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

Bao-Sen Shieh,Yuh-Wen Chiu,Shih-Hsiung Liang

doi:10.1371/journal.pone.0116794

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.

Highlights

Resource partitioning has long been a central concept in studying ecological communities [1]
Heterospecific spectral overlap was low in both city and mountain environments, city and mountain cicada assemblages were subject to significantly different levels of anthropogenic or interspecific noise
The present study provides the first comparison of the spectral and temporal partitioning of cicada assemblages in city and mountain environments

Summary

Introduction

Resource partitioning has long been a central concept in studying ecological communities [1]. Various strategies are used to avoid the negative effects of acoustic competition, including the partitioning of acoustic features or partitioning of calling in time and space [2]. Evidence for acoustic partitioning has been found in many animal assemblages, such as those of frogs [3, 4], birds [5, 6], and crickets [7, 8]. For animals that have their peak breeding season at the same time of year and show no evidence for the partitioning of calling time on a diel scale, interspecific masking might effectively be reduced by the partitioning of acoustic features [6]. Chek et al [3] suggested that partitioning in time and in space were the most important strategies to reduce interspecific acoustic competition

Methods

Results

Conclusion