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Signal theory predicts organisms should evolve signals that are conspicuous to intended receivers in natural signalling environments. Cleaner shrimps remove ectoparasites from reef fish clients and many signal their intent to clean by whipping long, white antennae. As white is a reliably conspicuous colour in aquatic environments, we hypothesized that selection has acted to increase broad-spectrum antennal reflectance in cleaners. Using scanning electron microscopy, optical models and reflectance measurements, we found that the antennae in three obligate cleaner species from two families (Palaemonidae and Lysmatidae) had thick (∼6 µm) chitinous layers or densely packed high refractive index spheres (300-400 nm diameter), which models show increase reflectance (400-700 nm). Two facultative and non-cleaning species had no visible antennae ultrastructure beyond the chitinous exoskeleton. Antennae reflectance was significantly higher in obligate cleaners than in facultative and non-cleaning species. Our results suggest that some obligate cleaners may have evolved ultrastructures that increase the conspicuousness of their antennae as signals.

A variety of organisms exhibit collective movement, including schooling fish and flocking birds, where coordinated behavior emerges from the interactions between group members. Despite the prevalence of collective movement in nature, little is known about the neural mechanisms producing each individuals behavior within the group. Here we discuss how a neurobiological approach can enrich our understanding of collective behavior by determining the mechanisms by which individuals interact. We provide examples of sensory systems for social communication during collective movement, highlight recent discoveries about neural systems for detecting the position and actions of social partners, and discuss opportunities for future research. Understanding the neurobiology of collective behavior can provide insight into how nervous systems function in a dynamic social world.

To communicate is to move. There is no way around that. Ifwe pick up comprehensive handbooks or introductory textsin movement science (Hong and Bartlett (2008)) we seethat there is very rich knowledge and tractable mathematicalmodels about different aspects of movements. Yet, we findno chapter on communicative movements. While the fieldof speech motor control is a developed area on its own(Parrell and Lammert (2019)), there is no movement scienceof communication proper, which would include whole-body-,hand-gestural-, signed-, and inter-bodily actions.

Studies of meaning in human and primate communication face, in principle, similar methodological problems. In both cases, meaning is not observable directly, but must be inferred from more indirect sources, such as directly observable behavior. Recent work in probabilistic cognitive modeling of language use has therefore developed methods of inferring latent se- mantic meaning through the lens of a probabilistic model of language use. In this paper, we explore how to adapt such an approach for insightful investigations of primate communication. Towards this end, we develop a suitable probabilistic model of processes that generate communicative behavior by making use of functionally specified latent meaning representations. As a proof of concept, we apply this model to a rich, annotated data set of orangutan communicative dyadic interaction and conclude that explicit probabilistic modeling can provide additional insights for the study of animal communication pertaining to the context-dependent nature of signals and the gradual evolution of human communication systems.

Video recording is a widely used tool for studying animal behavior, especially in fields such as primatology. Primatologists rely on video data to analyze and research topics such as social grooming to uncover subtle mechanisms behind complex social behavior and structures. Insights into these social behaviors may provide us with a better understanding of our closest living relatives, but also new theories and insights into our own behavior. However, analyzing this type of data using manual annotation is currently a time-consuming task. Here we present an end-to-end pipeline to track chimpanzee (Pan troglodytes) poses using DeepLabCut (DLC) which then serves as input to a support vector machine. This classifier was trained to detect role transitions within grooming interactions. We replicate a recent study showing that DLC has usability value for chimpanzee data collected in natural environments. Our combined method of tracking and classification is remarkably successful in detecting the presence of grooming, indicating the directionality and a change in turn with an accuracy above 86% on unseen videos. We can identify particular pose features used in the classification of grooming, which will contribute to the exploration of turn-taking dynamics on a scale that would otherwise be difficult to attain with traditional methods. Finally, our pipeline can in principle be applied to recognize a variety of other socially interactive behaviors that are largely recognizable by (joint) postural states.

Nonhuman animal models continue to be indispensable in neuroscience research for the foreseeable future. In recent years, animal‐right activists have been increasing the pressure on politicians and policymakers to phase out animal research. To address this pressure, we should adapt our communication habits, to be more open and transparent about (our) animal research and most importantly to expand the methods we use to communicate about our research and increase the extend of this outreach. In this editorial, we discuss the why and how of animal research communication. [ABSTRACT FROM AUTHOR]

Facial expressions are essential in animal communication, and facial expression-based pain scales have been developed for different species. Automated pain recognition offers a valid alternative to manual annotation with growing evidence across species. This study applied machine learning (ML) methods, using a pre-trained VGG-16 base and a Support Vector Machine classifier to automate pain recognition in caprine patients in hospital settings, evaluating different frame extraction rates and validation techniques. The study included goats of different breed, age, sex, and varying medical conditions presented to the University of Florida's Large Animal Hospital. Painful status was determined using the UNESP-Botucatu Goat Acute Pain Scale. The final dataset comprised images from 40 goats (20 painful, 20 non-painful), with 2,253 'non-painful' and 3,154 'painful' images at 1 frame per second (FPS) extraction rate and 7,630 'non-painful' and 9,071 'painful' images at 3 FPS. Images were used to train deep learning-based models with different approaches. The model input was raw images, and pain presence was the target attribute (model output). For the single train-test split and 5-fold cross-validation, the models achieved approximately 80% accuracy, while the subject-wise 10-fold cross-validation showed mean accuracies above 60%. These findings suggest ML's potential in goat pain assessment. [ABSTRACT FROM AUTHOR]

Many building blocks of human language can be found within the vocal communication systems of other species, most notably songbirds. One of the most prominent of these building blocks is syntax. While studies of syntax are abundant, a lack of consensus on the definition of syntax in non‐human animal communication studies has led to much debate. Consistent and deliberate use of terminology is needed to facilitate understanding across disciplines. In addition, new terminology may better describe syntactic structure found in vocal signals that are devoid of semantic associations, such as birdsong. Here, we propose two terms to describe the types of syntax commonly found in birdsong: sequential syntax and dialectical syntax. Sequential syntax can be defined as the rules that govern the patterns of sound without regard to semantic meaning. Dialectic syntax can be defined as sequential syntax that is distinct among different populations or groups with behavioral significance for those groups. Taken together, these two terms can describe the type of syntax seen in ornamental signals, such as birdsong. [ABSTRACT FROM AUTHOR]

Auditory streaming underlies a receiver's ability to organize complex mixtures of auditory input into distinct perceptual "streams" that represent different sound sources in the environment. During auditory streaming, sounds produced by the same source are integrated through time into a single, coherent auditory stream that is perceptually segregated from other concurrent sounds. Based on human psychoacoustic studies, one hypothesis regarding auditory streaming is that any sufficiently salient perceptual difference may lead to stream segregation. Here, we used the eastern grey treefrog, Hyla versicolor, to test this hypothesis in the context of vocal communication in a non-human animal. In this system, females choose their mate based on perceiving species-specific features of a male's pulsatile advertisement calls in social environments (choruses) characterized by mixtures of overlapping vocalizations. We employed an experimental paradigm from human psychoacoustics to design interleaved pulsatile sequences (ABAB...) that mimicked key features of the species' advertisement call, and in which alternating pulses differed in pulse rise time, which is a robust species recognition cue in eastern grey treefrogs. Using phonotaxis assays, we found no evidence that perceptually salient differences in pulse rise time promoted the segregation of interleaved pulse sequences into distinct auditory streams. These results do not support the hypothesis that any perceptually salient acoustic difference can be exploited as a cue for stream segregation in all species. We discuss these findings in the context of cues used for species recognition and auditory streaming. [ABSTRACT FROM AUTHOR]

