1
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Ręk P, Magrath RD. The quality of avian vocal duets can be assessed independently of the spatial separation of signallers. Sci Rep 2023; 13:16438. [PMID: 37777561 PMCID: PMC10543378 DOI: 10.1038/s41598-023-43508-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 09/25/2023] [Indexed: 10/02/2023] Open
Abstract
Interactions among groups are often mediated through signals, including coordinated calls such as duets, and the degree of temporal coordination within a group can affect signal efficacy. However, in addition to intrinsic duet quality, the spatial arrangement of callers also affects the timing of calls. So, can listeners discriminate temporal effects caused by intrinsic duet quality compared to spatial arrangement? Such discrimination would allow assessment of quality of duets produced by a pair, as distinct from transient extrinsic spatial effects. To address this issue, we studied experimentally the influence of intrinsic duet quality and spatial arrangement on the efficacy of Australian magpie-lark (Grallina cyanoleuca) vocal duets. Breeding pairs duet at varying distances from each other and to multiple neighbours. Coordinated duets are more effective territorial signals than uncoordinated duets, but it remains unclear whether listeners can discriminate the effects of quality and spatial arrangement. Our playback experiment showed that any deviation from perfect regularity of partners' notes reduced duet efficacy, but that lack of coordination due to spatial separation (slower tempo and offset of notes) had a lower effect on efficacy than effects due to intrinsic quality (irregularity). Our results therefore provide experimental evidence that the temporal organisation of group vocalisations could signal coalition quality independently of spatial effects.
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Affiliation(s)
- Paweł Ręk
- Department of Behavioural Ecology, Faculty of Biology, Institute of Environmental Biology, Adam Mickiewicz University, Poznań, Poland.
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, 2601, Australia.
| | - Robert D Magrath
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, 2601, Australia
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2
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Jirik KJ, Dominguez JA, Abdulkarim I, Glaaser J, Stoian ES, Almanza LJ, Lee N. Parasitoid-host eavesdropping reveals temperature coupling of preferences to communication signals without genetic coupling. Proc Biol Sci 2023; 290:20230775. [PMID: 37583323 PMCID: PMC10427829 DOI: 10.1098/rspb.2023.0775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 07/24/2023] [Indexed: 08/17/2023] Open
Abstract
Receivers of acoustic communication signals evaluate signal features to identify conspecifics. Changes in the ambient temperature can alter these features, rendering species recognition a challenge. To maintain effective communication, temperature coupling-changes in receiver signal preferences that parallel temperature-induced changes in signal parameters-occurs among genetically coupled signallers and receivers. Whether eavesdroppers of communication signals exhibit temperature coupling is unknown. Here, we investigate if the parasitoid fly Ormia ochracea, an eavesdropper of cricket calling songs, exhibits song pulse rate preferences that are temperature coupled. We use a high-speed treadmill system to record walking phonotaxis at three ambient temperatures (21, 25, and 30°C) in response to songs that varied in pulse rates (20 to 90 pulses per second). Total walking distance, peak steering velocity, angular heading, and the phonotaxis performance index varied with song pulse rates and ambient temperature. The peak of phonotaxis performance index preference functions became broader and shifted to higher pulse rate values at higher temperatures. Temperature-related changes in cricket songs between 21 and 30°C did not drastically affect the ability of flies to recognize cricket calling songs. These results confirm that temperature coupling can occur in eavesdroppers that are not genetically coupled with signallers.
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Affiliation(s)
| | | | - Iya Abdulkarim
- Department of Biology, St Olaf College, Northfield, MN, USA
| | | | | | | | - Norman Lee
- Department of Biology, St Olaf College, Northfield, MN, USA
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3
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Mikel-Stites MR, Salcedo MK, Socha JJ, Marek PE, Staples AE. Reconsidering tympanal-acoustic interactions leads to an improved model of auditory acuity in a parasitoid fly. BIOINSPIRATION & BIOMIMETICS 2023; 18:035007. [PMID: 36854192 DOI: 10.1088/1748-3190/acbffa] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 02/28/2023] [Indexed: 06/18/2023]
Abstract
Although most binaural organisms locate sound sources using neurological structures to amplify the sounds they hear, some animals use mechanically coupled hearing organs instead. One of these animals, the parasitoid flyOrmia ochracea(O. ochracea), has astoundingly accurate sound localization abilities. It can locate objects in the azimuthal plane with a precision of 2°, equal to that of humans, despite an intertympanal distance of only 0.5 mm, which is less than1/100th of the wavelength of the sound emitted by the crickets that it parasitizes.O. ochraceaaccomplishes this feat via mechanically coupled tympana that interact with incoming acoustic pressure waves to amplify differences in the signals received at the two ears. In 1995, Mileset aldeveloped a model of hearing mechanics inO. ochraceathat represents the tympana as flat, front-facing prosternal membranes, though they lie on a convex surface at an angle from the flies' frontal and transverse planes. The model works well for incoming sound angles less than±30∘but suffers from reduced accuracy (up to 60% error) at higher angles compared to response data acquired fromO. ochraceaspecimens. Despite this limitation, it has been the basis for bio-inspired microphone designs for decades. Here, we present critical improvements to this classic hearing model based on information from three-dimensional reconstructions ofO. ochracea's tympanal organ. We identified the orientation of the tympana with respect to a frontal plane and the azimuthal angle segment between the tympana as morphological features essential to the flies' auditory acuity, and hypothesized a differentiated mechanical response to incoming sound on the ipsi- and contralateral sides that depend on these features. We incorporated spatially-varying model coefficients representing this asymmetric response, making a new quasi-two-dimensional (q2D) model. The q2D model has high accuracy (average errors of under 10%) for all incoming sound angles. This improved biomechanical model may inform the design of new microscale directional microphones and other small-scale acoustic sensor systems.
