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Kleindorfer S, Brouwer L, Hauber ME, Teunissen N, Peters A, Louter M, Webster MS, Katsis AC, Sulloway FJ, Common LK, Austin VI, Colombelli-Négrel D. Nestling Begging Calls Resemble Maternal Vocal Signatures When Mothers Call Slowly to Embryos. Am Nat 2024; 203:267-283. [PMID: 38306283 DOI: 10.1086/728105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2024]
Abstract
AbstractVocal production learning (the capacity to learn to produce vocalizations) is a multidimensional trait that involves different learning mechanisms during different temporal and socioecological contexts. Key outstanding questions are whether vocal production learning begins during the embryonic stage and whether mothers play an active role in this through pupil-directed vocalization behaviors. We examined variation in vocal copy similarity (an indicator of learning) in eight species from the songbird family Maluridae, using comparative and experimental approaches. We found that (1) incubating females from all species vocalized inside the nest and produced call types including a signature "B element" that was structurally similar to their nestlings' begging call; (2) in a prenatal playback experiment using superb fairy wrens (Malurus cyaneus), embryos showed a stronger heart rate response to playbacks of the B element than to another call element (A); and (3) mothers that produced slower calls had offspring with greater similarity between their begging call and the mother's B element vocalization. We conclude that malurid mothers display behaviors concordant with pupil-directed vocalizations and may actively influence their offspring's early life through sound learning shaped by maternal call tempo.
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McLean CR, Mata A, Kline RJ, Berg KS. Early corticosterone increases vocal complexity in a wild parrot: An organizational role of the hypothalamic-pituitary-adrenal axis in vocal learning? J Neuroendocrinol 2024:e13365. [PMID: 38200690 DOI: 10.1111/jne.13365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 12/03/2023] [Accepted: 12/22/2023] [Indexed: 01/12/2024]
Abstract
The neuroendocrinology of vocal learning is exceptionally well known in passerine songbirds. Despite huge life history, genetic and ecological variation across passerines, song learning tends to occur as a result of rises in gonadal and non-gonadal sex steroids that shape telencephalic vocal control circuits and song. Parrots are closely related but independently evolved different cerebral circuits for vocal repertoire acquisition in both sexes that serve a broader suite of social functions and do not appear to be shaped by early androgens or estrogens; instead, parrots begin a plastic phase in vocal development at an earlier life history stage that favors the growth, maturation, and survival functions of corticosteroids. As evidence, corticosterone (CORT) supplements given to wild green-rumped parrotlets (Forpus passerinus) during the first week of vocal babbling resulted in larger vocal repertoires in both sexes in the remaining days before fledging. Here, we replicate this experiment but began treatment 1 week before in development, analyzing both experiments in one model and a stronger test of the organizational effects of CORT on repertoire acquisition. Early CORT treatment resulted in significantly larger repertoires compared to late treatment. Both treatment groups showed weak negative effects on the early, reduplicated stage of babbling and strong, positive effects of CORT on the later, variegated stage. Results are consistent with more formative effects of corticosteroids at earlier developmental stages and a role of the hypothalamic-pituitary-adrenal axis (HPA) in vocal repertoire acquisition. Given the early emergence of speech in human ontogeny, parrots are a promising model for understanding the putative role of the HPA axis in the construction of neural circuits that support language acquisition.
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Affiliation(s)
- Celia R McLean
- Department of Biology, University of Texas Rio Grande Valley, Brownsville, Texas, USA
| | - Astolfo Mata
- Centro de Ecología, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela
- Centre National de la Recherche Scientifique, Universite de Strasbourg, Strasbourg, France
| | - Richard J Kline
- Department of Biology, University of Texas Rio Grande Valley, Brownsville, Texas, USA
- School of Earth Environmental and Marine Sciences, University of Texas Rio Grande Valley, Brownsville, Texas, USA
| | - Karl S Berg
- Department of Biology, University of Texas Rio Grande Valley, Brownsville, Texas, USA
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Vernes SC, Devanna P, Hörpel SG, Alvarez van Tussenbroek I, Firzlaff U, Hagoort P, Hiller M, Hoeksema N, Hughes GM, Lavrichenko K, Mengede J, Morales AE, Wiesmann M. The pale spear-nosed bat: A neuromolecular and transgenic model for vocal learning. Ann N Y Acad Sci 2022; 1517:125-142. [PMID: 36069117 PMCID: PMC9826251 DOI: 10.1111/nyas.14884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Vocal learning, the ability to produce modified vocalizations via learning from acoustic signals, is a key trait in the evolution of speech. While extensively studied in songbirds, mammalian models for vocal learning are rare. Bats present a promising study system given their gregarious natures, small size, and the ability of some species to be maintained in captive colonies. We utilize the pale spear-nosed bat (Phyllostomus discolor) and report advances in establishing this species as a tractable model for understanding vocal learning. We have taken an interdisciplinary approach, aiming to provide an integrated understanding across genomics (Part I), neurobiology (Part II), and transgenics (Part III). In Part I, we generated new, high-quality genome annotations of coding genes and noncoding microRNAs to facilitate functional and evolutionary studies. In Part II, we traced connections between auditory-related brain regions and reported neuroimaging to explore the structure of the brain and gene expression patterns to highlight brain regions. In Part III, we created the first successful transgenic bats by manipulating the expression of FoxP2, a speech-related gene. These interdisciplinary approaches are facilitating a mechanistic and evolutionary understanding of mammalian vocal learning and can also contribute to other areas of investigation that utilize P. discolor or bats as study species.
