structures responsible for high-frequency/ultrasound sensitivity. Our results confirm the matching of vocalization spectra and inner ear tuning in this species. Compared to most anurans,
H. cavitympanum
has a hyperextended hearing range spanning from audible to ultrasonic frequencies, far above the previously established ‘spectral limits’ for the amphibian ear. The exceptional high-frequency sensitivity in the inner ear of
H. cavitympanum
illustrates the remarkable plasticity of the auditory system and the extent to which evolution can modify a sensory system to adapt it to its environment.
PDF
