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Versatility and stereotypy of free-tailed bat songs.

Bohn KM, Schmidt-French B, Schwartz C, Smotherman M, Pollak GD - PLoS ONE (2009)

Bottom Line: Second, we found that although song construction was similar across regions, the number of syllables within phrases, and the number and order of phrases in songs varied greatly within and among individuals.We found broad scale phrase-order rules and certain higher order combinations that were highly preferred.We conclude that free-tailed bat songs are composed of highly stereotyped phrases hierarchically organized by a common set of syntactical rules.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Texas A&M University, College Station, Texas, USA. kbohn@bio.tamu.edu

ABSTRACT
In mammals, complex songs are uncommon and few studies have examined song composition or the order of elements in songs, particularly with respect to regional and individual variation. In this study we examine how syllables and phrases are ordered and combined, ie "syntax", of the song of Tadarida brasiliensis, the Brazilian free-tailed bat. Specifically, we test whether phrase and song composition differ among individuals and between two regions, we determine variability across renditions within individuals, and test whether phrases are randomly ordered and combined. We report three major findings. First, song phrases were highly stereotyped across two regions, so much so that some songs from the two colonies were almost indistinguishable. All males produced songs with the same four types of syllables and the same three types of phrases. Second, we found that although song construction was similar across regions, the number of syllables within phrases, and the number and order of phrases in songs varied greatly within and among individuals. Last, we determined that phrase order, although diverse, deviated from random models. We found broad scale phrase-order rules and certain higher order combinations that were highly preferred. We conclude that free-tailed bat songs are composed of highly stereotyped phrases hierarchically organized by a common set of syntactical rules. However, within global species-specific patterns, songs male free-tailed bats dynamically vary syllable number, phrase order, and phrase repetitions across song renditions.

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Spectrograms of songs from bats from the two regions.Two bats are from Austin (A and B) and two from College Station (C and D). Each chirp phrase is enclosed by a dashed rectangle, each trill is enclosed by an oval, and each buzz is enclosed by a solid rectangle. Time waveforms (Figure S1) and audio files (Audio S1–S4) of each of these songs are also provided. All songs are variants of the chirp-trill-buzz song type.
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pone-0006746-g002: Spectrograms of songs from bats from the two regions.Two bats are from Austin (A and B) and two from College Station (C and D). Each chirp phrase is enclosed by a dashed rectangle, each trill is enclosed by an oval, and each buzz is enclosed by a solid rectangle. Time waveforms (Figure S1) and audio files (Audio S1–S4) of each of these songs are also provided. All songs are variants of the chirp-trill-buzz song type.

Mentions: We first compared the phrase features at the two locations and found that the composition and structure of phrases did not differ (Table 1, Phrase Variables). Chirps were present in the songs of all males from both locations (Fig. 2). Chirp phrases at both locations had similar A and B syllables (Fig. 2), and there was no difference between the two locations in the number of A syllables that preceded each B syllable or in the number of B syllables per phrase (Table 1). The other two phrases, trills and buzzes, were also recorded from bats at the two locations. There was no difference in the number of syllables in either trills or buzzes between the two locations (Table 1).


Versatility and stereotypy of free-tailed bat songs.

Bohn KM, Schmidt-French B, Schwartz C, Smotherman M, Pollak GD - PLoS ONE (2009)

Spectrograms of songs from bats from the two regions.Two bats are from Austin (A and B) and two from College Station (C and D). Each chirp phrase is enclosed by a dashed rectangle, each trill is enclosed by an oval, and each buzz is enclosed by a solid rectangle. Time waveforms (Figure S1) and audio files (Audio S1–S4) of each of these songs are also provided. All songs are variants of the chirp-trill-buzz song type.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2727915&req=5

pone-0006746-g002: Spectrograms of songs from bats from the two regions.Two bats are from Austin (A and B) and two from College Station (C and D). Each chirp phrase is enclosed by a dashed rectangle, each trill is enclosed by an oval, and each buzz is enclosed by a solid rectangle. Time waveforms (Figure S1) and audio files (Audio S1–S4) of each of these songs are also provided. All songs are variants of the chirp-trill-buzz song type.
Mentions: We first compared the phrase features at the two locations and found that the composition and structure of phrases did not differ (Table 1, Phrase Variables). Chirps were present in the songs of all males from both locations (Fig. 2). Chirp phrases at both locations had similar A and B syllables (Fig. 2), and there was no difference between the two locations in the number of A syllables that preceded each B syllable or in the number of B syllables per phrase (Table 1). The other two phrases, trills and buzzes, were also recorded from bats at the two locations. There was no difference in the number of syllables in either trills or buzzes between the two locations (Table 1).

Bottom Line: Second, we found that although song construction was similar across regions, the number of syllables within phrases, and the number and order of phrases in songs varied greatly within and among individuals.We found broad scale phrase-order rules and certain higher order combinations that were highly preferred.We conclude that free-tailed bat songs are composed of highly stereotyped phrases hierarchically organized by a common set of syntactical rules.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Texas A&M University, College Station, Texas, USA. kbohn@bio.tamu.edu

ABSTRACT
In mammals, complex songs are uncommon and few studies have examined song composition or the order of elements in songs, particularly with respect to regional and individual variation. In this study we examine how syllables and phrases are ordered and combined, ie "syntax", of the song of Tadarida brasiliensis, the Brazilian free-tailed bat. Specifically, we test whether phrase and song composition differ among individuals and between two regions, we determine variability across renditions within individuals, and test whether phrases are randomly ordered and combined. We report three major findings. First, song phrases were highly stereotyped across two regions, so much so that some songs from the two colonies were almost indistinguishable. All males produced songs with the same four types of syllables and the same three types of phrases. Second, we found that although song construction was similar across regions, the number of syllables within phrases, and the number and order of phrases in songs varied greatly within and among individuals. Last, we determined that phrase order, although diverse, deviated from random models. We found broad scale phrase-order rules and certain higher order combinations that were highly preferred. We conclude that free-tailed bat songs are composed of highly stereotyped phrases hierarchically organized by a common set of syntactical rules. However, within global species-specific patterns, songs male free-tailed bats dynamically vary syllable number, phrase order, and phrase repetitions across song renditions.

Show MeSH