scholarly journals Vocal production learning in the pale spear-nosed bat, Phyllostomus discolor

2020 ◽  
Vol 16 (4) ◽  
pp. 20190928 ◽  
Author(s):  
Ella Z. Lattenkamp ◽  
Sonja C. Vernes ◽  
Lutz Wiegrebe
Keyword(s):  
Mammalian Species ◽  
Vocal Learning ◽  
Acoustic Signals ◽  
Auditory Target ◽  
Animal Kingdom ◽  
Vocal Production ◽  
Learning Capacity ◽  
Directional Change ◽  
Set Up ◽  
Phyllostomus Discolor

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.

scholarly journals A researcher's guide to the comparative assessment of vocal production learning

2021 ◽  
Vol 376 (1836) ◽  
pp. 20200237
Author(s):  
Ella Z. Lattenkamp ◽  
Stephen G. Hörpel ◽  
Janine Mengede ◽  
Uwe Firzlaff
Keyword(s):  
Sound Production ◽  
Production Systems ◽  
Experimental Studies ◽  
Vocal Learning ◽  
Comparative Assessment ◽  
Theme Issue ◽  
Acoustic Parameters ◽  
Animal Kingdom ◽  
Vocal Production ◽  
Five Factors

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’.

scholarly journals Knowing the Enemy: Inducible Defences in Freshwater Zooplankton

Diversity ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 147 ◽  
Author(s):  
Patricia Diel ◽  
Marvin Kiene ◽  
Dominik Martin-Creuzburg ◽  
Christian Laforsch
Keyword(s):  
Life History ◽  
Chemical Cues ◽  
Prey Species ◽  
Inducible Defences ◽  
Animal Kingdom ◽  
Predator Species ◽  
Freshwater Zooplankton ◽  
Taxonomic Range ◽  
Set Up ◽  
Made In

Phenotypic plasticity in defensive traits is an appropriate mechanism to cope with the variable hazard of a frequently changing predator spectrum. In the animal kingdom these so-called inducible defences cover the entire taxonomic range from protozoans to vertebrates. The inducible defensive traits range from behaviour, morphology, and life-history adaptations to the activation of specific immune systems in vertebrates. Inducible defences in prey species play important roles in the dynamics and functioning of food webs. Freshwater zooplankton show the most prominent examples of inducible defences triggered by chemical cues, so-called kairomones, released by predatory invertebrates and fish. The objective of this review is to highlight recent progress in research on inducible defences in freshwater zooplankton concerning behaviour, morphology, and life-history, as well as difficulties of studies conducted in a multipredator set up. Furthermore, we outline costs associated with the defences and discuss difficulties as well as the progress made in characterizing defence-inducing cues. Finally, we aim to indicate further possible routes in this field of research and provide a comprehensive table of inducible defences with respect to both prey and predator species.

scholarly journals Re-evaluating vocal production learning in non-oscine birds

2021 ◽  
Vol 376 (1836) ◽  
Author(s):  
Carel ten Cate
Keyword(s):  
Comparative Studies ◽  
Comparative Research ◽  
Vocal Learning ◽  
Limited Evidence ◽  
Theme Issue ◽  
Vocal Production ◽  
Broad Definition ◽  
Interspecific Variations ◽  
Phylogenetic Framework ◽  
Definition Of

The study of vocal production learning in birds is heavily biased towards oscine songbirds, making the songbird model the reference for comparative studies. However, as vocal learning was probably ancestral in songbirds, interspecific variations might all be variations on a single theme and need not be representative of the nature and characteristics of vocal learning in other bird groups. To assess the possible mechanisms of vocal learning and its evolution therefore requires knowledge about independently evolved incidences of vocal learning. This review examines the presence and nature of vocal production learning in non-songbirds. Using a broad definition of vocal learning and a comparative phylogenetic framework, I evaluate the evidence for vocal learning and its characteristics in non-oscine birds, including well-known vocal learners such as parrots and hummingbirds but also (putative) cases from other taxa. Despite the sometimes limited evidence, it is clear that vocal learning occurs in a range of different, non-related, taxa and can be caused by a variety of mechanisms. It is more widespread than often realized, calling for more systematic studies. Examining this variation may provide a window onto the evolution of vocal learning and increase the value of comparative research for understanding vocal learning in humans. This article is part of the theme issue ‘Vocal learning in animals and humans’.