Animal communicators worldwide employ intuitive interspecies communication (IIC) to engage in detailed, two-way communication with nonhuman animals. IIC's potential for doing research with rather than on animals has been insufficiently explored, due to contingent onto-epistemological biases. Cooperating with animal communicators as interpreters, pilot interviews with felines were conducted. Challenges included clearly filtering the animals' voices and bridging ontological divides and communication modes. Nevertheless, the interviews produced clear, distinct, and consistent responses, challenging and confronting both animal communicators and the researcher to reflect on their perspectives, expectations and assumptions. Engaging animals as research participants through IIC simultaneously unsettles hierarchical divides between humans and other animals, as well as between different ways of knowing. IIC can support researchers and (non)human participants in the co-creation of novel methodological multispecies strategies that form a practical counterpart to the largely theoretical explorations of the ontological and species turns, and further multivocality in academia. [ABSTRACT FROM AUTHOR]

Animal signals are dynamic traits that can undergo considerable spatial and temporal changes and that are influenced by factors such as age, health condition and interactions with both the abiotic and biotic environment. However, much of our understanding of signal changes throughout an individual's lifetime stems from cross‐sectional, often laboratory‐based, studies focused on visual and auditory signals. Longitudinal field investigations of temporal variation in chemical signals, especially in vertebrates, remain rare despite chemical communication being the most ubiquitous form of information exchange in the natural world. To remedy this, we conducted a unique, replicated field experiment to study the temporal signal dynamics in free‐living lizard populations on natural islands. Specifically, we collected scent marks from individually marked lizards across five populations during the spring of two consecutive years and analysed the lipophilic chemical composition of these scent marks. Our findings demonstrate that the overall scent mark composition of individual lizards changed over time, shifting consistently in both direction and magnitude from year to year among individuals and across replicate populations. Similar patterns were observed for the chemical richness and diversity of scent marks. Temporal variation in the relative proportions of three potentially socially relevant signalling compounds in lizard scent marks revealed a more complex pattern: α‐tocopherol remained stable over time, oleic acid decreased and the change in octadecanoic acid proportion was body size‐dependent. Together, our results provide novel insights into how individual vertebrate chemical signals may fluctuate across space and time. We discuss the potential causes of the observed temporal variability and its consequences for chemical signal evolution. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

ABSTRACT Recent years have seen a dramatic rise in the use of passive acoustic monitoring (PAM) for biological and ecological applications, and a corresponding increase in the volume of data generated. However, data sets are often becoming so sizable that analysing them manually is increasingly burdensome and unrealistic. Fortunately, we have also seen a corresponding rise in computing power and the capability of machine learning algorithms, which offer the possibility of performing some of the analysis required for PAM automatically. Nonetheless, the field of automatic detection of acoustic events is still in its infancy in biology and ecology. In this review, we examine the trends in bioacoustic PAM applications, and their implications for the burgeoning amount of data that needs to be analysed. We explore the different methods of machine learning and other tools for scanning, analysing, and extracting acoustic events automatically from large volumes of recordings. We then provide a step‐by‐step practical guide for using automatic detection in bioacoustics. One of the biggest challenges for the greater use of automatic detection in bioacoustics is that there is often a gulf in expertise between the biological sciences and the field of machine learning and computer science. Therefore, this review first presents an overview of the requirements for automatic detection in bioacoustics, intended to familiarise those from a computer science background with the needs of the bioacoustics community, followed by an introduction to the key elements of machine learning and artificial intelligence that a biologist needs to understand to incorporate automatic detection into their research. We then provide a practical guide to building an automatic detection pipeline for bioacoustic data, and conclude with a discussion of possible future directions in this field. [ABSTRACT FROM AUTHOR]

Language is unbounded in its generativity, enabling the flexible combination of words into novel sentences. Critically, these constructions are intelligible to others due to our ability to derive a sentence's compositional meaning from the semantic relationships among its components. Some animals also concatenate meaningful calls into compositional-like combinations to communicate more complex information. However, these combinations are structurally highly stereotyped, suggesting a bounded system of holistically perceived signals that impedes the processing of novel variants. Using long-term data and playback experiments on pied babblers, we demonstrate that, despite production stereotypy, they can nevertheless process structurally modified and novel combinations of their calls, demonstrating a capacity for deriving meaning compositionally. Furthermore, differential responses to artificial combinations by fledglings suggest that this compositional sensitivity is acquired ontogenetically. Our findings demonstrate animal combinatorial systems can be flexible at the perceptual level and that such perceptual flexibility may represent a precursor of language-like generativity. [ABSTRACT FROM AUTHOR]

Most organic carbon delivered to the seafloor is degraded within the bioturbated layer. Theory and empirical evidence have shown that organic carbon reactivity relates to the age of a particle. However, due to particle mixing, the age‐depth linear relation induced by sediment accretion is obfuscated. Here we combine a Lagrangian particle tracking model that resolves the age distribution of particles in the bioturbated zone and couple it to age‐dependent organic carbon degradation. Depth profiles for organic carbon concentration, reactivity and degradation rate are presented for sediments receiving low and high reactivity organic carbon in coastal, continental slope and deep‐sea environments. Our results show that a simple first‐order kinetics model suffices for well‐mixed sediments and systems receiving pre‐processed materials. A reactive continuum approach is needed for poorly mixed sediments receiving highly reactive organic carbon and for sediments below the bioturbated layer. Plain Language Summary: Animals inhabiting marine sediments mix particles and impact organic carbon degradation kinetics and degradation rates. Experiments and theory have shown that organic carbon reactivity declines as degradation progresses with time. However, most studies employ a constant reactivity. Here we couple an individual particle mixing model with age‐dependent reactivity and show that a constant reactivity model is adequate for well‐mixed sediments and for sediments receiving organic carbon that has already been degraded elsewhere. An age‐dependent reactivity model is needed for poorly mixed sediments receiving highly reactive organic carbon. Key Points: Age‐dependent organic carbon kinetics is coupled to a Lagrangian particle tracking modelOrganic carbon concentrations, reactivities and degradation rates in the bioturbated zone are presentedA simple first‐order (one‐G) model suffices for well‐mixed sediments and sediments receiving pre‐processed organic carbon [ABSTRACT FROM AUTHOR]

