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

Song features that differed between female and male blue-capped cordon-bleus.(a) size of syllable repertoire, (b) minimum coefficient of variation for mean pitch goodness, (c) number of syllables per song, (d) duration of song (s). For (a) and (b) single values per subject, for (c) and (d) individual means ± SD are displayed. Note that for each feature subjects are displayed in ascending order within their sex group. Filled symbols represent females, open symbols represent males. For statistics see Table 2.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3198478&req=5

pone-0026485-g003: Song features that differed between female and male blue-capped cordon-bleus.(a) size of syllable repertoire, (b) minimum coefficient of variation for mean pitch goodness, (c) number of syllables per song, (d) duration of song (s). For (a) and (b) single values per subject, for (c) and (d) individual means ± SD are displayed. Note that for each feature subjects are displayed in ascending order within their sex group. Filled symbols represent females, open symbols represent males. For statistics see Table 2.

Mentions: Males sang twice as many different syllable types than females (25 versus 12, see Table 2, Fig. 3). Also, their song tended to be longer than that of females and this seemed to be due to the larger number of syllables that males incorporated into a given song - even though the difference in the number of syllables per song between females and males was not significant after correction for multiple testing (Table 2, Fig. 3). Females and males did not differ in the size of song type repertoires, the proportion of repeated syllables, the tempo and the change of pitch, both measured as the difference from last to first syllable and as correlation between pitch and sequential order of a syllable. There were no clear differences in the spectro-temporal features of females and males, i.e. none of these traits revealed a significant difference after correction for multiple testing (Table 2). However, males reached a higher level of song stereotypy with regard to pitch goodness: for this parameter males reached a significantly lower rendition-to-rendition variation than females (Fig. 3). All other measures of spectro-temporal stereotypy failed to detect sex-specific differences in the song of blue-capped cordon-bleus, and females and males did also not differ with regard to the sequential stereotypy (Table 2). The sexual dimorphism in song stereotypy with regard to pitch goodness might be related to a higher abundance of harmonic stacks in the song of males. To rule out this possibility, we compared the proportions of harmonic stacks and another characteristic class of syllables, the buzz syllables (rapid and repeated frequency modulation, with few obvious harmonics) in the repertoires of females and males. Harmonic stacks made up 24.5±23.5% of syllables in the repertoires of females and 29.2±10.4% in the repertoires of males and this proportion was not different (independent samples t-test: t = −0.55, df = 16, p = 0.59). Buzz syllables made up 13.7±1.3% of syllables in the repertoires of females and 11.2±0.3% in the repertoires of males and this proportion was also not different (independent samples t-test: t = 0.56, df = 9, p = 0.59).


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

Geberzahn N, Gahr M - PLoS ONE (2011)

Song features that differed between female and male blue-capped cordon-bleus.(a) size of syllable repertoire, (b) minimum coefficient of variation for mean pitch goodness, (c) number of syllables per song, (d) duration of song (s). For (a) and (b) single values per subject, for (c) and (d) individual means ± SD are displayed. Note that for each feature subjects are displayed in ascending order within their sex group. Filled symbols represent females, open symbols represent males. For statistics see Table 2.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0026485-g003: Song features that differed between female and male blue-capped cordon-bleus.(a) size of syllable repertoire, (b) minimum coefficient of variation for mean pitch goodness, (c) number of syllables per song, (d) duration of song (s). For (a) and (b) single values per subject, for (c) and (d) individual means ± SD are displayed. Note that for each feature subjects are displayed in ascending order within their sex group. Filled symbols represent females, open symbols represent males. For statistics see Table 2.
Mentions: Males sang twice as many different syllable types than females (25 versus 12, see Table 2, Fig. 3). Also, their song tended to be longer than that of females and this seemed to be due to the larger number of syllables that males incorporated into a given song - even though the difference in the number of syllables per song between females and males was not significant after correction for multiple testing (Table 2, Fig. 3). Females and males did not differ in the size of song type repertoires, the proportion of repeated syllables, the tempo and the change of pitch, both measured as the difference from last to first syllable and as correlation between pitch and sequential order of a syllable. There were no clear differences in the spectro-temporal features of females and males, i.e. none of these traits revealed a significant difference after correction for multiple testing (Table 2). However, males reached a higher level of song stereotypy with regard to pitch goodness: for this parameter males reached a significantly lower rendition-to-rendition variation than females (Fig. 3). All other measures of spectro-temporal stereotypy failed to detect sex-specific differences in the song of blue-capped cordon-bleus, and females and males did also not differ with regard to the sequential stereotypy (Table 2). The sexual dimorphism in song stereotypy with regard to pitch goodness might be related to a higher abundance of harmonic stacks in the song of males. To rule out this possibility, we compared the proportions of harmonic stacks and another characteristic class of syllables, the buzz syllables (rapid and repeated frequency modulation, with few obvious harmonics) in the repertoires of females and males. Harmonic stacks made up 24.5±23.5% of syllables in the repertoires of females and 29.2±10.4% in the repertoires of males and this proportion was not different (independent samples t-test: t = −0.55, df = 16, p = 0.59). Buzz syllables made up 13.7±1.3% of syllables in the repertoires of females and 11.2±0.3% in the repertoires of males and this proportion was also not different (independent samples t-test: t = 0.56, df = 9, p = 0.59).

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