The use of Vocalizations of the Sambirano Mouse Lemur (<Emphasis Type="Italic">Microcebus sambiranensis</Emphasis>) in an Acoustic Survey of Habitat Preference

Primate vocalizations convey a variety of information to conspecifics. The acoustic traits of these vocalizations are an effective vocal fingerprint to discriminate between sibling species for taxonomic diagnosis. However, the vocal behavior of nocturnal primates has been poorly studied and there are few studies of their vocal repertoires. We compiled a vocal repertoire for the Endangered Sambirano mouse lemur, Microcebus sambiranensis, an unstudied nocturnal primate of northwestern Madagascar, and compared the acoustic properties of one of their call types to those of M. murinus and M. rufus. We recorded vocalizations from radio-collared individuals using handheld recorders over 3 months. We also conducted an acoustic survey to measure the vocal activity of M. sambiranensis in four forest habitat types at the study site. We identified and classified five vocalization types in M. sambiranensis. The vocal repertoires of the three Microcebus species contain very similar call types but have different acoustic properties, with one loud call type, the whistle, having significantly different acoustic properties between species. Our acoustic survey detected more calls of M. sambiranensis in secondary forest, riparian forest, and forest edge habitats, suggesting that individuals may prefer these habitat types over primary forest. Our results suggest interspecific differences in the vocal repertoire of mouse lemurs, and that these differences can be used to investigate habitat preference via acoustic surveys.     

Acoustic repertoire of the singing cicada <Emphasis Type="Italic">Cicadetta cantilatrix</Emphasis> Sueur et Puissant, 2007 (Homoptera,Cicadidae) from Russia

The singing cicada Cicadetta cantilatrix Sueur et Puissant, 2007, only recently described from Western Europe, was found in Russia. The acoustic repertoire of this species is studied, oscillograms and sonograms of the signals emitted by individuals from the south of Moscow Province are provided for the first time.     

Repeated decrease in vocal repertoire size in Streptopelia doves

Most bird species produce different acoustic signals in different behavioural contexts. This intraspecific variation in signal types is thought to be the result of selection for optimal communication in each context. Doves in the genus Streptopelia have three distinct behavioural contexts in which they produce coo vocalizations. Some Streptopelia species have three acoustically similar coo vocalizations associated with the three contexts, but in others the coo vocalizations differ in acoustic structure. Using a well-resolved phylogeny, we examined whether acoustic differentiation between coo types was the ancestral state. Unexpectedly, the results showed that the common ancestor of Streptopelia had differentiated coos rather than a single coo type. This result implies that context-specific acoustic signals disappeared from the vocal repertoire independently at least two times. We further tested whether different context-dependent signal types follow different evolutionary pathways and whether they differ in rate of evolutionary change. We found that the long-range signal (perch-coo) evolves at a higher rate than the short-range signal (bow-coo). These results are discussed in relation to selection for species recognition and transmission requirements.     

Individual Signature in Canary Songs: Contribution of Multiple Levels of Song Structure

Through variations in features, both within and between individuals, songs of male passerines provide information on the identity of the singer. In domesticated canaries (Serinus canaria), these variations remain, for a large part, to be investigated. This led us to question whether individual identity might be coded at one or more hierarchical levels of song organization, i.e. in acoustic parameters, in the syllable repertoire and in the delivery order of syllables. A song as a whole had numerous individual distinctive acoustic features. However, the structure of its individual signature appeared to be complex. A repertoire combined syllables never sung by other individuals with those shared by other birds. But, most of the individual‐specific syllables that accounted for 16% of a repertoire did not recur frequently. Variation in sequences of multiple syllable types appeared to reflect the individual identity of a male canary. Nearly all sequences larger than three syllable types were specific to the individual that produced them. Some of these occurred recurrently in songs and differed in their acoustic structure between individuals. Focusing upon recurrent sequences might allow vocal recognition of an individual without requiring the knowledge of its full repertoire. However, acoustic parameters and repertoire composition might also serve as additional cues to limit confusion between individuals.     