Machine learning approaches for pattern recognition are increasingly popular. However, the underlying algorithms are often not open source, may require substantial data for model training, and are not geared toward specific tasks. We used open-source software to build a green toad breeding call detection algorithm that will aid in field data analysis. We provide instructions on how to reproduce our approach for other animal sounds and research questions. Our approach using 34 green toad call sequences and 166 audio files without green toad sounds had an accuracy of 0.99 when split into training (70%) and testing (30%) datasets. The final algorithm was applied to amphibian sounds newly collected by citizen scientists. Our function used three categories: "Green toad(s) detected", "No green toad(s) detected", and "Double check". Ninety percent of files containing green toad calls were classified as "Green toad(s) detected", and the remaining 10% as "Double check". Eighty-nine percent of files not containing green toad calls were classified as "No green toad(s) detected", and the remaining 11% as "Double check". Hence, none of the files were classified in the wrong category. We conclude that it is feasible for researchers to build their own efficient pattern recognition algorithm. [ABSTRACT FROM AUTHOR]

The study of how animals adapt their behaviors depending on weather variables has gained particular significance in the context of climate change. This exploration offers insights into endangered species' potential threats and provides information on the direction to take in conservation activities. In this context, noninvasive, cost‐effective, and potentially long‐term monitoring systems, such as Passive Acoustic Monitoring (PAM), become particularly appropriate. Our study investigates the relationship between weather variables and the vocal behavior of Indri indri, the sole singing lemur species, within Madagascar's Maromizaha New Protected Area. Using PAM, we explore the factors shaping the vocalization patterns of this primate species in response to some environmental factors in their natural habitat. Analysis of an extensive audio data set collected across different years revealed the differential influence of temperature and precipitation on Indri indri vocal activity. We found that rainfall negatively influenced the emission of the vocalizations while warmer temperatures correlated with a greater emission of songs. The various environmental factors we considered also affected the timing of vocal emissions, showing the same pattern. Furthermore, our study confirms, once again, the strength of PAM as a valuable tool for studying vocal animal communication quickly, giving us information about long‐term behavioral patterns that would be difficult to get in other ways. This research gives us further valuable information about how indris use vocalizations in their environment and how they adjust to environmental changes. Research highlights: Indri indri, the only singing lemur, emits songs daily, a behavior strictly linked to intergroup territory spacing.We explored the influence of weather conditions on indris' songs in the Maromizaha New Protected Area using Passive Acoustic Monitoring (PAM) and an automated detection algorithm.Indris adjusted their singing behavior based on weather conditions: rain and low temperatures are associated with decreased frequency. Rain determined delayed song emission in the morning. This suggests this behavior's plasticity is linked to energetic costs.Our study widens the knowledge of the behavior of an endangered species of nonhuman primates. It also showcases the strength of PAM in the conservation and behavioral study of different species. [ABSTRACT FROM AUTHOR]

This paper provides a comprehensive review of the use of computational bioacoustics as well as signal and speech processing techniques in the analysis of primate vocal communication. We explore the potential implications of machine learning and deep learning methods, from the use of simple supervised algorithms to more recent self‐supervised models, for processing and analyzing large data sets obtained within the emergence of passive acoustic monitoring approaches. In addition, we discuss the importance of automated primate vocalization analysis in tackling essential questions on animal communication and highlighting the role of comparative linguistics in bioacoustic research. We also examine the challenges associated with data collection and annotation and provide insights into potential solutions. Overall, this review paper runs through a set of common or innovative perspectives and applications of machine learning for primate vocal communication analysis and outlines opportunities for future research in this rapidly developing field. Research Highlights: ‐Recent machine learning and deep learning methods provide innovative tools for the study of primate vocal communication.‐Applied to massive acoustic recordings, they offer new perspectives for better identifying and studying primate vocal productions.‐We provide a comprehensive review of established approaches and latest advances in this rapidly evolving field. [ABSTRACT FROM AUTHOR]

Among territorial birds, the number of conspecific neighbours sets the social context of communication. There have been many investigations of vocal behaviour and its important role in territory defense and mate attraction in birds; however, the effect of the density of conspecific neighbours on avian communication has received little attention. In this study, we reviewed the literature on the influence of local density on vocal communication in birds, exploring how the number of conspecific neighbours influences avian vocal behaviour, by conducting a literature review following the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) in two databases: Web of Science and Scopus. We also included additional articles from a more flexible search in Google Scholar. We found 19 studies of birds that included data on vocal behaviour in relation to the number of conspecific neighbours. The majority of these studies (14 of 19) showed that local density influences avian vocal behaviour. Overall, these studies revealed an effect of local density of conspecifics on song rate (expressed as song rate, syllable rate, solo song rate, or singing rate). Other vocal behaviours that were shown to vary with local density included song-type switching, song duration, peak frequency, and song variation. Most studies focused on temperate-zone species where males are the predominant singers. Our results reveal a bias towards the study of male songs in the context of local density, with very few studies on female song; this corresponds with a historical geographical focus on temperate birds. We present experimental design suggestions for future investigations, including predictions for males and females of tropical and temperate species. Finally, we argue that more research on this topic is needed, and that investigations of vocal communication will benefit from further study of the influence of density on avian vocal behaviour. [ABSTRACT FROM AUTHOR]

Species recognition can be interpreted as the identification of sexual compatibility among individuals, which is related to the assessment of partner quality. This compatibility can be assessed using visual signals of conspecifics such as body coloration. Fiddler crabs constitute a group with a global distribution, comprising over 100 species with diverse colours. They perceive these body colours and use them for intersexual communication, primarily through signalling of the hypertrophied claw of males. However, few species have been investigated regarding the role of body coloration as a species-specific signal, and it remains unknown whether other body regions, such as the carapace, convey information about individual quality or species identity. Hence, this study aimed to examine whether carapace coloration of two sympatric fiddler crab species (Leptuca leptodactyla and Leptuca cumulanta) affects species recognition. To do this, we used individual females of L. leptodactyla that were subjected to a binomial choice of males with claws and carapaces reflecting different colours, simulating conspecifics (L. leptodactyla) or heterospecifics (L. cumulanta). We observed that females were unable to distinguish conspecifics from heterospecifics using only claw colour. On the other hand, we discovered that the white carapace coloration of L. leptodactyla was crucial for females to identify conspecific males. This is the first study to demonstrate that carapace coloration of male fiddler crabs functions in species recognition, reinforcing the idea that body traits beyond sexual ornaments can influence animal communication, affecting species identity and/or mate selection. • We examined whether Leptuca fiddler crabs use male body colour in species recognition. • Females chose males based solely on carapace colour. • Female L. laptodactyla chose L. cumulanta males with white painted carapaces. • Claw colour did not play a crucial role in interspecific recognition. [ABSTRACT FROM AUTHOR]

