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Context-related acoustic variation in male fallow deer (Dama dama) groans.

Charlton BD, Reby D - PLoS ONE (2011)

Bottom Line: We attribute this to the increased arousal state typically associated with this context.This indicates that, contrary to our predictions, male fallow deer do not exaggerate the acoustic impression of their body size by further lowering their formant frequencies in the presence of potential mating partners and competitors.Furthermore, since the magnitude of the variation in groan minimum formant frequency spacing remains small compared to documented inter-individual differences, our findings are consistent with the hypothesis that formants are reliable static cues to body size during intra- and inter-sexual advertisement that do not concurrently encode dynamic motivation-related information.

View Article: PubMed Central - PubMed

Affiliation: Department of Cognitive Biology, University of Vienna, Vienna, Austria.

ABSTRACT
While social and behavioural contexts are known to affect the acoustic structure of vocal signals in several mammal species, few studies have investigated context-related acoustic variation during inter-sexual advertisement and/or intra-sexual competition. Here we recorded male fallow deer groans during the breeding season and investigated how key acoustic parameters (fundamental frequency and formant frequencies) vary as a function of the social context in which they are produced. We found that in the presence of females, male fallow deer produced groans with higher mean fundamental frequency when vocal males were also present than they did when no vocal males were in close vicinity. We attribute this to the increased arousal state typically associated with this context. In addition, groan minimum formant frequency spacing was slightly, but significantly lower (indicating marginally more extended vocal tracts) when males were alone than when potential mates and/or competitors were nearby. This indicates that, contrary to our predictions, male fallow deer do not exaggerate the acoustic impression of their body size by further lowering their formant frequencies in the presence of potential mating partners and competitors. Furthermore, since the magnitude of the variation in groan minimum formant frequency spacing remains small compared to documented inter-individual differences, our findings are consistent with the hypothesis that formants are reliable static cues to body size during intra- and inter-sexual advertisement that do not concurrently encode dynamic motivation-related information.

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Estimated marginal means ± SE for the effect of social context (alone, with a vocal male, with a female, with a female and a vocal male) on mean F0 (A) and minimum ΔF (B).Mean responses sharing the same letter are not significantly different.
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pone-0021066-g001: Estimated marginal means ± SE for the effect of social context (alone, with a vocal male, with a female, with a female and a vocal male) on mean F0 (A) and minimum ΔF (B).Mean responses sharing the same letter are not significantly different.

Mentions: The social context of recording had a significant effect on groan F0 (F3, 246 = 3.637, p = 0.013). The pair-wise comparisons showed that males with females produced groans with higher mean F0 when another vocal male was present (mean ± S.E. = 32.1±0.93 Hz) than they did when no other vocal male was close by (mean ± S.E. = 29.2±0.97 Hz; P = 0.032) or when they were alone (mean ± S.E. = 29.4±0.92 Hz; P = 0.030), but not significantly higher than when only a vocal male was present (mean ± S.E. = 30.2±1.11 Hz; P = 0.359) (see Figure 1A). No significant differences were detected in the mean F0 of male groans between the other social contexts (see Figure 1A).


Context-related acoustic variation in male fallow deer (Dama dama) groans.

Charlton BD, Reby D - PLoS ONE (2011)

Estimated marginal means ± SE for the effect of social context (alone, with a vocal male, with a female, with a female and a vocal male) on mean F0 (A) and minimum ΔF (B).Mean responses sharing the same letter are not significantly different.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3113910&req=5

pone-0021066-g001: Estimated marginal means ± SE for the effect of social context (alone, with a vocal male, with a female, with a female and a vocal male) on mean F0 (A) and minimum ΔF (B).Mean responses sharing the same letter are not significantly different.
Mentions: The social context of recording had a significant effect on groan F0 (F3, 246 = 3.637, p = 0.013). The pair-wise comparisons showed that males with females produced groans with higher mean F0 when another vocal male was present (mean ± S.E. = 32.1±0.93 Hz) than they did when no other vocal male was close by (mean ± S.E. = 29.2±0.97 Hz; P = 0.032) or when they were alone (mean ± S.E. = 29.4±0.92 Hz; P = 0.030), but not significantly higher than when only a vocal male was present (mean ± S.E. = 30.2±1.11 Hz; P = 0.359) (see Figure 1A). No significant differences were detected in the mean F0 of male groans between the other social contexts (see Figure 1A).

Bottom Line: We attribute this to the increased arousal state typically associated with this context.This indicates that, contrary to our predictions, male fallow deer do not exaggerate the acoustic impression of their body size by further lowering their formant frequencies in the presence of potential mating partners and competitors.Furthermore, since the magnitude of the variation in groan minimum formant frequency spacing remains small compared to documented inter-individual differences, our findings are consistent with the hypothesis that formants are reliable static cues to body size during intra- and inter-sexual advertisement that do not concurrently encode dynamic motivation-related information.

View Article: PubMed Central - PubMed

Affiliation: Department of Cognitive Biology, University of Vienna, Vienna, Austria.

ABSTRACT
While social and behavioural contexts are known to affect the acoustic structure of vocal signals in several mammal species, few studies have investigated context-related acoustic variation during inter-sexual advertisement and/or intra-sexual competition. Here we recorded male fallow deer groans during the breeding season and investigated how key acoustic parameters (fundamental frequency and formant frequencies) vary as a function of the social context in which they are produced. We found that in the presence of females, male fallow deer produced groans with higher mean fundamental frequency when vocal males were also present than they did when no vocal males were in close vicinity. We attribute this to the increased arousal state typically associated with this context. In addition, groan minimum formant frequency spacing was slightly, but significantly lower (indicating marginally more extended vocal tracts) when males were alone than when potential mates and/or competitors were nearby. This indicates that, contrary to our predictions, male fallow deer do not exaggerate the acoustic impression of their body size by further lowering their formant frequencies in the presence of potential mating partners and competitors. Furthermore, since the magnitude of the variation in groan minimum formant frequency spacing remains small compared to documented inter-individual differences, our findings are consistent with the hypothesis that formants are reliable static cues to body size during intra- and inter-sexual advertisement that do not concurrently encode dynamic motivation-related information.

Show MeSH