scholarly journals Morphological facilitators for vocal learning explored through the syrinx anatomy of a basal hummingbird

2020 ◽  
Author(s):  
Amanda Monte ◽  
Alexander F. Cerwenka ◽  
Bernhard Ruthensteiner ◽  
Manfred Gahr ◽  
Daniel N. Düring
Keyword(s):  
Sound Production ◽  
Three Dimensional ◽  
Vocal Learning ◽  
Dimensional Structure ◽  
Micro Computed Tomography ◽  
Vocal Production ◽  
Precise Control ◽  
Acoustic Space ◽  
Biomechanical Factors ◽  
Intrinsic Musculature

AbstractVocal learning is a rare evolutionary trait that evolved independently in three avian clades: songbirds, parrots, and hummingbirds. Although the anatomy and mechanisms of sound production in songbirds are well understood, little is known about the hummingbird’s vocal anatomy. We use high-resolution micro-computed tomography (μCT) and microdissection to reveal the three-dimensional structure of the syrinx, the vocal organ of the black jacobin (Florisuga fusca), a phylogenetically basal hummingbird species. We identify three unique features of the black jacobin’s syrinx: (i) a shift in the position of the syrinx to the outside of the thoracic cavity and the related loss of the sterno-tracheal muscle, (ii) complex intrinsic musculature, oriented dorso-ventrally, and (iii) ossicles embedded in the medial vibratory membranes. Their syrinx morphology allows vibratory decoupling, precise control of complex acoustic parameters, and a large redundant acoustic space that may be key biomechanical factors facilitating the occurrence of vocal production learning.

scholarly journals Vocal learning and the dimensionality of the mating environment

2019 ◽  
Author(s):  
Jan Verpooten
Keyword(s):  
Vocal Learning ◽  
Vocal Music ◽  
Humpback Whales ◽  
Research Attention ◽  
Learning Capacity ◽  
Selection Processes ◽  
Spatial Environment ◽  
New Perspective ◽  
Spatial Dimensionality ◽  
The Impact

Vocal learning, the capacity to add new vocalizations to one’s repertoire, has gained much research attention because it is a key prerequisite for spoken language and vocal music. As a result, major progress has been made regarding its developmental, genetic and morphological underpinnings. However, why it evolved and, more specifically, why it is so peculiarly distributed across species, remain long standing questions. For instance, animals as distinct as hummingbirds and humpback whales share well-developed vocal learning capacity in common with humans, while this ability appears quite limited in nonhuman primates. In order to tackle these questions, this article brings together existing hypotheses, such as about the evolutionary functions of vocal learning and the impact of the spatial environment on sexual selection processes. Consistent with these hypotheses, I suggest, based on a systematic review of the latest evidence, that the cross-species distribution of vocal learning is associated with the spatial dimensionality of ancestral environments, and that this association is mediated by mate choice. This new perspective on the evolution of vocal learning is expected to open up novel avenues for further research on this pivotal cognitive ability. One implication is that human vocal learning may have evolved in (semi-)arboreal hominins at the base of the human clade, such as Ardipithecus ramidus, and thus much earlier than commonly assumed.

scholarly journals Seasonal regulation of singing-driven gene expression associated with song plasticity in the canary, an open-ended vocal learner

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Shin Hayase ◽  
Chengru Shao ◽  
Masahiko Kobayashi ◽  
Chihiro Mori ◽  
Wan-chun Liu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Neural Activity ◽  
Molecular Mechanisms ◽  
Vocal Learning ◽  
Motor Nucleus ◽  
Vocal Plasticity ◽  
Learning Capacity ◽  
Induction Rate ◽  
Song Acquisition ◽  
Activity Dependent