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Affiliation(s)
- Max R Mikel-Stites
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA 24061, United States of America
- Engineering Mechanics program, Virginia Tech, Blacksburg, VA 24061, United States of America
- Department of Mathematics, Virginia Tech, Blacksburg, VA 24061, United States of America
| | - Mary K Salcedo
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA 24061, United States of America
| | - John J Socha
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA 24061, United States of America
| | - Paul E Marek
- Department of Entomology, Virginia Tech, Blacksburg, VA 24061, United States of America
| | - Anne E Staples
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA 24061, United States of America
- Engineering Mechanics program, Virginia Tech, Blacksburg, VA 24061, United States of America
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4
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Legett HD, Aihara I, Bernal XE. The dual benefits of synchronized mating signals in a Japanese treefrog: attracting mates and manipulating predators. Philos Trans R Soc Lond B Biol Sci 2021; 376:20200340. [PMID: 34420389 PMCID: PMC8380967 DOI: 10.1098/rstb.2020.0340] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/08/2021] [Indexed: 12/31/2022] Open
Abstract
In dense mating aggregations, such as leks and choruses, acoustic signals produced by competing male conspecifics often overlap in time. When signals overlap at a fine temporal scale the ability of females to discriminate between individual signals is reduced. Yet, despite this cost, males of some species deliberately overlap their signals with those of conspecifics, synchronizing signal production in the chorus. Here, we investigate two hypotheses of synchronized mating signals in a Japanese treefrog (Buergeria japonica): (1) increased female attraction to the chorus (the beacon effect hypothesis) and (2) reduced attraction of eavesdropping predators (the eavesdropper avoidance hypothesis). Our results from playback experiments on female frogs and eavesdropping micropredators (midges and mosquitoes) support both hypotheses. Signal transmission and female phonotaxis experiments suggest that away from the chorus, synchronized calls are more attractive to females than unsynchronized calls. At the chorus, however, eavesdroppers are less attracted to calls that closely follow an initial call, while female attraction to individual signals is not affected. Therefore, synchronized signalling likely benefits male B. japonica by both increasing attraction of females to the chorus and reducing eavesdropper attacks. These findings highlight how multiple selective pressures likely promoted the evolution and maintenance of this behaviour. This article is part of the theme issue 'Synchrony and rhythm interaction: from the brain to behavioural ecology'.
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Affiliation(s)
- Henry D. Legett
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Ikkyu Aihara
- Graduate School of Systems and Information Engineering, University of Tsukuba, Ibaraki 305-8573, Japan
| | - X. E. Bernal
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
- Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Balboa, Ancón, Panama
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5
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Mason AC. Cues for Directional Hearing in the Fly Ormia ochracea. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.679064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Insects are often small relative to the wavelengths of sounds they need to localize, which presents a fundamental biophysical problem. Understanding novel solutions to this limitation can provide insights for biomimetic technologies. Such an approach has been successful using the fly Ormia ochracea (Diptera: Tachinidae) as a model. O. ochracea is a parasitoid species whose larvae develop as internal parasites within crickets (Gryllidae). In nature, female flies find singing male crickets by phonotaxis, despite severe constraints on directional hearing due to their small size. A physical coupling between the two tympanal membranes allows the flies to obtain information about sound source direction with high accuracy because it generates interaural time-differences (ITD) and interaural level differences (ILD) in tympanal vibrations that are exaggerated relative to the small arrival-time difference at the two ears, that is the only cue available in the sound stimulus. In this study, I demonstrate that pure time-differences in the neural responses to sound stimuli are sufficient for auditory directionality in O. ochracea.
