Using Autonomous Recording Units to Detect Variation in Cicada Calling Pattern Across Urbanized and Green Spaces

ABSTRACT Technological advances in Autonomous Recording Units (ARUs) have facilitated broad‐scale and high‐resolution acoustic monitoring of wildlife. Although acoustic monitoring has been widely applied to bats and birds, relatively few studies have focused on invertebrates, despite their significant contributions to soundscapes. Cicadas, which produce loud, continuous calls, are particularly suitable for acoustic monitoring and can strongly shape soundscapes in urban ecosystems. Therefore, we conducted continuous acoustic monitoring of cicadas at six sites in the Tokyo–Kanagawa metropolitan region, including both urban and green spaces. Recordings were made over 61 days, from June to August 2024, corresponding to the cicada activity period. Spectrograms were generated, and species were identified by manually detecting characteristic call frequency patterns and subsequently verifying them aurally. Results showed that six cicada species were detected. The timing of first calls was broadly consistent with previous studies but showed site‐specific differences, likely reflecting local habitat conditions. Diel activity patterns revealed that Platypleura kaempferi and Graptopsaltria nigrofuscata extended their calling into nighttime hours at urban sites, possibly due to artificial illumination and elevated nighttime temperatures resulting from the urban heat island effect. By contrast, Hyalessa maculaticollis , Tanna japonensis , Meimuna opalifera , and Cryptotympana facialis maintained diurnal calling patterns regardless of site type. These results highlight interspecific variation in calling phenology and responses to local conditions, including urbanization, and demonstrate the effectiveness of ARUs for long‐term monitoring of cicada activity.