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Multiple song features are related to paternal effort in common nightingales.

Bartsch C, Weiss M, Kipper S - BMC Evol. Biol. (2015)

Bottom Line: Using RFID technology to record male feeding visits to the nest, we found that nightingale males substantially contribute to chick feeding.We found that several song features, namely measures of song complexity and song sequencing, were correlated with male feeding rates.Females may assess future paternal care on the basis of song features identified in our study and thus these features may have evolved to signal direct benefits to females.

View Article: PubMed Central - PubMed

Affiliation: Animal Behavior Group, Freie Universität Berlin, Takustraße 6, 14195, Berlin, Germany. connebartsch@gmail.com.

ABSTRACT

Background: Sexual ornamentation may be related to the degree of paternal care and the 'good-parent' model predicts that male secondary characters honestly advertise paternal investment. In most birds, males are involved in bringing up the young and successful reproduction highly depends on male contribution during breeding. In passerines, male song is indicative of male attributes and for few species it has been shown that song features also signal paternal investment to females. Males of nightingales Luscinia megarhynchos are famous for their elaborate singing but so far there is only little knowledge on the role of male song in intersexual communication, and it is unknown whether male song predicts male parenting abilities.

Results: Using RFID technology to record male feeding visits to the nest, we found that nightingale males substantially contribute to chick feeding. Also, we analyzed male nocturnal song with focus on song features that have been shown to signal male quality before. We found that several song features, namely measures of song complexity and song sequencing, were correlated with male feeding rates. Moreover, the combination of these song features had strong predictive power for male contribution to nestling feeding.

Conclusions: Since male nightingales are involved in chick rearing, paternal investment might be a crucial variable for female mate choice in this species. Females may assess future paternal care on the basis of song features identified in our study and thus these features may have evolved to signal direct benefits to females. Additionally we underline the importance of multiple acoustic cues for female mating decisions especially in species with complex song such as the nightingale.

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Example songs of nightingale song categories. The acoustic patterns that constitute categories are underlined in grey. (a): whistle song, characterized by a homotype series of repeated elements with a narrow frequency band and little or no frequency modulation. (b): trill song, characterized by a rapid broad-band trill consisting of repeated elements with little frequency modulation but covering a large frequency range. (c): buzz song, characterized by a long, non-repeated buzz element produced by a very fast repetition of sound units in a narrow and rather low frequency range
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Fig1: Example songs of nightingale song categories. The acoustic patterns that constitute categories are underlined in grey. (a): whistle song, characterized by a homotype series of repeated elements with a narrow frequency band and little or no frequency modulation. (b): trill song, characterized by a rapid broad-band trill consisting of repeated elements with little frequency modulation but covering a large frequency range. (c): buzz song, characterized by a long, non-repeated buzz element produced by a very fast repetition of sound units in a narrow and rather low frequency range

Mentions: The common nightingale Luscinia megarhynchos is a socially monogamous passerine and from few previous observations it is known that males provide paternal care during breeding. They, for example, feed the female during incubation, provide food to nestlings and readily defend the nest against potential predators [32, 33]; CB, personal observation). Thus, reproductive success seems to be highly dependent on male contribution, making it most probable that in nightingales male parenting abilities are a crucial factor in mate choice. Furthermore, nightingales belong to the most versatile singers of the temperate zone [20]. Males have very large song repertoires of up to 250 different song types (approx. 180 different song types per male, e.g. [34, 35]) with large repertoire birds being older [36], being in better condition and arriving earlier at the breeding grounds [35]. Within repertoires, specific features of certain songs seem to carry information that might be important during different behavioral contexts, which constitutes the basis for the formation of song categories (e.g. buzz songs: [37]; trill songs: [38]; whistle songs: [39, 40]; see also Fig. 1). Furthermore, the nightingale is an excellent model to study the functional aspect of complex ‘syntax-like’ rules of song delivery. Song sequencing in nightingales is neither fully fixed (e.g. singing in an A-Z manner), nor random, but instead follows sequential rules that are partly controlled by early learning and memory retrieval processes, e.g. [41–43]. However, these sequential rules are not fully deterministic, but offer potential for behavioral plasticity both short- and long-term. For example, males change their repertoire composition and song sequencing with age, which is most probably attributed to an adjustment to the breeding population [44–46], or they change the sequencing of songs in response to playbacks [47]. Also, the usage of specific song types (i.e. song categories) is related to different behavioral contexts or different times during the day and the breeding cycle, e.g. [39, 48–52] which additionally affects the sequencing of songs. Very recently it has been shown that the sequential ordering of song types is related to male attributes. For example, older males sing their songs more ordered (i.e. they sing song sequences repeatedly in the same order) and membership to a population seems to be encoded in song sequencing (i.e. members of the same population share song sequences) [46, 47]. These findings imply that the sequential ordering of nightingale song may carry information which is relevant for females during mate choice.Fig. 1


Multiple song features are related to paternal effort in common nightingales.

