社会网络分析法及其在动物行为学研究中的应用

近年来,社会网络分析法被广泛用于动物行为学研究。它通过量化动物社会关系中的特定属性 (如中心度和中心势),可辨识动物群体中的关键个体及其在群体中的作用,揭示动物社会交往的形成机制,深化人们对动物社会性起源、个体行为与种群动态格局间关系的理解。本文简要介绍了社会网络分析法的发展史和基本概念,然后阐述了如何建立网络及选择常用指标,强调了创建原模型的必要性及途径。最后着重评述了社会网络分析法在动物行为学研究中的应用现状,并提出未来应当关注直接身体接触 (如打斗和理毛) 和非肢体接触 (如声音通讯) 等不同交往形式的变动过程,以此构建社会交往的动态网络。同时也需要加强种间社交网络的研究,以便增进人们对社会行为的生态功能以及合作理论等问题的理解。     

中国野生脊椎动物鸣声监测与生物声学研究进展

<正>声音(鸣声)通讯是许多动物类群的重要通讯方式,在动物社群交流和繁殖活动中起着非常重要的作用。采用鸣声通讯的动物类群十分丰富,包括哺乳类、鸟类、两栖爬行类、鱼类和昆虫,这些类群的生境涵盖了陆地、淡水和海洋等各类生态系统。生物声学研究最初以描述动物的声音特征为主,     

鸟类鸣声与个体适合度关系的研究进展

鸣声蕴藏着丰富的生物学信息,是鸟类间信息交流最主要的方式之一。本文综述了鸟类鸣声行为与包括个体状态(体征、激素水平和健康状况)、社会等级及繁殖(性选择和成效)在内的个体适合度关系的研究进展。文章总结发现,鸟类的鸣声水平与单一体征参数关系的研究结果不稳定,鸣声可能受个体内部的多种激素调控,并与个体的社会等级有直接关系。雌雄个体鸣声均与繁殖有一定相关性,但双亲鸣声行为策略存在差异。鸣声对繁殖适合度的影响受到其他因素如物种、婚配制度等因素的影响。鸟类鸣声代表的生物学信息是个体身体质量的综合体现,与鸟类个体适合度的关系较为复杂。为解释鸣声所代表的生物学信息,需要从适合度的多个角度(社会等级、身体状况和繁殖情况等)来考虑多种鸣声参数。     

蛙类声音通讯研究进展

声音通讯包含鸣声的产生、传播及对鸣声的感知与行为响应。对大多数无尾两栖类而言,雄性个体间的竞争(即雄雄竞争)、雌性配偶识别与选择几乎完全依赖声音通讯,因此准确及时的声音信息传递与接收对蛙类的生存和繁殖起着决定性作用。本文总结了蛙类鸣叫特征及其产生机制,归纳了声音通讯在蛙类性选择中的功能及协同进化,探讨了鸣声感知的神经机制及声音通讯的内分泌机制。最后对蛙类声音通讯研究方向进行了展望,并提出了可能的解决方案。     

灵长类声行为研究进展

灵长类动物以鸣声、触觉、视觉及化学物等方式进行通讯,树栖性动物偏重声通讯;地栖性的主要是声音及视觉;夜行性多为声音和化学通讯。声通讯作为灵长类动物通讯的主要形式,自然选择的作用使动物声通讯趋于完善而不需其它通讯媒介的辅助,因而声行为是灵长类通讯研究中的重要内容。     

环境噪声对临安和阜阳两地白头鹎鸣声频率的影响

为了解环境噪声对白头鹎(Pycnonotus sinensi)鸣声频率的影响,在浙江临安和安徽阜阳两地分别对白头鹎在高低噪声水平环境中的鸣声做了研究。把用数码录音机记录到的鸣声输入计算机,利用计算机声谱分析系统进行分析,再对每一鸣声的每个音节的主频进行Mann—Whitney U检验。结果显示：高噪声水平区和低噪声水平区相比,在两地白头鹎每一鸣声的各音节主频中,最低和最高主频以及第I、Ⅱ音节的主频都有显著提高;在阜阳第Ⅲ音节的主频也有显著提高。这表明白头鹎可以通过提高声音频率来避免环境噪声对鸣声的影响,从而保证噪声环境中声信息的有效传递;而噪声对各音节的不同影响也表明,同一鸣句的各音节,对于噪声通讯中的信息识别,具有不同的地位。     

