scholarly journals Hearing sensitivity: An underlying mechanism for niche differentiation in gleaning bats

2021 ◽  
Vol 118 (36) ◽  
pp. e2024943118 ◽  
Author(s):  
Inga Geipel ◽  
Ella Z. Lattenkamp ◽  
M. May Dixon ◽  
Lutz Wiegrebe ◽  
Rachel A. Page

Tropical ecosystems are known for high species diversity. Adaptations permitting niche differentiation enable species to coexist. Historically, research focused primarily on morphological and behavioral adaptations for foraging, roosting, and other basic ecological factors. Another important factor, however, is differences in sensory capabilities. So far, studies mainly have focused on the output of behavioral strategies of predators and their prey preference. Understanding the coexistence of different foraging strategies, however, requires understanding underlying cognitive and neural mechanisms. In this study, we investigate hearing in bats and how it shapes bat species coexistence. We present the hearing thresholds and echolocation calls of 12 different gleaning bats from the ecologically diverse Phyllostomid family. We measured their auditory brainstem responses to assess their hearing sensitivity. The audiograms of these species had similar overall shapes but differed substantially for frequencies below 9 kHz and in the frequency range of their echolocation calls. Our results suggest that differences among bats in hearing abilities contribute to the diversity in foraging strategies of gleaning bats. We argue that differences in auditory sensitivity could be important mechanisms shaping diversity in sensory niches and coexistence of species.

2021 ◽  
Vol 288 (1942) ◽  
pp. 20202600
Author(s):  
Ella Z. Lattenkamp ◽  
Martina Nagy ◽  
Markus Drexl ◽  
Sonja C. Vernes ◽  
Lutz Wiegrebe ◽  
...  

Differences in auditory perception between species are influenced by phylogenetic origin and the perceptual challenges imposed by the natural environment, such as detecting prey- or predator-generated sounds and communication signals. Bats are well suited for comparative studies on auditory perception since they predominantly rely on echolocation to perceive the world, while their social calls and most environmental sounds have low frequencies. We tested if hearing sensitivity and stimulus level coding in bats differ between high and low-frequency ranges by measuring auditory brainstem responses (ABRs) of 86 bats belonging to 11 species. In most species, auditory sensitivity was equally good at both high- and low-frequency ranges, while amplitude was more finely coded for higher frequency ranges. Additionally, we conducted a phylogenetic comparative analysis by combining our ABR data with published data on 27 species. Species-specific peaks in hearing sensitivity correlated with peak frequencies of echolocation calls and pup isolation calls, suggesting that changes in hearing sensitivity evolved in response to frequency changes of echolocation and social calls. Overall, our study provides the most comprehensive comparative assessment of bat hearing capacities to date and highlights the evolutionary pressures acting on their sensory perception.


2019 ◽  
Vol 205 (6) ◽  
pp. 847-854 ◽  
Author(s):  
Tongliang Wang ◽  
Handong Li ◽  
Jianguo Cui ◽  
Xiaofei Zhai ◽  
Haitao Shi ◽  
...  

Abstract Hearing sensitivity is of general interest from the perspective of understanding the functionality and evolution of vertebrate auditory systems. Sexual dimorphism of auditory systems has been reported in several species of vertebrates, but little is known about this phenomenon in turtles. Some morphological characteristics, such as middle ear and tympanic membrane that influence the hearing sensitivity of animals can result in hearing sexual dimorphism. To examine whether sexual dimorphism in hearing sensitivity occurs in turtles and to compare hearing characteristics with respect to the shape of the tympanic membrane, we measured the hearing sensitivity and tympanum diameter in both sexes of Trachemys scripta elegans. The results showed that, with the exception of 0.9 kHz, auditory brainstem response thresholds were significantly lower in females than in males for frequencies in the 0.2–1.1 kHz range, indicating that the hearing of females shows greater sensitivity. No significant differences were detected in the tympanum diameter of both sexes. These results showed that sexually dimorphic hearing sensitivity has evolved in turtles; however, this difference does not appear to be related to differences in the size of the tympanic membrane. The possible origin and function of the sexual differences in auditory characteristic are discussed.


2006 ◽  
Vol 17 (09) ◽  
pp. 667-676 ◽  
Author(s):  
Ashley W. Harkrider ◽  
Joanna W. Tampas

Studies of acceptable noise level (ANL) consistently report large intersubject variability in acceptance of background noise while listening to speech. This variability is not related to age, gender, hearing sensitivity, type of background noise, speech perception in noise performance, or efferent activity of the medial olivocochlear pathway. An exploratory study was conducted to determine if differences in aggregate responses from the peripheral and central auditory system can account for intersubject variability in ANL. Click-evoked otoacoustic emissions (CEOAEs), binaural auditory brainstem responses (ABRs), and middle latency responses (MLRs) were measured in females with normal hearing with low (n = 6) versus high (n = 7) ANLs. Results of this preliminary study indicate no differences between the groups for CEOAEs or waves I or III of the ABR. Differences between the two groups emerge for the amplitudes of wave V of the ABR and for the Na-Pa component of the MLR, suggesting that physiological variations arising from more central regions of the auditory system may mediate background noise acceptance.


