Five species of the subfamily Cicadinae are found in urban areas at the center of the Korean peninsula, including Cryptotympana atrata, Hyalessa fuscata, Meimuna mongolica, Meimuna opalifera and Graptopsaltria nigrofuscata. Out of those species, the densities of C. atrata and H. fuscata are generally high in the urban area. I hypothesized that there is a vigorous acoustic interaction where two species are abundant. We tested this hypothesis by conducting the 24-h recording experiments in four localities: Gwacheon(GC), Jamsil(JS), Ewha University(EU) and Yangpyeong(YP). Based on the preliminary enumeration surveys of exuviae, GC and JS were designated as high density localities and EU and JS were as low density localities. The results of 24-h recordings and abiotic factor based on the multinomial logistic regression showed that C. atrata and H. fuscata were negatively correlated in high density area GC and JS. In JS and EU, the density of H. fuscata is close to each other. However, the probability of chorusing in JS is significantly lower than EU. This might be due to acoustic competition between two species. Moreover, we confirmed that the choruses of males of C. atrata produced loud choruses usually during the day when temperature high and males of H. fuscata produced calling song throughout the day but peaked in the morning and night. Consequently, multi-species cicada in different temporal pattern probably cannot be explained by only acoustic interaction but the combination of both abiotic and biotic factors probably constrain multi-species cicada to call together during the limited time windows.

Collection of ecological data such as the temporo-spatial distribution of a species is very difficult, due to broad distribution over large areas, phenology, and lack of resources for field survey. Citizen science, which is a cooperative scientific endeavor between researchers and interested citizens, is ideal for collecting large-scale ecological data. However, lack of proper equipment, species identification, and/or communication between researchers and participants are hindrance for a successful citizen science project. Here, we introduce the concept and methods of large-scale ecological data collection using smartphone apps. Most of the ecological data typically consist of sound or video recording, picture, geographic coordinate, and notes. There are several apps that can collect some or all of these ecological data. Furthermore, the result of a survey can be reported to researchers using Google Docs. The data collected by non-specialists can be validated by cross-checking of the survey report by Google Docs and the ecological data sent by apps. Finally, we report the results of a citizen science project in which temporo-spatial distributions of cicada species in Korea were studied via smartphone apps and Google Docs.