Intrasexual selection drives sensitivity to pitch, formants and duration in the competitive calls of fallow bucks
Open access
Date
2015-08Type
- Journal Article
Abstract
Background
Mammal vocal parameters such as fundamental frequency (or pitch; f o ) and formant dispersion often provide information about quality traits of the producer (e.g. dominance and body size), suggesting that they are sexually selected. However, little experimental evidence exists demonstrating the importance of these cues in intrasexual competition, particularly f o . Male Fallow deer (bucks) produce an extremely low pitched groan. Bucks have a descended larynx and generate f o well below what is expected for animals of their size. Groan parameters are linked to caller dominance, body size and condition, suggesting that groans are the product of sexual selection. Using a playback experiment, we presented bucks with groans that had been manipulated to alter vocal cues to these male characteristics and compared the response to the same, non-modified (natural) groans.
Results
We experimentally examined the ability of bucks to utilise putative cues to dominance (f o ), body size (formant frequencies) and condition (groan duration), when assessing competitors. We found that bucks treated groans with lowered f o (more dominant), and lowered formant frequencies (larger caller) as more threatening. By contrast, groans with raised formant frequencies (smaller caller), and shorter durations (more fatigued caller) were treated as less threatening.
Conclusions
Our results indicate that intrasexual selection is driving groans to concurrently convey caller dominance, body size and condition. They represent the first experimental demonstration of the importance of f o in male competition in non-human mammals, and show that bucks have advanced perception abilities that allow them to extract information based on relatively small changes in key parameters. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000103611Publication status
publishedExternal links
Journal / series
BMC Evolutionary BiologyVolume
Pages / Article No.
Publisher
BioMed CentralSubject
Body size; Condition; Dominance; Fundamental frequency; Male-male competition; Sexual selection; Signalling; VocalOrganisational unit
08682 - Einheit für Verhalten, Gesundheit und Tierwohl
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