The communicative life of a social carnivore: acoustic repertoire of the ring-tailed coati (Nasua nasua)

The coati is a highly social mammal that features sophisticated cognitive and social abilities. We hypothesized that the ring-tailed coati, Nasua nasua, uses an extensive acoustic repertoire that correlates to their diverse range of social interactions. We tested this hypothesis by observing and recording a free-ranging managed population of N. nasua in Tietê Ecological Park (PET), in the municipality of São Paulo, State of São Paulo, Brazil. Of 404 h of sampling, 47 h of coati vocalizations were recorded over 3 years. Additional records were obtained opportunistically on other free-living populations at PET by using passive acoustic monitoring. We describe here an acoustic repertoire composed of 15 calls (12 basic calls, 2 rhythmic calls and the non-random complex calls composed of three or four different units). This diverse repertoire of signals was used in contact/cohesion regulation, foraging activities, alert or potential threat situations, playing and fighting interactions and during social isolation and acute distress. The contact call (chirp) is produced through biphonation, and other non-linear phenomena are present. Our study found a complex vocal repertoire that encourages further studies to describe the evolution of the cognitive characteristics and social abilities of ring-tailed coatis.     

Development of vocal behaviour in Peking ducklings

Vocal communication appears to play an important role in maintaining group cohesion in broods of Peking ducklings (Anas platyrhynchos). In order to describe the development of the vocal repertoire of the young, the present study examined the vocalizations of six ducklings from several hours before hatching through 48 h posthatching. Vocalizations were recorded in standardized situations in the laboratory, including the presence of conspecific peers, exposure to maternal calls, and social isolation. A major methodological aim of the present study was to determine whether the vocal repertoire of the ducklings would sort itself on objectively measured acoustic features without the necessity of experimenter preclassification (as has been relied upon in the past). This objective procedure produced two acoustically distinct (and conventional) types: (a) contentment calls, which have short note durations, fast repetition rates, and low pitch, and are elicited by the presence of peers and/or the maternal call; (b) distress calls, with longer note durations, slower repetition rates, and higher pitch, which are uttered in social isolation and emerge in mature form only after hatching. A simple physiological model based on respiratory activity is proposed to account for the acoustic variation between the two vocalization types.     

Contextual flexibility in the vocal repertoire of an Amazon parrot

Background

Understanding the role of avian vocal communication in social organisation requires knowledge of the vocal repertoire used to convey information. Parrots use acoustic signals in a variety of social contexts, but no studies have evaluated cross-functional use of acoustic signals by parrots, or whether these conform to signal design rules for different behavioural contexts. We statistically characterised the vocal repertoire of 61 free-living Lilac-crowned Amazons (Amazona finschi) in nine behavioural contexts (nesting, threat, alarm, foraging, perched, take-off, flight, landing, and food soliciting). We aimed to determine whether parrots demonstrated contextual flexibility in their vocal repertoire, and whether these acoustic signals follow design rules that could maximise communication.

Results

The Lilac-crowned Amazon had a diverse vocal repertoire of 101 note-types emitted at least twice, 58 of which were emitted ≥5 times. Threat and nesting contexts had the greatest variety and proportion of exclusive note-types, although the most common note-types were emitted in all behavioural contexts but with differing proportional contribution. Behavioural context significantly explained variation in acoustic features, where threat and nesting contexts had the highest mean frequencies and broad bandwidths, and alarm signals had a high emission rate of 3.6 notes/s. Three Principal Components explained 72.03 % of the variation in temporal and spectral characteristics of notes. Permutated Discriminant Function Analysis using these Principal Components demonstrated that 28 note-types (emitted by >1 individual) could be correctly classified and significantly discriminated from a random model.

Conclusions

Acoustic features of Lilac-crowned Amazon vocalisations in specific behavioural contexts conformed to signal design rules. Lilac-crowned Amazons modified the emission rate and proportional contribution of note-types used in each context, suggesting the use of graded and combinatorial variation to encode information. We propose that evaluation of vocal repertoires based on note-types would reflect the true extent of a species’ vocal flexibility, and the potential for combinatorial structures in parrot acoustic signals.

