title: Size and quality information in acoustic signals of Rhinolophus ferrumequinum in distress situations.
abstract: Many animals produce alarm or distress calls when they encounter predators. Previous studies have shown that the distress calls of some birds can also signal the quality of the bird as prey to predators. In this case, both predator and prey may benefit from sharing information about prey's ability to escape. However, little is known about whether echolocation pulses and distress calls in bats convey size and quality information in distress situations. This study investigates the relationship between echolocation, distress calls, and the health of the callers to determine whether these signals are reliable indicators of sender's attributes and quality. The spectro-temporal structure of echolocation pulses and distress calls from captured greater horseshoe bats, Rhinolophus ferrumequinum, were found to be correlated to their body size, body condition, and T-cell-mediated immunocompetence. The peak frequency of echolocation pulses was found to be positively correlated with the bats' forearm length. However, regression analysis has shown that no significant relationship exists between distress calls and overall body size, or between distress calls and overall health. These results suggest that the peak frequency of echolocation pulses may be a reliable index signal to attract conspecifics, but distress calls of bats may not convey information about their size or overall quality as conspecifics or prey. These results indicate that distress calls in bats may only convey their emotional state, to attract conspecifics and facilitate estimation of predation risk.
authors.affiliation: Jilin Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Jingyue St 2555, Changchun 130024, China.
authors.forename: Tinglei
authors.initials: T
authors.lastname: Jiang
authors.affiliation: Jilin Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Jingyue St 2555, Changchun 130024, China.
authors.forename: Xiaobin
authors.initials: X
authors.lastname: Huang
authors.affiliation: Jilin Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Jingyue St 2555, Changchun 130024, China; College of Animal Science and Technology, Jilin Agricultural University, Xincheng ST 2888, Changchun 130118, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Wu
authors.affiliation: Jilin Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Jingyue St 2555, Changchun 130024, China. Electronic address: fengj@nenu.edu.cn.
authors.forename: Jiang
authors.initials: J
authors.lastname: Feng
mesh_terms: D000162:Acoustics; D000818:Animals; D049628:Body Size; D002685:Chiroptera / Q000502:physiology*; D004455:Echolocation; D011235:Predatory Behavior; D012919:Social Behavior; D013018:Sound Spectrography; D014828:Vocalization, Animal / Q000502:physiology*
keywords: Acoustic communication; Bats; Distress calls; Honest signal; Prey quality