scholarly journals The ultrasound guide: katydid ear pinnae code for bat call detection

2021 ◽  
Author(s):  
Christian Pulver ◽  
Emine Celiker ◽  
Charlie Woodrow ◽  
Inga Geipel ◽  
Carl Soulsbury ◽  
...  
Keyword(s):  
Numerical Modelling ◽  
Sound Pressure ◽  
Arms Race ◽  
Directional Hearing ◽  
Predator Detection ◽  
Predator Prey ◽  
Ultrasound Guide ◽  
Pressure Time ◽  
Receiver System ◽  
Sound Detection

Early predator detection is a key component of the predator-prey arms race, and has driven the evolution of multiple animal hearing systems. Katydids (Insecta) have a sophisticated ear consisting of paired tympana on each foreleg that receive sound externally and internally, creating a pressure-time difference receiver system capable of sensitive and accurate directional hearing, despite the small size of katydids. Some katydid species have pinnae of unknown function, which form cavities around the outer tympanal surfaces and have been hypothesised to influence the external sound paths. Combining experimental biophysics and numerical modelling on 3D ear geometries, we investigated pinna function in the katydid Copiphora gorgonensis. Pinnae induced large sound-pressure gains that enhanced sound detection at high ultrasonic frequencies (>60 kHz), matching the echolocation range of their nocturnal insectivorous bat predators. Comparing pinna resonances of sympatric katydid species supported these findings, and suggests that pinnae may have evolved for enhanced predator detection.

scholarly journals Bone conduction pathways confer directional cues to salamanders

2021 ◽  
Author(s):  
G. Capshaw ◽  
J. Christensen-Dalsgaard ◽  
D. Soares ◽  
C. E. Carr
Keyword(s):  
Evolutionary History ◽  
Sound Pressure ◽  
Bone Conduction ◽  
Auditory Brainstem ◽  
Directional Hearing ◽  
Sound Detection ◽  
Brainstem Response ◽  
Sound Reception ◽  
Detection And Localization ◽  
Mechanical Disturbances

Sound and vibration are generated by mechanical disturbances within the environment, and the ability to detect and localize these acoustic cues is generally important for survival, as suggested by the early emergence of inherently directional otolithic ears in vertebrate evolutionary history. However, fossil evidence indicates that the water-adapted ear of early terrestrial tetrapods lacked specialized peripheral structures to transduce sound pressure (e.g., tympana). Early terrestrial hearing therefore should have required nontympanic (or extratympanic) mechanisms for sound detection and localization. Here we used atympanate salamanders to investigate the efficacy of extratympanic pathways to support directional hearing in air. We assessed peripheral encoding of directional acoustic information using directionally-masked auditory brainstem response recordings. We used laser Doppler vibrometry to measure the velocity of sound pressure-induced head vibrations as a key extratympanic mechanism for aerial sound reception in atympanate species. We found that sound generates head vibrations that vary with the angle of the incident sound. This extratympanic pathway for hearing supports a figure-eight pattern of directional auditory sensitivity to airborne sound in the absence of a pressure-transducing tympanic ear.

Design of a Biomimetic Directional Microphone Diaphragm

2000 ◽  
Author(s):  
C. Gibbons ◽  
R. N. Miles
Keyword(s):  
Sound Pressure ◽  
Capacitive Sensor ◽  
Sound Level ◽  
Pressure Level ◽  
The Self ◽  
Mode Shapes ◽  
Directional Hearing ◽  
The Finite Element Method ◽  
Mechanical Coupling ◽  
Directional Microphone

Abstract A miniature silicon condenser microphone diaphragm has been designed that exhibits good predicted directionality, sensitivity, and reliability. The design was based on the structure of a fly’s ear (Ormia ochracea) that has highly directional hearing through mechanical coupling of the eardrums. The diaphragm that is 1mm × 2mm × 20 microns is intended to be fabricated out of polysilicon through microelectromechanical micromachining. It was designed through the finite-element method in ANSYS in order to build the necessary mode shapes and frequencies into the mechanical behavior of the design. Through postprocessing of the ANSYS data, the diaphragm’s response to an arbitrary sound source, sensitivity, robustness, and Articulation Index - Directivity Index (AI-DI) were predicted. The design should yield a sensitivity as high as 100 mV/Pa, an AI-DI of 4.764 with Directivity Index as high as 6 between 1.5 and 5 kHz. The diaphragm structure was predicted be able to withstand a sound pressure level of 151.74 dB. The sound level that would result in collapse of the capacitive sensor is 129.9 dB.. The equivalent sound level due to the self-noise of the microphone is predicted to be 30.8 dBA.

