Urbanization has a direct impact on species abundance and diversity in many species. Some cicada species have become numerous in urban areas, causing a nuisance to city dwellers in Korea. Male cicadas produce calling songs that are attractive to conspecific, receptive females. To understand the possible factors important for population density, we estimated the relative abundance of cicada species in central Korea by conducting the complete enumeration survey of exuviae and the calling index survey. Exuviae collection was conducted in three regions that may differ in three representative habitats: metropolitan, suburban, and country. Based on the exuviae survey, Hyalessa fuscata was the dominant species in all three regions. The population densities of all cicada species in metropolitan and suburban regions were 5.7 and 12.0 times higher than those in the country region. Particularly, the population densities of Cryptotympana atrata were at least 23.5 times higher than that in the country region. Based on the calling index survey that relied on male calling songs to estimate the relative abundance of cicada species in central Korea, the relative density of C. atrata was higher in urban areas than in rural areas. Thus, the results of both surveys were consistent in that C. atrata had unusually high population densities in metropolitan and suburban regions, contributing to noise pollution in the metropolitan Seoul. Possible factors for high density of C. atrata in urban areas are suggested.

• Yikwon Jang(Division of Ecoscience, Ewha Womans University)