Study site
The field observation was carried out in a grassfield located in PyeongChang-gun, Gangwon-do, Korea (37°34’53.9”N 128°24’58.6”E, altitude: 590 m). The site was a rectangular grassy field (area: 30×8 m = 240 m²) containing diverse herbaceous plants. The field was enclosed by oak and pine trees, and cicadas were exclusively observed within this area. Throughout the observations, we measured temperature and humidity using a thermometer and humidity meter (Testo 174H Mini data logger, Germany). Notably, the temperature and humidity variations during the three observation periods (detailed below) within a day corresponded closely to the observation time (i.e., temperature always increased but humidity decreased from morning to mid-afternoon observation period) (Figure S1). As a result, temperature and humidity were excluded from the subsequent analysis.