scholarly journals THE FEATURES OF THE COMBINED RECEIVER UNIT OPERATION ABOARD UNDERWATER GLIDER

2020 ◽  
Author(s):  
Б.А. Касаткин ◽  
С.Б. Касаткин
Keyword(s):  
Sound Pressure ◽  
Sound Field ◽  
Aquatic Area ◽  
Unit Operation ◽  
Underwater Glider ◽  
Informative Parameters ◽  
Intensity Vector ◽  
Receiver System ◽  
Combined Receiver ◽  
Receiver Unit

При работе приемной системы на борту движущегося носителя возникает специфическая проблема уменьшения собственных шумов носителя, уровень которых зависит от типа приемной системы и алгоритмов обработки сигналов. В настоящей работе рассматриваются особенности работы комбинированного приемника на борту подводного планера (глайдера) в собственных шумах обтекания, которые возникают при изменении горизонта позиционирования глайдера. Предложено полное описание энергетической структуры звукового поля, включающее 16 информативных параметров. В их число входят квадрат звукового давления, компоненты комплексного вектора интенсивности, компоненты вещественного ротора вектора интенсивности и квадратичные компоненты комплексного вектора градиента давления. Приводятся результаты натурного эксперимента, выполненного в мелком море, в котором глайдер, оснащенный комбинированным приемником, периодически изменял горизонт позиционирования в режиме погружение – всплытие. Анализируются в сравнительном плане уровни шумов обтекания на выходе канала звукового давления и на выходе векторных каналов при различном определении информативных параметров, характеризующих звуковое поле в скалярно-векторном описании. Приводятся оценки уровня шумов обтекания, подтверждающие преимущества комбинированного приемника в сравнении с гидрофоном при его работе в составе бортовой приемной системы в ближнем поле собственных шумов обтекания. Рассматриваются особенности работы комбинированного приемника на борту подводного планера (глайдера) в собственных шумах обтекания, которые возникают при изменении горизонта позиционирования глайдера. Анализируются в сравнительном плане уровни шумов обтекания на выходе канала звукового давления и на выходе векторных каналов при различном определении информативных параметров, характеризующих звуковое поле в скалярно-векторном описании. Приводятся результаты натурного эксперимента, подтверждающие преимущества комбинированного приемника в сравнении с гидрофоном при его работе в составе бортовой приемной системы в ближнем поле собственных шумов обтекания. While operating aboard moving carrier, the receiver system faces a specific problem of reducing self-noises of the carrier, the magnitude of which depends on the type of receiver system and algorithms of signal processing. The present work considers the features of the combined receiver unit operation aboard underwater glider in self-generated flow noises, originated when the glider positioning horizon is changed. The complete description of the energetic structure of the sound field, including 16 informative parameters, is proposed. The list of parameters includes sound pressure squared, components of the complex intensity vector, components of the real curl of an intensity vector, and quadratic components of the complex vector of the pressure gradient. The theoretical background is supported by the results of the marine trials conducted in the shallow aquatic area. In it, the underwater glider equipped with the combined receiver unit sequentially changed the positioning horizon in the “submerging-emerging” mode. The levels of flow noise on the output of the sound pressure channel and the output of the vector channel are comparatively analyzed for different determinations of informative parameters, characterizing the sound field in the scalar-vector description. The presented estimates of flow noises levels confirm the advantages of a combined receiver unit compared to a hydrophone while operating as a part of the on-board receiver system in a near field on self-generated flow noises.

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.

Directional Hearing in the Japanese Quail (Coturnix Coturnix Japonica): I. Acoustic Properties of the Auditory System

1980 ◽  
Vol 86 (1) ◽  
pp. 135-151
Author(s):  
K. G. HILL ◽  
D. B. LEWIS ◽  
M. E. HUTCHINGS ◽  
R. B. COLES
Keyword(s):  
Auditory System ◽  
Sound Pressure ◽  
External Surface ◽  
Acoustic Properties ◽  
Coturnix Japonica ◽  
Directional Hearing ◽  
Coturnix Coturnix Japonica ◽  
Coturnix Coturnix ◽  
External Pressures ◽  
Air Space