1987 ◽  
Vol 30 (4) ◽  
pp. 494-502 ◽  
Author(s):  
Kathleen C.M. Campbell ◽  
Paul J. Abbas

Auditory brainstem responses were recorded in two groups of adult subjects with asymmetric sensorineural hearing loss. Clicks were presented at repetition rates of 9.7, 39.7, 49.7, and 59.7/s. One group was composed of 20 patients with no known otoneurologic lesion (cochlear group), and one group was composed of 8 patients with a surgically confirmed acoustic neuroma in the ear with poorer hearing sensitivity (retrocochlear group). Detection of wave V at different repetition rates was not significantly different between the two groups. Average wave-V latency shift was not significantly different between the two groups as repetition rate increased from 9.7/s to 39.7/s but was significantly greater for the retroeochlear group as repetition rate increased from 9.7/s to 49.7/s and 59.7/s. However, the wave-V latency shift showed no improvement over the slow-rate interaural wave-V latency difference in discriminating between the two groups of patients. No significant correlation between the amount of wave-V latency shift and hearing loss at 2000 Hz or 4000 Hz was found for the ears with poorer hearing sensitivity.


2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Devan A. Keesling ◽  
Jordan Paige Parker ◽  
Jason Tait Sanchez

iChirp-evoked auditory brainstem responses (ABRs) yield a larger wave V amplitude at low intensity levels than traditional broadband click stimuli, providing a reliable estimation of hearing sensitivity. However, advantages of iChirp stimulation at high intensity levels are unknown. We tested to see if high-intensity (i.e., 85 dBnHL) iChirp stimulation results in larger and more reliable ABR waveforms than click. Using the commercially available Intelligent Hearing System SmartEP platform, we recorded ABRs from 43 normal hearing young adults. We report that absolute peak latencies were more variable for iChirp and were ~3 ms longer: the latter of which is simply due to the temporal duration of the signal. Interpeak latencies were slightly shorter for iChirp and were most evident between waves I-V. Interestingly, click responses were easier to identify and peak-to-trough amplitudes for waves I, III and V were significantly larger than iChirp. These differences were not due to residual noise levels. We speculate that high intensity iChirp stimulation reduces neural synchrony and conclude that for retrocochlear evaluations, click stimuli should be used as the standard for ABR neurodiagnostic testing.


2019 ◽  
Author(s):  
Jichao Wang ◽  
Handong Li ◽  
Tongliang Wang ◽  
Bo Chen ◽  
Jianguo Cui ◽  
...  

AbstractDevelopmental plasticity of hearing sensitivity (DPHS) has been verified in some groups of vertebrates. Turtles face a trade-off between terrestrial and aquatic hearing in different acoustic environments throughout ontogeny. However, how chelonian hearing sensitivity changes throughout ontogeny is still unclear. To verify DPHS in turtles, auditory brainstem responses (ABR) were compared using hearing thresholds and latencies in female red-eared slider (Trachemys scripta elegans) aged 1 week, 1 month, 1 year, and 5 years, and the results showed hearing sensitivity bandwidths of approximately 200–1100, 200–1100, 200–1300, and 200–1400 Hz, respectively. The lowest threshold sensitivity was approximately 600□Hz. Below 600 Hz, ABR threshold decreased rapidly with increasing age (1 week to 1 year), with significant differences between age groups, but no significant difference between the 1- and 5-year age groups (stimulus frequency, 200–600 Hz). Above 600 Hz, ABR threshold was the lowest in the 5-year age group. These findings show that aging was accompanied by hearing sensitivity changes, suggesting rapid, frequency-segmented development during ontogeny. This variability in hearing sensitivity differs from that reported in other vertebrates, and allows adaptation to acoustically distinct environments throughout ontogeny. Our findings further elucidate the developmental patterns of the vertebrate auditory system.


2021 ◽  
Author(s):  
Antoine Gazaix ◽  
Patrick GRILLAS ◽  
Guillaume PAPUGA ◽  
Hugo FONTES ◽  
Florent Sabatier ◽  
...  

Abstract The ecological niche defines the favorable range of a species in a multidimensional space of ecological factors that determine the presence and function of individuals. This fundamental concept in ecology is widely used to understand plant species coexistence and segregation. In this study we test for ecological differentiation among six annual Lythrum species that are characteristic of temporary pools in the South of France, where they either coexist or occur separately. We first analysed the co-occurrence of species at two different geographical scales: cluster analyses of species presence in 10 km grid cells and coexistence in 0.25m2 quadrats within populations of each species. Second, for three to nine populations of each species, we quantified a range of biotic and abiotic parameters using point contacts and soil measurements in three 0.25m2 quadrats per population. We performed PCA on all variables, and analysed each variable separately to compare the ecological niche features of the six species. A phenological index was assessed for the plant community of each site. We detected highly localised niche differentiation in terms of soil pH (all species) and for a range of variables among pairs of species. The six species also showed marked differences in flowering period relative to the mean and variability of flowering time in their local community. These fine-scaled niche differences are associated with phylogenetic distances among species and may contribute to species’ coexistence. These results are integrated in a conservation management plan for the habitat of the rarest species in this group.


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