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6
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Dobbs OL, Talavera JB, Rossi SM, Menjivar S, Gray DA. Signaler-receiver-eavesdropper: Risks and rewards of variation in the dominant frequency of male cricket calls. Ecol Evol 2020; 10:12364-12371. [PMID: 33209294 PMCID: PMC7663976 DOI: 10.1002/ece3.6866] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 09/01/2020] [Accepted: 09/10/2020] [Indexed: 11/09/2022] Open
Abstract
Signals are important for communication and mating, and while they can benefit an individual, they can also be costly and dangerous. Male field crickets call in order to attract female crickets, but gravid females of a parasitoid fly species, Ormia ochracea, are also attracted to the call and use it to pinpoint male cricket hosts. Conspicuousness of the call can vary with frequency, amplitude, and temporal features. Previous work with this system has only considered temporal variation in cricket calls, both large scale, that is, amount of calling and at what time of evening, and small scale, that is, aspects of chirp rate, pulse rate, and numbers of pulses per chirp. Because auditory perception in both crickets and flies relies on the matching of the peak frequency of the call with the peripheral sensory system, peak frequency may be subject to selection both from female crickets and from female flies. Here, we used field playbacks of four different versions of the same male Gryllus lineaticeps calling song that only differed in peak frequency (3.3, 4.3, 5.3, and 6.3 kHz) to test the relative attractiveness of the calls to female crickets and female flies. Our results clearly show that lower frequency calls enhance male safety from fly parasitism, but that the enhanced safety would come at a cost of reduced attraction of female crickets as potential mates. The results imply that eavesdropper pressure can disrupt the matched coevolution of signalers and receivers such that the common concept of matched male-female signaler-receiver coevolution may actually be better described as male-female-predator signaler-receiver-eavesdropper coevolution.
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Affiliation(s)
- Olivia L. Dobbs
- Department of BiologyCalifornia State University NorthridgeNorthridgeCAUSA
| | | | - Sarina M. Rossi
- Department of BiologyCalifornia State University NorthridgeNorthridgeCAUSA
| | - Stephanie Menjivar
- Department of BiologyCalifornia State University NorthridgeNorthridgeCAUSA
| | - David A. Gray
- Department of BiologyCalifornia State University NorthridgeNorthridgeCAUSA
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7
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Lee N, Kirtley AT, Pressman IS, Jirik KJ, Koucoulas D, Mason AC. Developing a Phonotaxis Performance Index to Uncover Signal Selectivity in Walking Phonotaxis. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00334] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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8
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Simões PMV, Ingham R, Gibson G, Russell IJ. Masking of an auditory behaviour reveals how male mosquitoes use distortion to detect females. Proc Biol Sci 2018; 285:rspb.2017.1862. [PMID: 29367389 DOI: 10.1098/rspb.2017.1862] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 01/03/2018] [Indexed: 11/12/2022] Open
Abstract
The mating behaviour of many mosquito species is mediated essentially by sound: males follow and mate with a female mid-flight by detecting and tracking the whine of her flight-tones. The stereotypical rapid frequency modulation (RFM) male behaviour, initiated in response to the detection of the female's flight-tones, has provided a means of investigating these auditory mechanisms while males are free-flying. Mosquitoes hear with their antennae, which vibrate to near-field acoustic excitation. The antennae generate nonlinear vibrations (distortion products, DPs) at frequencies that are equal to the difference between the two simultaneously presented tones, e.g. the male and female flight-tones, which are detected by mechanoreceptors in the auditory Johnston's organ (JO) at the base of the antenna. Recent studies indicated the male mosquito's JO is tuned not to the female flight-tone, but to the frequency difference between the male and female flight-tones. To test the hypothesis that mosquitoes detect this frequency difference, Culex quinquefasciatus males were presented simultaneously with a female flight-tone and a masking tone, which should suppress the male's RFM response to sound. The free-flight behavioural and in vivo electrophysiological experiments revealed that acoustic masking suppresses the RFM response to the female's flight-tones by attenuating the DPs generated in the nonlinear vibration of the antennae. These findings provide direct evidence in support of the hypothesis that male mosquitoes detect females when both are in flight through difference tones generated in the vibrations of their antennae owing to the interaction between their own flight-tones and those of a female.
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Affiliation(s)
- P M V Simões
- School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton BN2 4GJ, UK
| | - R Ingham
- School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton BN2 4GJ, UK
| | - G Gibson
- Natural Resources Institute, University of Greenwich, Chatham, Kent ME4 4TB, UK
| | - I J Russell
- School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton BN2 4GJ, UK
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9
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Albert JT, Kozlov AS. Comparative Aspects of Hearing in Vertebrates and Insects with Antennal Ears. Curr Biol 2017; 26:R1050-R1061. [PMID: 27780047 DOI: 10.1016/j.cub.2016.09.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The evolution of hearing in terrestrial animals has resulted in remarkable adaptations enabling exquisitely sensitive sound detection by the ear and sophisticated sound analysis by the brain. In this review, we examine several such characteristics, using examples from insects and vertebrates. We focus on two strong and interdependent forces that have been shaping the auditory systems across taxa: the physical environment of auditory transducers on the small, subcellular scale, and the sensory-ecological environment within which hearing happens, on a larger, evolutionary scale. We briefly discuss acoustical feature selectivity and invariance in the central auditory system, highlighting a major difference between insects and vertebrates as well as a major similarity. Through such comparisons within a sensory ecological framework, we aim to emphasize general principles underlying acute sensitivity to airborne sounds.
