Phaneropterinae is the largest subfamily within the bush-crickets/ katydids (Tettigonioidea), with about 2451 species, and with a world-wide distribution. Its acoustic communication differs from all other tettigonioid groups in that females primarily and typically respond to the male calling song with their own acoustic reply, a behaviour referred to as duetting. This type of response seems to have been lost only in a few species with wingless females.
According to our literature review, information about the song patterns of about 330 species of Phaneropterinae have been published world-wide. Included in this number are ca 170 species of Barbitistini, a flightless West Palearctic tribe, which are treated separately. In the present study we summarize information from the above 330 species. We examine the morphology of stridulatory and hearing organs, and analyze the acoustic signals for frequency, number of syllables and number of interval types. We also have examined if and how responding by sound may have influenced other aspects of the acoustic communication system, especially the structure of the male calling song.
Overall, the songs of male Phaneropterinae are similar to those of other tettigonioids. However, some Phaneropterinae species with very long and complex songs are found on all continents, exceeding in these characters nearly all other Ensifera species. These songs contain several different types of syllables and intervals of various duration. Because of this high interspecific variability (reaching from very simple to extremely complex), male phaneropterine songs are by far more variable than those of other tettigonioid families.
However, since there are so few data on the behaviour of most Phaneropterinae species, and especially for females, we still are limited in our understanding of the reasons behind the song variability. Sexual selection by females choosing to respond preferentially to certain song types could be an important evolutionary force, but probably only in combination with some unknown ecological and behavioural factors.
