@article {57884, title = {Performance of Doppler shift compensation in bats varies with species rather than with environmental clutter}, journal = {Animal Behaviour}, volume = {158}, year = {2019}, month = {Jan-12-2019}, pages = {109 - 120}, abstract = {

The performance of vocal motor control is crucial for vocal communication; however, its evolution and ecological drivers are largely unknown. Doppler shift compensation (DSC), which has been found only in bats, represents an excellent model for studying the mechanisms and evolution of vocal control. We tested whether species that are more dependent on DSC for pulse\–echo separation have a more precise DSC and whether changes in environmental clutter would result in adjustments in DSC performance. We recorded the echolocation and flight behaviour of the greater horseshoe bat, Rhinolophus ferrumequinum, and the great leaf-nosed bat, Hipposideros armiger, flying through a corridor and a window in turn. The DSC precision in H. armiger was significantly lower than that of R. ferrumequinum; the offset between the reference frequency and resting frequency, however, was not significantly different between the two species. We also studied the DSC of H. armiger flying through windows of different sizes. Their flight speed decreased significantly with reduced window size. However, DSC precision and the offset did not vary significantly with window size. Our results suggest that DSC is more precise in rhinolophids, which have a higher demand for pulse\–echo separation by DSC, than in hipposiderids. Changes in environmental clutter do not necessarily result in adjustments of DSC performance. Functional importance associated with high-performance vocal control may be critical in shaping the precision of vocal control in the course of evolution. Instead, habitat clutter encountered by vocalizing animals may not play an important role.

}, issn = {00033472}, doi = {10.1016/j.anbehav.2019.10.008}, author = {Zhang, Yu and Lin, Aiqing and Ding, Jianan and Yang, Xinyao and Jiang, Tinglei and Liu, Ying and Feng, Jiang} } @article {53581, title = {Acoustic signalling of aggressive intent in the agonistic encounters of female Asian particoloured bats}, journal = {Animal Behaviour}, volume = {149}, year = {2019}, month = {Jan-03-2019}, pages = {65 - 75}, abstract = {

The signals of animal aggressive intent can communicate aggression levels to competitors, thereby settling conflicts at an early stage and thus reducing energy costs. We tested whether aggressive vocalizations of female Asian particoloured bats, Vespertilio sinensis, encode aggressive intent during agonistic encounters that occur whenever an intruder pushes a resident to obtain a more central roosting spot. Our results showed that the number of noisy/tonal syllables of the disturbed bats met the three criteria used to define aggressive intent. First, the number and ratio of tonal syllables were significantly greater when intruders continued to push, and the number and ratio of noisy syllables were significantly greater when they stopped pushing (context criterion). Second, skin temperature related to emotional arousal during aggressive interaction generally increased when intruders stopped pushing but was unchanged or decreased when they continued pushing (predictive criterion). Finally, bats preferentially selected stimuli with more tonal syllables, and they spent more time approaching more noisy syllables in a two-choice playback experiment (response criterion). Thus, we propose that the number of noisy/tonal syllables within aggressive vocalizations of female Asian particoloured bats functions to signal aggressive intent.

}, keywords = {aggressive intent, aggressive vocalizations, skin temperature}, issn = {00033472}, doi = {10.1016/j.anbehav.2019.01.012}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0003347219300132}, author = {Zhao, Xin and Jiang, Tinglei and Liu, Heng and Wang, Yuze and Liu, Ying and Feng, Jiang} } @article {53434, title = {Social vocalizations of big-footed myotis (Myotis macrodactylus) during foraging}, journal = {Integrative Zoology}, year = {2018}, month = {Feb-12-2020}, abstract = {

Acoustic signals play a crucial role in transmitting information and maintaining social stability in gregarious animals, especially in echolocating bats which rely primarily on biological sonar for navigating in the dark. In the context of foraging without relying on tactile, visual, or olfactory cues, acoustic signals convey information not only on food, but also on ownership and defense of resources. However, studies on such information remain fragmentary. In the present study, we aim to document the social vocal repertoire of Myotis macrodactylus at natural foraging sites. Multiple acoustic analyses and spectrographic classification revealed a rich foraging vocal repertoire comprising 6 simple syllables and 2 composites. Discriminant function analyses associated with a subset-validation procedure provided an optimal method to spectrographically classify all recorded sounds into different syllable types. Multidimensional scaling of median values of multiple parameters further confirmed notable differences among these syllables in a three-dimensional space. In addition, Euclidean distance analysis showed that there were some spectral similarities between specific social vocal syllables and feeding buzzes, which implied a potential jamming role. Altogether, the data indicate that bats at foraging sites under natural conditions used variant social vocalizations with different functions in addition to echolocation calls, providing supporting evidence for further work on the function and vocal mechanisms of acoustic communication in mammals.

}, keywords = {bats, foraging, Social calls, Spectro-temporal features}, doi = {10.1111/1749-4877.12367}, url = {http://doi.wiley.com/10.1111/1749-4877.12367}, author = {Guo, Dongge and Luo, Bo and Zhang, Kangkang and LIU, Muxun and Metzner, Walter and Liu, Ying and Feng, Jiang} } @article {50497, title = {Social calls honestly signal female competitive ability in Asian particoloured bats}, journal = {Animal Behaviour}, volume = {127}, year = {2017}, month = {Jan-05-2017}, pages = {101 - 108}, abstract = {

Why a variety of social animals vocalize during agonistic foraging interactions remains obscure. One possibility is that these signals advertise the signaller\&$\#$39;s competitive ability, playing a role in the defence of food resources, yet there is limited evidence in support of this idea. Here, we used adult female Asian particoloured bats, Vespertilio sinensis, to test whether individual variation in competitive ability when foraging can be explained by social calls. Using synchronized infrared video and audio recording, we monitored bat social vocalizations, dominance rank and weight gain in triads under controlled food conditions. Additionally, subsequent playbacks, consisting of experimental stimuli, echolocation pulses and silence, were presented to feeding bats in a laboratory. Analyses showed that females uttered low-frequency social calls composed of one to five syllable types during feeding competition. The rates of social vocalizations increased with reduced food availability. Interestingly, dominance score and weight gain correlated weakly with body size, but positively with call rate and associated parameters. Playback of social calls inhibited the visits of bats to the focal food dish compared to playback of silence and echolocation pulses. The amount of food consumed was greatly reduced in the presence of experimental stimuli versus controls. Collectively, these results highlight that acoustic signals serve as an honest indicator of bat competitive ability.

}, keywords = {aggressive interaction, bats, competitive ability echolocation, foraging, social call}, issn = {00033472}, doi = {10.1016/j.anbehav.2017.03.012}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0003347217300842}, author = {Luo, Bo and Lu, Guanjun and Chen, Kelly and Guo, Dongge and Huang, Xiaobin and Liu, Ying and Feng, Jiang} }