Limited genetic differentiation between acoustically divergent populations of urban and rural silvereyes (Zosterops lateralis)
The bioacoustic attributes of vocalisations made by birds in urban environments often differ markedly from those of rural conspecifics. Whether such differences are result from genetic divergence between urban and rural populations, or from plasticity or cultural evolution of song remains poorly understood. Silvereyes (Zosterops lateralis) show evidence of acoustic adaptation to urban noise, modifying both their songs and calls in cities when compared to rural areas. We investigated whether these differences were associated with corresponding morphological and neutral genetic differences. Across six pairs of geographically separate urban and rural populations, all morphological traits measured were similar. Furthermore, genetic analyses of variation at nine microsatellite loci revealed high levels of genetic connectivity between populations, and similar levels of heterozygosity in both habitat types. Consistent directional shifts in song attributes of city birds across large geographic areas thus do not appear to be accompanied by associated morphological or neutral genetic divergence.
KeywordsUrbanization Silvereye Population genetics Zosterops lateralis
We thank three anonymous reviewers for helpful comments improving the manuscript. We thank J. Kruckel for field assistance, G. Fry, A. Leishman, D. Paton, D. Williams, E. Woehler, R. Fuller, and A. Fletcher for assistance in locating and banding, the Australian National Botanic Gardens (ACT), Namadgi National Park (ACT), Glenorchy City Council (Tas), Brisbane City Council (Qld), Munghorn Gap Nature Reserve (NSW), Kogarah City Council (NSW), Darebin City Council (Vic) and Darebin Parklands Association (Vic) for permission to conduct work on their lands.
Procedures were undertaken with the approval of the following agencies: Animal Ethics Committee at the University of Melbourne, Director-General’s Animal Care and Ethics Committee at the NSW Department of Primary Industries, and Wildlife Ethics Committee at the SA Department for Environment and Heritage.
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