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Affiliation(s)
- Joerg T Albert
- UCL Ear Institute, 332 Gray's Inn Road, London WC1X 8EE, UK.
| | - Andrei S Kozlov
- Department of Bioengineering, Imperial College London, London SW7 2AZ, UK.
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10
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Lee N, Mason AC. How spatial release from masking may fail to function in a highly directional auditory system. eLife 2017; 6. [PMID: 28425912 PMCID: PMC5443663 DOI: 10.7554/elife.20731] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 04/19/2017] [Indexed: 11/13/2022] Open
Abstract
Spatial release from masking (SRM) occurs when spatial separation between a signal and masker decreases masked thresholds. The mechanically-coupled ears of Ormia ochracea are specialized for hyperacute directional hearing, but the possible role of SRM, or whether such specializations exhibit limitations for sound source segregation, is unknown. We recorded phonotaxis to a cricket song masked by band-limited noise. With a masker, response thresholds increased and localization was diverted away from the signal and masker. Increased separation from 6° to 90° did not decrease response thresholds or improve localization accuracy, thus SRM does not operate in this range of spatial separations. Tympanal vibrations and auditory nerve responses reveal that localization errors were consistent with changes in peripheral coding of signal location and flies localized towards the ear with better signal detection. Our results demonstrate that, in a mechanically coupled auditory system, specialization for directional hearing does not contribute to source segregation.
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Affiliation(s)
- Norman Lee
- Department of Biological Sciences, Integrative Behaviour and Neuroscience Group, University of Toronto Scarborough, Toronto, Canada
| | - Andrew C Mason
- Department of Biological Sciences, Integrative Behaviour and Neuroscience Group, University of Toronto Scarborough, Toronto, Canada
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11
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Hartbauer M, Römer H. Rhythm Generation and Rhythm Perception in Insects: The Evolution of Synchronous Choruses. Front Neurosci 2016; 10:223. [PMID: 27303257 PMCID: PMC4885851 DOI: 10.3389/fnins.2016.00223] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 05/06/2016] [Indexed: 11/15/2022] Open
Abstract
Insect sounds dominate the acoustic environment in many natural habitats such as rainforests or meadows on a warm summer day. Among acoustic insects, usually males are the calling sex; they generate signals that transmit information about the species-identity, sex, location, or even sender quality to conspecific receivers. Males of some insect species generate signals at distinct time intervals, and other males adjust their own rhythm relative to that of their conspecific neighbors, which leads to fascinating acoustic group displays. Although signal timing in a chorus can have important consequences for the calling energetics, reproductive success and predation risk of individuals, still little is known about the selective forces that favor the evolution of insect choruses. Here, we review recent advances in our understanding of the neuronal network responsible for acoustic pattern generation of a signaler, and pattern recognition in receivers. We also describe different proximate mechanisms that facilitate the synchronous generation of signals in a chorus and provide examples of suggested hypotheses to explain the evolution of chorus synchrony in insects. Some hypotheses are related to sexual selection and inter-male cooperation or competition, whereas others refer to the selection pressure exerted by natural predators. In this article, we summarize the results of studies that address chorus synchrony in the tropical katydid Mecopoda elongata, where some males persistently signal as followers although this reduces their mating success.
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Affiliation(s)
- Manfred Hartbauer
- Behavioural Ecology and Neurobiology, Institute of Zoology, University of GrazGraz, Austria
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12
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Keeping up with the neighbor: a novel mechanism of call synchrony in Neoconocephalus ensiger katydids. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2016; 202:225-34. [PMID: 26809565 DOI: 10.1007/s00359-016-1068-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 01/09/2016] [Accepted: 01/11/2016] [Indexed: 10/22/2022]
Abstract
During solo calling, pulse periods gradually changed by up to 15% over several minutes. Pairs of calling males synchronized their pulses. The pulse rate (10-14 Hz) was considerably faster than the rate of synchronized signal units in other insects (0.5-3 Hz). Within each pulse cycle, males made only small adjustments to their pulse period, leading to regular switches of leader and follower roles. Large-scale timing adjustments only occurred in response to large delays. Stimulation with single pulses had no predictable effect on the timing of the male's next pulse, resulting in a flat phase response curve. When entrained to a stimulus with a faster pulse period, males briefly interrupted calling; they resumed calling largely synchronized with the stimulus. Throughout the stimulus, males made gradual changes to their pulse period, similar to those during pair calling. After the stimulus ended, pulse periods increased over several minutes, but did not return to their pre-stimulus values. Thus social context and intrinsic state of the males influenced pulse period in Neoconocephalus ensiger. These results indicate that N. ensiger males synchronize calls by adjusting their intrinsic pulse period, instead of adjusting the timing of individual pulses, as described in other synchronizing insects.
