scholarly journals Lung-to-ear sound transmission does not improve directional hearing in green treefrogs (Hyla cinerea)

2020 ◽  
Author(s):  
Jakob Christensen-Dalsgaard ◽  
Norman Lee ◽  
Mark A. Bee
Keyword(s):  
Vibration Amplitude ◽  
Sexual Communication ◽  
Sound Transmission ◽  
The State ◽  
Directional Hearing ◽  
Hyla Cinerea ◽  
Lung Inflation ◽  
Amplitude Difference ◽  
Green Treefrog ◽  
Green Treefrogs

ABSTRACTAmphibians are unique among extant vertebrates in having middle ear cavities that are internally coupled to each other and to the lungs. In frogs, the lung-to-ear sound transmission pathway can influence the tympanum’s inherent directionality, but what role such effects might play in directional hearing remain unclear. In this study of the American green treefrog (Hyla cinerea), we tested the hypothesis that the lung-to-ear sound transmission pathway functions to improve directional hearing, particularly in the context of interspecific sexual communication. Using laser vibrometry, we measured the tympanum’s vibration amplitude in females in response to a frequency modulated sweep presented from 12 sound incidence angles in azimuth. Tympanum directionality was determined across three states of lung inflation (inflated, deflated, reinflated) both for a single tympanum in the form of the vibration amplitude difference (VAD) and for binaural comparisons in the form of the interaural vibration amplitude difference (IVAD). The state of lung inflation had negligible effects (typically less than 0.5 dB) on both VADs and IVADs at frequencies emphasized in the advertisement calls produced by conspecific males (834 Hz and 2730 Hz). Directionality at the peak resonance frequency of the lungs (1558 Hz) was improved by ≅ 3 dB for a single tympanum when the lungs were inflated versus deflated, but IVADs were not impacted by the state of lung inflation. Based on these results, we reject the hypothesis that the lung-to-ear sound transmission pathway functions to improve directional hearing in frogs.SUMMARY STATEMENTContrary to prevailing views on the mechanisms of hearing in frogs, the lung-to-ear pathway for sound transmission does not improve directional hearing in these vociferous vertebrates.

scholarly journals Lung-to-ear sound transmission does not improve directional hearing in green treefrogs (Hyla cinerea)

2020 ◽  
Vol 223 (20) ◽  
pp. jeb232421
Author(s):  
Jakob Christensen-Dalsgaard ◽  
Norman Lee ◽  
Mark A. Bee
Keyword(s):  
Vibration Amplitude ◽  
Sexual Communication ◽  
Sound Transmission ◽  
The State ◽  
Directional Hearing ◽  
Hyla Cinerea ◽  
Lung Inflation ◽  
Amplitude Difference ◽  
Green Treefrog ◽  
Green Treefrogs

ABSTRACTAmphibians are unique among extant vertebrates in having middle ear cavities that are internally coupled to each other and to the lungs. In frogs, the lung-to-ear sound transmission pathway can influence the tympanum's inherent directionality, but what role such effects might play in directional hearing remains unclear. In this study of the American green treefrog (Hyla cinerea), we tested the hypothesis that the lung-to-ear sound transmission pathway functions to improve directional hearing, particularly in the context of intraspecific sexual communication. Using laser vibrometry, we measured the tympanum's vibration amplitude in females in response to a frequency modulated sweep presented from 12 sound incidence angles in azimuth. Tympanum directionality was determined across three states of lung inflation (inflated, deflated, reinflated) both for a single tympanum in the form of the vibration amplitude difference (VAD) and for binaural comparisons in the form of the interaural vibration amplitude difference (IVAD). The state of lung inflation had negligible effects (typically less than 0.5 dB) on both VADs and IVADs at frequencies emphasized in the advertisement calls produced by conspecific males (834 and 2730 Hz). Directionality at the peak resonance frequency of the lungs (1558 Hz) was improved by ∼3 dB for a single tympanum when the lungs were inflated versus deflated, but IVADs were not impacted by the state of lung inflation. Based on these results, we reject the hypothesis that the lung-to-ear sound transmission pathway functions to improve directional hearing in frogs.

