Social call divergence in bats: a comparative analysis

Luo, Bo; Huang, Xiaobin; Li, Yuanyuan; Lu, Guanjun; Zhao, Jianlun; Zhang, Kangkang; Zhao, Hanbo; Liu, Ying; Feng, Jiang

doi:10.1093/beheco/arw184

Cited by 22 publications

(19 citation statements)

References 49 publications

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“…Contact calls may be additionally used to retrieve group mates before foraging (Boughman & Wilkinson, ). Interestingly, recent studies show that encoding signatures for recognition among an increasing number of group members may strongly explain social call structure (Luo et al, ). Individual and/or group signatures in echolocation signals have also been recorded in some species, including the big brown bat (Masters, Raver & Kazial, ), the African large‐eared free‐tailed bat Otomops martiensseni (Fenton et al, ), the greater mouse‐eared bat Myotis myotis (Yovel et al, ), and the greater sac‐winged bat, S. bilineata (Knörnschild et al, ).…”

Section: Why Do Bats Communicate?mentioning

confidence: 99%

Social communication in bats

2018

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Bats represent one of the most diverse mammalian orders, not only in terms of species numbers, but also in their ecology and life histories. Many species are known to use ephemeral and/or unpredictable resources that require substantial investment to find and defend, and also engage in social interactions, thus requiring significant levels of social coordination. To accomplish these tasks, bats must be able to communicate; there is now substantial evidence that demonstrates the complexity of bat communication and the varied ways in which bats solve some of the problems associated with their unique life histories. However, while the study of communication in bats is rapidly growing, it still lags behind other taxa. Here we provide a comprehensive overview of communication in bats, from the reasons why they communicate to the diversity and application of different signal modalities. The most widespread form of communication is the transmission of a signaller's characteristics, such as species identity, sex, individual identity, group membership, social status and body condition, and because many species of bats can rely little on vision due to their nocturnal lifestyles, it is assumed that sound and olfaction are particularly important signalling modes. For example, research suggests that secretions from specialized glands, often in combination with urine and saliva, are responsible for species recognition in several species. These olfactory signals may also convey information about sex and colony membership. Olfaction may be used in combination with sound, particularly in species that emit constant frequency (CF) echolocation calls, to recognize conspecifics from heterospecifics, yet their simple structure and high frequency do not allow much information of individual identity to be conveyed over long distances. By contrast, social calls may encode a larger number of cues of individual identity, and their lower frequencies increase their range of detection. Social calls are also known to deter predators, repel competitors from foraging patches, attract group mates to roost sites, coordinate foraging activities, and are used during courtship. In addition to sound, visual displays such as wing flapping or hovering may be used during courtship, and swarming around roost sites may serve as a visual cue of roost location. However, visual communication in bats still remains a poorly studied signal modality. Finally, the most common form of tactile communication known in bats is social grooming, which may be used to signal reproductive condition, but also to facilitate and strengthen cooperative interactions. Overall, this review demonstrates the rapid advances made in the study of bat social communication during recent years, and also identifies topics that require further study, particularly those that may allow us to understand adaptation to rapidly changing environmental conditions.

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Section: Why Do Bats Communicate?mentioning

confidence: 99%

Social communication in bats

2018

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“…Where dispersal is high, or populations are large, more signal variants will be required to ensure misidentification is rare. Indeed, positive correlations between group size and signal diversity have been reported in bats (Luo et al 2017) and chickadees (Freeberg 2006), and there is evidence that species-level signal variability is linked with coloniality in swallows (Medvin et al 1993). There may be a threshold population size beyond which individual identity signals do not evolve, either because of the difficulties of recognizing large numbers of individuals, or because of group instability (Rohwer 1982).…”

Section: Introductionmentioning

confidence: 99%

Population fragmentation drives up genetic diversity in signals of individual identity

Dytham

Thom

2020

Oikos

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Many species advertise their unique identity to conspecifics using dedicated individuality signals: one familiar example is human faces. But how unique in the global population do these signals need to be? While human faces are highly variable, each person interacts with many fewer individuals than are found in the total population. This raises the question of how evolutionary mechanisms drive up population‐wide diversity when selection occurs at such a local level. We use an individual‐based model in which individuals broadcast their identity and quality in separate, genetically‐coded signals. Mimicking, for example, scent marking mammal species, females in the model assess males using the quality signal, then attempt to relocate the highest quality male using his identity signal. We ask how population fragmentation affects genetic diversity in the individual identity‐signalling region under sexual selection, predicting one of two opposing outcomes: 1) divided populations evolve fewer signal variants globally, since repetition of signals is not costly when individuals interact only with local conspecifics, or 2) stochasticity in mutation and selection cause divergence among subpopulations, increasing the global number of signal variants. We show that local selection drives up global genetic diversity substantially in fragmented populations, even with extremely low rates of dispersal. Because new signal variants arise by mutation and then sweep through their subpopulation, a fragmented population has more global signal variation. This result furthers our understanding of how high levels of diversity in individuality signals are maintained.

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“…Echolocating bats have two vocal repertoires, echolocation calls for orientation and a variety of communication calls for social activities [24][25][26]. Recordings from both eld and laboratory studies indicate that utterances from individual bats often overlap in both time and frequency, which provides an excellent template for research on overlapping sound separation in animals.…”

Section: Introductionmentioning

confidence: 99%

Separating Overlapping Bat Calls with a Bi-directional Long Short-term Memory Network

Zhang

Liu

Song

et al. 2020

Preprint

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Background: Acquiring clear and usable audio recordings is critical for acoustic analysis of animal vocalizations. Bioacoustics studies commonly face the problem of overlapping signals, which can impede the structural identification of vocal units, but the issue is often ignored, as there is currently no satisfactory solution. This study presents a bi-directional long short-term memory (BLSTM) network to separate overlapping bat calls and reconstruct waveforms. The separation quality was evaluated using seven temporal-spectrum parameters. The applicability of this method for bat calls was assessed using six different species. In addition, clustering analysis was conducted with separated echolocation calls from each bat species. Results: All syllables in the overlapping calls were separated with high robustness across species. A comparison between the seven temporal-spectrum parameters showed no significant difference and negligible deviation between the extracted and original calls, indicating high separation quality. Clustering analysis also produced an accuracy of 93.8%, suggesting the reconstructed waveforms could be reliably used. Conclusions: The study extends the application of deep neural network to separate overlapping animal sound. These results suggest the proposed technique is a convenient and automated approach for separating overlapping calls using a BLSTM network. This powerful deep neural network approach has the potential to solve complex problems in bioacoustics.

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Social call divergence in bats: a comparative analysis

Cited by 22 publications

References 49 publications

Social communication in bats

Social communication in bats

Population fragmentation drives up genetic diversity in signals of individual identity

Separating Overlapping Bat Calls with a Bi-directional Long Short-term Memory Network

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