Living organisms throughout the animal kingdom habitually communicate with multi-modal signals that use multiple sensory channels. Such composite signals vary in their communicative function, as well as the extent to which they are recombined freely. Humans typically display complex forms of multi-modal communication, yet the evolution of this capacity remains unknown. One of our two closest living relatives, chimpanzees, also produce multi-modal combinations and therefore may offer a valuable window into the evolutionary roots of human communication. However, a currently neglected step in describing multi-modal systems is to disentangle non-random combinations from those that occur simply by chance. Here we aimed to provide a systematic quantification of communicative behaviour in our closest living relatives, describing non-random combinations produced across auditory and visual modalities. Through recording the behaviour of wild chimpanzees from the Kibale forest, Uganda we generated the first repertoire of non-random combined vocal and visual components. Using collocation analysis, we identified more than 100 vocal-visual combinations which occurred more frequently than expected by chance. We also probed how multi-modal production varied in the population, finding no differences in the number of visual components produced with vocalisations as a function of age, sex or rank. As expected, chimpanzees produced more visual components alongside vocalizations during longer vocalization bouts, however, this was only the case for some vocalization types, not others. We demonstrate that chimpanzees produce a vast array of combined vocal and visual components, exhibiting a hitherto underappreciated level of multi-modal complexity. Significance: In humans and non-humans, acoustic communicative signals are typically accompanied by visual information. Such "multi-modal communication" has been argued to function for increasing redundancy as well as for creating new meaning. However, a currently neglected step when describing multi-modal systems and their functions is to disentangle non-random combinations from those that occur simply by chance. These data are essential to providing a faithful illustration of a species' multi-modal communicative behaviour. Through recording the behaviour of wild chimpanzees from the Kibale forest, Uganda we aimed to bridge this gap in understanding and generated the first repertoire of non-random combined vocal and visual components in animals. Our data suggest chimpanzees combine many components flexibly and these results have important implications for our understanding of the complexity of multi-modal communication already existing in the last common ancestor of humans and chimpanzees. [ABSTRACT FROM AUTHOR]

Simple Summary: This research looked at how sheep farmers and industry actors in the UK understand, think about, and define "positive animal welfare". It, therefore, involved interviewing farmers and industry experts, including veterinarians and advisors. The study found that how the farmers (n = 25) and industry actors (n = 11) perceived and viewed what positive animal welfare is differed from those perceptions held by scientists. Some of the study participants linked positive welfare to "positive stockmanship" and "good animal welfare" frames, while others proposed broader ideas and meanings, linked to existing scientific positive welfare definitions, including considering "high welfare" states and "happy, healthy" dimensions. Overall, the findings suggested that scientists should work closely with farmers and industry actors to bridge the gap between academic discourse and perceived meanings held by the farmers and by the industry, to develop practical and effective methods for understand how stakeholders define this concept, and the adoption of positive animal welfare approaches and practices. This research examines how sheep farmers and industry actors in the United Kingdom (UK) understand and conceptualize what animal welfare scientists term 'positive animal welfare'. It explores their awareness of the concept, and how they interpret it using a qualitative approach. Participants were recruited using a snowballing, purposive sample approach, resulting in 25 sheep farmers and 11 industry actors (veterinarians, farming organizations, advisors, and supply chain) being interviewed. To collect data, a combined approach involving semi-structured interviews and a facilitated workshop were used between April 2021 and March 2022. Data were then thematically analyzed using a hybrid of inductive and deductive coding process. The findings suggested that the perceptions of farmers and industry actors in the study regarding positive welfare differ from contemporary academic discourses. Overall, around 7 of the farmers equated positive welfare with "positive stockmanship", while six of them expressed "good animal welfare" definitions associated with the Five Freedoms. In contrast, most industry actors (6) expressed interpretations associated with high welfare standards (going above minimum recommended practices) and positive mental experiences (3). Emerging discourses revealed the link between self-identity, social identity and what positive welfare is, the importance of knowledge exchange, and the need for practical indicators through language rephrasing. There is a clear need to enhance and improve knowledge dissemination strategies, particularly in the UK, where much research is being conducted on positive animal welfare. [ABSTRACT FROM AUTHOR]

Assortative or disassortative aggression – when individuals display more aggression towards conspecifics with similar or different phenotypic characteristics – can either maintain polymorphisms or facilitate gene flow between populations depending on which direction the aggression is aimed. Deciphering which factors elicit or prevent aggression is crucial to improving our knowledge of the origin and maintenance of reproductive barriers and subsequent speciation. The Peruvian mimic poison frog, Ranitomeya imitator, is a monogamous and territorial species that has evolved into four distinct color-pattern morphs in a mimetic radiation. Here we use historical landscape genetic data and competition trials between male individuals sourced from different populations and color-pattern morphs to show that the level of aggression between individuals is not associated with color morph or body size but rather with source population. Individuals spent more time in combat with individuals from their own deme (genetically homogeneous population), irrespective of color morph or size. These findings indicate that genotypic similarity is correlated with increased aggression in R. imitator, though the mechanism by which R. imitator males identify conspecifics as territorial threats remains unclear. As body size and color morph were not significantly associated with aggression levels, this study emphasizes the necessity of further research to identify whether other phenotypic traits are influencing territorial behavior between male frogs, and if these factors play a role in increasing gene flow, or conversely, the formation of reproductive barriers between populations. [ABSTRACT FROM AUTHOR]

Male frogs court females from within crowded choruses, selecting for mechanisms allowing them to call at favourable times relative to the calls of rivals and background chorus noise. To accomplish this, males must continuously evaluate the fluctuating acoustic scene generated by their competitors for opportune times to call. Túngara frogs produce highly frequency- and amplitude-modulated calls from within dense choruses. We used similarly frequency- and amplitude-modulated playback tones to investigate the sensory basis of their call-timing decisions. Results revealed that different frequencies present throughout this species' call differed in their degree of call inhibition, and that lower-amplitude tones were less inhibitory. Call-timing decisions were then driven by fluctuations in inhibition arising from underlying frequency- and amplitude-modulation patterns, with tone transitions that produced steeper decreases in inhibition having higher probabilities of triggering calls. Interactions between the varied behavioural sensitivities to different conspecific call frequencies revealed here, and the stereotyped amplitude- and frequency-modulation patterns present in this species' calls, can explain previously surprising patterns observed in túngara frog choruses. This highlights the importance of understanding the specific sensory drivers underpinning conspecific signalling interactions, and reveals how sensory systems can mediate the interplay between signal perception and production to facilitate adaptive communication strategies. [ABSTRACT FROM AUTHOR]

ABSTRACT Colorful traits play an important role in animal communication. Melanin‐based colorations are the most extended color traits in animals and are produced by two types of endogenous melanic pigments: eumelanins and pheomelanins, the last ones being the least studied in the context of communication. The production of pheomelanin requires a semi‐essential amino acid, cysteine, which is also used for the synthesis of an important endogenous antioxidant, glutathione. Hence, it has been proposed that the synthesis of pheomelanin and glutathione may compete for the cysteine available in the organism. In that case, pheomelanic colorations are predicted to be less intense when the individual is facing an oxidative challenge, and therefore, they would provide information on the oxidative status of the bearer. Here, we experimentally evaluated this hypothesis using male Japanese quails (Coturnix japonica) as a model of study, a species with pheomelanin‐based plumage in the breast and cheeks. During feather growth, individuals were exposed to one of three possible conditions: Control (saline), an endogenous oxidative challenge (Escherichia coli lipopolysaccharide injections), or an exogenous oxidative challenge (paraquat injections). Contrary to predictions, we found that: (1) Birds from the three groups exhibited less intense pheomelanic colorations in feathers after the experimental manipulation, and the magnitude of this change did not differ among groups. (2) There was no effect of the experimental treatments on the proportion reduced/oxidized glutathione, an index of oxidative status. (3) Lipid peroxidation was lower after the experimental manipulation, with birds exposed to the paraquat challenge experiencing a stronger decline than other groups. (4) Cysteine and total glutathione levels decreased after the experimental manipulation, with no differences per group in the magnitude of the decline. Taken together the results do not support the hypothesis that oxidative status plays a key role at determining the variation in the intensity of pheomelanic colorations. [ABSTRACT FROM AUTHOR]