斑胸草雀的鸣声学习

鸣声是鸟类重要的生物学特征和分类特征。由于生理结构和神经控制方面的差异,不同种群和同一种群的不同个体都有自己特有的鸣声特征,正是利用这些特征,鸟类才能在集群、取食、迁徙、喂雏、御敌和求偶等行为中进行通讯。作为一种能够利用语音信息进行交流的高等脊椎动物,斑胸草雀的鸣声特别是鸣啭能力获得,需要有一个适宜的学习对象,并在一段特定的时间内,经历复杂的学习过程才能实现。     

杭州市区白头鹎鸣声的微地理差异

2002年5—8月,对中国东部浙江省杭州市区的白头鹎鸣声的微地理差异进行研究。在约60 km2的 研究区内,选择8个调查点(4个城区,4个丘陵山地),录制了80个雄性白头鹎的511个鸣声样本,并随机选 取每一调查点的20个鸣声样本进行分析。其结果显示,白头鹎在杭州市区至少有8种微地理鸣声方言,每个微 地理鸣声方言都有一典型鸣句;它们在听觉上、波形结构、音节组成、音节频谱特征等方面均不相同。有的一 路之隔的相邻微地理鸣声方言之间存在明显差异;部分区域出现鸣声混合现象;有的个体还具有“多语”功 能。白头鹎鸣声产生微地理差异的原因可能与鸟类个体的扩散和城市中鸟类栖息地的人为改变有关。     

杂色山雀指名亚种繁殖期的鸣声行为

2012年3～7月,对辽宁仙人洞自然保护区9巢18只杂色山雀(Parus varius varius)个体及其雏鸟的鸣声进行了录音,共获取了9种类型鸣叫(呼唤、警戒、报警、恫吓、驱逐、惊叫、喂食、雏鸟乞食、集群)和5种类型鸣唱.通过语图分析得出音节类型18种,频率范围为800 ～18 900 Hz.对杂色山雀不同个体鸣声特征参数的比较发现,鸣声的句子和音节时长在不同个体之间存在显著性差异,而最高频率、最低频率在不同个体间均无显著性差异.本研究实现了对杂色山雀繁殖期鸣声参数的量化,有助于进一步研究其繁殖行为.     

腾冲拟髭蟾繁殖期鸣声特征

为了研究腾冲拟髭蟾(Leptobrachium tengchongense)的繁殖期鸣声特征,2018年2月27日,利用TASCAM DR-40专业录音机,在野外录制了6只个体总共78个有效鸣声,随后利用Raven Pro?v.1.5声音分析软件对鸣声进行分析。结果表明,繁殖期的雄性腾冲拟髭蟾发出求偶鸣声及竞争鸣声两种不同类型鸣声,均为单音节鸣叫,且鸣声主频均为1.31～1.50 kHz。求偶鸣声的时长为(147±30.1)ms,所含脉冲数为(15±2.4)pulses/s;竞争鸣声为雄蟾听到附近其他个体鸣叫后所发出的较拖长的鸣声,其鸣声时长为(610±187.0)ms,所含脉冲数为(28±10.7)pulses/s。不同个体之间的鸣叫时长和鸣叫间隔存在差异,这可能与个体的体型大小有关,但需要更多的数据去证实。我们根据调查结果,分析讨论当前腾冲拟髭蟾所面临的主要威胁及其保育策略。     

Sexual dimorphism and bilateral asymmetry of syrinx and vocal tract in the European starling (Sturnus vulgaris)

