LAUSR

Signals containing parameter trade-offs are likely to be honest indicators of signaler quality, because they are difficult to produce. Signals with a trill-rate/bandwidth trade-off have been described for many songbird species, one mouse and one non-human primate species. However, there were no reports about whether there is a vocal performance trade-off in social calls of bats. This study investigated (1) a possible vocal performance trade-off in territorial calls of male Great Himalayan leaf-nosed bats, Hipposideros armiger, recorded from nine locations in south China, and (2) the relationships between vocal performance (vocal deviation and consistency) and caller's quality (body mass) to determine whether vocal performance honestly indicates a caller's quality. Vocal deviation measures the deviation of a call relative to an extreme call and vocal consistency measures the spectral consistency across a string of syllables. Our results showed a significant negative correlation between syllable repetition rate and frequency bandwidth, suggesting a vocal performance trade-off similar to the one in songbirds. Further, there was a significant negative relationship between body mass and vocal deviation, but no significant correlation between body mass and vocal consistency. This study provides the first empirical evidence for a vocal performance trade-off of social calls in bats, and the potential for the level of performance to indicate caller quality. This article is protected by copyright. All rights reserved.