Both the concept of NATIVE SPEAKER/SIGNER and the term itself have been widely critiqued across fields of language research. However, this term is still often used uncritically by linguists, with some disciplines centering the behavior and knowledge of NATIVE SPEAKERS as the main object of inquiry. We argue that the term NATIVE SPEAKER/SIGNER should not be treated as an objective analytic category. Instead, it is a LANGUAGE-IDEOLOGICAL ASSEMBLAGE, a cluster of related language ideologies that assume essentialized relationships between linguistic practices and social identities. By valorizing normative modes of language learning and use, NATIVENESS excludes already marginalized language users. Rather than simply avoiding the term or replacing it, we argue that linguists must interrogate the role of this concept and its associated theoretical baggage. We anticipate that moving away from NATIVENESS and the ideas surrounding it will encourage linguists to account for the diverse linguistic repertoires held by all language users, force theoretical approaches to center nonnormative language use, and lead overall to a more accurate and just discipline. [ABSTRACT FROM AUTHOR]

This document is a response to critics of the book "The Birth of Ethics." The author acknowledges the quality of the critiques and responds to the criticisms raised by Adam Lerner regarding natural properties in moral concepts, moral realism, and why individuals should be moral. The author argues that despite differences in perspectives, there can still be a procedural understanding of multi-lateral desirability that allows for convergence on certain moral issues. The text also discusses the question of why individuals should behave morally and act in accordance with their own moral values, emphasizing the importance of maintaining integrity and fostering mutual reliance. The author clarifies their argument about Erewhonian ethical concepts and addresses other points raised by M&P, including the relationship between genealogy and the functionalist account of ethical concepts. The text explores moral functionalism, counterfactual genealogy, and the concept of genealogy itself. The author engages with critiques and emphasizes the need for speculative accuracy in genealogical analysis, while also introducing the idea of a creature-construction account. [Extracted from the article]

Reactive oxygen species (ROS) play a crucial role as signaling molecules in both plant and animal cells, enabling rapid responses to various stimuli. Among the many cellular mechanisms used to generate and transduce ROS signals, ROS-induced-ROS release (RIRR) is emerging as an important pathway involved in the responses of various multicellular and unicellular organisms to environmental stresses. In RIRR, one cellular compartment, organelle, or cell generates or releases ROS, triggering an increased ROS production and release by another compartment, organelle, or cell, thereby giving rise to a fast propagating ROS wave. This RIRR-based signal relay has been demonstrated to facilitate mitochondria-to-mitochondria communication in animal cells and long-distance systemic signaling in plants in response to biotic and abiotic stresses. More recently, it has been discovered that different unicellular microorganism communities also exhibit a RIRR cell-to-cell signaling process triggered by a localized stress treatment. However, the precise mechanism underlying the propagation of the ROS signal among cells within these unicellular communities remained elusive. In this study, we employed a reaction-diffusion model incorporating the RIRR mechanism to analyze the propagation of ROS-mediated signals. By effectively balancing production and scavenging processes, our model successfully reproduces the experimental ROS signal velocities observed in unicellular green algae (Chlamydomonas reinhardtii) colonies grown on agar plates, furthering our understanding of intercellular ROS communication. [Display omitted] [ABSTRACT FROM AUTHOR]

Fiddler crabs have been used as model organisms in many laboratory and field studies. In their natural environment, social interaction with other fiddler crabs (conspecific or heterospecific) is recurrent, but manipulative studies involving these crabs as models are often performed with isolated individuals. The isolation of an animal can interfere in the behaviors recorded as response variables. Thus, the aim of this study was to evaluate whether the presence of other individuals affects the performance of behaviors of fiddler crabs Leptuca uruguayensis. We tested two hypotheses in the field: (1) the visual stimulus of the crab assemblage affects the activity of male fiddler crabs; and (2) the presence of other conspecific affects the activity of male fiddler crabs depending on the sexes of the individuals present. We found the activities of L. uruguayensis males mediated by social interactions does not depend exclusively on visual stimuli. Physical interaction with other conspecifics of both sexes enables the perception of stimuli which can influence the waving behavior of L. uruguayensis males. We suggest that behavioral studies with this model should consider the presence of other individuals. Understanding the behavioral complexity of a model organism contributes to more robust experiments with greater control of interfering variables. [ABSTRACT FROM AUTHOR]

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Copyright of Cuadernos del Centro de Estudios de Diseño y Comunicación is the property of Cuadernos del Centro de Estudios de Diseno y Comunicacion and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Color signals which mediate behavioral interactions across taxa and contexts are often thought of as color 'patches' - parts of an animal that appear colorful compared to other parts of that animal. Color patches, however, cannot be considered in isolation because how a color is perceived depends on its visual background. This is of special relevance to the function and evolution of signals because backgrounds give rise to a fundamental tradeoff between color signal detectability and discriminability: as its contrast with the background increases, a color patch becomes more detectable, but discriminating variation in that color becomes more difficult. Thus, the signal function of color patches can only be fully understood by considering patch and background together as an integrated whole.

Simple Summary: Our research focuses on the franciscana dolphin, the most threatened dolphin in the southwestern Atlantic, mainly due to its frequent entanglement in artisanal gillnets. This has led to their classification as vulnerable. To better understand their sounds and communication, we recorded and analysed the sounds of both wild dolphins and those in a rehabilitation centre. We found that neonate dolphins emit sounds that differ from those of juveniles. Interestingly, the sounds made by juvenile dolphins are similar to those of wild dolphins. We also discovered patterns in the way dolphins produce clicks, sounds which are important for feeding and communication. Our findings highlight the need to protect calf dolphins and suggest that it might be possible to create tools to identify dolphins by their age, based on their sounds. This research is important for conservation efforts and could help in creating better protection strategies for these dolphins. The franciscana dolphin is a small, vulnerable species often caught in artisanal gillnets. This study aims to provide a comprehensive assessment of their acoustic capabilities by using advanced equipment to collect a large dataset of wideband, continuous recordings. We examined the detailed acoustic signals of franciscana dolphins, comparing the sounds from rehabilitated dolphins in captivity with those of wild dolphins near fishing nets. Significant differences in acoustic characteristics were found between neonates and older dolphins, with juvenile and wild dolphins showing similar features. For the first time, repetition patterns in click production were identified, highlighting the importance of understanding the context of these sounds in regards to feeding and communication. This study emphasizes the need for detecting neonates for species protection and suggests the potential for developing acoustic classifiers specific to different age groups. Our findings offer valuable insights for conservation efforts and the development of protection strategies for franciscana dolphins. [ABSTRACT FROM AUTHOR]

