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Acoustic and temporal partitioning of cicada assemblages in city and mountain environments.

Shieh BS, Liang SH, Chiu YW - PLoS ONE (2015)

Bottom Line: Heterospecific spectral overlap was low in both city and mountain environments, although city and mountain cicada assemblages were subject to significantly different levels of anthropogenic or interspecific noise.Furthermore, for the common species found in both environments, the calling activity patterns at both seasonal and diel time scales were significantly consistent across sites and across environments.As a result, cicada assemblages in city environments with low species diversity do not demonstrate a more significant temporal partitioning than those in mountain environments with high species diversity.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung, Taiwan.

ABSTRACT
Comparing adaptations to noisy city environments with those to natural mountain environments on the community level can provide significant insights that allow an understanding of the impact of anthropogenic noise on invertebrates that employ loud calling songs for mate attraction, especially when each species has its distinct song, as in the case of cicadas. In this study, we investigated the partitioning strategy of cicada assemblages in city and mountain environments by comparing the acoustic features and calling activity patterns of each species, recorded using automated digital recording systems. Our comparison of activity patterns of seasonal and diel calling revealed that there was no significant temporal partitioning of cicada assemblages in either environment. In addition, there was no correlation between the acoustic distance based on spectral features and temporal segregation. Heterospecific spectral overlap was low in both city and mountain environments, although city and mountain cicada assemblages were subject to significantly different levels of anthropogenic or interspecific noise. Furthermore, for the common species found in both environments, the calling activity patterns at both seasonal and diel time scales were significantly consistent across sites and across environments. We suggest that the temporal calling activity is constrained by endogenous factors for each species and is less flexible in response to external factors, such as anthropogenic noise. As a result, cicada assemblages in city environments with low species diversity do not demonstrate a more significant temporal partitioning than those in mountain environments with high species diversity.

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Spectrograms of cicada calling songs of mixed patterns.
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pone.0116794.g003: Spectrograms of cicada calling songs of mixed patterns.

Mentions: All cicada calling songs were classified into three categories according to the time-frequency patterns on spectrograms: (A) tonal band patterns, which consists of continuous frequency bands only (Fig. 1); (B) pulse trains patterns, which consists of monotypic pulse notes (Fig. 2); and (C) mixed patterns, which consists of more than two types of pulse notes or different types of notes such as pulse and frequency bands (Fig. 3). For calling songs of mixed patterns, a song sample was easily defined by examining the smallest stereotypic repetition of similar elements on the spectrograms (a repetition song). However, for most calling songs consisting of tonal band patterns and pulse trains patterns, the clear separation of individual calling songs from recordings of the automated digital systems was rare. Therefore, we cropped a 15–30 sec long calling sound of good quality as a sample from each recording for those species (a cropped song). In addition, we adjusted the low cut frequency for each species to remove the noise before making parameter measurements on the spectrograms. The sample unit and low cut frequency for each species were set as follows: a cropped song and 3 kHz low cut frequency for Cr. atrata (S1 Sound), a cropped song and 3 kHz low cut frequency for Ch. ochracea (S2 Sound), a cropped song and 1 kHz low cut frequency for S. watanabei (S3 Sound), a repetition song and 6 kHz low cut frequency for Pl. takasagona (S4 Sound), a cropped song and 1.5 kHz low cut frequency for Cr. holsti (S5 Sound), a cropped song and 2 kHz low cut frequency for Cr. takasagona (S6 Sound), a cropped song and 2 kHz low cut frequency for T. viridis (S7 Sound), a repetition song and 3 kHz low cut frequency for L. sakaii (S8 Sound); a repetition song and 1 kHz low cut frequency for E. gina (S9 Sound), a repetition song and 5 kHz low cut frequency for Mo. formosana (S10 Sound), a repetition song and 1.5 kHz low cut frequency for Me. opalifera (S11 Sound), a repetition song and 1 kHz low cut frequency for Po. linearis (S12 Sound), and a repetition song and 1 kHz low cut frequency for T. taipinensis (S13 Sound).