     

Four type of sounds for one winner: vocalizations during territorial behavior in the red-mouthed goby <Emphasis Type="Italic">Gobius cruentatus</Emphasis> (Pisces Gobiidae)

During territorial encounters, the acoustic repertoire of Gobius cruentatus consists of four types of sound emissions: a tonal sound, a noisy tonal sound, a train of individual pulses, and a complex sound. The complex sound is made of two distinct elements, an initial tonal part followed by pulses. This is the largest acoustic repertoire described so far in gobiid fish during aggressive interaction. Sounds are emitted, mainly by the residents, when fish have already started the interaction but before the encounter is settled. Therefore, sounds seem to have a threatening function.     

Cultural transmission within maternal lineages: vocal clans in resident killer whales in southern Alaska

Cultural lineages are based on learned social traditions that are stable for several generations. When cultural lineages also reflect common ancestry and/or are shared by individuals that live together they are called clans. The existence of clans among killer whales has been previously proposed but has not been confirmed. Here, we show that clans exist among resident type killer whales, Orcinus orca, in southern Alaska. Resident killer whales live in stable matrilines from which emigration of either sex has not been observed. Matrilines that associate regularly (≥50% observation time) are called pods. Pods are believed to consist of closely related matrilines and share a unique repertoire of discrete call types. Pods that share parts of their repertoire form what Ford (1991, Canadian Journal of Zoology,69, 1454-1483) called an acoustic clan. Here, we identified discrete call types of seven pods from southern Alaska, using a method based on human discrimination of distinct aural and visual (spectrogram) differences. Mitochondrial DNA of members of each pod was also analysed. The repertoires of the seven pods were compared and two acoustically distinct groups of pods were identified. Each group was monomorphic for a different mitochondrial D-loop haplotype. Nevertheless, pods from different clans associated frequently. It thus appears that the acoustic similarities within groups, which we presume to be cultural, reflect common ancestry, and that these groups therefore meet the above definition of clans. We also argue that a combination of cultural drift and selection are the main mechanisms for the maintenance of clans. Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.     

白腹管鼻蝠成体交流声波多样性

小蝙蝠亚目即通常所说的蝙蝠,是哺乳动物中群居程度最高的类群之一,主要依靠声学信号在黑暗环境中进行交流并维持社群结构,很多蝙蝠种类的交流声波具有极高的多样性,但是目前关于特定种类蝙蝠交流声波的研究还比较缺乏。我们通过录制白腹管鼻蝠(Murina leucogaster)成体的声波,深入研究其交流声波声谱特征,根据交流声波在声谱图上的形状对声波类型进行初步划分,并利用主成分分析(PCA)和判别分析(DFAs)进行验证。结果表明,其交流声波在声谱结构上具有较高多样性,分为16种不同的音节类型,其中包括13种简单音节和3种组合音节,大多数音节都具有多谐波结构。简单音节可分为9种调频音节、2种准恒频音节和2种噪音,组合音节由简单音节无间隔地组合而成。第一谐波最大频率、第一谐波带宽、持续时间为与调频音节类型相关的主要参数。本研究结果为今后进一步开展研究蝙蝠发声行为的行为学意义和声波交流的神经生理学机制方面的研究奠定了基础。     

Buzzwords in Females’ Ears? The Use of Buzz Songs in the Communication of Nightingales (Luscinia megarhynchos)

Differences in individual male birds’ singing may serve as honest indicators of male quality in male-male competition and female mate choice. This has been shown e.g. for overall song output and repertoire size in many bird species. More recently, differences in structural song characteristics such as the performance of physically challenging song components were analysed in this regard. Here we show that buzz elements in the song of nightingales (Luscinia megarhynchos) hold the potential to serve as indicators of male quality and may therefore serve a communicative function. Buzzes were produced with considerable differences between males. The body weight of the males was correlated with one measure of these buzzes, namely the repetition rate of the buzz subunits, and individuals with larger repertoires sang buzzes at higher subunit-rates. A model of buzz performance constraints suggested that buzzes were sung with different proficiencies. In playback experiments, female nightingales showed more active behaviour when hearing buzz songs. The results support the idea that performance differences in the acoustic fine structure of song components are used in the communication of a large repertoire species such as the nightingale.     