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Affiliation(s)
- Sonja C. Vernes
- School of BiologyUniversity of St AndrewsSt AndrewsUK,Neurogenetics of Vocal Communication GroupMax Planck Institute for PsycholinguisticsNijmegenThe Netherlands
| | - Paolo Devanna
- School of BiologyUniversity of St AndrewsSt AndrewsUK,Neurogenetics of Vocal Communication GroupMax Planck Institute for PsycholinguisticsNijmegenThe Netherlands
| | - Stephen Gareth Hörpel
- School of BiologyUniversity of St AndrewsSt AndrewsUK,Neurogenetics of Vocal Communication GroupMax Planck Institute for PsycholinguisticsNijmegenThe Netherlands,TUM School of Life SciencesTechnical University of MunichFreisingGermany
| | - Ine Alvarez van Tussenbroek
- School of BiologyUniversity of St AndrewsSt AndrewsUK,Neurogenetics of Vocal Communication GroupMax Planck Institute for PsycholinguisticsNijmegenThe Netherlands
| | - Uwe Firzlaff
- TUM School of Life SciencesTechnical University of MunichFreisingGermany
| | - Peter Hagoort
- Neurobiology of Language DepartmentMax Planck Institute for PsycholinguisticsNijmegenThe Netherlands
| | - Michael Hiller
- LOEWE Centre for Translational Biodiversity Genomics, Faculty of Biosciences, Senckenberg Research Institute, Goethe‐UniversityFrankfurtGermany
| | - Nienke Hoeksema
- Neurogenetics of Vocal Communication GroupMax Planck Institute for PsycholinguisticsNijmegenThe Netherlands,Neurobiology of Language DepartmentMax Planck Institute for PsycholinguisticsNijmegenThe Netherlands
| | - Graham M. Hughes
- School of Biology and Environmental ScienceUniversity College DublinBelfieldIreland
| | - Ksenia Lavrichenko
- Neurogenetics of Vocal Communication GroupMax Planck Institute for PsycholinguisticsNijmegenThe Netherlands
| | - Janine Mengede
- Neurogenetics of Vocal Communication GroupMax Planck Institute for PsycholinguisticsNijmegenThe Netherlands
| | - Ariadna E. Morales
- LOEWE Centre for Translational Biodiversity Genomics, Faculty of Biosciences, Senckenberg Research Institute, Goethe‐UniversityFrankfurtGermany
| | - Maximilian Wiesmann
- Department of Medical ImagingAnatomyRadboud University Medical Center, Donders Institute for Brain, Cognition & Behavior, Center for Medical Neuroscience, Preclinical Imaging Center PRIME, Radboud Alzheimer CenterNijmegenThe Netherlands
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Verga L, Sroka MGU, Varola M, Villanueva S, Ravignani A. Spontaneous rhythm discrimination in a mammalian vocal learner. Biol Lett 2022; 18:20220316. [PMID: 36285461 PMCID: PMC9597408 DOI: 10.1098/rsbl.2022.0316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Rhythm and vocal production learning are building blocks of human music and speech. Vocal learning has been hypothesized as a prerequisite for rhythmic capacities. Yet, no mammalian vocal learner but humans have shown the capacity to flexibly and spontaneously discriminate rhythmic patterns. Here we tested untrained rhythm discrimination in a mammalian vocal learning species, the harbour seal (Phoca vitulina). Twenty wild-born seals were exposed to music-like playbacks of conspecific call sequences varying in basic rhythmic properties. These properties were called length, sequence regularity, and overall tempo. All three features significantly influenced seals' reaction (number of looks and their duration), demonstrating spontaneous rhythm discrimination in a vocal learning mammal. This finding supports the rhythm–vocal learning hypothesis and showcases pinnipeds as promising models for comparative research on rhythmic phylogenies.