Sexually dimorphic vocal behavior in zebra finches (Taeniopygia guttata) is associated with a 100% larger syrinx in males and other morphological adaptations of the sound source. The songbird syrinx consists of two independent sound sources, whose specialization for different spectral ranges may be reflected in morphological properties, but the morphology of labia and syringeal skeleton have not been investigated for lateralized specializations. Similarly, little is known whether the morphology of the songbird vocal tract reflects differences in vocal behavior. Here, we tested the hypothesis that different vocal behavior and specialization is reflected in the morphology. We investigated syringeal and upper vocal tract morphology of male and female European starlings (Sturnus vulgaris). Female starlings exhibit smaller vocal repertoires and sing at lower rates than males. In males, the left syrinx produces mostly low frequencies, while the right one is used for higher notes. Macroscopic and histological techniques were used to record nineteen measurements from the syrinx and the vocal tract which were tested for sexual differences in syrinx and vocal tract and for lateral asymmetry within the syrinx. Sexually dimorphic vocal behavior is reflected in the morphology of the starling syrinx. Males have a larger syrinx with the size difference attributable to increased muscle mass and three enlarged elements of the syringeal skeleton. The upper vocal tract, however, does not differ between males and females. Distinct lateralization was found in two elements of the syringeal skeleton of females, and the labia in the left syrinx are larger than those on the right in both sexes. The sexual dimorphism of the syringeal size is smaller in starlings (35%) than in zebra finches (100%), which is consistent with the different vocal behavior of females in both species. The morphological differences between the two sound sources are discussed in relation to their vocal performance. J. Morphol., 2011. © 2011 Wiley‐Liss, Inc.     

Age- and sex-specific patterns of vocal behavior in De Brazza's monkeys (Cercopithecus neglectus)

Although vocal production is strongly genetically determined in nonhuman primates, vocal usage is more likely to be influenced by experience. Nonetheless, sex differences in both production and usage can be found in the vocal repertoire of adults, but little attention has been paid to their ontogeny. Here, we provide the first comprehensive analysis of the vocal repertoire of De Brazza's monkeys (Cercopithecus neglectus), with particular attention to age- and sex-specific patterns. This species has special interest because it is the only monogamous species of guenons, but it nevertheless shares the strong sexual morphological and behavioral dimorphism seen in other guenons. A structurally based classification of calls recorded in 23 captive individuals has been cross-validated by an analysis of the associated contexts of emission. We identified sound units that could be uttered alone or concatenated to form 10 call types, including only three types shared by all age-sex-classes. Both age- and sex-discrepancy in terms of phonation could be explained by maturational changes and morphological dimorphism. In general, call production and usage parallel those seen in other guenons, suggesting that phylogeny and sexual dimorphism play important roles in vocal communication in this species. However, the boundary between adult male and female vocal repertoires appeared to be less strict than previously reported, suggesting that both sexes have the capacity to produce calls of the other sex but that social roles may constrain this expression. Similarly, age-specific vocal patterns would reflect respective social roles, and experience to some extent. Finally, calling rates would reflect age-/sex-specific degree of involvement in intragroup social networks. These findings highlight the relative importance of phylogeny, morphology, and social system on the shaping of individual repertoires in nonhuman primates.     

Vocal networks remain stable after a disturbance in Emei music frogs

Social network analysis has been widely used to investigate the dynamics of social interactions and the evolution of social complexity across a range of taxa. Anuran species are highly dependent on vocal communication in mate choice; however, these species have rarely been the subject of social network analysis. The present study used social network analysis to investigate whether vocal network structures are consistent in Emei music frog (Babina daunchina) after the introduction of a simulated exotic rival of varying competitiveness into the social group. We broadcasted six categories of artificial calls (either highly sexually attractive calls produced from inside male nests or calls of low sexual attractiveness produced outside nests with three, five or seven notes, respectively) to simulate an intruder with different levels of competitiveness. We then constructed vocal networks for two time periods (before and after the disturbance) and quantified three network metrics (strength, closeness, and betweenness) that measure different aspects of individual‐level position. We used the mean values of these network metrics to evaluate group‐level changes in network structure. We found that the mean strength, mean closeness and mean betweenness were consistent between two time periods in all ponds, despite the fact that the positions of some individuals had changed markedly after disturbance. In addition, there was no significant interaction effect between period and numbers of notes on the three network metrics. These finding suggest that the structure of vocal networks in Emei music frogs remain stable at the group level after a conspecific disturbance, regardless of the intruder's competitiveness.     