AbstractSongbirds are one of the few animal taxa that possess vocal learning abilities. Different species of songbirds exhibit species-specific learning programs during song acquisition. Songbirds with open-ended vocal learning capacity, such as the canary, modify their songs during adulthood. Nevertheless, the neural molecular mechanisms underlying open-ended vocal learning are not fully understood. We investigated the singing-driven expression of neural activity-dependent genes (Arc, Egr1, c-fos, Nr4a1, Sik1, Dusp6, and Gadd45β) in the canary to examine a potential relationship between the gene expression level and the degree of seasonal vocal plasticity at different ages. The expression of these genes was differently regulated throughout the critical period of vocal learning in the zebra finch, a closed-ended song learner. In the canary, the neural activity-dependent genes were induced by singing in the song nuclei throughout the year. However, in the vocal motor nucleus, the robust nucleus of the arcopallium (RA), all genes were regulated with a higher induction rate by singing in the fall than in the spring. The singing-driven expression of these genes showed a similar induction rate in the fall between the first year juvenile and the second year adult canaries, suggesting a seasonal, not age-dependent, regulation of the neural activity-dependent genes. By measuring seasonal vocal plasticity and singing-driven gene expression, we found that in RA, the induction intensity of the neural activity-dependent genes was correlated with the state of vocal plasticity. These results demonstrate a correlation between vocal plasticity and the singing-driven expression of neural activity-dependent genes in RA through song development, regardless of whether a songbird species possesses an open- or closed-ended vocal learning capacity.

scholarly journals Prenatal auditory learning in avian vocal learners and non-learners

2021 ◽  
Vol 376 (1836) ◽  
pp. 20200247
Author(s):  
Diane Colombelli-Négrel ◽  
Mark E. Hauber ◽  
Christine Evans ◽  
Andrew C. Katsis ◽  
Lyanne Brouwer ◽  
...  
Keyword(s):  
Information Acquisition ◽  
Gene Activation ◽  
Vocal Learning ◽  
Response Strength ◽  
Response Patterns ◽  
In Ovo ◽  
Vocal Production ◽  
Auditory Learning ◽  
New Research ◽  
Sound Learning

Understanding when learning begins is critical for identifying the factors that shape both the developmental course and the function of information acquisition. Until recently, sufficient development of the neural substrates for any sort of vocal learning to begin in songbirds was thought to be reached well after hatching. New research shows that embryonic gene activation and the outcome of vocal learning can be modulated by sound exposure in ovo . We tested whether avian embryos across lineages differ in their auditory response strength and sound learning in ovo , which we studied in vocal learning (Maluridae, Geospizidae) and vocal non-learning (Phasianidae, Spheniscidae) taxa. While measuring heart rate in ovo , we exposed embryos to (i) conspecific or heterospecific vocalizations, to determine their response strength, and (ii) conspecific vocalizations repeatedly, to quantify cardiac habituation, a form of non-associative learning. Response strength towards conspecific vocalizations was greater in two species with vocal production learning compared to two species without. Response patterns consistent with non-associative auditory learning occurred in all species. Our results demonstrate a capacity to perceive and learn to recognize sounds in ovo , as evidenced by habituation, even in species that were previously assumed to have little, if any, vocal production learning. This article is part of the theme issue ‘Vocal learning in animals and humans’.

scholarly journals Vocal production learning in mammals revisited

2021 ◽  
Vol 376 (1836) ◽  
pp. 20200244
Author(s):  
Vincent M. Janik ◽  
Mirjam Knörnschild
Keyword(s):  
Experimental Studies ◽  
Vocal Learning ◽  
Type Result ◽  
Theme Issue ◽  
Vocal Production ◽  
Learning Skills ◽  
Acoustic Models ◽  
Vocal Convergence ◽  
The Subject ◽  
Underlying Mechanisms

