Sound emission and reception tuning in three cicada species sharing the same habitat.

Many animal species acoustically communicate at the same place and time generating complex acoustic environments. However, the acoustic parameter space is usually structured, with each species emitting identifiable signals. While signal partitioning has been reported, very few analyses include the mechanical spectral response of auditory organs. The loud chorus generated by three cicadas (Cicada orni, Cicadatra atra, and Lyristes plebejus) was studied. The vibration pattern of L. plebejus shows traveling waves as previously observed in Ctra. atra. The spectral properties of both calling songs and tympanal auditory systems primarily indicate that each species uses its own frequency band. Male tympanal membranes (TMs) are tuned to their own song's dominant frequency, except for C. orni, which is sensitive to the lowest frequency band of its song. In contrast, female TMs are broadly tuned to the male songs. Ctra. atra females differ by tuning to frequencies slightly higher than the male song. Hence, acoustic space partitioning occurs for both emitter and receiver, but does not seem to fully preclude interference risk as some spectral overlap exists. In addition to the local physical ecology of each species, selective attention to conspecific signals is likely to be enhanced by further mechanical and neuronal processing.