Animal Physiology, Institute for Neurobiology, University of Tübingen, Tübingen, Germany.
PLoS One. 2019 Sep 6;14(9):e0221792. doi: 10.1371/journal.pone.0221792. eCollection 2019.
Swarming is a characteristic behavior of bats that occurs in different social contexts. We studied the swarming behavior of Myotis nattereri at a maternity colony and at an autumn swarming site in South-West Germany by using synchronized sound and video recordings. Swarming was always associated with social vocalizations consisting of four frequently occurring call types. Call type A was a short call with a broadband steep-shallow-steep downward frequency modulation. Call type B consisted of two elements beginning with a broadband upward hooked element followed by a steep frequency modulated element. Call type C showed a characteristic rapid downward-upward-downward frequency modulation. Call type D was a long sinusoidal trill-like call with high variability in signal structure. All call types were recorded at the maternity colony, as well as at the autumn swarming site, but the incidence of each call type differed distinctly between the study sites. At the maternity roost, type A calls were most commonly produced. We found evidence for an individual signature in this call type and suggest that this social call has the function of a contact call in Natterer's bats. At the autumn swarming site, type D calls were the most common social calls; in contrast, this call type was recorded only twice at the maternity roost. The occurrence of trills mainly at the autumn swarming site and their high variability suggests that trills function as male advertisement calls in M. nattereri.
群集是蝙蝠的一种特征行为，发生在不同的社会环境中。我们通过同步声音和视频记录，研究了德国西南部一个繁殖地和一个秋季群集地点的蝙蝠的群集行为。群集总是与社会发声有关，这些发声由四种经常出现的叫声类型组成。叫声类型 A 是一种带有宽带陡峭浅陡峭向下频率调制的短叫声。叫声类型 B 由两个元素组成，开始时是一个宽带向上钩状元素，后面跟着一个陡峭的频率调制元素。叫声类型 C 显示出一种特征性的快速向下向上向下频率调制。叫声类型 D 是一种长的正弦颤音样叫声，信号结构变化很大。所有叫声类型都在繁殖地和秋季群集地点被记录下来，但每种叫声类型的发生率在两个研究地点明显不同。在繁殖地，叫声类型 A 最常见。我们在这种叫声类型中发现了个体特征的证据，并认为这种社会叫声在 Natterer 的蝙蝠中具有联络叫声的功能。在秋季群集地点，叫声类型 D 是最常见的社会叫声；相比之下，这种叫声类型在繁殖地只记录到两次。颤音主要在秋季群集地点出现，且变化很大，这表明颤音在 M. nattereri 中作为雄性广告叫声。