Our understanding of bird song, a model system for animal communication and the neurobiology of learning, depends critically on making reliable, validated comparisons between the complex multidimensional syllables that are used in songs. However, most assessments of song similarity are based on human inspection of spectrograms, or computational methods developed from human intuitions. Using a novel automated operant conditioning system, we collected a large corpus of zebra finches' (Taeniopygia guttata) decisions about song syllable similarity. We use this dataset to compare and externally validate similarity algorithms in widely-used publicly available software (Raven, Sound Analysis Pro, Luscinia). Although these methods all perform better than chance, they do not closely emulate the avian assessments. We then introduce a novel deep learning method that can produce perceptual similarity judgements trained on such avian decisions. We find that this new method outperforms the established methods in accuracy and more closely approaches the avian assessments. Inconsistent (hence ambiguous) decisions are a common occurrence in animal behavioural data; we show that a modification of the deep learning training that accommodates these leads to the strongest performance. We argue this approach is the best way to validate methods to compare song similarity, that our dataset can be used to validate novel methods, and that the general approach can easily be extended to other species. Author summary: How do birds hear the differences between their songs? This fascinating question carries implications, since the study of bird song, a model system for the neurobiology of learning and animal communication, depends critically on our ability to assess the similarity of songs. Traditionally, researchers compare sounds by human assessment, or use computational methods based on human intuitions about similarity. However, neither approach is connected to birds' own perception of sound similarity. Here, using a novel automated operant conditioning system, we recorded many thousands of acoustic judgments of similarity from zebra finches, and used this perceptual decision data for the first time to train a deep learning system. The trained system outperforms other computational methods for the task of making the same judgments as birds. This algorithm to compare song similarity, together with the potential of extending the general approach to other species, places the study of bird song on a firmer footing. [ABSTRACT FROM AUTHOR]

The increasing expansion of urban areas leads to the emergence of new noisy environments that can affect animal communication. Calls play a crucial role in the mating displays of anurans, and the negative impact of anthropogenic noise-induced auditory masking has been reported in several species. We investigated the acoustic variation in 96 males (n =  971 calls) of the treefrog Boana pulchella across acoustically undisturbed sites and different noise conditions, associated with urban areas (URBAN) and roads (ROAD), in Central Argentina. We analyzed the effect of anthropogenic noise conditions on 6 temporal (call duration [CD], intercall interval, first and second note duration, internote interval, and call rate) and 3 spectral (dominant frequency of first and second note, frequency difference between them) call properties. The effects of temperature and size on acoustical variables were controlled. We observed differences in all call attributes among the noise conditions, except for intercall interval. Males exposed to URBAN and ROAD exhibited significant changes in CD, dominant frequency of the second note, and frequency difference between them. URBAN males had longest internote interval, while ROAD individuals displayed increased first and second note duration and call rates. Interestingly, ROAD males exhibited immediate changes in call rate in direct response to passing heavy vehicles. Our study emphasizes the impact of anthropogenic noise on the acoustic characteristics of B. pulchella calls. Understanding how animals adapt to noisy environments is crucial in mitigating the adverse effects of urbanization on their communication systems. Future investigations should explore whether the observed call adjustments are effective in avoiding or mitigating the negative consequences of anthropogenic noise on reproductive success. [ABSTRACT FROM AUTHOR]

Anurans have several characteristics in their acoustic communication that distinguish them. These characteristics are influenced by body-related, environmental and social variables. However, the complexity of anuran repertoire and the effect of such variables on it are still understudied. Dendropsophus minutus is a Neotropical treefrog that has a wide repertoire composed of three notes, grouped in at least 71 unique combinations. To quantify complexity, we used the entropy measurement, since it measures the randomness of a sequence. Therefore, we could test if repertoire complexity in D. minutus is related with body condition, social context, and environmental variables. We recorded vocalisations of 80 males in three sites and found 44 unique note combinations not described before, increasing the species' repertoire to 115 combinations. We observed that the species has near maximum entropy for note frequency, but a low entropy for note sequencies, showing a clear a bias for some note combinations. We found a positive relationship between repertoire complexity and air temperature. Thus, based on our results, the complexity of this species' repertoire is an additional trait influenced by climate, and should be considered in future studies. [ABSTRACT FROM AUTHOR]

Acoustic communication in animals can be affected by multiple biotic (intra and interspecific) and abiotic (e.g., wind and rain) natural noises. In addition, human beings produce additional novel sources of noise, which can reduce or inhibit the reception of acoustic signals by conspecifics, leading to behavioral changes. In this study, we investigated whether sound of conspecifics and road noise additively affect the acoustic parameters of the advertisement call of males of a Yellow Heart‐tongued Frog (Phyllodytes luteolus). We hypothesized that males that vocalize in choruses (males calling nearby) and in areas close to highways (anthropic noise) will increase their temporal and spectral acoustic parameters, respectively, to avoid acoustic signal masking. We recorded the vocalizations of 38 males in environments close (N = 18) to and distant (N = 20) from highways in different social contexts (many or few individuals calling nearby). Contrary to our expectation, the results indicated that males calling in areas close to highways had lower dominant frequency calls than those from natural areas (far from highways), and that the density of males in the chorus had no influence on the acoustic parameters. Furthermore, we found a positive relationship between body size and intensity, indicating that larger individuals can emit calls that can reach greater distances. The advertisement call of Phyllodytes luteolus has a high dominant frequency, with little overlap with the frequency of anthropic noises (roads), which may explain its presence and reproductive success of this species in bromeliads from urbanized areas. [ABSTRACT FROM AUTHOR]

Studying ultrasonic vocalizations (USVs) plays a crucial role in understanding animal communication, particularly in the field of ethology and neuropharmacology. Communication is associated with social behaviour; so, USVs study is a valid assay in behavioural readout and monitoring in this context. This paper delved into an investigation of ultrasonic communication in mice treated with Cannabis sativa oil (CS mice), which has been demonstrated having a prosocial effect on behaviour of mice, versus control mice (vehicle‐treated, VH mice). To conduct this study, we created a dataset by recording audio‐video files and annotating the duration of time that test mice spent engaging in social activities, along with categorizing the types of emitted USVs. The analysis encompassed the frequency of individual sounds as well as more complex sequences of consecutive syllables (patterns). The primary goal was to examine the extent and nature of diversity in ultrasonic communication patterns emitted by these two groups of mice. As a result, we observed statistically significant differences for each considered pattern length between the two groups of mice. Additionally, the study extended its research by considering specific behaviours, aiming to ascertain whether dissimilarities in ultrasonic communication between CS and VH mice are more pronounced or subtle within distinct behavioural contexts. Our findings suggest that while there is variation in USV communication between the two groups of mice, the degree of this diversity may vary depending on the specific behaviour being observed. [ABSTRACT FROM AUTHOR]