Vocal production learning, the ability to modify the structure of vocalizations as a result of hearing those of others, has been studied extensively in birds but less attention has been given to its occurrence in mammals. We summarize the available evidence for vocal learning in mammals from the last 25 years, updating earlier reviews on the subject. The clearest evidence comes from cetaceans, pinnipeds, elephants and bats where species have been found to copy artificial or human language sounds, or match acoustic models of different sound types. Vocal convergence, in which parameter adjustments within one sound type result in similarities between individuals, occurs in a wider range of mammalian orders with additional evidence from primates, mole-rats, goats and mice. Currently, the underlying mechanisms for convergence are unclear with vocal production learning but also usage learning or matching physiological states being possible explanations. For experimental studies, we highlight the importance of quantitative comparisons of seemingly learned sounds with vocal repertoires before learning started or with species repertoires to confirm novelty. Further studies on the mammalian orders presented here as well as others are needed to explore learning skills and limitations in greater detail. This article is part of the theme issue ‘Vocal learning in animals and humans’.

scholarly journals Fellatio among male sanctuary-living chimpanzees during a period of social tension

Behaviour ◽  
2020 ◽  
Vol 158 (1) ◽  
pp. 77-87
Author(s):  
Jake S. Brooker ◽  
Christine E. Webb ◽  
Zanna Clay
Keyword(s):  
Sexual Behaviour ◽  
Mammalian Species ◽  
Great Apes ◽  
Adult Males ◽  
Behavioural Flexibility ◽  
Same Sex ◽  
Animal Kingdom ◽  
Post Conflict ◽  
Close Relatives ◽  
Conflict Period

Abstract Same-sex sexual behaviour has been documented across the animal kingdom, and is thought to reflect and enhance dyadic cooperation and tolerance. For instance, same-sex fellatio — the reception of a partner’s penis into another’s mouth — has been reported in several mammalian species other than humans. Although same-sex sexual behaviour is observed in our close relatives, the chimpanzees, fellatio appears to be very rare — as yet there are no published reports clearly documenting its occurrence. At Chimfunshi Wildlife Orphanage in Zambia, we observed an instance of fellatio occurring during a post-conflict period between two adult male chimpanzees (born and mother-reared at the sanctuary) where one of the males was the victim. We discuss this event with respect to the putative functions of homosexual behaviour in great apes. Given its rarity in chimpanzees, this fellatio between adult males also highlights the apparent behavioural flexibility present in our close relatives.

scholarly journals Phylogenetic and kinematic constraints on avian flight signals

2019 ◽  
Vol 286 (1911) ◽  
pp. 20191083
Author(s):  
K. S. Berg ◽  
S. Delgado ◽  
A. Mata-Betancourt
Keyword(s):  
Body Mass ◽  
High Speed ◽  
Vocal Learning ◽  
Power Stroke ◽  
Future Research ◽  
Vocal Production ◽  
Vocal Plasticity ◽  
Avian Flight ◽  
Physiological Limits ◽  
Kinematic Relationship

Many birds vocalize in flight. Because wingbeat and respiratory cycles are often linked in flying vertebrates, birds in these cases must satisfy the respiratory demands of vocal production within the physiological limits imposed by flight. Using acoustic triangulation and high-speed video, we found that avian vocal production in flight exhibits a largely phasic and kinematic relationship with the power stroke. However, the sample of species showed considerable flexibility, especially those from lineages known for vocal plasticity (songbirds, parrots and hummingbirds), prompting a broader phylogenetic analysis. We thus collected data from 150 species across 12 avian orders and examined the links between wingbeat period, flight call duration and body mass. Overall, shorter wingbeat periods, controlling for ancestry and body mass, were correlated with shorter flight call durations. However, species from vocal learner lineages produced flight signals that, on average, exceeded multiple phases of their wingbeat cycle, while vocal non-learners had signal periods that were, on average, closer to the duration of their power stroke. These results raise an interesting question: is partial emancipation from respiratory constraints a necessary step in the evolution of vocal learning or an epiphenomenon? Our current study cannot provide the answer, but it does suggest several avenues for future research.

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