SONG RECOGNITION BY TEMPORAL CUES IN A GROUP OF CLOSELY-RELATED BUSH-CRICKET SPECIES (GENUS TETTIGONIA)

Female phonotaxis of Tettigonia viridissima ru and T. caudata was inve stigated on a walking compensator to determine the temporal parameters of the male song used for song recognition, and to compare them with the previously described pulse rate filtering of T. cantans. The T. ca ntans song is continuous with a approximate to 30-Hz pulse rate. The T . caudata song has a higher pulse rate (approximate to 40 Hz) and duty cycle than T. cantans and a distinct verse structure. The T. viridiss ima song is continuous with a double-pulse pattern. While the pulse ra te is essential for song recognition in T. cantans, neither pulse rate not verse structure were essential for song recognition in T. caudata : females responded to signals above a minimum duty cycle. T. viridiss ima females did not require the double-pulse structure, but a single l ong pulse, equivalent to the duration of the double pulses and interva l between them, was effective. Song attractiveness was limited by a mi nimum duration of the merged double pulse, and by minimum and maximum duration of the interval between them. Pulse rate recognition had litt le if any importance in either of the species investigated. Thus, the three congeners use different mechanisms for temporal song recognition .