Despite the great diversity of Brazilian anuran species, there are still many knowledge gaps about the acoustic communication of these animals. Among the species, those classified as 'Data Deficient' have the greatest gaps in knowledge on their behavior. This is the case of Boana ericae, a species belonging to the Boana pulchella group, endemic to the Chapada dos Veadeiros National Park region, in the northeast of the state of Goiás, Central Brazil. Three distinct call types (A, B, and C) are currently known for B. ericae, with the type A call associated with attracting reproductive partners and the type C call presenting a territorial function. We recorded the vocalizations of 10 individuals of this species and found the presence of vocalizations composing three new note types (D, E, and F). Our results indicate that air temperature and body condition influenced the acoustic parameters of the advertisement and aggressive calls of this species. We also observed that some acoustic parameters of the advertisement calls can be used for individual recognition for showing greater variation among individuals than intra-individually. Our results add new information regarding the vocal repertoire in this species, expanding their known intra-individual classification of the acoustic parameters. [ABSTRACT FROM AUTHOR]

Simple Summary: Canine behavioral disorders have become one of the most common concerns and challenging issues among dog owners. Therefore, to face this challenge, searching for novel therapeutic methods is highly required. Accumulated data show that mammals' gut microbiome, immune system, and nervous system are in continuous communication and influence animal physiology and behavior. This review aimed to summarize and discuss the most important scientific pieces of evidence on the relationship between mental disorders and gut microbiota in dogs, simultaneously presenting comparable outcomes in humans and rodent models. A comprehensive overview of crucial mechanisms of the gut–brain axis is included. Additionally, the possible effects of the fecal microbiome transplantation procedure as a new tool to manipulate gut microbiota are discussed. Canine behavioral disorders have become one of the most common concerns and challenging issues among dog owners. Thus, there is a great demand for knowledge about various factors affecting dogs' emotions and well-being. Among them, the gut–brain axis seems to be particularly interesting, especially since in many instances the standard treatment or behavioral therapies insufficiently improve animal behavior. Therefore, to face this challenge, the search for novel therapeutic methods is highly required. Existing data show that mammals' gut microbiome, immune system, and nervous system are in continuous communication and influence animal physiology and behavior. This review aimed to summarize and discuss the most important scientific evidence on the relationship between mental disorders and gut microbiota in dogs, simultaneously presenting comparable outcomes in humans and rodent models. A comprehensive overview of crucial mechanisms of the gut–brain axis is included. This refers especially to the neurotransmitters crucial for animal behavior, which are regulated by the gut microbiome, and to the main microbial metabolites—short-chain fatty acids (SCFAs). This review presents summarized data on gut dysbiosis in relation to the inflammation process within the organism, as well as the activation of the hypothalamic–pituitary–adrenal (HPA) axis. All of the above mechanisms are presented in this review in strict correlation with brain and/or behavioral changes in the animal. Additionally, according to human and laboratory animal studies, the gut microbiome appears to be altered in individuals with mental disorders; thus, various strategies to manipulate the gut microbiota are implemented. This refers also to the fecal microbiome transplantation (FMT) method, based on transferring the fecal matter from a donor into the gastrointestinal tract of a recipient in order to modulate the gut microbiota. In this review, the possible effects of the FMT procedure on animal behavioral disorders are discussed. [ABSTRACT FROM AUTHOR]

Animal communication is frequently studied with conventional network representations that link pairs of individuals who interact, for example, through vocalization. However, acoustic signals often have multiple simultaneous receivers, or receivers integrate information from multiple signallers, meaning these interactions are not dyadic. Additionally, non-dyadic social structures often shape an individual's behavioural response to vocal communication. Recently, major advances have been made in the study of these non-dyadic, higher-order networks (e.g. hypergraphs and simplicial complexes). Here, we show how these approaches can provide new insights into vocal communication through three case studies that illustrate how higher-order network models can: (i) alter predictions made about the outcome of vocally coordinated group departures; (ii) generate different patterns of song synchronization from models that only include dyadic interactions; and (iii) inform models of cultural evolution of vocal communication. Together, our examples highlight the potential power of higher-order networks to study animal vocal communication. We then build on our case studies to identify key challenges in applying higher-order network approaches in this context and outline important research questions that these techniques could help answer. This article is part of the theme issue 'The power of sound: unravelling how acoustic communication shapes group dynamics'. [ABSTRACT FROM AUTHOR]

Animal vocal communication research traditionally focuses on acoustic and contextual features of calls, yet substantial information is also contained in response selectivity and timing during vocalization events. By examining the spatiotemporal structure of vocal interactions, we can distinguish between 'broadcast' and 'exchange' signalling modes, with the former potentially serving to transmit signallers' general state and the latter reflecting more interactive signalling behaviour. Here, we tracked the movements and vocalizations of wild meerkat (Suricata suricatta) groups simultaneously using collars to explore this distinction. We found evidence that close calls (used for maintaining group cohesion) are given as signal exchanges. They are typically given in temporally structured call–response sequences and are also strongly affected by the social environment, with individuals calling more when they have more neighbours and juveniles responding more to adults than the reverse. In contrast, short note calls appear mainly in sequences produced by single individuals and show little dependence on social surroundings, suggesting a broadcast signalling mode. Despite these differences, both call categories show similar clustering in space and time at a group level. Our results highlight how the fine-scale structure of vocal interactions can give important insights into the usage and function of signals in social groups. This article is part of the theme issue 'The power of sound: unravelling how acoustic communication shapes group dynamics.' [ABSTRACT FROM AUTHOR]

Communication takes place within a network of multiple signallers and receivers. Social network analysis provides tools to quantify how an individual's social positioning affects group dynamics and the subsequent biological consequences. However, network analysis is rarely applied to animal communication, likely due to the logistical difficulties of monitoring natural communication networks. We generated a simulated communication network to investigate how variation in individual communication behaviours generates network effects, and how this communication network's structure feeds back to affect future signalling interactions. We simulated competitive acoustic signalling interactions among chorusing individuals and varied several parameters related to communication and chorus size to examine their effects on calling output and social connections. Larger choruses had higher noise levels, and this reduced network density and altered the relationships between individual traits and communication network position. Hearing sensitivity interacted with chorus size to affect both individuals' positions in the network and the acoustic output of the chorus. Physical proximity to competitors influenced signalling, but a distinctive communication network structure emerged when signal active space was limited. Our model raises novel predictions about communication networks that could be tested experimentally and identifies aspects of information processing in complex environments that remain to be investigated. This article is part of the theme issue 'The power of sound: unravelling how acoustic communication shapes group dynamics'. [ABSTRACT FROM AUTHOR]