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13
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Gai Y, Ruhland JL, Yin TCT. Behavior and modeling of two-dimensional precedence effect in head-unrestrained cats. J Neurophysiol 2015; 114:1272-85. [PMID: 26133795 DOI: 10.1152/jn.00214.2015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 06/29/2015] [Indexed: 11/22/2022] Open
Abstract
The precedence effect (PE) is an auditory illusion that occurs when listeners localize nearly coincident and similar sounds from different spatial locations, such as a direct sound and its echo. It has mostly been studied in humans and animals with immobile heads in the horizontal plane; speaker pairs were often symmetrically located in the frontal hemifield. The present study examined the PE in head-unrestrained cats for a variety of paired-sound conditions along the horizontal, vertical, and diagonal axes. Cats were trained with operant conditioning to direct their gaze to the perceived sound location. Stereotypical PE-like behaviors were observed for speaker pairs placed in azimuth or diagonally in the frontal hemifield as the interstimulus delay was varied. For speaker pairs in the median sagittal plane, no clear PE-like behavior occurred. Interestingly, when speakers were placed diagonally in front of the cat, certain PE-like behavior emerged along the vertical dimension. However, PE-like behavior was not observed when both speakers were located in the left hemifield. A Hodgkin-Huxley model was used to simulate responses of neurons in the medial superior olive (MSO) to sound pairs in azimuth. The novel simulation incorporated a low-threshold potassium current and frequency mismatches to generate internal delays. The model exhibited distinct PE-like behavior, such as summing localization and localization dominance. The simulation indicated that certain encoding of the PE could have occurred before information reaches the inferior colliculus, and MSO neurons with binaural inputs having mismatched characteristic frequencies may play an important role.
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Affiliation(s)
- Yan Gai
- Department of Neuroscience, University of Wisconsin, Madison, Wisconsin; and Department of Biomedical Engineering, Saint Louis University, St. Louis, Missouri
| | - Janet L Ruhland
- Department of Neuroscience, University of Wisconsin, Madison, Wisconsin; and
| | - Tom C T Yin
- Department of Neuroscience, University of Wisconsin, Madison, Wisconsin; and
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14
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Brown AD, Stecker GC, Tollin DJ. The precedence effect in sound localization. J Assoc Res Otolaryngol 2015; 16:1-28. [PMID: 25479823 PMCID: PMC4310855 DOI: 10.1007/s10162-014-0496-2] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 10/13/2014] [Indexed: 11/29/2022] Open
Abstract
In ordinary listening environments, acoustic signals reaching the ears directly from real sound sources are followed after a few milliseconds by early reflections arriving from nearby surfaces. Early reflections are spectrotemporally similar to their source signals but commonly carry spatial acoustic cues unrelated to the source location. Humans and many other animals, including nonmammalian and even invertebrate animals, are nonetheless able to effectively localize sound sources in such environments, even in the absence of disambiguating visual cues. Robust source localization despite concurrent or nearly concurrent spurious spatial acoustic information is commonly attributed to an assortment of perceptual phenomena collectively termed "the precedence effect," characterizing the perceptual dominance of spatial information carried by the first-arriving signal. Here, we highlight recent progress and changes in the understanding of the precedence effect and related phenomena.
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Affiliation(s)
- Andrew D. Brown
- />Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO 80045 USA
| | - G. Christopher Stecker
- />Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37232 USA
| | - Daniel J. Tollin
- />Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO 80045 USA
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15
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Lakes-Harlan R, Lehmann GUC. Parasitoid flies exploiting acoustic communication of insects-comparative aspects of independent functional adaptations. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2014; 201:123-32. [PMID: 25369901 DOI: 10.1007/s00359-014-0958-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 10/20/2014] [Accepted: 10/25/2014] [Indexed: 11/26/2022]
Abstract
Two taxa of parasitoid Diptera have independently evolved tympanal hearing organs to locate sound producing host insects. Here we review and compare functional adaptations in both groups of parasitoids, Ormiini and Emblemasomatini. Tympanal organs in both groups originate from a common precursor organ and are somewhat similar in morphology and physiology. In terms of functional adaptations, the hearing thresholds are largely adapted to the frequency spectra of the calling song of the hosts. The large host ranges of some parasitoids indicate that their neuronal filter for the temporal patterns of the calling songs are broader than those found in intraspecific communication. For host localization the night active Ormia ochracea and the day active E. auditrix are able to locate a sound source precisely in space. For phonotaxis flight and walking phases are used, whereby O. ochracea approaches hosts during flight while E. auditrix employs intermediate landings and re-orientation, apparently separating azimuthal and vertical angles. The consequences of the parasitoid pressure are discussed for signal evolution and intraspecific communication of the host species. This natural selection pressure might have led to different avoidance strategies in the hosts: silent males in crickets, shorter signals in tettigoniids and fluctuating population abundances in cicadas.
