Limits...
Undirected (solitary) birdsong in female and male blue-capped cordon-bleus (Uraeginthus cyanocephalus) and its endocrine correlates.

Geberzahn N, Gahr M - PLoS ONE (2011)

Bottom Line: However, in both sexes the overall plasma testosterone concentrations were low (ca. 300 pg/ml) and did not correlate with the sexually dimorphic song motor pattern.Despite such low concentrations, the increase in the rate of solitary song coincided with an increase in the level of testosterone.Our findings suggest that the occurrence of solitary song but not its motor pattern might be under the control of testosterone in female and male cordon-bleus.

View Article: PubMed Central - PubMed

Affiliation: Department of Behavioural Neurobiology, Max Planck Institute for Ornithology, Seewiesen, Germany. nicole.geberzahn@u-psud.fr

ABSTRACT

Background: Birdsong is a popular model system in research areas such as vocal communication, neuroethology or neuroendocrinology of behaviour. As most research has been conducted on species with male-only song production, the hormone-dependency of male song is well established. However, female singing and its mechanisms are poorly understood.

Methodology/principal findings: We characterised the song and its endocrine correlates of blue-capped cordon-bleus (Uraeginthus cyanocephalus), a species in which both sexes sing. Like other estrildids, they produce directed song during courtship and undirected (or solitary) song in isolation, i.e. when the mate is not visible or absent. We compare solitary song of blue-capped cordon-bleus to published descriptions of the song of its relative, the zebra finch (Taeniopygia guttata). Solitary song of cordon-bleus shared some overall song features with that of zebra finches but differed in spectro-temporal song features, sequential stereotypy and sequential organisation. The song of cordon-bleus was dimorphic with respect to the larger size of syllable repertoires, the higher song duration and the lower variability of pitch goodness (measuring the pureness of harmonic sounds) in males. However, in both sexes the overall plasma testosterone concentrations were low (ca. 300 pg/ml) and did not correlate with the sexually dimorphic song motor pattern. Despite such low concentrations, the increase in the rate of solitary song coincided with an increase in the level of testosterone. Furthermore, the latency to start singing after the separation from the mate was related to hormone levels.

Conclusions/significance: Our findings suggest that the occurrence of solitary song but not its motor pattern might be under the control of testosterone in female and male cordon-bleus.

Show MeSH

Related in: MedlinePlus

All males and females with high testosterone levels sang rapidly after separation from their mate.Latency to sing solitary song (s) as a function of testosterone concentration (pg/ml) in the blood plasma. Filled symbols and the solid line represent females; open symbols and the broken line represent males.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3198478&req=5

pone-0026485-g005: All males and females with high testosterone levels sang rapidly after separation from their mate.Latency to sing solitary song (s) as a function of testosterone concentration (pg/ml) in the blood plasma. Filled symbols and the solid line represent females; open symbols and the broken line represent males.

Mentions: To investigate whether the occurrence of solitary song was correlated with an increase of testosterone, we first compared the level of testosterone during baseline condition and during solitary-song-induced condition. As there were no differences in the level of testosterone between males and females in both conditions (baseline: independent samples t-test: t = −1.44, df = 15, p = 0.17; solitary-song-induced: independent samples t-test: t = −1.33, df = 16, p = 0.20) we pooled data of males and females to compare between the different treatment conditions. Birds had significantly higher levels of testosterone in the solitary-induced condition than in the baseline condition (mean ± SD mean: 375.29±204.70 versus 239.32±103.20 pg/ml, paired-samples t-test: t = −3.05, df = 16, p = 0.008, Fig. 4) and when testing the sexes separately a trend remained for both of them (paired-samples t-test: females t = −2.02, df = 8, p = 0.08; males: t = −2.22, df = 7, p = 0.06, Fig. 4). Reanalysing these data including the one outlier (one male had a level of testosterone of 1767.84 pg/ml in the baseline condition) did not change the results except that males' levels of testosterone in the reanalysis clearly did not differ between baseline and solitary-induced condition when tested separately. Furthermore, we compared levels of testosterone in the solitary-song-induced condition with performance related song features. Testosterone did not correlate with the number of songs produced in the one hour of separation (Pearson's correlation test: r = 0.27, N = 18, p = 0.28). Visual inspection of the graphs plotting latency to sing against the concentration of testosterone suggested a trend in females, but the correlation just failed to be significant (Pearson's correlation test: r = −0.65, N = 9, p = 0.06; Fig. 5). In males, no such trend could be observed (Pearson's correlation test: r = −0.15, N = 9, p = 0.69; Fig. 5). Thus, those blue-capped cordon-bleu females with higher levels of testosterone tended to sing earlier after their mate was removed, besides that all males started to sing early. However, when analysing data of females and males together, the relationship between testosterone and latency to sing becomes significant (Pearson's correlation test: r = −0.49, N = 18, p = 0.04). Thus, further studies are needed to confirm that this is an effect in females only. Finally, we compared levels of testosterone in the solitary-song-induced condition (pooled for both sexes) with overall song features, spectro-temporal features and stereotypy. None of these parameters correlated with the level of testosterone (Spearman's rank or Pearson's correlations test: overall song features: /r/<0.32, N = 18, p>0.19; spectro-temporal features: /r/<0.37, N = 18, p>0.12; spectro-temporal stereotypy: /r/<0.25, N = 18, p>0.30, sequential stereotypy: /r/<0.18, N = 18, p>0.47).


