Male cicadas use their songs as reproductive signals. Species-specific differences at songs, activity time, and timing of emergence may play an certain role on the coexistence of several species. When the similarity of peak frequency of song provides acoustic interferences among species, the peak frequency may shift, or the width of song frequency would be modified among cicada populations. In this study we compare the song frequencies of G. nigrofuscata between the population with and without the existence of Cryptotympana facialis of which song peak frequencies are similar to G. nigrofuscata. We analyze the variations of song frequencies through the difference of 1) study site, 2) body sizes, and 3) recording conditions.

We took samples of male cicadas of G. nigrofuscata and their songs in Kyoto and Niigata in summer of 2011. We recorded the individual cicada songs in a natural condition after identified them. We made dry specimens and measured their dimension. Acoustic measurements of recorded cicada songs were analyzed by Raven1.2 sound analysis software.

The result shows the body sizes of the G. nigrofuscata populations with and without C. facialis were not significantly different, and the peak frequencies of songs were also not different, suggesting that the peak frequency of song in G. nigrofuscata would not shift caused by the existence of C. facialis.