The auditory tympana in the quail, Coturnix coturnix japonica (L.) are internally coupled by an interaural air space. Unilaterally applied sound causing vibration of the ipsilateral tympanum is conducted through the interauralcavity to the inside surface of the contralateral tympanum. In a free soundfield at frequencies up to 3150 Hz, sound pressure at the external surface of the tympanum contralateral to the source is within about 3 dB of the pressure exterior to the ipsilateral tympanum. Sound pressures developed at the inner surfaces of the tympana are of similar amplitude to the external pressures at several frequencies in the range 800–6300 Hz. In addition, pressure ateach side of the tympanum ipsilateral to the source are generally out of phase, whereas pressures at each side of the contralateral tympanum are relatively close to the same phase. From measurements of amplitude and phase of the interacting pressures at the tympanum, the calculated driving pressure at the ipsilateral tympanum exceeds that at the contralateral tympanum by 10–20 dB over a range of frequencies. The auditory tympana in quail have considerable inherent directionality, therefore, due to their function aspressure-gradient receivers. Anatomical analogies with anurans and reptiles indicate that they derive directional hearing from the same acoustic mechanism that operates in the quail.

scholarly journals The role of sensory modalities in producing nonconsumptive effects for a crayfish–bass predator–prey system

2018 ◽  
Vol 96 (7) ◽  
pp. 680-691 ◽  
Author(s):  
Jessica L. Clark ◽  
Paul A. Moore
Keyword(s):  
Micropterus Salmoides ◽  
Interactive Effects ◽  
Predator Detection ◽  
Nonconsumptive Effects ◽  
Predator Prey ◽  
Rusty Crayfish ◽  
Sensory Modalities ◽  
Study Support ◽  
The Impact

The impact of nonconsumptive effects (NCEs) in structuring predator–prey interactions and trophic cascades is a prominent area of ecological research. For NCEs to occur, prey need to be able to detect the presence of predators through sensory mechanisms. The investigation of the role of different sensory modalities in predator detection has lagged behind the development of NCE-based theories. This study aimed to determine whether a hierarchy in the reliance upon sensory modalities exists in the rusty crayfish (Orconectes rusticus (Girard, 1852) = Faxonius rusticus (Girard, 1852)) for predator detection and if this hierarchy is altered across different sensory environments (flowing and nonflowing environments). Rusty crayfish were exposed to largemouth bass (Micropterus salmoides (Lacépède, 1802)) odor in either a flowing or nonflowing arena where behavior was recorded under different sensory lesions. Linear mixed models were conducted to determine the impact of lesions, flowing environments, and the interactive effects of lesions and flowing environments on the rusty crayfish ability to respond to predatory stimuli. Results from this study support the significance of sensory multimodality in the rusty crayfish for accurately detecting and assessing predatory threats. Results from this study also suggest a hierarchy in the reliance upon sensory modalities in the rusty crayfish that is dependent upon the environment and the location of rusty crayfish within an environment.

Hearing thresholds of small native Australian mammals – red-tailed phascogale (Phascogale calura), kultarr (Antechinomys laniger) and spinifex hopping-mouse (Notomys alexis)

2020 ◽  
Vol 190 (1) ◽  
pp. 342-351 ◽  
Author(s):  
Julie M Old ◽  
Carl Parsons ◽  
Melissa L Tulk
Keyword(s):  
Sound Pressure ◽  
Dynamic Range ◽  
Auditory Brainstem ◽  
Natural Environments ◽  
Predator Detection ◽  
Future Studies ◽  
Hearing Thresholds ◽  
Brainstem Response ◽  
Hearing Range ◽  
High Range

Abstract Hearing is essential for communication, to locate prey and to avoid predators. We addressed the paucity of information regarding hearing in Australian native mammals by specifically assessing the hearing range and sensitivity of the red-tailed phascogale (Phascogale calura), the kultarr (Antechinomys laniger) and the spinifex hopping-mouse (Notomys alexis). Auditory brainstem response (ABR) audiograms were used to estimate hearing thresholds within the range of 1–84 kHz, over a dynamic range of 0–80 dB sound pressure level (SPL). Phascogales had a hearing range of 1–40 kHz, kultarrs 1–35 kHz and hopping-mice 1–35 kHz, with a dynamic range of 17–59 dB SPL, 20–80 dB SPL and 30–73 dB SPL, respectively. Hearing for all species was most sensitive at 8 kHz. Age showed no influence on optimal hearing, but younger animals had more diverse optimal hearing frequencies. There was a relationship between males and their optimal hearing frequency, and greater interaural distances of individual males may be related to optimal hearing frequency. Because nocturnal animals use high-range hearing for prey or predator detection, our study suggests this may also be the case for the species examined in this study. Future studies should investigate their vocalizations and behaviour in their natural environments, and by exposing them to different auditory stimuli.