Vertical transmission of learned signatures in a wild parrot

Learned birdsong is a widely used animal model for understanding the acquisition of human speech. Male songbirds often learn songs from adult males during sensitive periods early in life, and sing to attract mates and defend territories. In presumably all of the 350+ parrot species, individuals of both sexes commonly learn vocal signals throughout life to satisfy a wide variety of social functions. Despite intriguing parallels with humans, there have been no experimental studies demonstrating learned vocal production in wild parrots. We studied contact call learning in video-rigged nests of a well-known marked population of green-rumped parrotlets (Forpus passerinus) in Venezuela. Both sexes of naive nestlings developed individually unique contact calls in the nest, and we demonstrate experimentally that signature attributes are learned from both primary care-givers. This represents the first experimental evidence for the mechanisms underlying the transmission of a socially acquired trait in a wild parrot population.     

What’s occurring? Ultrasonic signature whistle use in Welsh bottlenose dolphins (Tursiops truncatus)

Animal communication signals are diverse. The types of sounds that animals produce, and the way that information is encoded in those sounds, not only varies between species but can also vary geographically within a species. Therefore, an understanding of the vocal repertoire at the population level is important for providing insight into regional differences in vocal communication signals. One species whose vocal repertoire has received considerable attention is the bottlenose dolphin. This species is well known for its use of individually distinctive identity signals, known as signature whistles. Bottlenose dolphins use their signature whistles to broadcast their identity and to maintain contact with social companions. Signature whistles are not innate, but are learnt signals that develop within the first few months of an animal’s life. It is therefore unsurprising that studies which have characterized signature whistles in wild populations of bottlenose dolphins have provided evidence of geographic variation in signature whistle structure. Here, we describe the occurrence of signature whistles in a previously unexplored wild population of bottlenose dolphins in Cardigan Bay, Wales. We present the first occurrence of a signature whistle with an ultrasonic fundamental frequency component (>30 kHz), a frequency band that was not thought to be utilized by this species for whistle communication. We also describe the occurrence of an ultrasonic non-signature whistle. Our findings highlight the importance of conducting regional studies in order to fully quantify a species’ vocal repertoire, and call into question the efficacy of those studies that use restricted sampling rates.     

Anthropogenic noise affects female,not male house wren response to change in signaling network

Vocal signals mediate social relationships, and among networks of territorial animals, information is often shared via broadcast vocalizations. Anthropogenic noise may disrupt communication among individuals within networks, as animals change the way they vocalize in noise. Furthermore, constraints on signal transmission, including frequency masking and distance, may affect information exchange following a disruption in social networks. We tested the hypothesis that signaling interactions within networks of breeding male and female house wrens (Troglodytes aedon) depend on distance, ambient noise, and receiver nesting stage. We used playback experiments to simulate territorial intrusions with and without noise playbacks on the territories of established males and simultaneously recorded the vocal responses of neighbors. To examine whether intrusions impacted interactions between males, we used randomization tests to determine whether treatment, distance, noise, or nesting stage affected vocal coordination between challenged and neighboring males. We also quantified singing patterns to explore whether intrusions on territories of challenged males affected singing by males and females on neighboring territories. Males sang at the lowest rates and were less likely to overlap songs with the challenged male when their partner was laying, compared to males during early and late nesting stages. Noise and distance did not affect vocal coordination or male singing rates. Fewer females sang during the intruder-only treatment compared to the control and intrusions with noise. Added noise in the territories of challenged males may have masked signals, and as a result, females only changed their behavior during the intruder-only treatment. Our results suggest that the fertility of breeding partners may be more important to males than short-term changes on rival male territories. Elevated noise did little to alter male responses to threats within networks. Females appeared to eavesdrop on interactions involving neighboring males, but noise may have prevented detection of their interactions.     