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Affiliation(s)
- Reinhard Lakes-Harlan
- Institute for Animal Physiology, AG Integrative Sensory Physiology, Justus-Liebig-Universität Gießen, IFZ, Heinrich-Buff-Ring 26, 35392, Giessen, Germany,
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16
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Hartbauer M, Haitzinger L, Kainz M, Römer H. Competition and cooperation in a synchronous bushcricket chorus. ROYAL SOCIETY OPEN SCIENCE 2014; 1:140167. [PMID: 26064537 PMCID: PMC4448899 DOI: 10.1098/rsos.140167] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 09/04/2014] [Indexed: 06/04/2023]
Abstract
Synchronous signalling within choruses of the same species either emerges from cooperation or competition. In our study on the katydid Mecopoda elongata, we aim to identify mechanisms driving evolution towards synchrony. The increase of signal amplitude owing to synchronous signalling and the preservation of a conspecific signal period may represent cooperative mechanisms, whereas chorus synchrony may also result from the preference of females for leading signals and the resulting competition for the leader role. We recorded the timing of signals and the resulting communal signal amplitudes in small choruses and performed female choice experiments to identify such mechanisms. Males frequently timed their signals either as leader or follower with an average time lag of about 70 ms. Females selected males in such choruses on the basis of signal order and signal duration. Two-choice experiments revealed a time lag of only 70 ms to bias mate choice in favour of the leader. Furthermore, a song model with a conspecific signal period of 2 s was more attractive than a song model with an irregular or longer and shorter than average signal period. Owing to a high degree of overlap and plasticity of signals produced in 'four male choruses', peak and root mean square amplitudes increased by about 7 dB relative to lone singers. Modelling active space of synchronous males and solo singing males revealed a strongly increased broadcast area of synchronous signallers, but a slightly reduced per capita mating possibility compared with lone singers. These results suggest a strong leader preference of females as the ultimate causation of inter-male competition for timing signals as leader. The emerging synchrony increases the amplitude of signals produced in a chorus and has the potential to compensate a reduction of mating advantage in a chorus. We discuss a possible fitness benefit of males gained through a beacon effect and the possibility that signalling as follower is stabilized via natural selection.
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17
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Hartbauer M, Römer H. From microseconds to seconds and minutes-time computation in insect hearing. Front Physiol 2014; 5:138. [PMID: 24782783 PMCID: PMC3990047 DOI: 10.3389/fphys.2014.00138] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 03/20/2014] [Indexed: 11/30/2022] Open
Abstract
The computation of time in the auditory system of insects is of relevance at rather different time scales, covering a large range from microseconds to several minutes. At the one end of this range, only a few microseconds of interaural time differences are available for directional hearing, due to the small distance between the ears, usually considered too small to be processed reliably by simple nervous systems. Synapses of interneurons in the afferent auditory pathway are, however, very sensitive to a time difference of only 1–2 ms provided by the latency shift of afferent activity with changing sound direction. At a much larger time scale of several tens of milliseconds to seconds, time processing is important in the context species recognition, but also for those insects where males produce acoustic signals within choruses, and the temporal relationship between song elements strongly deviates from a random distribution. In these situations, some species exhibit a more or less strict phase relationship of song elements, based on phase response properties of their song oscillator. Here we review evidence on how this may influence mate choice decisions. In the same dimension of some tens of milliseconds we find species of katydids with a duetting communication scheme, where one sex only performs phonotaxis to the other sex if the acoustic response falls within a very short time window after its own call. Such time windows show some features unique to insects, and although its neuronal implementation is unknown so far, the similarity with time processing for target range detection in bat echolocation will be discussed. Finally, the time scale being processed must be extended into the range of many minutes, since some acoustic insects produce singing bouts lasting quite long, and female preferences may be based on total signaling time.
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Affiliation(s)
| | - Heiner Römer
- Institute of Zoology, Karl-Franzens University Graz Graz, Austria
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18
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Wang Y, Wang N, Wang D, Jia J, Liu J, Xie Y, Wen X, Li X. Local inhibition of GABA affects precedence effect in the inferior colliculus. Neural Regen Res 2014; 9:420-9. [PMID: 25206830 PMCID: PMC4146189 DOI: 10.4103/1673-5374.128250] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/26/2013] [Indexed: 11/25/2022] Open
Abstract
The precedence effect is a prerequisite for faithful sound localization in a complex auditory environment, and is a physiological phenomenon in which the auditory system selectively suppresses the directional information from echoes. Here we investigated how neurons in the inferior colliculus respond to the paired sounds that produce precedence-effect illusions, and whether their firing behavior can be modulated through inhibition with gamma-aminobutyric acid (GABA). We recorded extracellularly from 36 neurons in rat inferior colliculus under three conditions: no injection, injection with saline, and injection with gamma-aminobutyric acid. The paired sounds that produced precedence effects were two identical 4-ms noise bursts, which were delivered contralaterally or ipsilaterally to the recording site. The normalized neural responses were measured as a function of different inter-stimulus delays and half-maximal interstimulus delays were acquired. Neuronal responses to the lagging sounds were weak when the inter-stimulus delay was short, but increased gradually as the delay was lengthened. Saline injection produced no changes in neural responses, but after local gamma-aminobutyric acid application, responses to the lagging stimulus were suppressed. Application of gamma-aminobutyric acid affected the normalized response to lagging sounds, independently of whether they or the paired sounds were contralateral or ipsilateral to the recording site. These observations suggest that local inhibition by gamma-aminobutyric acid in the rat inferior colliculus shapes the neural responses to lagging sounds, and modulates the precedence effect.