Bartsch C, Weiss M, Kipper S - BMC Evol. Biol. (2015)

Example songs of nightingale song categories. The acoustic patterns that constitute categories are underlined in grey. (a): whistle song, characterized by a homotype series of repeated elements with a narrow frequency band and little or no frequency modulation. (b): trill song, characterized by a rapid broad-band trill consisting of repeated elements with little frequency modulation but covering a large frequency range. (c): buzz song, characterized by a long, non-repeated buzz element produced by a very fast repetition of sound units in a narrow and rather low frequency range
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4471916&req=5

Fig1: Example songs of nightingale song categories. The acoustic patterns that constitute categories are underlined in grey. (a): whistle song, characterized by a homotype series of repeated elements with a narrow frequency band and little or no frequency modulation. (b): trill song, characterized by a rapid broad-band trill consisting of repeated elements with little frequency modulation but covering a large frequency range. (c): buzz song, characterized by a long, non-repeated buzz element produced by a very fast repetition of sound units in a narrow and rather low frequency range
Mentions: The common nightingale Luscinia megarhynchos is a socially monogamous passerine and from few previous observations it is known that males provide paternal care during breeding. They, for example, feed the female during incubation, provide food to nestlings and readily defend the nest against potential predators [32, 33]; CB, personal observation). Thus, reproductive success seems to be highly dependent on male contribution, making it most probable that in nightingales male parenting abilities are a crucial factor in mate choice. Furthermore, nightingales belong to the most versatile singers of the temperate zone [20]. Males have very large song repertoires of up to 250 different song types (approx. 180 different song types per male, e.g. [34, 35]) with large repertoire birds being older [36], being in better condition and arriving earlier at the breeding grounds [35]. Within repertoires, specific features of certain songs seem to carry information that might be important during different behavioral contexts, which constitutes the basis for the formation of song categories (e.g. buzz songs: [37]; trill songs: [38]; whistle songs: [39, 40]; see also Fig. 1). Furthermore, the nightingale is an excellent model to study the functional aspect of complex ‘syntax-like’ rules of song delivery. Song sequencing in nightingales is neither fully fixed (e.g. singing in an A-Z manner), nor random, but instead follows sequential rules that are partly controlled by early learning and memory retrieval processes, e.g. [41–43]. However, these sequential rules are not fully deterministic, but offer potential for behavioral plasticity both short- and long-term. For example, males change their repertoire composition and song sequencing with age, which is most probably attributed to an adjustment to the breeding population [44–46], or they change the sequencing of songs in response to playbacks [47]. Also, the usage of specific song types (i.e. song categories) is related to different behavioral contexts or different times during the day and the breeding cycle, e.g. [39, 48–52] which additionally affects the sequencing of songs. Very recently it has been shown that the sequential ordering of song types is related to male attributes. For example, older males sing their songs more ordered (i.e. they sing song sequences repeatedly in the same order) and membership to a population seems to be encoded in song sequencing (i.e. members of the same population share song sequences) [46, 47]. These findings imply that the sequential ordering of nightingale song may carry information which is relevant for females during mate choice.Fig. 1

Bottom Line: Using RFID technology to record male feeding visits to the nest, we found that nightingale males substantially contribute to chick feeding.We found that several song features, namely measures of song complexity and song sequencing, were correlated with male feeding rates.Females may assess future paternal care on the basis of song features identified in our study and thus these features may have evolved to signal direct benefits to females.

View Article: PubMed Central - PubMed

Affiliation: Animal Behavior Group, Freie Universität Berlin, Takustraße 6, 14195, Berlin, Germany. connebartsch@gmail.com.

ABSTRACT

Background: Sexual ornamentation may be related to the degree of paternal care and the 'good-parent' model predicts that male secondary characters honestly advertise paternal investment. In most birds, males are involved in bringing up the young and successful reproduction highly depends on male contribution during breeding. In passerines, male song is indicative of male attributes and for few species it has been shown that song features also signal paternal investment to females. Males of nightingales Luscinia megarhynchos are famous for their elaborate singing but so far there is only little knowledge on the role of male song in intersexual communication, and it is unknown whether male song predicts male parenting abilities.

Results: Using RFID technology to record male feeding visits to the nest, we found that nightingale males substantially contribute to chick feeding. Also, we analyzed male nocturnal song with focus on song features that have been shown to signal male quality before. We found that several song features, namely measures of song complexity and song sequencing, were correlated with male feeding rates. Moreover, the combination of these song features had strong predictive power for male contribution to nestling feeding.

Conclusions: Since male nightingales are involved in chick rearing, paternal investment might be a crucial variable for female mate choice in this species. Females may assess future paternal care on the basis of song features identified in our study and thus these features may have evolved to signal direct benefits to females. Additionally we underline the importance of multiple acoustic cues for female mating decisions especially in species with complex song such as the nightingale.

Show MeSH