Mating Call Recognition in the Green Treefrog (Hyla Cinerea): The Significance of some Fine-temporal Properties

1978 ◽  
Vol 74 (1) ◽  
pp. 59-73 ◽  
Author(s):  
H. CARL GERHARDT
Keyword(s):  
Spectral Properties ◽  
Species Recognition ◽  
Biological Significance ◽  
Hyla Cinerea ◽  
Temporal Properties ◽  
Call Recognition ◽  
Mating Call ◽  
Mating Calls ◽  
Green Treefrog ◽  
Green Treefrogs

1. Two hundred and eighty-eight female green treefrogs responded in two-choice experiments using synthetic calls. The spectral properties of the sounds were similar; the fine-temporal properties were systematically varied. 2. Females preferred sounds in which the waveform periodicity was about 300/s, a rate typical of natural mating calls. They discriminated strongly against calls with periodicities of 100/s, 60/s and 50/s. Aperiodic calls and calls with periodicities of 225/s and 900/s were intermediate in attractiveness. 3. The results of four experiments indicated that periodicity preferences depended on corresponding changes in the amplitude-time envelopes of the signals. 4. Neurophysiological correlations and the implications of the behavioural results are discussed. 5. The biological significance in species recognition and in the differentiation of the mating call from other signals in the repertoire of the green treefrog is discussed.

The Significance of Some Spectral Features in Mating Call Recognition in the Green Treefrog (Hyla Cinerea)

1974 ◽  
Vol 61 (1) ◽  
pp. 229-241 ◽  
Author(s):  
H. CARL GERHARDT
Keyword(s):  
Spectral Features ◽  
Optimal Frequency ◽  
Hyla Cinerea ◽  
Frequency Bands ◽  
Bimodal Stimulus ◽  
Call Recognition ◽  
Mating Call ◽  
Spectral Peaks ◽  
Green Treefrog ◽  
Green Treefrogs

1. Synthetic calls with a waveform periodicity of 300/sec and a bimodal spectrum attracted female green treefrogs as effectively as natural calls. 2. Effectiveness was markedly reduced if the relative amplitude of the two spectral peaks differed by as little as 10 dB. 3. Optimal frequency bands were 900-1100 Hz in the low range and 2700-3300 Hz in the high. 4. Addition of components at 1800 and 2100 Hz rendered the call less attractive. 5. In the absence of a bimodal stimulus, most females responded to a call containing a single spectral peak in the high or low range. 6. Mating call recognition in the green treefrog is compared with that in the bullfrog.

Directional sound processing and interaural sound transmission in a small and a large grasshopper

1995 ◽  
Vol 198 (9) ◽  
pp. 1817-1827 ◽  
Author(s):  
A Michelsen ◽  
K Rohrseitz
Keyword(s):  
Outer Surface ◽  
Sound Pressure ◽  
Schistocerca Gregaria ◽  
Sound Transmission ◽  
Directional Hearing ◽  
Sound Processing ◽  
Low Frequencies ◽  
High Frequencies ◽  
Physical Mechanisms ◽  
Chorthippus Biguttulus

Physical mechanisms involved in directional hearing are investigated in two species of short-horned grasshoppers that differ in body length by a factor of 3­4. The directional cues (the effects of the direction of sound incidence on the amplitude and phase angle of the sounds at the ears) are more pronounced in the larger animal, but the scaling is not simple. At high frequencies (10­20 kHz), the sound pressures at the ears of the larger species (Schistocerca gregaria) differ sufficiently to provide a useful directionality. In contrast, at low frequencies (3­5 kHz), the ears must be acoustically coupled and work as pressure difference receivers. At 3­5 kHz, the interaural sound transmission is approximately 0.5 (that is, when a tympanum is driven by a sound pressure of unit amplitude at its outer surface, the tympanum of the opposite ear receives a sound pressure with an amplitude of 0.5 through the interaural pathway). The interaural transmission decreases with frequency, and above 10 kHz it is only 0.1­0.2. It still has a significant effect on the directionality, however, because the directional cues are large. In the smaller species (Chorthippus biguttulus), the interaural sound transmission is also around 0.5 at 5 kHz, but the directionality is poor. The reason for this is not the modest directional cues, but rather the fact that the transmitted sound is not sufficiently delayed for the ear to exploit the directional cues. Above 7 kHz, the transmission increases to approximately 0.8 and the transmission delay increases; this allows the ear to become more directional, despite the still modest directional cues.

Hyla cinerea (Schneider) (Green treefrog) 2n = 24

1973 ◽  
pp. 37-39
Author(s):  
Maria Luiza Beçak ◽  
Willy Beçak ◽  
Franklin L. Roberts ◽  
Robert N. Shoffner ◽  
E. Peter Volpe
Keyword(s):  
Hyla Cinerea ◽  
Green Treefrog
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