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Affiliation(s)
- Yanjun Wang
- Department of Otorhinolaryngology Head and Neck Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Ningyu Wang
- Department of Otorhinolaryngology Head and Neck Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Dan Wang
- Department of Otorhinolaryngology Head and Neck Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Jun Jia
- Department of Neurophysiology, Capital Medical University, Beijing, China
| | - Jinfeng Liu
- Department of Otorhinolaryngology Head and Neck Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Yan Xie
- Department of Neurophysiology, Capital Medical University, Beijing, China
| | - Xiaohui Wen
- Department of Otorhinolaryngology Head and Neck Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Xiaoting Li
- Department of Otorhinolaryngology Head and Neck Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
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Aung MS, Masuda H, Kobayashi T, Nakanishi H, Yamakawa T, Nishizawa NK. Iron biofortification of myanmar rice. FRONTIERS IN PLANT SCIENCE 2013; 4:158. [PMID: 23750162 PMCID: PMC3664312 DOI: 10.3389/fpls.2013.00158] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 05/07/2013] [Indexed: 05/07/2023]
Abstract
Iron (Fe) deficiency elevates human mortality rates, especially in developing countries. In Myanmar, the prevalence of Fe-deficient anemia in children and pregnant women are 75 and 71%, respectively. Myanmar people have one of the highest per capita rice consumption rates globally. Consequently, production of Fe-biofortified rice would likely contribute to solving the Fe-deficiency problem in this human population. To produce Fe-biofortified Myanmar rice by transgenic methods, we first analyzed callus induction and regeneration efficiencies in 15 varieties that are presently popular because of their high-yields or high-qualities. Callus formation and regeneration efficiency in each variety was strongly influenced by types of culture media containing a range of 2,4-dichlorophenoxyacetic acid concentrations. The Paw San Yin variety, which has a high-Fe content in polished seeds, performed well in callus induction and regeneration trials. Thus, we transformed this variety using a gene expression cassette that enhanced Fe transport within rice plants through overexpression of the nicotianamine synthase gene HvNAS1, Fe flow to the endosperm through the Fe(II)-nicotianamine transporter gene OsYSL2, and Fe accumulation in endosperm by the Fe storage protein gene SoyferH2. A line with a transgene insertion was successfully obtained. Enhanced expressions of the introduced genes OsYSL2, HvNAS1, and SoyferH2 occurred in immature T2 seeds. The transformants accumulated 3.4-fold higher Fe concentrations, and also 1.3-fold higher zinc concentrations in T2 polished seeds compared to levels in non-transgenic rice. This Fe-biofortified rice has the potential to reduce Fe-deficiency anemia in millions of Myanmar people without changing food habits and without introducing additional costs.
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Affiliation(s)
- May Sann Aung
- Laboratory of Plant Biotechnology, Department of Global Agricultural Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- Laboratory of Plant Cell Technology, Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Nonoichi, Ishikawa, Japan
| | - Hiroshi Masuda
- Laboratory of Plant Cell Technology, Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Nonoichi, Ishikawa, Japan
| | - Takanori Kobayashi
- Laboratory of Plant Cell Technology, Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Nonoichi, Ishikawa, Japan
| | - Hiromi Nakanishi
- Laboratory of Plant Biotechnology, Department of Global Agricultural Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Takashi Yamakawa
- Laboratory of Plant Biotechnology, Department of Global Agricultural Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Naoko K. Nishizawa
- Laboratory of Plant Biotechnology, Department of Global Agricultural Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- Laboratory of Plant Cell Technology, Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Nonoichi, Ishikawa, Japan
- *Correspondence: Naoko K. Nishizawa, Laboratory of Plant Cell Technology, Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, 1-308 Suematsu, Nonoichi, Ishikawa 921-8836, Japan. e-mail:
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Siegert ME, Römer H, Hashim R, Hartbauer M. Neuronal correlates of a preference for leading signals in the synchronizing bushcricket Mecopoda elongata (Orthoptera, Tettigoniidae). ACTA ACUST UNITED AC 2012; 214:3924-34. [PMID: 22071183 PMCID: PMC3236105 DOI: 10.1242/jeb.057901] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Acoustically interacting males of the tropical katydid Mecopoda elongata synchronize their chirps imperfectly, so that one male calls consistently earlier in time than the other. In choice situations, females prefer the leader signal, and it has been suggested that a neuronal mechanism based on directional hearing may be responsible for the asymmetric, stronger representation of the leader signal in receivers. Here, we investigated the potential mechanism in a pair of interneurons (TN1 neuron) of the afferent auditory pathway, known for its contralateral inhibitory input in directional hearing. In this interneuron, conspecific signals are reliably encoded under natural conditions, despite high background noise levels. Unilateral presentations of a conspecific chirp elicited a TN1 response where each suprathreshold syllable in the chirp was reliably copied in a phase-locked fashion. Two identical chirps broadcast with a 180 deg spatial separation resulted in a strong suppression of the response to the follower signal, when the time delay was 20 ms or more. Muting the ear on the leader side fully restored the response to the follower signal compared with unilateral controls. Time-intensity trading experiments, in which the disadvantage of the follower signal was traded against higher sound pressure levels, demonstrated the dominating influence of signal timing on the TN1 response, and this was especially pronounced at higher sound levels of the leader. These results support the hypothesis that the female preference for leader signals in M. elongata is the outcome of a sensory mechanism that originally evolved for directional hearing.