The study of animal sounds in biology and ecology relies heavily upon time–frequency (TF) visualisation, most commonly using the short‐time Fourier transform (STFT) spectrogram. This method, however, has inherent bias towards either temporal or spectral details that can lead to misinterpretation of complex animal sounds. An ideal TF visualisation should accurately convey the structure of the sound in terms of both frequency and time, however, the STFT often cannot meet this requirement. We evaluate the accuracy of four TF visualisation methods (superlet transform [SLT], continuous wavelet transform [CWT] and two STFTs) using a synthetic test signal. We then apply these methods to visualise sounds of the Chagos blue whale, Asian elephant, southern cassowary, eastern whipbird, mulloway fish and the American crocodile. We show that the SLT visualises the test signal with 18.48%–28.08% less error than the other methods. A comparison between our visualisations of animal sounds and their literature descriptions indicates that the STFT's bias may have caused misinterpretations in describing pygmy blue whale songs and elephant rumbles. We suggest that use of the SLT to visualise low‐frequency animal sounds may prevent such misinterpretations. Finally, we employ the SLT to develop 'BASSA', an open‐source, GUI software application that offers a no‐code, user‐friendly tool for analysing short‐duration recordings of low‐frequency animal sounds for the Windows platform. The SLT visualises low‐frequency animal sounds with improved accuracy, in a user‐friendly format, minimising the risk of misinterpretation while requiring less technical expertise than the STFT. Using this method could propel advances in acoustics‐driven studies of animal communication, vocal production methods, phonation and species identification. [ABSTRACT FROM AUTHOR]

For more than 300 years, the rain call of the Common Chaffinch (Fringilla coelebs) has been thought to herald rain—hence the name. However, the biological function of this vocalisation still remains unknown. Because rain calls are produced only by males during the breeding season, it has been suggested that the call serves a territorial function and that it may replace song in adverse situations, such as bad weather. However, it is unclear whether rain calls are linked to precipitation at all. Here, we explored the relationship between the occurrence of rain calls and the weather, based on the hypothesis that rain calls are produced instead of song during rainfall. For that purpose, we conducted three studies on different geographical and temporal scales: a large-scale analysis across Europe (relating 242 audio recordings from the Xeno-Canto archive to weather data) and two observational studies in Germany (one cross-sectional study surveying 509 Chaffinches and one longitudinal study on 49 selected males over a period of two weeks). We found no association between rain calls and rainfall in any of the three datasets (but males tended to produce more rain calls with increasing cloud cover and wind force). However, the occurrence of rain calls varied markedly with the social context, as males were more likely to rain–call in the presence of a female, suggesting a function within the pair bond. Overall, we press for more studies on bird calls, and the rain call (although inappropriately named) appears to be a particularly interesting candidate. [ABSTRACT FROM AUTHOR]

Conventional immunization methods such as intramuscular injections lack effective mucosal protection against pathogens that enter through the mucosal surfaces. Moreover, conventional therapy often leads to adverse events and compromised immunity, followed by complicated outcomes, leading to the need to switch to other options. Thus, a need to develop safe and effective treatment with long-term beneficial outcomes to reduce the risk of relapse is mandatory. Mucosal vaccines administered across mucosal surfaces, such as the respiratory or intestinal mucosa, to prompt robust localized and systemic immune responses to prevent the public from acquiring pathogenic diseases. Mucosal immunity contains a unique immune cell milieu that selectively identify pathogens and limits the transmission and progression of mucosal diseases, such as allergic dermatitis and inflammatory bowel disease (IBD). It also offers protection from localized infection at the site of entry, enables the clearance of pathogens on mucosal surfaces, and leads to the induction of long-term immunity with the ability to shape regulatory responses. Regulatory T (Treg) cells have been a promising strategy to suppress mucosal diseases. To find advances in mucosal treatment, we investigated the therapeutic effects of intranasal pep27 mutant immunization. Nasal immunization protects mucosal surfaces, but nasal antigen presentation appears to entail the need for an adjuvant to stimulate immunogenicity. Here, a novel method is developed to induce Tregs via intranasal immunization without an adjuvant to potentially overcome allergic diseases and gut and lung inflammation using lung–gut axis communication in animal models. The implementation of the pep27 mutant for these therapies should be preceded by studies on Treg resilience through clinical translational studies on dietary changes. [ABSTRACT FROM AUTHOR]

Copyright of Linguistische Berichte is the property of Helmut Buske Verlag Hamburg and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The population sizes of manatees in many regions remain largely unknown, primarily due to the challenging nature of conducting visual counts in turbid and inaccessible aquatic environments. Passive acoustic monitoring has shown promise for monitoring manatees in the wild. In this study, we present an innovative approach that leverages a convolutional neural network (CNN) for the detection, isolation and classification of manatee vocalizations from longterm audio recordings. To improve the effectiveness of manatee call detection and classification, the CNN works in two phases. First, a long-term audio recording is divided into smaller windows of 0.5 seconds and a binary decision is made as to whether or not it contains a manatee call. Subsequently, these vocalizations are classified into distinct vocal classes (4 categories), allowing for the separation and analysis of signature calls (squeaks). Signature calls are further subjected to clustering techniques to distinguish the recorded individuals and estimate the population size. The CNN was trained and validated using audio recordings from three different zoological facilities with varying numbers of manatees. Three different clustering methods (community detection with two different classifiers and HDBSCAN) were tested for their suitability. The results demonstrate the ability of the CNN to accurately detect manatee vocalizations and effectively classify the different call categories. In addition, our study demonstrates the feasibility of reliable population size estimation using HDBSCAN as clustering method. The integration of CNN and clustering methods offers a promising way to assess manatee populations in visually challenging and inaccessible regions using autonomous acoustic recording devices. In addition, the ability to differentiate between call categories will allow for ongoing monitoring of important information such as stress, arousal, and calf presence, which will aid in the conservation and management of manatees in critical habitats. [ABSTRACT FROM AUTHOR]

While rhythm can facilitate and enhance many aspects of behavior, its evolutionary trajectory in vocal communication systems remains enigmatic. We can trace evolutionary processes by investigating rhythmic abilities in different species, but research to date has largely focused on songbirds and primates. We present evidence that cetaceans--whales, dolphins, and porpoises--are a missing piece of the puzzle for understanding why rhythm evolved in vocal communication systems. Cetaceans not only produce rhythmic vocalizations but also exhibit behaviors known or thought to play a role in the evolution of different features of rhythm. These behaviors include vocal learning abilities, advanced breathing control, sexually selected vocal displays, prolonged mother-infant bonds, and behavioral synchronization. The untapped comparative potential of cetaceans is further enhanced by high interspecific diversity, which generates natural ranges of vocal and social complexity for investigating various evolutionary hypotheses. We show that rhythm (particularly isochronous rhythm, when sounds are equally spaced in time) is prevalent in cetacean vocalizations but is used in different contexts by baleen and toothed whales. We also highlight key questions and research areas that will enhance understanding of vocal rhythms across taxa. By coupling an infraorder-level taxonomic assessment of vocal rhythm production with comparisons to other species, we illustrate how broadly comparative research can contribute to a more nuanced understanding of the prevalence, evolution, and possible functions of rhythm in animal communication. [ABSTRACT FROM AUTHOR]