The function and mechanism of vocal accommodation in humans and other primates

The study of non‐human animals, in particular primates, can provide essential insights into language evolution. A critical element of language is vocal production learning, i.e. learning how to produce calls. In contrast to other lineages such as songbirds, vocal production learning of completely new signals is strikingly rare in non‐human primates. An increasing body of research, however, suggests that various species of non‐human primates engage in vocal accommodation and adjust the structure of their calls in response to environmental noise or conspecific vocalizations. To date it is unclear what role vocal accommodation may have played in language evolution, in particular because it summarizes a variety of heterogeneous phenomena which are potentially achieved by different mechanisms. In contrast to non‐human primates, accommodation research in humans has a long tradition in psychology and linguistics. Based on theoretical models from these research traditions, we provide a new framework which allows comparing instances of accommodation across species, and studying them according to their underlying mechanism and ultimate biological function. We found that at the mechanistic level, many cases of accommodation can be explained with an automatic perception–production link, but some instances arguably require higher levels of vocal control. Functionally, both human and non‐human primates use social accommodation to signal social closeness or social distance to a partner or social group. Together, this indicates that not only some vocal control, but also the communicative function of vocal accommodation to signal social closeness and distance must have evolved prior to the emergence of language, rather than being the result of it. Vocal accommodation as found in other primates has thus endowed our ancestors with pre‐adaptations that may have paved the way for language evolution.     

The use of Artificial Neural Networks to classify primate vocalizations: a pilot study on black lemurs

The identification of the vocal repertoire of a species represents a crucial prerequisite for a correct interpretation of animal behavior. Artificial Neural Networks (ANNs) have been widely used in behavioral sciences, and today are considered a valuable classification tool for reducing the level of subjectivity and allowing replicable results across different studies. However, to date, no studies have applied this tool to nonhuman primate vocalizations. Here, we apply for the first time ANNs, to discriminate the vocal repertoire in a primate species, Eulemur macaco macaco. We designed an automatic procedure to extract both spectral and temporal features from signals, and performed a comparative analysis between a supervised Multilayer Perceptron and two statistical approaches commonly used in primatology (Discriminant Function Analysis and Cluster Analysis), in order to explore pros and cons of these methods in bioacoustic classification. Our results show that ANNs were able to recognize all seven vocal categories previously described (92.5–95.6%) and perform better than either statistical analysis (76.1–88.4%). The results show that ANNs can provide an effective and robust method for automatic classification also in primates, suggesting that neural models can represent a valuable tool to contribute to a better understanding of primate vocal communication. The use of neural networks to identify primate vocalizations and the further development of this approach in studying primate communication are discussed. Am. J. Primatol. 72:337–348, 2010. © 2009 Wiley‐Liss, Inc.     

Team of rivals: alliance formation in territorial songbirds is predicted by vocal signal structure

Cooperation and conflict are regarded as diametric extremes of animal social behaviour, yet the two may intersect under rare circumstances. We here report that territorial competitors in a common North American songbird species, the chipping sparrow (Spizella passerina), sometimes form temporary coalitions in the presence of simulated territorial intruders. Moreover, analysis of birds’ vocal mating signals (songs) reveals that coalitions occur nearly exclusively under specific triadic relationships, in which vocal performances of allies and simulated intruders exceed those of residents. Our results provide the first evidence that animals like chipping sparrows rely on precise assessments of mating signal features, as well as relative comparisons of signal properties among multiple animals in communication networks, when deciding when and with whom to form temporary alliances against a backdrop of competition and rivalry.