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Affiliation(s)
- M E Siegert
- Department of Zoology, Karl-Franzens University Graz, Graz, Austria
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Hartbauer M, Stabentheiner A, Römer H. Signalling plasticity and energy saving in a tropical bushcricket. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2011; 198:203-17. [PMID: 22095456 PMCID: PMC3282901 DOI: 10.1007/s00359-011-0700-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Revised: 10/27/2011] [Accepted: 11/03/2011] [Indexed: 11/30/2022]
Abstract
Males of the tropical bushcricket Mecopoda elongata synchronize their acoustic advertisement signals (chirps) in interactions with other males. However, synchrony is not perfect and distinct leader and follower roles are often maintained. In entrainment experiments in which conspecific signals were presented at various rates, chirps displayed as follower showed notable signal plasticity. Follower chirps were shortened by reducing the number and duration of syllables, especially those of low and medium amplitude. The degree of shortening depended on the time delay between leader and follower signals and the sound level of the entraining stimulus. The same signal plasticity was evident in male duets, with the effect that the last syllables of highest amplitude overlapped more strongly. Respiratory measurements showed that solo singing males producing higher chirp rates suffered from higher metabolic costs compared to males singing at lower rates. In contrast, respiratory rate was rather constant during a synchronous entrainment to a conspecific signal repeated at various rates. This allowed males to maintain a steady duty cycle, associated with a constant metabolic rate. Results are discussed with respect to the preference for leader signals in females and the possible benefits males may gain by overlapping their follower signals in a chorus.
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Affiliation(s)
- M Hartbauer
- Department of Zoology, Karl-Franzens Universität Graz, Graz, Austria.
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Sakaguchi KM, Gray DA. Host song selection by an acoustically orienting parasitoid fly exploiting a multispecies assemblage of cricket hosts. Anim Behav 2011. [DOI: 10.1016/j.anbehav.2011.01.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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23
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Howard DR, Lee N, Hall CL, Mason AC. Are Centrally Displaying Males Always the Centre of Female Attention? Acoustic Display Position and Female Choice in a Lek Mating Subterranean Insect. Ethology 2010. [DOI: 10.1111/j.1439-0310.2010.01858.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Cator LJ, Ng'Habi KR, Hoy RR, Harrington LC. Sizing up a mate: variation in production and response to acoustic signals in Anopheles gambiae. Behav Ecol 2010. [DOI: 10.1093/beheco/arq087] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Marshall VT, Gerhardt HC. A precedence effect underlies preferences for calls with leading pulses in the grey treefrog, Hyla versicolor. Anim Behav 2010; 80:139-145. [PMID: 20625471 DOI: 10.1016/j.anbehav.2010.04.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The temporal relationship between signals often has strong and repeatable influences on receiver behaviour. While several studies have shown that receivers prefer temporally leading signals, we show that the relative timing of signal elements within overlapping signals can also have repeatable influences on receiver responses. Female grey treefrogs, Hyla versicolor, preferred overlapping conspecific advertisement call alternatives in which pulses were in the leading position relative to pulses in an alternative. The preference was maintained even when the first pulse of the stimulus with leading pulses began after that of the call with following pulses. To rule out the possibility of masking interference of the pulse pattern, we used a split-pulse design in which the playback of two nonoverlapping pulse elements were synchronized from spatially separated speakers. Females were attracted to the source of the short (6 ms) leading pulse element, which did not attract females in isolation even though its amplitude was 24 dB lower than the long (24 ms) following element, which did attract females in isolation. Taken together, our results fall within a range of phenomena that have been classified as precedence effects. However, to our knowledge, showing localization based on successive leading pulses rather than the very first-arriving pulse is a novel discovery for nonhuman animals.
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