scholarly journals Use of visual and olfactory sensory cues by an apex predator in deciduous forests

2019 ◽  
Vol 97 (5) ◽  
pp. 488-494 ◽  
Author(s):  
Riley R. Lawson ◽  
Dillon T. Fogarty ◽  
Scott R. Loss
Keyword(s):  
Visual Cues ◽  
Life History Evolution ◽  
Deciduous Forests ◽  
Apex Predator ◽  
Sensory Cues ◽  
Predator Detection ◽  
Predator Prey ◽  
Predator Foraging ◽  
Sensory Mechanisms

Predator–prey interactions influence behaviors and life-history evolution for both predator and prey species and also have implications for biodiversity conservation. A fundamental goal of ecology is to clarify mechanisms underlying predator–prey interactions and dynamics. To investigate the role of predator sensory mechanisms in predator–prey interactions, specifically in predator detection of prey, we experimentally evaluated importance of visual and olfactory cues for an apex predator, the coyote (Canis latrans Say, 1823). Unlike similar studies, we examined use of sensory cues in a field setting. We used trail cameras and four replicated treatments — visual only, olfactory only, visual and olfactory combined, and a control — to quantify coyote visitation rates in North American deciduous forests during fall 2016. Coyote visitation was greatest for olfactory-only and visual-only cues, followed by the combined olfactory–visual cue; all cues attracted more coyotes than the control (i.e., olfactory = visual > olfactory–visual > control). Our results suggest this apex predator uses both olfactory and visual cues while foraging for prey. These findings from a field study of free-roaming coyotes increase understanding of predator foraging behavior, predator–prey interactions, and sensory ecology. Our study also suggests future directions for field evaluations of the role of different sensory mechanisms in predator foraging and prey concealment behaviors.

scholarly journals Seismic sensitivity and bone conduction mechanisms enable extratympanic hearing in salamanders

2020 ◽  
Vol 223 (24) ◽  
pp. jeb236489
Author(s):  
G. Capshaw ◽  
D. Soares ◽  
J. Christensen-Dalsgaard ◽  
C. E. Carr
Keyword(s):  
Sound Pressure ◽  
Bone Conduction ◽  
Low Frequency ◽  
Threshold Level ◽  
Auditory Brainstem ◽  
Common Mechanism ◽  
Experimental Conditions ◽  
Airborne Sound ◽  
Sound Detection ◽  
Brainstem Response

ABSTRACTThe tympanic middle ear is an adaptive sensory novelty that evolved multiple times in all the major terrestrial tetrapod groups to overcome the impedance mismatch generated when aerial sound encounters the air–skin boundary. Many extant tetrapod species have lost their tympanic middle ears, yet they retain the ability to detect airborne sound. In the absence of a functional tympanic ear, extratympanic hearing may occur via the resonant qualities of air-filled body cavities, sensitivity to seismic vibration, and/or bone conduction pathways to transmit sound from the environment to the ear. We used auditory brainstem response recording and laser vibrometry to assess the contributions of these extratympanic pathways for airborne sound in atympanic salamanders. We measured auditory sensitivity thresholds in eight species and observed sensitivity to low-frequency sound and vibration from 0.05–1.2 kHz and 0.02–1.2 kHz, respectively. We determined that sensitivity to airborne sound is not facilitated by the vibrational responsiveness of the lungs or mouth cavity. We further observed that, although seismic sensitivity probably contributes to sound detection under naturalistic scenarios, airborne sound stimuli presented under experimental conditions did not produce vibrations detectable to the salamander ear. Instead, threshold-level sound pressure is sufficient to generate translational movements in the salamander head, and these sound-induced head vibrations are detectable by the acoustic sensors of the inner ear. This extratympanic hearing mechanism mediates low-frequency sensitivity in vertebrate ears that are unspecialized for the detection of aerial sound pressure, and may represent a common mechanism for terrestrial hearing across atympanic tetrapods.

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