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Affiliation(s)
- Laura Verga
- Comparative Bioacoustics Research Group, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands,Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Marlene G. U. Sroka
- Department of Behavioural Biology, University of Münster, Münster, Germany,Research Department, Sealcentre Pieterburen, Pieterburen, The Netherlands
| | - Mila Varola
- Comparative Bioacoustics Research Group, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands,Research Department, Sealcentre Pieterburen, Pieterburen, The Netherlands
| | - Stella Villanueva
- Research Department, Sealcentre Pieterburen, Pieterburen, The Netherlands
| | - Andrea Ravignani
- Comparative Bioacoustics Research Group, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands,Research Department, Sealcentre Pieterburen, Pieterburen, The Netherlands,Center for Music in the Brain, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
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Abstract
Vocal production learning (VPL) is the experience-driven ability to produce novel vocal signals through imitation or modification of existing vocalizations. A parallel strand of research investigates acoustic allometry, namely how information about body size is conveyed by acoustic signals. Recently, we proposed that deviation from acoustic allometry principles as a result of sexual selection may have been an intermediate step towards the evolution of vocal learning abilities in mammals. Adopting a more hypothesis-neutral stance, here we perform phylogenetic regressions and other analyses further testing a potential link between VPL and being an allometric outlier. We find that multiple species belonging to VPL clades deviate from allometric scaling but in the opposite direction to that expected from size exaggeration mechanisms. In other words, our correlational approach finds an association between VPL and being an allometric outlier. However, the direction of this association, contra our original hypothesis, may indicate that VPL did not necessarily emerge via sexual selection for size exaggeration: VPL clades show higher vocalization frequencies than expected. In addition, our approach allows us to identify species with potential for VPL abilities: we hypothesize that those outliers from acoustic allometry lying above the regression line may be VPL species. Our results may help better understand the cross-species diversity, variability and aetiology of VPL, which among other things is a key underpinning of speech in our species. This article is part of the theme issue 'Voice modulation: from origin and mechanism to social impact (Part II)'.
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Affiliation(s)
- Andrea Ravignani
- Comparative Bioacoustics Group, Max Planck Institute for Psycholinguistics, Wundtlaan 1, 6525 XD Nijmegen, The Netherlands
| | - Maxime Garcia
- Animal Behaviour, Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, Zurich 8051, Switzerland.,Center for the Interdisciplinary Study of Language Evolution, University of Zurich, Zurich 8032, Switzerland
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6
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Abstract
Vocal plasticity can occur in response to environmental and biological factors, including conspecifics' vocalizations and noise. Pinnipeds are one of the few mammalian groups capable of vocal learning, and are therefore relevant to understanding the evolution of vocal plasticity in humans and other animals. Here, we investigate the vocal plasticity of harbour seals (Phoca vitulina), a species with vocal learning abilities observed in adulthood but not puppyhood. To evaluate early mammalian vocal development, we tested 1-3 weeks-old seal pups. We tailored noise playbacks to this species and age to induce seal pups to shift their fundamental frequency (f0), rather than adapt call amplitude or temporal characteristics. We exposed individual pups to low- and high-intensity bandpass-filtered noise, which spanned-and masked-their typical range of f0; simultaneously, we recorded pups' spontaneous calls. Unlike most mammals, pups modified their vocalizations by lowering their f0 in response to increased noise. This modulation was precise and adapted to the particular experimental manipulation of the noise condition. In addition, higher levels of noise induced less dispersion around the mean f0, suggesting that pups may have actively focused their phonatory efforts to target lower frequencies. Noise did not seem to affect call amplitude. However, one seal showed two characteristics of the Lombard effect known for human speech in noise: significant increase in call amplitude and flattening of spectral tilt. Our relatively low noise levels may have favoured f0 modulation while inhibiting amplitude adjustments. This lowering of f0 is unusual, as most animals commonly display no such f0 shift. Our data represent a relatively rare case in mammalian neonates, and have implications for the evolution of vocal plasticity and vocal learning across species, including humans. This article is part of the theme issue 'Voice modulation: from origin and mechanism to social impact (Part I)'.
