大菊头蝠和中菊头蝠分娩声波的特征

动物的声学信号在信息传递和维持社群稳定等方面扮演了非常重要的角色，特别是对于占据夜空生态位并集群生活的蝙蝠，它们日间栖息于几乎没有光照的洞穴中。这些夜行性蝙蝠主要借助声信号介导重要生活史事件，包括生殖、觅食、通讯和空间导航等。分娩是动物生殖活动中的关键一环，决定了后代甚至母体的生死。一直以来野生动物的分娩行为，特别是分娩叫声鲜有研究。本研究以大菊头蝠(Rhinolophus luctus)和中菊头蝠(R. affinis)为研究对象，捕捉并录制其在分娩过程中的声信号，进而开展声谱分析和统计分类。研究发现，大菊头蝠和中菊头蝠在分娩过程中分别发出了6种和4种类型的交流声波。基于子集验证的判别式分析表明，大多数的音节类型都被正确划分。纳入多种声学参数的多维尺度分析显示，不同音节类型在三维图像中差异显著。此外，欧几里得距离分析发现，种间的叫声差异远大于种内的叫声差异。本研究结果可为深入揭示夜行哺乳动物的叫声功能和发声机制提供参考。

Characteristics of Calls of Woolly Horseshoe Bat Rhinolophus luctus and Intermediate Horseshoe Bat R. affinis During Parturition

[Objectives] Acoustic signals play a crucial role in transmitting information and maintaining social stability in animals, especially in gregarious bats which are considered to occupy the ecological niche of the night sky and rely primarily on biological sonar for navigating in the dark. Acoustic signals mediate a variety of life history events in nocturnal bats, including reproduction, foraging, communication and spatial navigation. The parturition is a crucial part of animal reproductive activity, directly determining the survival of offspring and their female parent. There has been little research on the parturition behavior of wild animals, particularly the vocalizations during parturition. In the present study, we aim to document the social vocal repertoire of Rhinolophus luctus and R. affinis during parturition. [Methods] We caught the pregnant bats with mist net or hand net from a nursery colony in Nanyang, Henan Province. All bats were taken into a temporary laboratory near the roost, and then were given mealworms and water. Vocalizations were picked up with the ultrasonic acquisition system using a sample rate of 250 kHz at 16 bits/sample. The pregnant bat’s behavior was monitored via an infrared camera. We measured 8 spectro-temporal parameters from the oscillogram and spectrogram to quantify syllable features (Table 1 and 2). Then multiple statistical analyses were conducted to map the acoustic boundaries of different syllables. [Results] A total of 89 syllables were obtained, among which 6 and 4 types were distinguished from the Woolly Horseshoe Bat and the Intermediate Horseshoe Bat, respectively (Fig. 1). The cumulative sum of the two largest eigenvalues (corresponding to the ?rst two principal components) obtained from the principal components analysis explained 71.36% of the total variation (Table 3). Based on the results of the discriminant function analyses associated with a subset-validation procedure, 40.5% of syllable types were correctly classified, which was significantly higher than expected by chance (Fig. 2a). Multidimensional scaling of mean values of multiple parameters further confirmed notable differences among these syllables in a three-dimensional space (Fig. 2b). In addition, Euclidean distance analysis showed that there were more significant differences between interspecific relationship than intraspecific relationship (Table 4). [Conclusion] Our results indicate that these two bat species use relatively variant social vocalizations with different spectro-temporal features during parturition. Altogether, the data will provide a reference for further work on the function and vocal mechanisms of acoustic communication in nocturnal mammals.