Undirected (solitary) birdsong in female and male blue-capped cordon-bleus (Uraeginthus cyanocephalus) and its endocrine correlates.

Geberzahn N, Gahr M - PLoS ONE (2011)

All males and females with high testosterone levels sang rapidly after separation from their mate.Latency to sing solitary song (s) as a function of testosterone concentration (pg/ml) in the blood plasma. Filled symbols and the solid line represent females; open symbols and the broken line represent males.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3198478&req=5

pone-0026485-g005: All males and females with high testosterone levels sang rapidly after separation from their mate.Latency to sing solitary song (s) as a function of testosterone concentration (pg/ml) in the blood plasma. Filled symbols and the solid line represent females; open symbols and the broken line represent males.
Mentions: To investigate whether the occurrence of solitary song was correlated with an increase of testosterone, we first compared the level of testosterone during baseline condition and during solitary-song-induced condition. As there were no differences in the level of testosterone between males and females in both conditions (baseline: independent samples t-test: t = −1.44, df = 15, p = 0.17; solitary-song-induced: independent samples t-test: t = −1.33, df = 16, p = 0.20) we pooled data of males and females to compare between the different treatment conditions. Birds had significantly higher levels of testosterone in the solitary-induced condition than in the baseline condition (mean ± SD mean: 375.29±204.70 versus 239.32±103.20 pg/ml, paired-samples t-test: t = −3.05, df = 16, p = 0.008, Fig. 4) and when testing the sexes separately a trend remained for both of them (paired-samples t-test: females t = −2.02, df = 8, p = 0.08; males: t = −2.22, df = 7, p = 0.06, Fig. 4). Reanalysing these data including the one outlier (one male had a level of testosterone of 1767.84 pg/ml in the baseline condition) did not change the results except that males' levels of testosterone in the reanalysis clearly did not differ between baseline and solitary-induced condition when tested separately. Furthermore, we compared levels of testosterone in the solitary-song-induced condition with performance related song features. Testosterone did not correlate with the number of songs produced in the one hour of separation (Pearson's correlation test: r = 0.27, N = 18, p = 0.28). Visual inspection of the graphs plotting latency to sing against the concentration of testosterone suggested a trend in females, but the correlation just failed to be significant (Pearson's correlation test: r = −0.65, N = 9, p = 0.06; Fig. 5). In males, no such trend could be observed (Pearson's correlation test: r = −0.15, N = 9, p = 0.69; Fig. 5). Thus, those blue-capped cordon-bleu females with higher levels of testosterone tended to sing earlier after their mate was removed, besides that all males started to sing early. However, when analysing data of females and males together, the relationship between testosterone and latency to sing becomes significant (Pearson's correlation test: r = −0.49, N = 18, p = 0.04). Thus, further studies are needed to confirm that this is an effect in females only. Finally, we compared levels of testosterone in the solitary-song-induced condition (pooled for both sexes) with overall song features, spectro-temporal features and stereotypy. None of these parameters correlated with the level of testosterone (Spearman's rank or Pearson's correlations test: overall song features: /r/<0.32, N = 18, p>0.19; spectro-temporal features: /r/<0.37, N = 18, p>0.12; spectro-temporal stereotypy: /r/<0.25, N = 18, p>0.30, sequential stereotypy: /r/<0.18, N = 18, p>0.47).

Bottom Line: However, in both sexes the overall plasma testosterone concentrations were low (ca. 300 pg/ml) and did not correlate with the sexually dimorphic song motor pattern.Despite such low concentrations, the increase in the rate of solitary song coincided with an increase in the level of testosterone.Our findings suggest that the occurrence of solitary song but not its motor pattern might be under the control of testosterone in female and male cordon-bleus.

View Article: PubMed Central - PubMed

Affiliation: Department of Behavioural Neurobiology, Max Planck Institute for Ornithology, Seewiesen, Germany. nicole.geberzahn@u-psud.fr

ABSTRACT

Background: Birdsong is a popular model system in research areas such as vocal communication, neuroethology or neuroendocrinology of behaviour. As most research has been conducted on species with male-only song production, the hormone-dependency of male song is well established. However, female singing and its mechanisms are poorly understood.

Methodology/principal findings: We characterised the song and its endocrine correlates of blue-capped cordon-bleus (Uraeginthus cyanocephalus), a species in which both sexes sing. Like other estrildids, they produce directed song during courtship and undirected (or solitary) song in isolation, i.e. when the mate is not visible or absent. We compare solitary song of blue-capped cordon-bleus to published descriptions of the song of its relative, the zebra finch (Taeniopygia guttata). Solitary song of cordon-bleus shared some overall song features with that of zebra finches but differed in spectro-temporal song features, sequential stereotypy and sequential organisation. The song of cordon-bleus was dimorphic with respect to the larger size of syllable repertoires, the higher song duration and the lower variability of pitch goodness (measuring the pureness of harmonic sounds) in males. However, in both sexes the overall plasma testosterone concentrations were low (ca. 300 pg/ml) and did not correlate with the sexually dimorphic song motor pattern. Despite such low concentrations, the increase in the rate of solitary song coincided with an increase in the level of testosterone. Furthermore, the latency to start singing after the separation from the mate was related to hormone levels.

Conclusions/significance: Our findings suggest that the occurrence of solitary song but not its motor pattern might be under the control of testosterone in female and male cordon-bleus.

Show MeSH
Related in: MedlinePlus