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Affiliation(s)
- Laura Torres Borda
- Comparative Bioacoustics Group, Max Planck Institute for Psycholinguistics, Wundtlaan 1, 6525 XD Nijmegen, The Netherlands
- Research Department, Sealcentre Pieterburen, Hoofdstraat 94-A, 9968 AG Pieterburen, The Netherlands
| | - Yannick Jadoul
- Comparative Bioacoustics Group, Max Planck Institute for Psycholinguistics, Wundtlaan 1, 6525 XD Nijmegen, The Netherlands
- Artificial Intelligence Lab, Vrije Universiteit Brussel, 1050 Elsene/Ixelles, Belgium
| | - Heikki Rasilo
- Artificial Intelligence Lab, Vrije Universiteit Brussel, 1050 Elsene/Ixelles, Belgium
| | - Anna Salazar Casals
- Research Department, Sealcentre Pieterburen, Hoofdstraat 94-A, 9968 AG Pieterburen, The Netherlands
| | - Andrea Ravignani
- Comparative Bioacoustics Group, Max Planck Institute for Psycholinguistics, Wundtlaan 1, 6525 XD Nijmegen, The Netherlands
- Research Department, Sealcentre Pieterburen, Hoofdstraat 94-A, 9968 AG Pieterburen, The Netherlands
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7
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Abstract
Songbirds as a whole are considered to be vocal production learners, meaning that they modify the structure of their vocalizations as a result of experience with the vocalizations of others. The more than 4000 species of songbirds, however, vary greatly in crucial features of song development. Variable features include: (i) the normality of the songs of early-deafened birds, reflecting the importance of innate motor programmes in song development; (ii) the normality of the songs of isolation-reared birds, reflecting the combined importance of innate auditory templates and motor programmes; (iii) the degree of selectivity in choice of external models; (iv) the accuracy of copying from external models; and (v) whether or not learning from external models continues into adulthood. We suggest that because of this variability, some songbird species, specifically those that are able to develop songs in the normal range without exposure to external models, can be classified as limited vocal learners. Those species that require exposure to external models to develop songs in the normal range can be considered complex vocal learners. This article is part of the theme issue 'Vocal learning in animals and humans'.
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Affiliation(s)
- William A. Searcy
- Department of Biology, University of Miami, Coral Gables, FL 33124, USA
| | - Jill Soha
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Susan Peters
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Stephen Nowicki
- Department of Biology, Duke University, Durham, NC 27708, USA
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Lattenkamp EZ, Hörpel SG, Mengede J, Firzlaff U. A researcher's guide to the comparative assessment of vocal production learning. Philos Trans R Soc Lond B Biol Sci 2021; 376:20200237. [PMID: 34482725 DOI: 10.1098/rstb.2020.0237] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Vocal production learning (VPL) is the capacity to learn to produce new vocalizations, which is a rare ability in the animal kingdom and thus far has only been identified in a handful of mammalian taxa and three groups of birds. Over the last few decades, approaches to the demonstration of VPL have varied among taxa, sound production systems and functions. These discrepancies strongly impede direct comparisons between studies. In the light of the growing number of experimental studies reporting VPL, the need for comparability is becoming more and more pressing. The comparative evaluation of VPL across studies would be facilitated by unified and generalized reporting standards, which would allow a better positioning of species on any proposed VPL continuum. In this paper, we specifically highlight five factors influencing the comparability of VPL assessments: (i) comparison to an acoustic baseline, (ii) comprehensive reporting of acoustic parameters, (iii) extended reporting of training conditions and durations, (iv) investigating VPL function via behavioural, perception-based experiments and (v) validation of findings on a neuronal level. These guidelines emphasize the importance of comparability between studies in order to unify the field of vocal learning. This article is part of the theme issue 'Vocal learning in animals and humans'.
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Affiliation(s)
- Ella Z Lattenkamp
- Division of Neurobiology, Department of Biology II, LMU Munich, Germany.,Neurogenetics of Vocal Communication Group, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands
| | - Stephen G Hörpel
- Neurogenetics of Vocal Communication Group, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands.,Department of Animal Sciences, Chair of Zoology, TU Munich, Germany
| | - Janine Mengede
- Neurogenetics of Vocal Communication Group, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands
| | - Uwe Firzlaff
- Department of Animal Sciences, Chair of Zoology, TU Munich, Germany
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9
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Abstract
Acoustic allometry is the study of how animal vocalizations reflect their body size. A key aim of this research is to identify outliers to acoustic allometry principles and pinpoint the evolutionary origins of such outliers. A parallel strand of research investigates species capable of vocal learning, the experience-driven ability to produce novel vocal signals through imitation or modification of existing vocalizations. Modification of vocalizations is a common feature found when studying both acoustic allometry and vocal learning. Yet, these two fields have only been investigated separately to date. Here, we review and connect acoustic allometry and vocal learning across mammalian clades, combining perspectives from bioacoustics, anatomy and evolutionary biology. Based on this, we hypothesize that, as a precursor to vocal learning, some species might have evolved the capacity for volitional vocal modulation via sexual selection for 'dishonest' signalling. We provide preliminary support for our hypothesis by showing significant associations between allometric deviation and vocal learning in a dataset of 164 mammals. Our work offers a testable framework for future empirical research linking allometric principles with the evolution of vocal learning.