Identification and Characteristics of Signature Whistles in Wild Bottlenose Dolphins (Tursiops truncatus) from Namibia

A signature whistle type is a learned, individually distinctive whistle type in a dolphin''s acoustic repertoire that broadcasts the identity of the whistle owner. The acquisition and use of signature whistles indicates complex cognitive functioning that requires wider investigation in wild dolphin populations. Here we identify signature whistle types from a population of approximately 100 wild common bottlenose dolphins (Tursiops truncatus) inhabiting Walvis Bay, and describe signature whistle occurrence, acoustic parameters and temporal production. A catalogue of 43 repeatedly emitted whistle types (REWTs) was generated by analysing 79 hrs of acoustic recordings. From this, 28 signature whistle types were identified using a method based on the temporal patterns in whistle sequences. A visual classification task conducted by 5 naïve judges showed high levels of agreement in classification of whistles (Fleiss-Kappa statistic, κ = 0.848, Z = 55.3, P<0.001) and supported our categorisation. Signature whistle structure remained stable over time and location, with most types (82%) recorded in 2 or more years, and 4 identified at Walvis Bay and a second field site approximately 450 km away. Whistle acoustic parameters were consistent with those of signature whistles documented in Sarasota Bay (Florida, USA). We provide evidence of possible two-voice signature whistle production by a common bottlenose dolphin. Although signature whistle types have potential use as a marker for studying individual habitat use, we only identified approximately 28% of those from the Walvis Bay population, despite considerable recording effort. We found that signature whistle type diversity was higher in larger dolphin groups and groups with calves present. This is the first study describing signature whistles in a wild free-ranging T. truncatus population inhabiting African waters and it provides a baseline on which more in depth behavioural studies can be based.     

Day and night sounds of the Guiana dolphin, <Emphasis Type="Italic">Sotalia guianensis</Emphasis> (Cetacea: Delphinidae) in southeastern Brazil

Many cetaceans are known to be acoustically active at night. However, for most dolphin species, there is little information about their nocturnal acoustic activities. To study the acoustic repertoire of Sotalia guianensis, diurnal and nocturnal sounds (whistles, burst pulses, low-frequency narrowband (LFN) sounds, and clicks) were identified in the Cananéia estuary (25° 01′ S–25° 13′ S/47° 52′ W–48° 06′ W), south of the state of São Paulo, southeastern Brazil, during April, June, and November of 2012. The emission rate of these sounds was compared between daytime and nighttime using the chi-squared statistical test. The mean values of the acoustic parameters of whistles, burst pulses, LFN sounds, and clicks were compared using the t test. Whistles, burst pulses, and LFN sounds were more frequent at night, as these individuals require greater acoustic communication in the absence of light, mainly for social communication. Echolocation emission rates were similar in both day and nighttime. Dolphin sound structure also varied throughout the day, with dolphins emitting lower-frequency sounds at night. Low-frequency sounds, with longer wavelengths, provide many advantages for dolphins active at night because such sounds propagate greater distances. This study demonstrates that the sounds produced by S. guianensis are dependent on the time of day, with social communication sounds being more influenced by the presence of light.     