Acoustic and temporal partitioning of cicada assemblages in city and mountain environments.

Shieh BS, Liang SH, Chiu YW - PLoS ONE (2015)

Spectrograms of cicada calling songs of mixed patterns.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4295890&req=5

pone.0116794.g003: Spectrograms of cicada calling songs of mixed patterns.
Mentions: All cicada calling songs were classified into three categories according to the time-frequency patterns on spectrograms: (A) tonal band patterns, which consists of continuous frequency bands only (Fig. 1); (B) pulse trains patterns, which consists of monotypic pulse notes (Fig. 2); and (C) mixed patterns, which consists of more than two types of pulse notes or different types of notes such as pulse and frequency bands (Fig. 3). For calling songs of mixed patterns, a song sample was easily defined by examining the smallest stereotypic repetition of similar elements on the spectrograms (a repetition song). However, for most calling songs consisting of tonal band patterns and pulse trains patterns, the clear separation of individual calling songs from recordings of the automated digital systems was rare. Therefore, we cropped a 15–30 sec long calling sound of good quality as a sample from each recording for those species (a cropped song). In addition, we adjusted the low cut frequency for each species to remove the noise before making parameter measurements on the spectrograms. The sample unit and low cut frequency for each species were set as follows: a cropped song and 3 kHz low cut frequency for Cr. atrata (S1 Sound), a cropped song and 3 kHz low cut frequency for Ch. ochracea (S2 Sound), a cropped song and 1 kHz low cut frequency for S. watanabei (S3 Sound), a repetition song and 6 kHz low cut frequency for Pl. takasagona (S4 Sound), a cropped song and 1.5 kHz low cut frequency for Cr. holsti (S5 Sound), a cropped song and 2 kHz low cut frequency for Cr. takasagona (S6 Sound), a cropped song and 2 kHz low cut frequency for T. viridis (S7 Sound), a repetition song and 3 kHz low cut frequency for L. sakaii (S8 Sound); a repetition song and 1 kHz low cut frequency for E. gina (S9 Sound), a repetition song and 5 kHz low cut frequency for Mo. formosana (S10 Sound), a repetition song and 1.5 kHz low cut frequency for Me. opalifera (S11 Sound), a repetition song and 1 kHz low cut frequency for Po. linearis (S12 Sound), and a repetition song and 1 kHz low cut frequency for T. taipinensis (S13 Sound).

Bottom Line: Heterospecific spectral overlap was low in both city and mountain environments, although city and mountain cicada assemblages were subject to significantly different levels of anthropogenic or interspecific noise.Furthermore, for the common species found in both environments, the calling activity patterns at both seasonal and diel time scales were significantly consistent across sites and across environments.As a result, cicada assemblages in city environments with low species diversity do not demonstrate a more significant temporal partitioning than those in mountain environments with high species diversity.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung, Taiwan.

ABSTRACT
Comparing adaptations to noisy city environments with those to natural mountain environments on the community level can provide significant insights that allow an understanding of the impact of anthropogenic noise on invertebrates that employ loud calling songs for mate attraction, especially when each species has its distinct song, as in the case of cicadas. In this study, we investigated the partitioning strategy of cicada assemblages in city and mountain environments by comparing the acoustic features and calling activity patterns of each species, recorded using automated digital recording systems. Our comparison of activity patterns of seasonal and diel calling revealed that there was no significant temporal partitioning of cicada assemblages in either environment. In addition, there was no correlation between the acoustic distance based on spectral features and temporal segregation. Heterospecific spectral overlap was low in both city and mountain environments, although city and mountain cicada assemblages were subject to significantly different levels of anthropogenic or interspecific noise. Furthermore, for the common species found in both environments, the calling activity patterns at both seasonal and diel time scales were significantly consistent across sites and across environments. We suggest that the temporal calling activity is constrained by endogenous factors for each species and is less flexible in response to external factors, such as anthropogenic noise. As a result, cicada assemblages in city environments with low species diversity do not demonstrate a more significant temporal partitioning than those in mountain environments with high species diversity.

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