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Affiliation(s)
- Maxime Garcia
- Animal Behaviour, Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8051 Zurich, Switzerland
- Center for the Interdisciplinary Study of Language Evolution, University of Zurich, 8032 Zurich, Switzerland
| | - Andrea Ravignani
- Comparative Bioacoustics Group, Max Planck Institute for Psycholinguistics, Wundtlaan 1, 6525 XD Nijmegen, The Netherlands
- Research Department, Sealcentre Pieterburen, Hoofdstraat 94a, 9968 AG Pieterburen, The Netherlands
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10
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Abstract
Vocal production learning (VPL), or the ability to modify vocalizations through the imitation of sounds, is a rare trait in the animal kingdom. While humans are exceptional vocal learners, few other mammalian species share this trait. Owing to their singular ecology and lifestyle, bats are highly specialized for the precise emission and reception of acoustic signals. This specialization makes them ideal candidates for the study of vocal learning, and several bat species have previously shown evidence supportive of vocal learning. Here we use a sophisticated automated set-up and a contingency training paradigm to explore the vocal learning capacity of pale spear-nosed bats. We show that these bats are capable of directional change of the fundamental frequency of their calls according to an auditory target. With this study, we further highlight the importance of bats for the study of vocal learning and provide evidence for the VPL capacity of the pale spear-nosed bat.
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Affiliation(s)
- Ella Z Lattenkamp
- Neurogenetics of Vocal Communication Group, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands.,Division of Neurobiology, Ludwig-Maximilians University Munich, Germany
| | - Sonja C Vernes
- Neurogenetics of Vocal Communication Group, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Lutz Wiegrebe
- Division of Neurobiology, Ludwig-Maximilians University Munich, Germany
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11
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Abstract
The comparative approach can provide insight into the evolution of human speech, language and social communication by studying relevant traits in animal systems. Bats are emerging as a model system with great potential to shed light on these processes given their learned vocalizations, close social interactions, and mammalian brains and physiology. A recent framework outlined the multiple levels of investigation needed to understand vocal learning across a broad range of non-human species, including cetaceans, pinnipeds, elephants, birds and bats. Here, we apply this framework to the current state-of-the-art in bat research. This encompasses our understanding of the abilities bats have displayed for vocal learning, what is known about the timing and social structure needed for such learning, and current knowledge about the prevalence of the trait across the order. It also addresses the biology (vocal tract morphology, neurobiology and genetics) and evolution of this trait. We conclude by highlighting some key questions that should be answered to advance our understanding of the biological encoding and evolution of speech and spoken communication. This article is part of the theme issue 'What can animal communication teach us about human language?'
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Affiliation(s)
- Sonja C Vernes
- Neurogenetics of Vocal Communication Group, Max Planck Institute for Psycholinguistics, PO Box 310, Nijmegen 6500 AH, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Kapittelweg 29, Nijmegen 6525 EN, The Netherlands
| | - Gerald S Wilkinson
- Department of Biology, University of Maryland, College Park, MD 20742, USA
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Villain AS, Boucaud ICA, Bouchut C, Vignal C. Parental influence on begging call structure in zebra finches (Taeniopygia guttata): evidence of early vocal plasticity. R Soc Open Sci 2015; 2:150497. [PMID: 26716009 PMCID: PMC4680624 DOI: 10.1098/rsos.150497] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 10/30/2015] [Indexed: 06/05/2023]
Abstract
Begging calls are signals of need used by young birds to elicit care from adults. Different theoretical frameworks have been proposed to understand this parent-offspring communication. But relationships between parental response and begging intensity, or between begging characteristics and proxies of a young's need remain puzzling. Few studies have considered the adjustment of nestling begging features to previous experience as a possible explanation of these discrepancies. In this study, we tested the effect of a heterospecific rearing environment on individual developmental trajectories of the acoustic structure of nestling begging calls. Fifty-two zebra finch chicks were fostered either to Bengalese finch or to zebra finch parents, and begging calls were recorded at several stages of nestling development. Acoustic analyses revealed that the development of the spectral features of the begging calls differed between experimental conditions: chicks reared by Bengalese finches produced higher pitched and less broadband begging calls than chicks reared by conspecific parents. Differences were stronger in males than females and were not explained by differences in growth rate. We conclude that nestling begging calls can be plastic in response to social interactions with parents.
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