Acoustic signals in katydids (Orthoptera,Tettigonidae). Communication 2

Three basic trends in the development of acoustic communication in Tettigonioidea are distinguished. The first one is observed in predatory tettigoniids and conocephalids. It is associated with the improvement of the territorial behavior and results in the appearance of territorial, aggressive and protest sounds (only males stridulate) in the acoustic repertoire. The second trend is caused by the development of defensive mechanisms. It is observed in phytophagous katydids belonging to the family Bradyporidae dwelling in deserts and other exposed habitats. As a rule, their acoustic repertoire includes long-lasting calling songs and disturbance (protest) sounds; rather often, these sounds are produced both by males and females. The unmasking effect of signals is compensated for by specific defense adaptations. The third evolutionary tendency is most completely expressed in phytophagous Phaneropteridae and phytophilous Bradyporidae (Ephippigerinae) as a result of the predator press and the improvement of sexual behavior. It leads to appearance of a “slow” system of communication, when the unmasking effect of songs is minimized by the decrease in the acoustic activity of males. Females produce response signals, while males produce complex calling, courtship, and confirming sounds. The temporal pattern of a signal is one of the most reliable criteria for the discrimination of species and subspecies. It is difficult to use physical parameters of sounds as a criterion for the differentiation of taxa at the superspecies rank, since acoustical signalling is obviously a subject of evolution of the acoustic community rather than of the taxon. Parallelisms and convergences are observed in the evolution of acoustic communication systems, but complex analysis allows revealing the initial type of the acoustic system and defining the reasons for adaptive reorganizations.     

Structural Classification of Wild Boar (Sus scrofa) Vocalizations

Determining whether a species' vocal communication system is graded or discrete requires definition of its vocal repertoire. In this context, research on domestic pig (Sus scrofa domesticus) vocalizations, for example, has led to significant advances in our understanding of communicative functions. Despite their close relation to domestic pigs, little is known about wild boar (Sus scrofa) vocalizations. The few existing studies, conducted in the 1970s, relied on visual inspections of spectrograms to quantify acoustic parameters and lacked statistical analysis. Here, we use objective signal processing techniques and advanced statistical approaches to classify 616 calls recorded from semi‐free ranging animals. Based on four spectral and temporal acoustic parameters—quartile Q25, duration, spectral flux, and spectral flatness—extracted from a multivariate analysis, we refine and extend the conclusions drawn from previous work and present a statistically validated classification of the wild boar vocal repertoire into four call types: grunts, grunt‐squeals, squeals, and trumpets. While the majority of calls could be sorted into these categories using objective criteria, we also found evidence supporting a graded interpretation of some wild boar vocalizations as acoustically continuous, with the extremes representing discrete call types. The use of objective criteria based on modern techniques and statistics in respect to acoustic continuity advances our understanding of vocal variation. Integrating our findings with recent studies on domestic pig vocal behavior and emotions, we emphasize the importance of grunt‐squeals for acoustic approaches to animal welfare and underline the need of further research investigating the role of domestication on animal vocal communication.     

Evolutionary Dynamics of the OR Gene Repertoire in Teleost Fishes: Evidence of an Association with Changes in Olfactory Epithelium Shape

Teleost fishes perceive their environment through a range of sensory modalities, among which olfaction often plays an important role. Richness of the olfactory repertoire depends on the diversity of receptors coded by homologous genes classified into four families: OR, TAAR, VR1, and VR2. Herein, we focus on the OR gene repertoire. While independent large contractions of the OR gene repertoire associated with ecological transitions have been found in mammals, little is known about the diversity of the OR gene repertoire and its evolution in teleost fishes, a group that includes more than 34,000 living species. We analyzed genomes of 163 species representing diversity in this large group. We found a large range of variation in the number of functional OR genes, from 15 in the Broad-nose Pipefish Syngnathus typhle and the Ocean Sunfish Mola mola, to 429 in the Zig-zag Eel Mastacembelus armatus. The number of OR genes was higher in species when a multilamellar olfactory rosette was present. Moreover, the number of lamellae was correlated with the richness of the OR gene repertoire. While a slow and balanced birth-and-death process generally drives the evolution of the OR gene repertoire, we inferred several episodes of high rates of gene loss, sometimes followed by large gains in the number of OR genes. These gains coincide with morphological changes of the olfactory organ and suggest a strong functional association between changes in the morphology and the evolution of the OR gene repertoire.